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... brilliant and very influential... stands up as an impressive and
enduring work of philosophy, outstanding in its sweep, clarity and
penetration.' Colin McGinn, Times Higher Education Supplement
"(when) these lectures were first published eight years ago (in a
collection), they stood analytic philosophy on its ear. Everybody
was either furious,
or exhilarated, or thoroughly perplexed. No one
was indifferent. This welcome republication in a separate volume
(with a helpful new preface, but no substantive changes) provides
a chance to look back at a modern classic, and to say something
about why it was found so shocking and liberating.' Richard Rorty,
London Review of Books
"Naming and Necessity' has had a great and increasing influence. It
redirected philosophical attention to neglected questions of natural
and metaphysical necessity and to the connections between these
and theories of naming, and of identity. This seminal work, to
which today's thriving essentialist metaphysics largely owes its
impetus, is here reissued in a newly corrected form with a new
preface by the author. If there is such a thing as essential reading in
metaphysics, or in philosophy of language, this is it.
Also by Saul Kripke
Wittgenstein on Rules and Private Language
Basil Blackwell
ISBN 0 631 12801 8
NA
NECE
KRIF
*KI
Naming
and Necessity
SAUL KRIPKE

Saul A. Kripke
Basil Blackwell

1616
PrAs
Copyright c: Saul A. Kripke 1972. 1980
First published in
G. Harman and D. Davidson (editors). Semantics of Natural Language
(D. Reidel Publishing Co..
Dordrecht. Netherlands and Boston. USA. 1972)|
Revised and enlarged edition first published 1980
Paperoack contion 1981
Reprinted 1984. 1986. 1988. 1990
Basil Blackwell Lid
108 Cowley Road. Oxford OX4 IJF. UK
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similar condition including this condition being imposed on the
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A CIP catalogue record for this book is available from
the British Library.
ISBN 0-631-10151-9
ISBN 0-631-12801-8 Pbk
Printed in Great Britain by Billing & Sons Lid. Worcester
for
MARGARET

CONTENTS
Preface
Lecture I
Lecture II
Lecture
III
Addenda
22
71
106
ISO

PREFACE
Originally I had intended to revise or augment Naming and
Necessity extensively. Considerable time has elapsed, and I have
come to realize that any extensive revision or expansion would
delay the appearance of a separate, less expensive edition of
Naming and Necessity indefinitely. Further, as far as revision is
concerned, there is something to be said for preserving a work
in its original form, warts and all. I have thus followed a very
conservative policy of correction for the present printing.
Obvious printing errors have been corrected, and slight changes
have been made to make various sentences or formulations
clearer.' A good indication of my conservative policy is in
fo note 56. In that footnote the letter-nomenclature for the
various objects involved, inexplicably garbled in the original
printing, has been corrected; but I make no mention of the fact
that the argument of the footnote now seems to me to have
problems which I did not know when I wrote it and which
at least require further discussion.?
The same considerations lead me to give up any serious
attempt to use this preface to amplify my previous argument,
to fill in lacunae, or to deal with serious criticisnis or difficulties.
" I thank Margaret Gilbert for her valuable help in this editing.
= Although I have not had time for careful study of Nathan Salmon's criticism (Joumal of Philosophy (1979), pp. 703-25) of this footnote, it seems likely
that his criticism of the argument, though related to mine, is not the same and
reconstructs it in a way that does not correspond to my exact intent and makes
the argument unnecessarily weak. Also, I think I had no ambition in this short
footnote rigorously to prove 'essentialism from the theory of reference' alone.
The footnote was so compressed that readers might casily reconstruct the
details in differing ways.

Obviously, aside from such amplification in the preface, there
are passages in the monograph other than just footnote s6 that
I might modify. I do stand by the principal theses of my work,
and the pressure for much revision is not intense. I will, however, use this preface briefly to describe the background and
genesis of the leading ideas of this nonograph, and to discuss
a few misapprehensions that seem to be common. I am afraid
that I must disappoint those readers who already found the
exposition in the monograph satisfactory on these points.
Relatively little will be added to deal with what I see as the
more substantive problems of the monograph. The issues
explained further-mostly related to
modality and rigid
designation—may already have been clear to most readers. On
the other hand, those readers who felt sympathetic to some
of the objections mentioned here may well be justified in
wishing for a more thorough treatment. I fear that in most
cases, the treatment of disputed points allowable in the space of
a preface is simply too short to convince many readers who
were inclined to believe the objections. To some extent, brief
treatments of objections may do more harm than good, since
the reader who was confused may think that if this is all that
can be replied, the original objection must have been cogent.
Nevertheless, I thought I should register briefly why I think
certain reactions are misconceived. I hope that in some cases I
will be able to write at greater length. Here I must plead that a
thorough discussion is impossible within the bounds of this
preface.
Readers who are new to this book can use the preface for
further clarification of certain points, and for a brief history of
their genesis. I would recommend that such readers not read
» Thus some published criticisms are not discussed here because they are
so frivolous that I hope they are not given wide credence; others because they
are too substantive; and yet other: simply for lack of space. I leave it to the
reader to decide which category subsumes any particular example.
NAMINC AND NECASSITY
the preface first, but that they return to it for clarification (if
necessary) after they have read the main text. The preface is
not written in such a way as to be completely self-contained.
The ideas in Naming and Necessity evolved in the early sixties
—most of the views were formulated in about 1963-64. Of
course the work grew out of earlier formal work in the model
theory of modal logic. Already when I worked on modal logic
it had seemed to me, as Wiggins has said, that the Leibnitzian principle of the indiscernibility of identicals* was as selfevident as the law of contradiction. That some philosophers
could have doubted it always seemed to me bizarre. The model
theoretic study of modal logic ('possible worlds' semantics)
could only confirm this conviction—the alleged counterexamples involving modal properties always turned out to
turn on some confusion: the contexts involved did not express
genuine properties, scopes were confused, or coincidence between individual concepts was confused with identity between
individuals. The model theory made this completely clear,
though it should have been clear enough on the intuitive level.
Waiving fussy considerations deriving from the fact that x need
not have necessary existence, it was clear from (x) [ (*= x)
and Leibnitz's law that identity is an 'internal relation:
(x) (y) (x = y > • x = y). (What pairs (x, y) could be counterexamples? Not pairs of distinct objects, for then the antecedent
is false; nor any pair of an object and itseli, for then the consequent is true.) If 'a' and "b' are rigid designators, it follows
that 'a = b', if truc, is a necessary truth. If 'a' and 'b' are not
rigid designators, no such conclusion follows about the statement 'a = b' (though the objects designated by 'a' and 'b' will
be necessarily identical).
In speaking of rigid designators, we are speaking of a
The principle that identicals have all properties in common; schematicall
s) (x)(x = y ^ Fx. >. Fy). Not to be confused with the identity of indisce
nibles.

possibility that certainly exists in a formal modal language.
Logically, we as yet are committed to no thesis about the status
of what we ordinarily call 'names' in natural language. We
must distinguish three distinct theses: (i) that identical objects
are necessarily identical; (ii) that true identity statements between rigid designators are necessary; (iii) that identity statements between what we call 'names' in actual language are
necessary. (i) and (i) are (self-evident) theses of philosophical
logic independent of natural language. They are related to
each other, though (i) is about objects and (ii) is metalinguistic.
(i) roughly follows' from (i), using substitution of rigid
designators for universal quantifiers—I say 'roughly' because
delicate distinctions about rigidity are relevant, see page 21 n. 21;
the analogous deduction for nonrigid designators is fallacious.)
From (ii) all that strictly follows about so-called 'names' in
natural language is that either they are not rigid or true identities
between them are necessary. Our intuitive idea of naming
suggests that names are rigid, but I suppose that at one time I
vaguely supposed, influenced by prevailing presuppositions, that
since obviously there are contingent identities between ordinary
so-called names, such ordinary names must not be rigid. However, it was already clear from (i) —without any investigation of
natural language-that the supposition, common to philosophical discussions of materialism at that time, that objects can be
"contingently identical", is false. Identity would be an internal
relation even if natural language had contained no rigid
designators. The confused reference to objects as 'contingently
identical" served illegitimately as a philosophical crutch: It
enabled philosophers simultaneously to think of certain designators as if they were non-rigid and hence found in 'contingent
identities") and as if they were rigid, the conflict being muddled
over by thinking of the corresponding objects as 'contingently
identical". Even before I clearly realized the true situation
regarding proper names, I felt little sympathy for the dark
doctrine of à relation of "contingent identity'. Uniquely
identifying properties can coincide contingently, but objects
cannot be 'contingently identical".
Eventually I came to realize-this realization inaugurated the
aforementioned work of 1963-64—that the received presuppositions against the necessity of identities between ordinary
names were incorrect, that the natural intuition that the names
of ordinary language are rigid designators can in fact be upheld." Part of the effort to make this clear involved the distinction between using a description to give a meaning and using it
to fix a reference. Thus at this stage I rejected the conventional
description theory as an account of meaning, though its
validity as an account of the fixing of a reference was left untouched. Probably I let myself be content with this position
momentarily, but the natural next step was to question whether
the description theory gave a correct account even of how the
references of names were fixed. The result appears in the second
of these lectures. It was a short step to realize that similar
remarks applied to terms for natural kinds. The other leading
¡deas came naturally as things 'fit into place'.
Let me not pay inadequate tribute to the power of the then
prevailing complex of ideas, emanating from Frege and from
Russell, that I then abandoned. The natural and uniform
manner by which these ideas appear to account for a variety of
philosophical problems--their marvelous internal cohcrenceis adequate explanation for their long appeal. I myself have been
shocked at the prevalence of some ideas in the philosophical
community which to me have little or no appeal, but I have
never placed the description theory of proper names in such a
category. Although I, with others, always felt some strain in
this edifice, it took some time to get free of its seductive power.
• It also became clear that a symbol of any actual or hypothetical language
that is not a rigid designator is so unlike the names of ordinary language that
it ought not to be called a 'name'. In particular, this would apply to a hypothetical abbreviation of a nonrigid definite description.

Although the idea is now a familiar one, I will give a brief
restatement of the idea of rigid designation, and the intuition
about names that underlies it. Consider:
(1)
Aristotle was fond of dogs.
A proper understanding of this statement involves an understanding both of the (extensionally correct) conditions under
which it is in fact true, and of the conditions under which a
counterfactual course of history, resembling the actual course
in some respects but not in others, would be correctly (partially) described by (1). Presumably everyone agrces that there
is a certain man—the philosopher we call 'Aristotle'-such
that, as a matter of fact, (I) is true if and only if he was fond
of dogs." The thesis of rigid designation is simply-subtle
points aside'-that the same paradigm applies to the truth
conditions of (r) as it describes counterfactual situations. That is,
(I) truly describes a counterfactual situation if and only if the
same aforementioned man would have been fond of dogs, had
that situation obtained. (Forget the counterfactual situations
where he would not have existed.) By contrast, Russell thinks
that (1) should be analyzed as something like:®
• That is everyone, even Russell, would agree that this is a true material
equivalence, given that there really was an Aristotle.
"In particular, we ignore the question what to say about counterfactual
situations in which Aristotle would not have existed. See page 21 note 21.
" Taking 'the last great philosopher of antiquity' to be the description
Russell associates with 'Aristotle'. Let admirers of Epicureanism, Stoicism,
etc., not be offended; if any reader thinks that someone later than Aristotle is
the true referent of the description given, let that reader substitute another one.
I assume Russell is right in that definite descriptions can at least sometimes
be interpreted nonrigidly. As I mention on page 59 footnote 22, some
philosophers think that, in addition, there is a rigid sense of definite descriptions. As I say in the latter footnote, I am not convinced of this, but if these
philosophers are right, my principal thesis is not affected. It contrasts names
with nonrigid descriptions, as advocated by Russell. See Section 2, pp. 258-61
of my paper, 'Speaker's Reference and Semantic Reference', Midwest Studies
in Philosophy, II (1977), pp.
255-76; also in Contemporary Perspectives in
the Philosophy of Language, edited by Peter A. French, Theodore E. Uchling,
2)
The last great philosopher of antiquity was fond of
dogs,
and that this in turn should be analyzed as
(3)
Exactly one person was last among the great philosophers of antiquity, and any such person was fond
of dogs.
The actual truth conditions of (3) agree extensionally with those
mentioned above for (1), assuming that Aristotle was the last
great philosopher of antiquity. But counterfactually, Russell's
conditions can vary wildly from those supposed by the
rigidity thesis. With respect to a counterfactual situation where
someone other than Aristotle would have been the last great
philosopher of antiquity, Russell's criterion would make that
other person's fondness for dogs the relevant issue for the
correctness of (I)!
So far I have said nothing that I did not think I had made
clear before. But it should be apparent from the explanation
that some criticisms are misunderstandings. Some have thought
that the simple fact that two people can have the same name
refutes the rigidity thesis. It is true that in the present monograph I spoke for simplicity as if each name had a unique
bearer. I do not in fact think, as far as the issue of rigidity is
concerned, that this is a major oversimplification. I believe
that many important theoretical issues about the semantics of
names (probably not all) would be largely unaffected had our
conventions required that no two things shall be given the
same name. In particular, as I shall explain, the issue of rigidity
would be unaffected.
For language as we have it, we could speak of names as
having a unique referent if we adopted a terminology, anal-
, and Howard K. Wettstein, University of Minnesota Press, Minneapo
79), pp. 6-27) for a brief discussion of the relation of the idea of rig
definite descriptions to Donnellan's 'referential" descriptions. I also discuss the
relation of both of these to the notion of scope.

ogous to the practice of calling homonyms distinct "words,
according to which uses of phonetically the same sounds to
name distinct objects count as distinct names. This terminology
certainly does not agree with the most common usage, ° but
I think it may have a great deal to recommend it for theoretical
purposes.
But the main point is that, however a philosophical theory
may treat such 'homonymous'" names, the issue is irrelevant to
the question of rigidity. As a speaker of my idiolect, I call only
one object 'Aristotle', though I am aware that other people,
including the man I call 'Onassis' or perhaps 'Aristotle Onassis,
had the same given name. Other readers may use 'Aristotle' to
name more than one object (person, or pct animal) and for
them (1) has no unambiguous truth conditions. When I spoke
of 'the truth conditions' of (1), I perforce assumed a particular
reading for (I). (So of course, does the classical description
theorist; this is not an issue between us. Classical description
theorists, too, tended to speak for simplicity as if names had
• Actually, the criterion should be subtler, and depends on one's theoretical
views. Thus, on the picture advocated in this monograph, two totally distinct
'historical chains' that by sheer accident assign phonetically the same name to
the same man should probably count as creating distinct names despite the
identity of the refcrents. The identity may well be unknown to the speaker, or
express a recent discovery. (Similarly, a description theorist who counts
names in the way suggested presumably would regard two phonetically
identical names with distinct associated descriptions as distinct, even if the
two descriptions happen uniquely to be true of the same object.) But distinctness of the referents will be a sufficient condition for distinctness of the names.
I should stress that I am not demanding or even advocating this usage, but
mention it as a possibility to which I am sympathetic. The point that rigidity
has nothing to do with the question of two people having phonetically the
same name holds whether this convention is adopted or not.
10 But perhaps one use of 'How inany names are there in this telephone
book?' is an exception (Anne Jacobson).
" By using this term, I do not mean to commit the analysis to a particular
view (see also the next footnote), though I suggest my own. I mean simply that
two people can have phonctically the same name.
unique references.) In practice it is usual to suppose that what
is meant in a particular use of a sentence is understood from
the context. In the present instance, that context made it clear
that it was the conventional use of "Aristotle' for the great
philosopher that was in question. Then, given this fixed understanding of (1), the question of rigidity is: Is the correctness of
(t), thus understood, determined with respect to each counterfactual situation by whether a certain single person would have
liked dogs (had that situation obtained)? I answer the question
affirmatively. But Russell seems to be committed to the
opposite view, even when what (I) expresses is fixed by the
context. Only given such a fixed understanding of (1) would
Russell read (I) as (3)—not if "Aristotle' meant Onassis!-but
the rigidity requirement is violated. This question is entirely
unaffected by the presence or absence in the language of other
readings of (1). For each such particular reading separately, we
can ask whether what is expressed would be true of a counterfactual situation if and only if some fixed individual has the
appropriate property. This is the question of rigidity.
Let me recapitulate the point, ignoring for this exposition
the delicate problems about 'propositions' to be mentioned at
the end of this preface. To speak of 'the truth conditions' of a
sentence such as (1), it must be taken to express a single proposition-otherwise its truth conditions even with respect to
the actual world are indeterminate. Thus ambiguous words or
homonyms (perhaps 'dog' in (r)) must be read in a determinate way (canine!), indexicals must be assigned determinate
references, syntactic ambiguities must be resolved, and it must
be fixed whether "Aristotle' names the philosopher or the
shipping magnate. Only given such a reading can Russell
propose an analysis such as (3)—rightly, no one ever faulted
him on this score. Then my objection to Russell is that all the
many propositions expressed by various readings of (r) (assuming that in all rcadings 'Aristotle' is a proper name) would, if

he were right, fail to conform to the rule of rigidity. That is, no
such proposition conforms to the rule that there is a single
individual and a single property such that, with respect to
every counterfactual situation, the truth conditions of the
proposition are the possession of the property by that individual, in that situation. (I am relying on the fact that in
practice Russell invariably interprets ordinary names nonrigidly.) That more than one proposition may be expressed
by (1) is irrelevant: the question is whether each such proposition is cvaluated as I describe, or is it not. The view applies
to each such proposition taken separately. Detailed questions
as to how the theory should incorporate the fact that our
linguistic practice allows two things to have phonetically the
same name need not be settled for this to be clear.!?
Another misconception concerns the relation of rigidity to
scope, which apparently I treated too briefly. It seems often to
be supposed that all the linguistic intuitions I adduce on behalf
of rigidity could just as well be handled by reading names in
various sentences as nonrigid designators with wide scopes,
analogously to wide scope descriptions. It would, indeed, be
possible to interpret some of these intuitions as results of scope
ambiguities instead of rigidity-this I recognize in the monograph. To this extent the objection is justified, but it seens to
me to be wrong to suppose that all our intuitions can be handled
in this way. I dealt with the question rather briefly, on page 62
and in the accompanying footnote 2s, but the discussion seems
to have been overlooked by many readers. In the footnote I
1 For example, some philosophers would assimilate proper names to
demonstratives. Their reference varies from utterance to utterance the way
that of a demonstrative does. This does not affect the issues discussed, since
he reference of a demonstrative must be given for a definite proposition to
›e expressed. Although I did not discuss the question in the present mono
graph, of course it was part of my view (p. 49 n. 16) that 'this", T, 'you', etc.,
are all rigid (even though their refcrences obviously vary with the context of
uttcrance). The rigidity of demonstratives has been stressed by David Kaplan.
II
adduce some linguistic phenomena that, I think, support the
rigidity intuition as opposed to an explanation in terms of
scope. Many of these readers even seem to have overlooked
the intuitive test for rigidity, as emphasized on pages 48-49.
I will not repeat or elaborate these considerations in this
preface, even though they seem to have been stated too briefly.
Exigencies of a preface may make the following remarks too
brief as well, but I shall discuss the scope question in the light
of the present explanation of rigidity.
It has even been asserted that my own view itself reduces to a
view about scopc, that the doctrine of rigidity simply is the
doctrine that natural language has a convention that a name,
in the context of any sentence, should be read with a large
scope including all modal operators.t3 This latter idca is particularly wide of the mark; in terms of modal logic, it represents
a technical error. Let me deal with it first. (1) and (2) are
'simple' sentences. Neither contains modal or other operators,
so there is no room for any scope distinctions." No scope
convention about more complex sentences affects the interpretation of these sentences. Yet the issue of rigidity makes
13 See Michael Dummett, Frege (Duckworth, 1973), p. 128. Unfortunately,
many of Dummett's other ideas or remarks on the relation of rigidity to scope
are technically erroneous-for example, on the same page he says that I hold
that descriptions are never (?) rigid and equates this view with the claim
that 'within a modal context, the scope of a definite description should always
be taken to exclude the modal operator. Also, some of his comments on
linguistic intuitions seem to me to be in error. I cannot deal with these matters
here.
* Actually the sentences in question are tensed and therefore can be interpreted in a formal language with tense opcrators. If we treat tense this way
(it can be treated in other ways), then other scope questions can arise owing to
the tense operators. The question at issue, however, is about the relation of
scope to modal operators, which does not arise in these sentences even if tense
operators are used in their analysis. The assertion that the sentences in question
give rise to no scope questions can be made literally true either by treating
tense without using operators or (better) by taking the copula in (r) and (2) to
be tenseless.

I2
sense as applied to both. My view is that 'Aristotle' in (I) is
rigid, but 'the last great philosopher of antiquity' in (2) is not.
No hypothesis about scope conventions for modal contexts
expresses this view;! it is a doctrine about the truth conditions,
with respect to counterfactual situations, of (the propositions
expressed by) all sentences, including simple sentences.
This shows that the view that reduces rigidity to scope in the
manner stated is simply in error. It also indicates one weakness
of the (rather more understandable) reaction that attempts to
use scope to replace rigidity. The doctrine of rigidity supposes
that a painting or picture purporting to represent a situation
correctly described by (I) must ipso facto purport to depict
Aristotle himself as fond of dogs. No picture, purporting to
represent someone else and his fondness for dogs, even if it
depicts the other individual as possessing all the properties we
use to identify Aristotle, represents a counterfactual situation
correctly described by (1). Doesn't this, in itself, obviously
represent our intuitions regarding (1)? The intuition is about
the truth conditions, in counterfactual situations, of (the proposition expressed by) a simple sentence. No wide-scope interpretation of certain modal contexts can take its place. To the
extent that a theory preserves this intuition, so much the better
for it.
Another remark, not so directly relying on counterfactual
situations, may illuminate matters. In the monograph I argued
that the truth conditions of It might have been the case that
Aristotle was fond of dogs' conform to the rigidity theory:
no proof that some person other than Aristotle might have been
18 The thesis that names are rigid in simple sentences is, however, equivalent
(ignoring complications arising from the possible nonexistence of the object)
to the thesis that if a modal operator governs a simple sentence containing a
name, the two readings with large and small scopes are equivalent. This is not
the same as the doctrine that natural language has a convention that only the
large scope reading is allowed. In fact, the equivalence makes sense only for a
language w here both readings are admissible.
13
both fond of dogs and the greatest philosopher of antiquity
is relevant to the truth of the quoted statement. The situation is
unchanged if we replace 'the greatest philosopher of antiquity'
by any other (nonrigid) definite description thought of as
identifying Aristotle. Similarly, I held, 'It might have been the
case that Aristotle was not a philosopher' expresses a truth,
though It might have been the case that the greatest philosopher of antiquity was not a philosopher' does not, contrary
to Russell's theory. (An analogous example could be given for
any other nonrigid identifying description.) Now the last
quoted sentence would express a truth if the description used
were read, contrary to my intent, with wide scope. So perhaps
it might be supposed that the problem simply arises from an
(unaccountable!) tendency to give "Aristotle' a wide scope
reading while the descriptions are given a small scope reading;
sentences with both names and descriptions, however, would
be subject in principle to both readings. My point, however,
was that the contrast would hold if all the sentences involved
were explicitly construed with small scopes (perhaps by inserting a colon after 'that'). Further, I gave examples (referred to
above) to indicate that the situation with names was not in fact
parallel to that with large scope descriptions. Proponents of
the contrary view often seem to have overlooked these
examples, but this is not my point here. The contrary view
must hold that our language and thought are, somehow, impotent to keep the distinction straight, that it is this which is
responsible for the difficulty. It is hard to see how this can be:
how did we make the distinction if we cannot make it? If the
formulation with a that clause really is so tangled that we are
unable to distinguish one reading of it from another, what
about:
(4)
What (1) expresses might have been the case.
Doesn't this express the desired assertion, with no scope
ambiguities? If not, what would do so? (The formulation

14
might be a bit more natural in a dialogue: "Aristotle was fond
of dogs. "That's not the case, though it might have been.)
Now my claim is that our understanding of (4) conforms to the
theory of rigidity. No possible situation in which anyone but
Aristotle himself was fond of dogs can be relevant.
My main remark, then, is that we have a direct intuition of
the rigidity of names, exhibited in our understanding of the
truth conditions of particular sentences. In addition, various
secondary phenomena, about 'what we would say', such as
the ones I mention in the monograph and others, give indircct
evidence of rigidity. How did Russell, for one, propose a
theory plainly incompatible with our direct intuitions of
rigidity? One rcason is that, here as elsewhere, he did not
consider modal questions; and the question of the rigidity of
names in natural language was rarely explicitly considcred
after him. Second, it seemed to Russell that various philosophical arguments necessitated a description theory of names and
an eliminative theory of descriptions. Russell acknowledged
that his views were incompatible with our naive reactions
(though the rigidity issue was not mentioned), but powerful
philosophical arguments seemed to him to compel adoption of
his theory. Regarding the question of rigidity, my own reply
took the form of a thought experiment, along the lines
sketched briefly for "identity and schmidentity' on page 108 of
the present monograph. In the present case I imagined a
hypothetical formal language in which a rigid designator a is
introduced with the ceremony, 'Let "a" (rigidly) denote the
unique object that actually has property F, when talking about
any situation, actual or counterfactual.' It seced clear that if
a speaker did introduce a designator into a language that way,
then in virtuc of his very linguistic act, he would be in a position
to say 'I know that Få, but nevertheless 'Fa' would express a
contingent truth (provided that F is not an essential property
of the unique object that possesses it). First, this showed that
IS
epistemic questions should be separated from questions of
necessity and contingency, and that to fix a reference is not to
give a synonym. More important, this situation indicated that
the evidence ordinarily adduced to show that names were
synonymous with descriptions could instead be rationalized by
this hypothetical model. In addition, the model satisfied our
intuitions of rigidity. Given this, the burden of the argument
scened to fall heavily on the philosopher who wished to deny
our natural intuition of rigidity. As I said above, the further
observation that ordinarily speakers do not even fix references
by identifying descriptions of the usual type came later.
I will say somcthing briefly about "possible worlds", ' (I hope
to claborate elsewhere.) In the present monograph I argued
against those misuses of the concept that regard possible worlds
as something like distant planets, like our own surroundings
but somehow existing in a different dimension, or that lead to
spurious problems of 'transworld identification'. Further, if
one wishes to avoid the W'eltangst and philosophical confusions
that many philosophers have associated with the 'worlds'
terminology, I recommended that "possible state (or history)
of the world', or "counterfactual situation' might be better.
One should even remind oneself that the 'worlds' terminology
can often be replaced by modal talk—-'It is possible that ...'
1 Some of the worst misinterpretations of rigidity would have had much
less currency if the relevant philosophical discussions had been conducted in
the context of a rigorous presentation in terms of "possible worlds semantics'.
I did not do this in the present monograph both because I did not wish to
rest the argument heavily on a formal model and because I wished the presentation to be philosophical rather than technical. To readers who are thoroughly
familiar with intensional semantics the rough outline of a presentation of my
views in these terms should be clear without an explicit development. Nevertheless, some misunderstandings of the rigidity concept-including some
aspects of these mentioned in this preface--led me to think that a technical
presentation might eliminate some misconceptions. Eventually considerations
of time and space led me to decide against including such material, but I may
give such a formal exposition elsewhere.

16 l
But I do not wish to leave any exaggerated impression that I
repudiate possible worlds altogether, or even that I regard
them as a mere formal device. My own use of them should
have been extensive enough to preclude any such misunderstanding. In fact, there are some conceptions of 'possible
worlds that I repudiate and some I do not. An analogy from
school—in fact, it is not merely an analogy-will help to
clarify my view. Two ordinary dice (call them die A and die B)
are thrown, displaying two numbers face up. For each die,
there are six possible results. Hence there are thirty-six possible
states of the pair of dice, as far as the numbers shown face-up
are concerned, thougli only one of these states corresponds to
the way the dice actually will come out. We all learned in
school how to compute the probabilities of various events
(assuming equiprobability of the states). For example, since
there are just two states--(die A, s; die B, 6) and (die A, 6;
die B, 5) —that yield a total throw of eleven, the probability
of throwing eleven is 2/36 = 1/18.
Now in doing these school exercises in probability, we were
in fact introduced at a tender age to a set of (miniature) 'possible
worlds'. The thirty-six possible states of the dice are literally
thirty-six "possible worlds', as long as we (fictively) ignore
everything about the world except the two dice and what
they show and ignore the fact that one or both dice might
not have existed). Only one of these miniworlds-the one
corresponding to the way the dice in fact come up-is the
actual world', but the others are of interest when we ask how
probable or improbable the actual outcome was (or will be).
Now in this elementary case, certain confusions can be
avoided. We have assumed that the dice actually do fall, that
some one of the thirty-six states is actual. Now the 'actual world'
in this case is the state of the dice that is actually realized.
Another entity, more 'concrete' than this state, is the Lesniewskian-Goodmanian physical entity which is the 'sum' of the
I7
two dice. This complex physical entity ('the dice,' thought of
as a single object) is before me on the table, after the throw,
and its actual position determines the actual state of the (two)
dice. But when we talk in school of thirty-six possibilities, in
no way do we need to posit that there are some thirty-five
ther entities, existent in some never-never land, corresponding
to the physical object before me. Nor need we ask whethe
these phantom entities are composed of (phanton) 'counterparts' of the actual individual dice, or are somehow composed
of the same individual dice themselves but in 'another dimension'. The thirty-six possibilities, the one that is actual included,
are (abstract) states of the dice, not complex physical entities.
Nor should any school pupil receive high marks for the
question 'How do we know, in the state where die A is six
and die B is five, whether it is die A or die B which is six?
Don't we need a "criterion of transstate identity" to identify
the die with a six—not the die with a five-with our die A?'
The answer is, of course, that the state (die A, 6; die B, s) is
given as such (and distinguished from the state (die B, 6; die A,
s)). The demand for some further 'criterion of transstate
identity' is so confused that no competent schoolchild would
be so perversely philosophical as to make it. The "possibilities'
simply are not given purely qualitatively (as in: one die, 6, the
other, 5). If they had been, there would have been just twentyone distinct possibilities, not thirty-six. And the states are not
phantom dice-pairs, viewed from afar, about which we can
raise epistemically meaningful questions of the form, 'Which
die is that?' Nor, when we regard such qualitatively identical
states as (A, 6; B, s) and (A, s; B, 6) as distinct, need we
suppose that A and B are qualitatively distinguishable in some
other respect, say, color. On the contrary, for the purposes
of the probability problem, the numerical face shown is
thought of as if it were the only property of each die. Finally,
in setting up this innocent little exercise regarding the fall of

18
the dice, with possibilities that are not described purely qualitatively, we make no obscure metaphysical commitment to dice
as 'bare particulars", whatever that might mean."
'Possible worlds'
are little more than the miniworlds of
school probability blown large. It is true that there are problems
in the general notion not involved in the miniature version.
The miniature worlds are tightly controlled, both as to the
objects involved (two dice), the relevant properties (number
on face shown), and (thus) the relevant idea of possibility.
"Possible worlds' are total 'ways the world might have been',
or states or histories of the entire world. To think of the totality
of all of them involves much more idealization, and more
mind-boggling questions, than the less ambitious elementary
school analogue. Certainly the philosopher of " possible worlds'
must take care that his technical apparatus not push him to ask
questions whose meaningfulness is not supported by our
original intuitions of possibility that gave the apparatus its
point. Further, in practice we cannot describe a complete
counterfactual course of events and have no need to do so. A
practical description of the extent to which the 'counterfactual
situation' differs in the relevant way from the actual facts is
sufficient; the "counterfactual situation' could be thought of as
a miniworld or a ministate, restricted to features of the world
relevant to the problem at hand. In practice this involves less
idealization both as to considering entire world histories and
as to considering all possibilities. For present purposes, however, the elementary analogue gives a fine model for the
1 With respect to possible states of the entire world, I do not mean to
assert categorically that, just as in the case of the dice, there are qualitatively
identical but distinct (counterfactual) states. What I do assert is that if there
is a philosophical argument excluding qualitatively identical but distinct
worlds, it cannot be based simply on the supposition that worlds must be
stipulated purely qualitatively.
What I defend is the propriety of giving
possible worlds in terms of certain particulars as well as qualitatively, whether
or not there are in fact qualitatively identical but distinct worlds.
19
appropriate morals regarding "possible worlds'. There is
nothing wrong in principle with taking thesc, for philosophical
or for technical purposes, as (abstract) entities—the innocence
of the grammar school analogue should allay any anxieties on
that score.'® (Indeed the general notion of 'sample space' that
fornıs the basis of modern probability theory is just that of
such a space of possible worlds.) However, we should avoid
the pitfalls that seem much more tempting to philosophers
with their grand worlds than to schoolchildren with their
modest versions. There are no special grounds to suppose that
possible worlds must be given qualitatively, or that there need
be any genuine problem of 'transworld identification'-the
fact that larger and more complex states are involved than in
the case of the dice makes no difference to this point. The
'actual world'-better, the actual state, or history of the world
-should not be confused with the enormous scattered object
18 I do not think of "possible worlds' as providing a reductive analysis in any
philosophically significant sense, that is, as uncovering the ultimate nature,
from either an epistemological or a metaphysical point of view, of modal
operators, propositions, etc., or as 'explicating' them. In the actual development of our thought, judgments involving directly expressed modal locutions
(it might have been the case that") certainly come earlier. The notion of a
"possible world", though it has its roots in various ordinary ideas of ways the
world might have been, comes at a much greater, and subsequent, level of
abstraction. In practice, n1o one who cannot understand the idea of possibility
is likely to understand that of a 'possible world' either. Philosophically, we
by no means need assume that one type of discourse is 'prior to' the other,
independently of the purposes at hand. The main and the original motivation
for the 'possible worlds analysis'-and the way it clarified modal logic—-was
that it enabled modal logic to be treated by the same set theoretic techniques
of model theory that proved so successful when applied to extensional logic.
It is also useful in making certain concepts clear.
To reiterate another point: the notion of all states of the entire world that
are possible in the broadest (metaphysical) sense involves a certain amount of
idealization, as well as philosophical questions I have not discussed. If we
restrict the worlds to a narrower class of miniworlds, essentially all the issues
regarding say, rigid designators, remain the same. So do the questions of
modal semantics.

20
that surrounds us. The latter might also have been called 'the
(actual) world', but it is not the relevant object here. Thus the
possible but not actual worlds are not phantom duplicates of
the 'world' in this other sense. Perhaps such confusions would
have been less likely but for the terminological accident that
possible worlds' rather than "possible states", or 'histories", of
the world, or "counterfactual situations' had been used. Certainly they would have been avoided had philosophers adhered
to the common practices of schoolchildren and probabilists."
A final issue: Some critics of my doctrines,
and some
sympathizers, seem to have read them as asserting, or at least
implying, a doctrine of the universal substitutivity of proper
names. This can be taken as saying that a sentence with 'Cicero'
in it expresses the same "proposition' as the corresponding one
with "Tully, that to believe the proposition expressed by the
one is to believe the proposition expressed by the other, or that
they are equivalent for all semantic purposes. Russell does seem
to have held such a view for "logically proper names', and it
seems congenial to a purcly 'Millian'
picture of naming, where
only the referent of the name contributes to what is expressed.
But I (and for all I know, even Mill) never intended to go so
far. My view that the English sentence 'Hesperus is Phosphorus'
could sometimes be used to raise an empirical issue while
"Hesperus is Hesperus' could not shows that I do not treat the
sentences as completely interchangeable. Further, it indicates
that the mode of fixing the reference is relevant to our epistemic
1• Compare, c.g., the 'moderate realism' regarding possible worlds of Robert
Stalnaker, 'Possible Worlds', Noßs, vol. 10 (1976), Pp. 65-75.
30 Michael Lockwood (On Predicating Proper Names', The Philosophical
Review, vol. 84, no. 4, October, 1975, PP. 471-498) points out (P. 491) that
Mill does not take 'Cicero is Tully' to mean the same as 'Cicero is Cicero' but
rather holds the view that it means that 'Cicero' and "Tully' are codesignative.
He also points out (p. 490) that Mill sces such a metalinguistic component in
all assertions involving names. I have not investigated the interpretation of
Mill further, so I have no view as to his exact doctrine.
2I
attitude toward the sentences expressed. How this relates to
the question what 'propositions' are expressed by these sentences, whether these 'propositions' are objects of knowledge
and belief, and in general, how to treat names in epistemic
contexts, are vexing questions. I have no 'official doctrine'
concerning them, and in fact I am unsure that the apparatus of
"propositions' does not break down in this area." Hence, I
sidestepped such questions; no firm doctrine regarding the
point should be read into my words.
" Reasons why I find these questions so vexing are to be found in my 'A
Puzzle About Belief', in Meaning and Use (ed. A. Margalit), Reidel, 1979,
pp. 239-283. Of course there may be more than one notion of "proposition",
depending on the demands we make of the notion. The thesis of rigidity does
of course imply interchangeability of codesignative names in modal contexts,
subject to the usual caveat about possible nonexistence.
Concerning rigidity: In many places, both in this preface and in the text of
this monograpi, I deliberately ignore delicate questions arising frons the
possible nonexistence of an object. I also ignore the distinction between 'de
jure rigidity, where the reference of a designator is stipulated to be a single
object, whether we are speaking of the actual world or of a counterfactual
situation, and mere 'de facto' rigidity, where a description 'the x such that Ex'
happens to use a predicate "F' that in each possible world is true of one and the
same unique object (e.g., 'the smallest prime' rigidly designates the number
two). Clearly my thesis about names is that they are rigid de jure, but in the
monograph I am content with the weaker assertion of rigidity. Since names
are rigid de jure-see p. 78 below-I say that a proper name rigidly designates
its referent even when we speak of counterfactual situations where that
referent would not have existed. Thus the issues about nonexistence are
affected. Various people have persuaded me that all these questions deserve a
more careful discussion than I gave them in the monograph, but I must leave
them here.

LECTURE I: JANUARY 20, 1970°
I hope that some people see some connection between the two
philosophy today, our views on these topics really have wide-
1 In January of 1970, I gave three talks at Princeton University transcribed
here. As the style of the transcript makes clear, I gave the talks without a
written text, and, in fact, without notes. The present text is lightly edited
rom the verbatim transcript; an occasional passage has been added to expanc
he thought, an occasional sentence has been rewritten, but no attempt ha:
been made to change the informal style of the original. Many of the footnotes
have been added to the original, but a few were originally spoken asides in the
talks themselves.
Thope the reader will bear these facts in mind as he reads the text. Imagining
it spoken, with proper pauses and emphases, may occasionally facilitate comprehension. I have agreed to publish the talks in this form with some reservations. The time allotted, and the informal style, necessitated a certain amount
of compression of the argument, inability to treat certain objections, and the
like. Especially in the concluding sections on scientific identities and the
mind-body problem thoroughness had to be sacrificed. Some topics essential
to a full presentation of the viewpoint argued here, especially that of existence
statements and empty names, had to be omitted altogether. Further, the
informality of the presentation may well have engendered a sacrifice of clarity
at certain points. All these defects were accepted in the interest of carly
publication. I hope that perhaps I will have the chance to do a more thorough
job later. To repeat, I hope the reader will bear in mind that he is largely
reading informal lectures, not only when he encounters repetitions or infelicities, but also when he encounters irreverence or com.
23
ranging implications for other problems in philosophy that
traditionally might be thought far-removed, like arguments
over the mind-body problem or the so-called "identity thesis'.
Materialism, in this form, often now gets involved in very
intricate ways in questions about what is necessary or
contingent in identity of properties-questions like that.
So, it is really very important to philosophers who may
want to work in many domains to get clear about these
concepts. Maybe I will say something about the mind-body
problem in the course of these talks. I want to talk also at some
point (I don't know if I can get it in) about substances and
natural kinds.
The way I approach these matters will be, in some ways,
quite different from what people are thinking today (though it
also has some points of contact with what some people have
been thinking and writing today, and if I leave people out in
informal talks like this, I hope that I will be forgiven). Some
of the views that I have are views which may at first glance
strike some as obviously wrong. My favorite example is this
(which I probably won't defend in the lectures—-for one thing
it doesn't ever convince anyone): It is a common claim in contemporary philosophy that there are certain predicates which,
though they are in fact empty-have null extension —have it
" Given a chance to add a footnote, I shall mention that Rogers Albritton,
Charles Chastain, Keith Donnellan, and Michael Slote (in addition to philosophers mentioned in the text, especially Hilary Putnam), have independently
expressed views with points of contact with various aspects of what I say
here. Albritton called the problems of necessity and a prioricity in natural
kinds to my attention, by raising the question whether we could discover that
lemons were not fruits. (I am not sure he would accept all my conclusions.)
I also recall the influence of early conversations with Albritton and with Peter
Geach on the essentiality of origins. The apology in the text still stands; I am
aware that the list in this footnote is far from comprehensive. I make no
attempt to enumerate those friends and students whose stimulating conversations have helped me. Thomas Nagel and Gilbert Harman deserve
special thanks for their help in editing the transcript.

24
as a matter of contingent fact and not as a matter of any sort of
necessity. Well, that I don't dispute; but an example which is
usually given is the example of unicorn. So it is said that though
we have all found out that there are no unicorns, of course
there might have been unicorns. Under certain circumstances
there would have been unicorns. And this is an example of
something I think is not the case. Perhaps according to me the
truth should not be put in terms of saying that it is necessary
that there should be no unicorns, but just that we can't say
under what circumstances there would have been unicorns.
Further, I think that even if archeologists or geologists were to
discover tomorrow some
fossils conclusively showing the
existence of animals in the past satisfying everything we know
about unicorns from the myth of the unicorn, that would
not show that there were unicorns. Now I don't know if I'm
going to have a chance to defend this particular view, but it's
an example of a surprising one. (I actually gave a seminar in
this institution where I talked about this view for a couple of
sessions.) So, some of my opinions are somewhat surprising;
but let us start out with some area that is perhaps not as surprising and introduce the methodology and problems of these
talks.
The first topic in the pair of topics is naming. By a name here
I will mean a proper name, i.e., the name of a person, a city, a
country, etc. It is well known that modern logicians also are
very interested in definite descriptions: phrases of the forms 'the
× such that ox', such as 'the man who corrupted Hadleyburg'.
Now, if one and only one man ever corrupted Hadleyburg,
then that man is the refcrent, in the logician's sense, of that
We will use the term "name' so that it does not
include definite descriptions of that sort, but only those things
which in ordinary language would be called 'proper names'. If
we want a common term to cover names and descriptions, we
may use the term "designator'.
25
It is a point, made by Donnellan, that under certain circumstances a particular speaker may use a definite description to
refer, not to the proper referent, in the sense that I've just
defined it, of that description, but to something else which he
wants to single out and which he thinks is the proper referent
of the description, but which in fact isn't. So you may say,
"The man over there with the champagne in his glass is happy',
though he actually only has water in his glass. Now, even
though there is no champagne in his glass, and there may be
another man in the room who does have champagne in his
glass, the speaker intended to refer, or maybe, in some sense of
'refer', did refer, to the man he thought had the champagne in
his glass. Nevertheless, I'm just going to use the term 'referent
Keith Donnellan, 'Reference and Definite Descriptions, Philosophical
Review 75 (1966), Pp. 281-304. See also Iconard Linsky, 'Reference and
Referents', in Philosophy and Ordinary Language (ed. Caton), University of
Illinois Press, Urbana, 1963. Donnellan's distinction seems applicable to
names as weil as to descriptions. Two men glimpse someone at a distance and
think they recognize him as Jones. 'What is Jones doing? "Raking the leaves'.
If the distant leaf-raker is actually Smith, then in some sense they are referring
to Smith, even though they both use "Jones' as a name of Jones. In the text, I
speak of the 'referent' of a name to mean the thing named by the name-e.g.,
Jones, not Smith-even though a speaker may sometimes properly be said to
use the name to refer to somcone else. Perhaps it would have been less misleading to use a technical term, such as "denote' rather than 'refer". My use of
'refer' is such as to satisfy the schema, "The referent of "X" is X', where 'X'
is replaccable by any name or description. I am tentatively inclined to believe,
in opposition to Donnellai, that his remarks about reference have little to do
with semantics or truth-conditions, though they may be relevant to a theory
of speech-acts. Space limitations do not permit nie to explain what I mean by
this, much less defend the view, except for a brief remark: Call the referent
of a name or description in my sense the "semantic referent'; for a name, this
is the thing named, for a description, the thing uniquely satisfying the
description.
Then the speaker may refer to something other than the semantic referent if
he has appropriate false beliefs. I think this is what happens in the naming
(Smith-Jone:) cases and also in the Donnellan 'champagne' case; the one
requires no theory that names are ambiguous, and the other requires no
modification of Russell's theory of descriptions.

26
NAMING AND NECBSSITY
of the description' to mean the object uniquely satisfying the
conditions in the definite description. This is the sense in which
it's been used in the logical tradition. So, if you have a description of the form 'the x such that ox', and there is exactly one x
such that ox, that is the referent of the description.
Now, what is the relation between names and descriptions?
There is a well known ductrine of John Stuart Mill, in his book
A System of Logic, that names have denotation but not connotation. To use one of his examples, when we use the name
'Dartmouth' to describe a certain locality in England, it may
be so called because it lies at the mouth of the Dart. But even,
he says, had the Dart (that's a river) changed its course so that
Dartmouth no longer lay at the mouth of the Dart, we could
still with propriety call this place "Dartmouth', even though
the name may suggest that it lies at the mouth of the Dart.
Changing Mill's terminology, perhaps we should say that a
name such as 'Dartmouth' does have a 'connotation' to some
people, namely, it does connote (not to me—-I never thought of
this that any place called 'Dartmouth' lies at the mouth of the
Dart. But then in some way it doesn't have a "sense'. At least,
it is not part of the meaning of the name 'Dartmouth' that the
town so naned lies at the mouth of the Dart. Someone who
said that Dartmouth did not lie at the Dart's mouth would not
contradict himself.
It should not be thought that every phrase of the form 'the
* such that Ex' is always used in English as a description rather
than a name. I guess everyone has heard about The Holy
Roman Empire, which was neither holy, Roman nor an
empire. Today we have The United Nations. Here it would
seem that since these things can be so-called even though they
are not Holy Roman United Nations, these phrases should be
regarded not as definite descriptions, but as names. In the case
of some terms, people might have doubts as to whether they're
names or descriptions; like 'God'—does it describe God as the
27
unique divine being or is it a name of God? But such cases
needn't necessarily bother us.
Now here I am making a distinction which is certainly made
in language. But the classical tradition of modern logic has
gone very strongly against Mill's view. Frege and Russell both
thought, and seemed to arrive at these conclusions independently of each other, that Mill was wrong in a very strong
sense: really a proper name, properly used, simply was a
definite description abbreviated or disguised. Frege specifically
said that such a description gave the sense of the name.*
Now the reasons against Mill's view and in favor of the
alternative view adopted by Frege and Russell are really very
powerful; and it is hard to see-—though one may be suspicious
of this view because names don't seem to be disguised descriptions—how the Frege-Russell view, or some suitable variant,
can fail to be the case.
Let me give an example of some of the arguments which
seem conclusive in favor of the view of Frege and Russell. The
basic problem for any view such as Mill's is how we can
determine what the referent of a name, as used by a given
" Strictly speaking, of course, Russell says that the names don't abbreviate
descriptions and don't have any sense; but then he also says that, just because
the things that we call "names' do abbreviate descriptions, they're not really
names. So, since Walter Scott, according to Russell, does abbreviate a description, 'Walter Scott' is not a name; and the only names that really exist in
ordinary language arc, perhaps, demonstratives such as 'this' or 'that', used
on a particular occasion to refer to an object with which the speaker is
"acquainted' in Russell's sense. Though we won't put things the way Russell
does, we could describe Russell as saying that names, as they are ordinarily
called, do have sense. They have sense in a strong way, namely, we should be
able to give a definite description such that the referent of the name, by
definition, is the object satisfying the description. Russell himself, since he
climinates descriptions from his primitive notation, seems to hold in 'On
Denoting' that the notion of 'sense' is illusory. In reporting Russell's views,
we thus deviate from him in two respects. First, we stipulate that 'names' shall
be names as ordinarily conceived, not Russell's "logically proper names';
second, we regard descriptions, and their abbreviations, as having sensc.

28
speaker, is. According to the description view, the answer is
clear. If Joe Doakes' is just snort for 'the man who corrupted
Hadleyburg', then whoever corrupted Hadleyburg uniquely is
the referent of the name 'Joe Doakes'. However, if there is not
such a descriptive content to the name, then how do people
ever use names to refer to things at all? Well, they may be in a
position to point to some things and thus determine the
references of certain names ostensively. This was Russell's
doctrine of acquaintance, which he thought the so-called
genuine or proper names satisfied. But of course ordinary
names refer to all sorts of people, like Walter Scott, to whom
we can't possibly point. And our reference here seems to be
determined by our knowledge of them. Whatever we know
about then determines the referent of the name as the unique
thing satisfying those properties. For example, if I use the
name "Napoleon', and someone asks, "To whom are you
referring?', I will answer something like, 'Napoleon was
emperor of the French in the early part of the nineteenth
century; he was eventually defeated at Waterloo', thus giving
a uniquely identifying description to determine the referent of
the name. Frege and Russell, then, appear to give the natural
account of how reference is determined here; Mill appears to
give none.
There are subsidiary arguments which, though they are
based on more specialized problems, are also motivations for
accepting the view. One is that sometimes we may discover
that two names have the same referent, and express this by an
identity statement. So, for example (I guess this is a hackneyed
example), you see a star in the evening and it's called 'Hesperus'.
(That's what we call it in the evening, is that right?—I hope it's
not the other way around.) We see a star in the morning and
call it 'Phosphorus'. Well, then, in fact we find that it's not a
star, but is the planet Venus and that Hesperus and Phosphorus
are in fact the same. So we express this by 'Hesperus is Phos-
29
phorus'. Here we're certainly not just saying of an object that
it's identical with itself. This is something that we discovered.
A very natural thing to say is that the real content [is that] the
star which we saw in the evening is the star which we saw in
the morning (or, more accurately, that the thing which we
saw in the evening is the thing which we saw in the morning).
This, then, gives the real meaning of the identity statement
in question; and the analysis in terms of descriptions does
Also we may raise the question whether a name has any
reference at all when we ask, c.g., whether Aristotle ever
existed. It seems natural here to think that what is questioned
is not whether this thing (man) existed. Once we've got the
thing, we know that it existed. What really is queried is
whether anything answers to the properties we associate with
the name—-in the case of Aristotle, whether any one Greek
philosopher produced certain works, or at last a suitable
number of them.
It would be nice to answer all of these arguments. I am not
entirely able to sce my way clear through every problem of
this sort that can be raised. Furthermorc, I'm pretty sure that I
won't have time to discuss all these questions in these lectures.
Nevertheless, I think it's pretty certain that the view of Frege
and Russell is false.
" When I speak of the Frege-Russell view and its variants, I include only
those versions which give a substantive theory of the reference of names. In
particular, Quine's proposal that in a 'canonical notation' a name such as
'Socrates' should be replaced by a description 'the Socratizer' (where 'Socratizes' is an invented predicate), and that the description should then be
eliminated by Russell's method, was not intended as a theory of reference for
names but as a proposed rcform of language with certain advantages. The
problems discussed here will all apply, mutatis mutandis, to the reformed
language; in particular, the question, 'How is the reference of "Socrates"
determined?" yields to the question, 'How is the extension of "Socratizes"
determined? Of course I do not suggest that Quine has ever claimed the

30
NAMUNG AND NECESSITY
Many people have said that the theory of Frege and Russell
is false, but, in my opinion, they have abandoned its letter
while retaining its spirit, namely, they have used the notion of
a cluster concept. Well, what is this? The obvious problem for
Frege and Russell, the one which comes immediately to mind,
is already mentioned by Frege himself. He said,
In the case of genuinely proper names like "Aristotle' opinions as
regards their sense may diverge. As such may, e.g., be suggested:
Plato's disciple and the teacher of Alexander the Great. Whoever
accepts this sense will interpret the meaning of the statement
"Aristotle was born in Stagira', differently from one who interpreted
the sense of "Aristotle' as the Stagirite teacher of Alexander the
Great. As long as the nominatum remains the same, these fluctuations in sense are tolerable. But they should be avoided in the system
of a demonstrative science and should not appear in a perfect
language.®
So, according to Frege, there is some sort of looseness or
weakness in our language. Some people may give one sense to
the name "Aristotle', others may give another. But of course
it is not only that; even a single speaker when asked 'What
description are you willing to substitute for the naine?' may
be quite at a loss. In fact, he may know many things about
him; but any particular thing that he knows he may feel clearly
expresses a contingent property of the object. If 'Aristotle'
meant the man who taught Alexander the Great, then saying
"Aristotle was a teacher of Alexander the Great' would be a
mere tautology. But surely it isn't; it expresses the fact that
Aristotle taught Alexander the Great, something we could
discover to be false. So, being the teacher of Alexander the Great
cannot be part of [the sense of] the name.
• Gottlob Frege, 'On Sense and Nominatum", translated by Herbert Feigl
in Readings in Philosophical Analysis (ed. by Herbert Feigl and Wilfrid Sellars),
Appleton Century Crofts, 1949, p. 86.
The nost common way out of this difficulty is to say 'really
it is not a weakness in ordinary language that we can't substitute a particular description for the name; that's all right.
What we really associate with the name is a family of descriptions.' A good example of this is (if I can find it) in Philosophical
Investigations, where the idea of family resemblances is introduced and with great power.
Consider this example. If one says 'Moses did not exist", this may
mean various things. It may mean: the Israelites did not have a
single leader when they withdrew from Egypt—or: their leader was
not called Moses—or: there cannot have been anyone who accomplished all that the Bible relates of Moses-... But when I make a
statement about Moses, —am I always ready to substitute some one
of those descriptions for 'Moses"? I shall perhaps say: by 'Moses' I
understand the man who did what the Bible relates of Moses, or at
any rate, a good deal of it. But how much? Have I decided how
much must be proved false for me to give up my proposition as
false? Has the name 'Moses' got a fixed and unequivocal use for me
in all possible cases?'
According to this view, and a locus classicus of it is Searle's
article on proper names,° the referent of a name is determined
not by a single description but by some cluster or family.
Whatever in some sense satisfies enough or most of the family
is the referent of the name. I shall return to this view later. It
may seem, as an analysis of ordinary language, quite a bit more
plausible than that of Frege and Russell. It may seem to keep
all the virtues and remove the defects of this theory.
Let me say (and this will introduce us to another new topic
before I really consider this theory of naming) that there are
two ways in which the cluster concept theory, or even the
Ludwig Wittgenstein, Philosophical Investigations, translated by G. E. M.
Anscombe, MacMillan, 1953,
•John R. Scarle, 'Proper Names', Mind 67 (1958), 166-73.

32
theory which requires a single description, can be viewed. Onc
way of regarding it says that the cluster or the single description
actually gives the meaning of the name; and when someone
says 'Walter Scott', he means the man such that such and such
and such and such.
Now another view might be that even though the description in some sense doesn't give the meaning of the name, it is
what determines its reference and although the phrase Walter
Scott' isn't synonymous with 'the man such that such and such
and such and such', or even maybe with the family (if something can be synonymous with a family), the family or the
single description is what is used to determine to whom someone is referring when he says 'Walter Scott'. Of course, if
when we hear his beliefs about Walter Scott we find that
they are actually much more nearly true of Salvador Dali,
then according to this theory the refcrence of this name is
going to be Mr. Dali, not Scott. There are writers, I think,
who explicitly deny that names have mcaning at all even more
strongly than I would but still use this picture of how the
referent of the name gets determined. A good case in point is
Paul Ziff, who says, very emphatically, that names don't have
meaning at all, [that] they are not a part of language in some
sense. But still, when he talks about how we determine what
the reference of the name was, then he gives this picture. Un-
fortunately I don't have the passage in question with me, but
this is what he says.?
• Ziff's most detailed statement of his version of the cluster-of-descriptions
theory of the reference of names is in 'About God", reprinted in Philosophical
Turnings, Cornell University Press, Ithaca, and Oxford University Press,
London, 1966, PP 94-96. A briefer statement is in his Semantic Analysis,
Cornell University Press, Ithaca, 1960, PP. 102-05 (esp. Pp. 103-04). The
latter passage suggests that names of things with which we are acquainted
should be treated somewhat differently (using ostension and baptism) from
names of historical figures, where the reference is determined by (a cluster of)
associated descriptions. On p. 93 of Semantic Analysis Ziff states that simple
33
The difference between using this theory as a theory of
meaning and using it as a theory of reference will come out a
little more clearly later on. But some of the attractiveness of
the theory is lost if it isn't supposed to give the meaning of the
name; for some of the solutions of problems that I've just
mentioned will not be right, or at least won't clearly be right,
if the description doesn't give the meaning of the name. For
example, if somcone said "Aristotle does not exist' means "there
is no man doing such and such', or in the example from
Wittgenstein, 'Moses does not exist', means 'no man did such
and such', that might depend and in fact, I think, does depend)
on taking the theory in question as a theory of the meaning of
the name 'Moses', not just as a theory of its reference. Well, I
don't know. Perhaps all that is immediate now is the other
way around: if "Moses' means the same as 'the man who did
such and such' then to say that Moses did not exist is to say
that the man who did such and such did not exist, that is, that
no one person did such and such. If, on the other hand, 'Moses'
is not synonymous with any description, then even if its
reference is in some sense determined by a description, statements containing the name cannot in general be analyzed by
replacing the name by a description, though they may be
materially equivalent to statements containing a description.
So the analysis of singular existence statements mentioned
above will have to be given up, unless it is established by some
special argument, independent of a general theory of the meaning of names; and the same applies to identity statements. In
any casc, I think it's false that 'Moses exists' means that at all.
strong generalization(s) about proper
names' are impossible; 'one can only
say what is so for the most part ... Nevertheless Ziff clearly states that a
cluster-of-descriptions theory is a reasonable such rough statement, at least
for historical figures. For Ziff's view that proper names ordinarily are not
words of the language and ordinarily do not have meaning, see pp. 85-89
and 93-94 of Semantic Analysis.

34
So we won't have to see if such a special argument can be
drawn up. 1°
Before I go any further into this problem, I want to talk
about another distinction which will be important in the
methodology of these talks. Philosophers have talked (and, of
course, there has been considerable controversy in recent
years over the meaningfulness of these notions) [about] various
categories of truth, which are called "a priori",
'analytic',
"necessary'-and sometimes even 'certain' is thrown into this
batch. The terms are often used as if whether there are things
answering to these concepts is an interesting question, but we
might as well regard them all as meaning the same thing. Now,
everyone remembers Kant (a bit) as making a distinction between 'a priori" and 'analytic'. So maybe this distinction is still
made. In contemporary discussion very few people, if any,
distinguish between the concepts of statements being a priori
and their being necessary. At any rate I shall not use the terms
"a priori" and 'necessary' interchangeably here.
Consider what the traditional characterizations of such terms
as 'a priori" and 'necessary' are. First the notion of a prioricity is a
concept of epistemology. I guess the traditional characterization
from Kant goes something like: a priori truths are those which
can be known independently of any experience. This introduces
another problem before we get off the ground, because there's
another modality in the characterization of 'a priori", namely,
it is supposed to be something which can be known independently of any experience. That means that in some sense it's
possible (whether we do or do not in fact know it independently
of any experience) to know this independently of any experience. And possible for whom? For God? For the Martians?
10 Those determinists who deny the importance of the individual in history
may well argue that had Moses never existed, someone else would have arisen
to achieve all that he did. Their claim cannot be refuted by appealing to a
correct philosophical theory of the meaning of 'Moses exists'.
35
Or just for people with minds like ours? To make this all clear
might [involve) a host of problems all of its own about what
sort of possibility is in question here. It might be best therefore,
instead of using the phrase "a priori truth', to the extent that one
uses it at all, to stick to the question of whether a particular
person or knower knows something a priori or believes it true
on the basis of a priori evidence.
I won't go further too much into the problems that might
arise with the notion of a prioricity here. I will say that some
philosophers somehow change the modality in this characterization from can to must. They think that if something belongs to
the realm of a priori knowledge, it couldn't possibly be known
empirically. This is just a mistake. Something may belong in
the realm of such statements that can be known a priori but still
may be known by particular people on the basis of experience.
To give a really common sense example: anyone who has
worked with a computing machine knows that the computing machine may give an answer to whether such and such
a number is prime. No one has calculated or proved that the
number is prime; but the machine has given the answer: this
number is prime. We, then, if we believe that the number is
prime, believe it on the basis of our knowledge of the laws of
physics, the construction of the machine, and so on. We therefore do not believe this on the basis of purely a priori evidence.
We believe it (if anything is a posteriori at all) on the basis of a
posteriori evidence. Nevertheless, maybe this could be known
a priori by someone who made the requisite calculations. So
'can be known a priori" doesn't mean 'must be known a priori".
The second concept which is in question is that of necessity.
Sometimes this is used in an epistemological way and might
then just mean a priori. And of course, sometimes it is used in a
physical way when people distinguish between physical and
logical necessity. But what I am concerned with here is a notion
which is not a notion of epistemology but of metaphysics,

36
in some (I hope) nonpejorative sense. We ask whether something might have been true, or might have been false. Well,
if something is false, it's obviously not necessarily true. If it
is true, night it have been otherwise? Is it possible that, in
this respect, the world should have been different from the
way it is? If the answer is "no', then this fact about the world is
a necessary one. If the answer is 'yes", then this fact about the
world is a contingent one. This in and of itself has nothing to
do with anyone's knowledge of anything. It's certainly a
philosophical thesis, and not a matter of obvious definitional
equivalence, either that everything a priori is necessary or that
everything necessary is a priori. Both concepts may be vague.
That may be another problem. But at any rate they are dealing
with two different domains, two different areas, the epistemological and the metaphysical. Consider, say, Fermat's last
theorem—or the Goldbach conjecture. The Goldbach conjecture says that an even number greater than 2 must be the
sum of two prime numbers. If this is true, it is presumably
necessary, and, if it is false, presumably necessarily false. We
are taking the classical view of mathematics here and assume
that in mathematical reality it is either true or false.
If the Goldbach conjecture is false, then there is an even
number, n, greater than 2, such that for no primes pe and pa,
both < n, does n= pr + pa. This fact about n, if true, is verifiable by direct computation, and thus is necessary if the results
of arithmetical computations are necessary. On the other hand,
if the conjecture is true, then every even number exceeding 2 is
the sum of two primes. Could it then be the case that, although
in fact every such even number is the sum of two primes, there
might have been such an even number which was not the sum
of two primes? What would that mean? Such a number would
have to be one of 4, 6, 8, 10, ...; and, by hypothesis, since we
are assuming Goldbach's conjecture to be true, each of these
can be shown, again by direct computation, to be the sum of
37
two primes. Goldbach's conjecture, then, cannot be contingently true or false; whatever truth-value it has belongs to
it by necessity.
But what we can say, of course, is that right now, as far as
we know, the question can come out either way. So, in the
absence of a mathematical proof deciding this question, none
of us has any a priori knowledge about this question in either
direction. We don't know whether Goldbach's conjecture is
true or false. So right now we certainly don't know anything
a priori about it.
Perhaps it will be alleged that we can in principle know a
priori whether it is true. Well, maybe we can. Of course an
infinite mind which can search through all the numbers can or
could. But I don't know whether a finite mind can or could.
Maybe there just is no mathematical proof whatsoever which
decides the conjecture. At any rate this might or might not be
the case. Maybe there is a mathematical proof deciding this
question; maybe every mathematical question is decidable by
an intuitive proof or disproof. Hilbert thought so; others have
thought not; still others have thought the question unintelligible unless the notion of intuitive proof is replaced by that
of formal proof in a single system. Certainly no one formal
system decides all mathematical questions, as we know from
Gödel. At any rate, and this is the important thing, the question
is not trivial; even though someone said that it's necessary, if
true at all, that every even number is the sum of two primes, it
doesn't follow that anyone knows anything a priori about it. It
doesn't even seem to me to follow without some further
philosophical argument (it is an interesting philosophical
question) that anyone could know anything a priori about
it. The "could", as I said, involves some other modality. We
mean that even if no one, perhaps even in the future, knows
or will know a priori whether Goldbach's conjecture is
right, in principle there is a way, which could have been

38
used, of answering the question a priori. This assertion is not
trivial.
The terms 'necessary' and a priori", then, as applied to statements, are not obvious synonyms. There may be a philosophical
argument connecting them, perhaps even identifying them; but
an argument is required, not simply the observation that the
two terms are clearly interchangeable. (I will argue below that
in fact they are not even coextensive-that necessary a posteriori truths, and probably contingent a priori truths,
both
exist.)
I think people have thought that these two things must mean
the same for these reasons:
First, if something not only happens to be true in the actual
world but is also true in all possible worlds, then, of course,
just by running through all the possible worlds in our heads,
we ought to be able with enough effort to see, if a statement
is necessary, that it is necessary, and thus know it a priori. But
really this is not so obviously feasible at all.
Second, I guess it's thought that, conversely, if something
is known a priori it must be necessary, because it was known
without looking at the world. If it depended on some contingent feature of the actual world, how could you know it
without looking? Maybe the actual world is one of the possible
worlds in which it would have been false. This depends on
the thesis that there can't be a way of knowing about the actual
world without looking that wouldn't be a way of knowing
the same thing about every possible world. This involves
problems of epistemology and the nature of knowledge; and
of course it is very vague as stated. But it is not really trivial
either. More important than any particular example of something which is alleged to be necessary and not a priori or a priori
and not necessary, is to see that the notions are different, that
it's not trivial to argue on the basis of something's being something which maybe we can only know a posteriori, that it's not
39
a necessary truth. It's not trivial, just because something is
known in some sense a priori, that what is known is a necessary
truth.
Another term used in philosophy is 'analytic. Here it won't
be too important to get any clearer about this in this talk. The
common examples of analytic statements, nowadays, are like
bachclors are unmarried. Kant (someone just pointed out to
me) gives as an example 'gold is a yellow metal", which seems
to me an extraordinary one, because it's something I think
that can turn out to be false. At any rate, let's just make it a
matter of stipulation that an analytic statement is, in some
sense, true by virtue of its meaning and true in all possible
worlds by virtue of its meaning.
Then something which is
analytically truc will be both necessary and a priori. (That's
sort of stipulative.)
• Another category I mentioned was that of certainty. Whatever certainty is, it's clearly not obviously the case that everything which is necessary is certain. Certainty is another
epistemological notion. Something can be known, or at least
rationally believed, a priori, without being quite certain.
You've read a proof in the math book; and, though you think
it's correct, maybe you've made a mistake. You often do make
mistakes of this kind. You've made a computation, perhaps
with an error.
There is one more question I want to go into in a preliminary way. Some philosophers have distinguished between
essentialism, the belief in modality de re, and a mere advocacy
of necessity, the belicf in modality de dicto. Now, some people
say: Let's give you the concept of necessity." A much worse
"By the way, it's a common attitude in philosophy to think that one
shouldn't introduce a notion until it's been rigorously defined (according to
some popular notion of rigor). Here I am just dealing with an intuitive notion
and will keep on the level of an intuitive notion. That is, we think that some
things, though they are in fact the case, might have been otherwise. I might
not have given these lectures today. If that's right, then it is possible that I

4°
thing, something creating great additional problems, is whether
we can say of any particular that it has necessary or contingent
properties, even make the distinction between necessary and
contingent properties. Look, it's only a statement or a state of
affairs that can be either necessary or contingent! Whether a
particular necessarily or contingently has a certain property
depends on the way it's described. This is perhaps closcly
rclated to the view that the way we refer to particular things
is by a description. What is Quinc's famous example? If we
consider the number 9, does it have the property of necessary
oddness? Has that number got to be odd in all possible worlds?
Certainly it's true in all possible worlds, Ict's say, it couldn't
have been otherwisc, that nine is odd. Of course, 9 could also
be cqually well picked out as the number of planets. It is not
necessary, not true in all possible worlds, that the number of
plancts is odd. For example if there had been cight planets, the
number of planets would not have been odd. And so it's
thought: Was it necessary or contingent that Nixon won the
election? (It might scem contingent, unless one has some view
of some incorable processes....) But this is a contingent
proporty of Nixon only relative to our referring to him as
'Nixon' (assuming 'Nixon' docsn't mean 'the man who won
the election at such and such a time'). But if we designate
Nixon as 'the man who won the clection in 1968", then it will
be a necessary truth, of course, that the man who won the
clection in 1968, won the clection in 1968. Similarly, whether
an object has the same proporty in all possible worlds depends
wouldn't have given these lectures today. Quite a diffcrent question is the
epistemological question, how any particular person knows that I gave these
lectures today. 1 suppose in that case he does know this is a posteriori. But, if
someone were born with an innate belief that I was going to give these lectures
today, who knows? Right now, anyway, let's suppose that people know this
a posteriori. At any rate, the two questions being asked are different.
4I
not just on the object itself, but on how it is described. So it's
argued.
It is even suggested in the literature, that though a notion of
necessity may have some sort of intuition behind it (we do
ink some things could have been otherwise; other thing
e don't think could have been otherwise), this notion [of
distinction between necessary and contingent properties) is just
a doctrine made up by some bad philosopher, who (I guess)
didn't realize that there are several ways of rcferring to the same
thing. I don't know if some philosophers have not realized
this; but at any rate it is very far from being true that this idea
[that a property can meaningfully be held to be essential or
accidental to an object independently of its description] is a
notion which has no intuitive content, which means nothing
to the ordinary man. Suppose that someone said, pointing to
Nixon, 'That's the guy who might have lost. Someone else
says 'Oh no, if you describe him as "Nixon", then he might
have lost; but, of course, describing him as the winner, then it
is not true that he might have lost'. Now which one is being
the philosopher, here, the unintuitive man? It scems to me
obviously to be the second. The second man has a philosophical
theory. The first man would say, and with great conviction,
'Well, of course, the winner of the election might have been
someone else. The actual winner, had the course of the campaign
been different, might have been the loser, and someone else
the winner; or there might have been no clection at all. So,
such terms as "the winner" and "the loser" don't designate the
same objects in all possible worlds. On the other hand, the
term "Nixon" is just a name of this man'. When you ask
whether it is necessary or contingent that Nixon won the
election, you are asking the intuitive question whether in some
counterfactual situation, this man would in fact have lost the
ciection. If someone thinks that the notion of a necessary or
contingent property (forget whether there are any nontrivial

42
necessary properties [and consider) just the meaningfulness of the
notion'?) is a philosopher's notion with no intuitive content,
he is wrong. Of course, some philosophers think that something's having intuitive content is very inconclusive evidence in
favor of it. I think it is very heavy evidence in favor of anything, myself. I really don't know, in a way, what more conclusive evidence one
can have about anything, ultimately
speaking. But, in any event, people who think the notion of
accidental property unintuitive have intuition
reversed, I
think.
Why have they thought this? While there are many motivations for people thinking this, one is this: The question of
essential properties so-called is supposed to be equivalent (and
it is equivalent) to the question of 'identity across possible
worlds'. Suppose we have someone, Nixon, and there's another
possible world where there is no one with all the properties
Nixon has in the actual world. Which one of these other people,
if any, is Nixon? Surely you must give some criterion of
identity here! If you have a criterion of identity, then you just
look in the other possible worlds at the man who is Nixon;
and the question whether, in that other possible world, Nixon
has certain properties, is well defined. It is also supposed to be
well defined, in terms of such notions, whether it's true in all
possible worlds, or there are some possible worlds in which
Nixon didn't win the election. But, it's said, the problems of
giving such criteria of identity are very difficult. Sometimes
12 The example I gave asserts a certain property—-clectoral victory-to be
accidental to Nixon, independently of how he is described. Of course, if the
notion of accidental property is meaningful, the notion of essential property
must be meaningful also. This is not to say that there are any essential properties
-though, in fact, I think there are. The usual argument questions the meaningfulness of essentialism, and says that whether a property is accidental or
essential to an object depends on how it is described. It is thus not the view
that all properties are accidental. Of course, it is also not the view, held by
some idealists, that all properties are essential, all rclations internal.
43
in the case of numbers it might seem casier (but even here it's
argued that it's quite arbitrary). For example, one might say,
and this is surely the truth, that if position in the series of
numbers is what makes the number 9 what it is, then if (in
another world) the number of planets had been 8, the number
of planets would be a different number from the one it actually
is. You wouldn't say that that number then is to be identified
with our number 9 in this world. In the case of other types of
objects, say people, material objects, things like that, has
anyone given a set of necessary and sufficient conditions for
identity across possible worlds?
Really, adequate necessary and sufficient conditions for
identity which do not beg the question are very rare in any
case. Mathematics is the only case I really know of where they
are given even within a possible world, to tell the truth. I don't
know of such conditions for identity of material objects over
time, or for people. Everyone knows what a problem this is.
But, let's forget about that. What seems to be more objectionable is that this depends on the wrong way of looking at what
a possible world is. One thinks, in this picture, of a possible
world as if it were like a foreign country. One looks upon it as
an observer. Maybe Nixon has moved to the other country
and maybe he hasn't, but one is given only qualities. One
can observe all his qualities, but, of course, one doesn't observe
that someone is Nixon. One observes that something has
red hair (or green or yellow) but not whether something
is Nixon. So we had better have a way of telling in terms
of propertics when we run into the same thing as we saw
before; we had better have a way of telling, when we
come across one of these other possible worlds, who was
Nixon.
Some logicians in their formal treatment of modal logic may
encourage this picture. A prominent example, perhaps, is
myself. Nevertheless, intuitively speaking, it seems to me not

44
to be the right way of thinking about the possible worlds. A
possible world isn't a distant country that we are coming
across, or viewing through a telescope. Generally speaking,
another possible world is too far away. Even if we travel
faster than light, we won't get to it. A possible world is given
by the descriptive conditions we associate with it. What do we
mean when we say 'In some other possible world I would not
have given this lecture today?' We just imagine the situation
where I didn't decide to give this lecture or decided to give it
on some other day. Of course, we don't imagine everything
that is true or falsc, but only those things rclevant to my giving
the lecture; but, in theory, everything needs to be decided to
make a total description of the world. We can't really imagine
that except in part; that, then, is a 'possible world. Why can't
it be part of the description of a possible world that it contains
Nixon and that in that world Nixon didn't win the election? It
might be a question, of course, whether such a world is possible.
(Here it would seem, prima facie, to be clearly possible.) But,
once we see that such a situation is possible, then we are given
that the man who might have lost the clection or did lose the
election in this possible world is Nixon, because that's part of
the description of the world. 'Possible worlds' are stipulated,
not discovered by powerful telescopes. There is no reason why
we cannot stipulate that, in talking about what would have
happened to Nixon in a certain counterfactual situation, we
are talking about what would have happened to him.
Of course, if somcone makes the demand that every possible
world has to be described in a purcly qualitative way, we can't
say, "Suppose Nixon had lost the clection', we must say, instead, something like, 'Suppose a man with a dog named
Checkers, who looks like a certain David Frye impersonation,
is in a certain possible world and loses the clection.' Well, does
he resemble Nixon enough to be identified with Nixon? A
very explicit and blatant example of this way of looking at
45
things is David Lewis's counterpart theory,' but the literature
on quantified modality is replete with it.! Why need we
make this demand? That is not the way we ordinarily think of
counterfactual situations. We just say suppose this man had
13 David K. Lewis, 'Counterpart Theory and Quantified Modal Logic',
Journal of Philosophy 65 (1968), 113-126. Lewis's elegant paper also suffers
from a purely formal difficulty: on his interpretation of quantified modality,
the familiar law (y) ((x) A(x) > A(y)) fails, if A(x) is allowed to contain modal
operators. (For example, (Jy) ((x) 0 (x#y is satisfiable but (3y) 0 (y ‡y)
is not.) Since Lewis's formal model follows rather naturally from his philosophical views on counterparts, and since the failure of universal instantiation for
modal properties is intuitively bizarre, it seems to me that this failure constitutes an additional argument against the plausibility of his philosophical
views. There are other, lesser, formal difficulties as well. I cannot elaborate
here.
Strictly speaking, Lewis's view is not a view of 'transworld identification'.
Rather, he thinks that similarities across possible worlds determine a counterpart relation which need be neither symmetric nor transitive. The counterpart
of something in another possible world is never identical with the thing itself.
Thus if we say 'Humphrey might have won the election (if only he had done
such-and-such), we are not talking about something that might have happened
to Humphrey but to soneone else, a "counterpart". Probabiy, however,
Humphrey could not care less whether someone else, no matter how much
resembling him, would have been victorious in another possible world. Thus,
Lewis's view seems to me even more bizarre than the usual notions of transworld identification that it replaces. The important issucs, however, are
common to the two views: the supposition that other possible worlds are like
other dimensions of a more inclusive universe, that they can be given only by
purely qualitative descriptions, and that therefore cither the identity relation
or the counterpart relation must be established in terms of qualitative
resemblance.
Many have pointed out to me that the father of counterpart theory is
probably Leibnitz. I will not go into such a historical question herc. It would
also be interesting to compare Lewis's views with the Wheelr-Everett
interpretation of quantum mechanics. I suspect that this view of plysics may
suffer from philosophical problems analogous to Lewis's counterpart theory;
it is certainly very similar in spirit.
1 Another locus classicus of the views I am criticizing, with more philo
sophical exposition than Lewis's paper, is a paper by David Kaplan on transworld identification. Unfortunately, this paper has never been published. It
does not represent Kaplan's present position.

46
lost. It is given that the possible world contains this man, and
that in that world, he had lost. There may be a problen about
what intuitions about possibility come to. But, if we have such
an intuition about the possibility of that (this man's electoral
loss), then it is about the possibility of that. It need not be
identified with the possibility of a man looking like such and
such, or holding such and such political views, or otherwise
qualitatively described, having lost. We can point to the man,
and ask what might have happened to him, had events been
different.
It might be said 'Let's suppose that this is true. It comes
down to the same thing, because whether Nixon could have
had certain properties, different from the ones he actually has,
is equivalent to the question whether the criteria of identity
across possible worlds include that Nixon does not have these
properties. But it doesn't really come to the same thing.
because the usual notion of a criterion of transworld identity
demands that we give purcly qualitative necessary and sufficient
conditions for someone being Nixon. If we can't imagine a
possible world in which Nixon doesn't have a certain property, then it's a necessary condition of someone being Nixon.
Or a necessary property of Nixon that he [has] that property. For example, supposing Nixon is in fact a human
being, it would scem that we cannot think of a possible
counterfactual situation in which he was, say, an inanimate
object; perhaps it is not even possible for him not to have been
a human being. Then it will be a necessary fact about Nixon
that in all possible worlds where he exists at all, he is human or
anyway he is not an inanimate object. This has nothing to do
with any requirement that there be purely qualitative sufficient
conditions for Nixonhood which we can spell out. And should
there be? Maybe there is some argument that there should be,
but we can consider these questions about necessary conditions
without going into any question about sufficient conditions.
47
Further, even if there were a purely qualitative set of necessary
and sufficient conditions for being Nixon, the view I advocate
would not demand that we find these conditions before we
can ask whether Nixon might have won the election, nor does
it demand that we restate the question in terms of such conditions. We can simply consider Nixon and ask what might
have happened to him had various circumstances been different.
So the two views, the two ways of looking at things, do seem
to me to make a difference.
Notice this question, whether Nixon could not have been a
human being, is a clear case where the question asked is not
epistemological. Suppose Nixon actually turned out to be an
automaton. That might happen. We might need evidence
whether Nixon is a human being or an automaton. But that is
a question about our knowledge. The question of whether
Nixon might have not been a human being, given that he is
one, is not a question about knowledge, a posteriori or a priori.
It's a question about, even though such and such things are
the case, what might have been the case otherwise.
This table is composed of molecules. Might it not have been
omposed of molecules? Certainly it was a scientific discover
f great moment that it was composed of molecules (o
atoms). But could anything be this very object and not be
composed of molecules? Certainly there is some feeling that
the answer to that must be 'no'. At any rate, it's hard to imagine
under what circumstances you would have this very object and
find that it is not composed of molecules. A quite different
question is whether it is in fact composed of molecules in the
actual world and how we know this. (I will go into more
detail about these questions about essence later on.)
I wish at this point to introduce something which I need in
the methodology of discussing the theory of names that I'm
talking about. We need the notion of identity across possible
worlds' as it's usually and, as I think, somewhat mislcadingly

48
called, 1° to explicate one distinction that I want to make now.
What's the difference between asking whether it's necessary
that 9 is greater than 7 or whether it's necessary that the
number of plancts is greater than 7? Why does one show anything more about cssence than the other? The answer to this
might be intuitively 'Well, look, the number of planets might
have been different from what it in fact is. It doesn't make any
sense, though, to say that nine might have been different from
what it in fact is. Let's use some termis quasi-technically. Let's
call something a rigid designator if in every possible world it
designates the same object, a nonrigid or accidental designator if
that is not the casc. Of course we don't require that the objects
exist in all possible worlds. Certainly Nixon might not have
existed if his parents had not gotten married, in the normal
course of things. When we think of a property as essential to
an object we usually mean that it is true of that object in any
case where it would have existed. A rigid designator of a
necessary existent can be called strongly rigid.
One of the intuitive theses I will maintain in these talks is
that names are rigid designators. Certainly they seem to satisfy
the intuitive test mentioned above: although someone other
than the U.S. President in 1970 might have been the U.S.
President in 1970 (c.g., Humphrey might have), no one other
than Nixon might have been Nixon. In the same way, a
1s Misleadingly, because the phrase suggests that there is a special problem of
"transworld identification', that we cannot trivially stipulate whom or what
we are talking about when we imagine another possible world. The term
"possible world' may also mislead; perhaps it suggests the "foreign country"
picture. I have sometimes used 'counterfactual situation' in the text; Michael
Slote has suggested that 'possible state (or history) of the world' might be less
misleading than "possible world'. It is better still, to avoid confusion, not to say,
In some possible world, Humphrey would have won' but rather, simply,
'Humphrey might have won'. The apparatus of possible words has (I hope)
been very useful as far as the set-theoretic model-theory of quantified modal
logic is concerned, but has encouraged philosophical pseudo-problems and
misleading pictures.
49
designator rigidly designates a certain object if it designates
that object wherever the object exists; if, in addition, the object
is a necessary existent, the designator can be called strongly rigid.
For example, 'the President of the U.S. in 1970' designates a
certain man, Nixon; but someone else (e.g., Humphrey) might
have been the President in 1970, and Nixon might not have;
so this designator is not rigid.
In these lectures, I will argue, intuitively, that proper names
are rigid designators, for although the man (Nixon) might not
have been the President, it is not the case that he might not
have been Nixon (though he might not have been called
'Nixon'). Those who have argued that to make sense of the
notion of rigid designator, we must antecedently make sense
of 'criteria of transworld identity' have precisely reversed the
cart and the horse; it is because we can refer (rigidly) to Nixon,
and stipulate that we are speaking of what might have happened
to him (under certain circumstances), that 'transworld identifications are unproblematic in such cases.1°
The tendency to demand purely qualitative descriptions of
counterfactual situations has many sources. One, perhaps, is
the confusion of the epistemological and the metaphysical,
between a prioricity and necessity. If someone identifies
necessity with a prioricity, and thinks that objects are named
by means of uniquely identifying properties, he may think
that it is the properties used to identify the object which, being
known about it a priori, must be used to identify it in all
possible worlds, to find out which object is Nixon. As against
this, I repeat: (1) Generally, things aren't "found out' about a
counterfactual situation, they are stipulated; (z) possible worlds
1 Of course I don't imply that language contains a name for every object.
Demonstratives can be used as rigid designators, and free variables can he used
as rigid designators of unspecified objects. Of course when we specify a
counterfactual situation, we do not describe the whole possible world, but
only the portion which interests us.

need not be given purely qualitatively, as if we were looking at
them through a telescope. And we will see shortly that the properties an object has in every counterfactual world have nothing
to do with properties used to identify it in the actual world."
Does the "problem' of 'transworld identification' make any
sense? Is it simply a pseudo-problem? The following, it seems
to me, can be said for it. Although the statement that England
fought Germany in 1943 perhaps cannot be reduced to any
statement about individuals, nevertheless in some sense it is
not a fact 'over and above' the collection of all facts about
persons, and their behavior over history. The sense in which
facts about nations are not facts 'over and above' those about
persons can be expressed in the observation that a description
of the world mentioning all facts about persons but omitting
those about nations can be a complete description of the world,
from which the facts about nations follow. Similarly, perhaps,
facts about material objects are not facts 'over and above' facts
about their constituent molecules. We may then ask, given a
description of a non-actualized possible situation in terms of
people, whether England still exists in that situation, or whether
a certain nation (described, say, as the one where Jones lives)
which would exist in that situation, is England. Similarly, given
certain counterfactual vicissitudes in the history of the molecules
of a table, T, one may ask whether T would exist, in that
situation, or whether a certain bunch of molecules, which in
that situation would constitute a table, constitute the very same
table T. In each case, we seck criteria of identity across possible
worlds for certain particulars in terms of those for other, more
"basic', particulars. If statements about nations (or tribes) are
not reducible to those about other more "basic' constituents, if
there is some 'open texture' in the relationship between them,
we can hardly expect to give hard and fast identity criteria;
1' See Lecture I, p. 53 (on Nixon), and Lecture II, pp. 74-7.
SI
nevertheless, in concrete cases we may be able to answer
whether a certain bunch of molecules would still constitute T,
though in some cases the answer may be indeterminate. I think
similar remarks apply to the problem of identity over time;
here too we are usually concerned with determinacy, the
identity of a 'complex' particular in terms of more "basic' ones.
(For example, if various parts of a table are replaced, is it the
same object?)
Such a conception of 'transworld identification, however,
differs considerably from the usual one. First, although we can
try to describe the world in terms of molecules, there is no
impropriety in describing it in terms of grosser entities: the
statement that this table might have been placed in another
room is perfectly proper, in and of itself. We need not use the
description in terms of molecules, or even grosser parts of the
table, thouglı we may. Unless we assume that some particulars
are 'ultimate', "basic' particulars, no type of description need
be regarded as privileged. We can ask whether Nixon might
have lost the election without further subtlety, and usually no
further subtlety is required. Second, it is not assumed that
necessary and sufficient conditions for what kinds of collections
18 There is some vagueness here. If a chip, or molecule, of a given table had
been replaced by another one, we would be content to say that we have the
same table. But if too many chips were different, we would seem to have a
different one. The same problem can, of course, arise for identity over time.
Where the identity relation is vague, it may seem intransitive; a chain of
apparent identities may yield an apparent non-identity. Some sort of 'counterpart notion (though not with Lewis's philosophical underpinnings
of
resemblance, foreign country worlds, etc.), may have some utility here. One
could say that strict identity applies only to the particulars (the molecules), and
the counterpart relation to the particulars 'composed' of them, the tables. The
counterpart relation can then be declared to be vague and intransitive. It
seems, however, utopian to suppose that we will ever reach a level of ultimate,
basic particulars for which identity relations are never vague and the danger of
intransitivity is eliminated. The danger usually does not arise in practice, so
we ordinarily can speak simply of identity without worry. Logicians have not
developed a logic of vagueness.

of molecules make up this table are possible; this fact I just
mentioned. Third, the attempted notion deals with criteria of
identity of particulars in terms of other particulars, not qualities.
I can refer to the table before me, and ask what might have
happened to it under certain circumstances; I can also refer to
its molecules. If, on the other hand, it is demanded that I
describe each counterfactual situation purely qualitatively, then
I can only ask whether a table, of such and such color, and so on,
would have certain properties; whether the table in question
would be this table, table T, is indeed moot, since all reference
to objects, as opposed to qualities, has disappcared. It is often
said that, if a counterfactual situation is described as one which
would have happened to Nixon, and if it is not assumed that
such a description is reducible to a purely qualitative onc, then
mysterious 'bare particulars' are assumed, propertyless substrata underlying the qualities. This is not so: I think that Nixon
is a Republican, not merely that he lies in back of Republicanism, whatever that means; I also think he might have been a
Democrat. The same holds for any other properties Nixon
may possess, except that some of these properties may be
essential. What I do deny is that a particular is nothing but a
'bundle of qualities', whatever that may miean. If a quality is
an abstract object, a bundle of qualities is all object of an even
higher degree of abstraction, not a particular. Philosophers
have come to the opposite view through a false dilemma: they
have asked, are these objects behind the bundle of qualities, or
is the object nothing but the bundle? Neither is the case; this
table is wooden, brown, in the room, etc. It has all these
properties and is not a thing without properties, behind them;
but it should not therefore be identified with the set, or 'bundle',
of its properties, nor with the subset of its essential properties.
Don't ask: how can I identify this table in another possible
world, except by its properties? I have the table in my hands,
I can point to it, and when I ask whether it might have been in
53
another room, I am talking, by definition, about it. I don't
have to identify it after seeing it through a telescope. If I am
talking about it, I am talking about it, in the same way as when
I say that our hands might have been painted green, I have
stipulated that I am talking about greenness. Some properties
of an object may be cssential to it, in that it could not have
failed to have them. But these properties are not used to
identify the object in another possible world, for such an
identification is not needed. Nor need the essential properties
of an object be the properties used to identify it in the actual
world, if indeed it is identified in the actual world by means of
properties (I have up to now left the question open).
So: the question of transworld identification makes some
sense, in terms of asking about the identity of an object via
questions about its component parts. But these parts are not
qualities, and it is not an object resembling the given one which
is in question. Theorists have often said that we identify objects
across possible worlds as objects resembling the given one in
the most important respects. On the contrary, Nixon, had he
decided to act otherwise, might have avoided politics like the
plague, though privately harboring radical opinions. Most
important, even when we can replace questions about an object
by questions about its parts, we need not do so. We can refer
to the object and ask what might have happened to it. So, we
do not begin with worlds (which are supposed somehow to be
real, and whose qualities, but not whose objects, are perceptible to us), and then ask about criteria of transworld
identification; on the contrary, we begin with the objects,
which we have, and can identify, in the actual world. We can
then ask whether certain things might have been true of the
objects.
Above I said that the Frege-Russell view that names are
introduced by description could be taken either as a theory of
the meaning of names (Frege and Russell seemed to take it this

S4
way) or merely as a theory of their reference. Let me give an
example, not involving what would usually be called a proper
name,' to illustrate this. Suppose someone stipulates that 100
degrees centigrade is to be the temperature at which water
boils at sea level. This isn't completely precise because the
pressure may vary at sea level. Of course, historically, a more
precise definition was given later. But let's suppose that this
were the definition. Another sort of example in the literature
is that one meter is to be the length of S where S is a certain
stick or bar in Paris. (Usually people who like to talk about these
defuitions then try to make 'the length of' into an 'opcrational"
concept. But it's not important.)
Wittgenstein says something very puzzling about this. He
says: "There is one thing of which one can say neither that it is
one meter long nor that it is not one meter long, and that is
the standard meter in Paris. But this is, of course, not to ascribe
any extraordinary property to it, but only to mark its peculiar
role in the language game of measuring with a meter rule.'"
This seems to be a very 'extraordinary property', actually, for
any stick to have. I think he must be wrong. If the stick is a
stick, for example, 39•37 inches long (I assume we have some
different standard for inches), why isn't it one meter long?
Anyway, let's suppose that he is wrong and that the stick is
one meter long. Part of the problem which is bothering
Wittgenstein is, of course, that this stick serves as a standard of
length and so we can't attribute length to it. Be this as it may
(well, it may not be), is the statement stick S is one meter
long', a necessary truth? Of course its length might vary in
time. We could make the definition more precise by stipulating
that one meter is to be the length of Sat a fixed time fo. Is it
then a necessary truth that stick S is one meter long at time to?
Someone who thinks that everything one knows a priori is
necessary might think: "This is the definition of a meter. By
10 Philosophical Investigations, $ so.
sS
definition, stick S is one meter long at fo. That's a necessary
truth.' But there seems to me to be no reason so to conclude,
even for a man who uses the stated definition of 'one meter'.
For he's using this definition not to give the meaning of what he
called the "meter', but to fix the reference. (For such an abstract
thing as a unit of length, the notion of reference may be
unclear. But let's suppose it's clear enough for the present
purposes.) He uses it to fix a reference. There is a certain length
which he wants to mark out. He marks it out by an accidental
property, namely that there is a stick of that length. Someone
else might mark out the same reference by another accidental
property. But in any case, even though he uses this to fix the
reference of his standard of length, a meter, he can still say, 'if
heat had been applied to this stick Sat fo, then at to stick S
would not have been one meter long.
Well, why can he do this? Part of the reason may lie in some
people's minds in the philosophy of science, which I don't want
to go into here. But a simple answer to the question is this:
Even if this is the only standard of length that he uses,?° there is
an intuitive difference between the phrase 'one meter' and the
phrase 'the length of S at to'. The first phrase is meant to
designate rigidly a certain length in all possible worlds, which
in the actual world happens to be the length of the stick S at fo.
On the other hand 'the length of S at to does not designate
anything rigidly. In some counterfactual situations the stick
might have been longer and in some shorter, if various stresses
and strains had been applied to it. So we can say of this stick,
the same way as we would of any other of the same substance
and length, that if heat of a given quantity had been applied to
it, it would have expanded to such and such a length. Such a
30 Philosophers of science may see the key to the problem in a view that
'one meter' is a 'cluster concepr. I am asking the reader hypothetically to
suppose that the 'definition' given is the only standard used to determine the
metric system. I think the problem would still arise.

56
counterfactual statement, being true of other sticks with
identical physical properties, will also be true of this stick.
There is no conflict t: ween that counterfactual statement and
the definition of 'one meter' as 'the length of S at to', because
the "definition", properly interpreted, does not say that the
phrase 'one meter' is to be synonymous (even when talking about
counterfactual situations) with the phrase 'the length of S at
to, but rather that we have determined the reference of the phrase
'one meter' by stipulating that 'one meter' is to be a rigid
designator of the length which is in fact the length of S at to.
So this does not make it a necessary truth that S is one meter
long at fo. In fact, under certain circumstances, S would not
have been one meter long. The rcason is that one designator
('one meter') is rigid and the other designator ('the length of
Sat to') is not.
What then, is the epistemological status of the statement Stick
S is one meter long at fo', for someone who has fixed the metric
systenı by reference to stick S? It would scem that he knows it
a priori. For if he used stick S to fix the reference of the term
'one meter', then as a result of this kind of "definition' (which
is not an abbreviative or synonymous definition), he knows
automatically, without further investigation, that S is one
meter long." On the other hand, even if S is used as the
standard of a meter, the metaphysical status of 'S is one meter
long' will be that of a contingent statement, provided that
"one meter' is regarded as a rigid designator: under appropriate
stresses and strains, heatings or coolings, S would have had a
length other than one meter even at fo. (Such statements as
'Water boils at 100°C at sea levl' can have a similar status.)
So in this sense, there are contingent a priori truths. More
important for present purposes, though, than accepting this
= Since the truth he knows is contingent, I choose not to call it 'analytic",
stipulatively requiring analytic truths to be both necessary and a priori. See
footnote 63.
57
example as an instance of the contingent a priori, is its illustration of the distinction between 'definitions' which fix a
reference and those which give a synonym.
In the case of names one might make this distinction too.
Suppose the reference of a name is given by a description or a
cluster of descriptions. If the name means the same as that
description or cluster of descriptions, it will not be a rigid
designator. It will not necessarily designate the same object in
all possible worlds, since other objects might have had the
given properties in other possible worlds, unless (of course) we
happened to usc essential properties in our description. So
suppose we say,
'Aristotle is the greatest man who studied
with Plato'. If we used that as a definition, the name 'Aristotle'
is to mean 'the greatest man who studied with Plato'. Then
of course in some other possible world that man night not
have studied with Plato and some other man would have
been Aristotle. If, on the other hand, we merely use the
description to fix the referent then that man will be the referent
of 'Aristotle' in all possible worlds. The only use of the description will have been to pick out to which man we mean to
refer. But then, when we say counterfactually suppose Aristotle
had never gone into philosophy at all', we need not mean
"suppose a man who studied with Plato, and taught Alexander
the Great, and wrote this and that, and so on, had never gone
into philosophy at all', which might seem like a contradiction.
We need only mean,
'suppose that that man had never gone
into philosophy at all'.
It seems plausible to suppose that, in some cases, the reference
of a name is indeed fixed via a description in the same way that
the metric system was fixed. When the mythical agent first
saw Hesperus, he may well have fixed his reference by saying,
'I shall use "Hesperus" as a name of the heavenly body appcaring in yonder position in the sky. He then fixed the reference
of 'Hesperus' by its apparent celestial position. Does it follow

58
that it is part of the meaning of the name that Hesperus has
such and such position at the time in question? Surely not:
if Hesperus had been hit earlier by a comet, it might have
been visible at a different position at that time. In such a
counterfactual situation we would say that Hesperus would
not have occupied that position, but not that Hesperus would
not have been Hesperus. The reason is that "Hesperus' rigidly
designates a certain heavenly body and 'the body in yonder
position' does not—a different body, or no body might have
been in that position, but no other body might have been
Hesperus (though another body, not Hesperus, might have
been called 'Hesperus'). Indeed, as I have said, I will hold that
names are always rigid designators.
Frege and Russcll certainly seem to have the full blown
theory according to which a proper name is not a rigid
designator and is synonymous with the description which
replaced it. But another theory might be that this description
is used to determine a rigid reference. These two alternatives
will have different consequences for the questions I was asking
before. If 'Moses' means 'the man who did such and such",
then, if no one did such and such, Moses didn't exist; and maybe 'no one did such and such' is even an analysis of "Moses
didn't exist. But if the description is used to fix a reference
rigidly, then it's clear that that is not what is meant by 'Moses
didn't exist", because we can ask, if we speak of a counterfactual case where no one did indeed do such and such, say,
lead the Israclites out of Egypt, does it follow that, in such a
situation, Moses wouldn't have existed? It would seem not.
For surely Moses might have just decided to spend his days
more pleasantly in the Egyptian courts. He might never have
gone into either politics or religion at all; and in that case
maybe no one would have done any of the things that the
Bible relates of Moses. That doesn't in itself mean that in such
a possible world Moses wouldn't have existed. If so, then
59
'Moses exists' means something different from 'the existence
and uniqueness conditions for a certain description are fulfilled'; and therefore this does not give an analysis of the
singular existential statement after all. If you give up the idea
that this is a theory of meaning and make it into a theory of
reference in the way that I have described, you give up some
of the advantages of the theory. Singular existential statements
and identity statements between names need some other
analysis.
Frege should be criticized for using the term "sense' in two
senses. For he takes the sense of a designator to be its meaning;
and he also takes it to be the way its reference is determined.
Identifying the two, he supposes that both are given by definite
descriptions. Ultimately, I will reject this second supposition
too; but even were it right, I reject the first. A description may
be used as synonymous with a designator, or it may be used to
fix its reference. The two Fregean senses of "sense' correspond
to two senses of 'definition' in ordinary parlance. They should
carefully be distinguished.
" Usually the Fregean sense is now interpreted as the meaning, which must
be carefully distinguished from a 'reference fixer'. We shall see below that
for most spcakers, unless they are the ones who initially give an object its
name, the referent of the name is determined by a 'causal' chain of communication rather than a description.
In the formal semantics of modal logic, the 'sense' of a term f is usually taken
to be the (possibly partial) function which assigns to cach possible world H the
referent of t in H. For a rigid designator, such a function is constant. This
notion of 'sense' relates to that of 'giving a meaning', not that of fixing a
reference. In this use of "sense", 'one meter" has a constant function as its sense,
though its reference is fixed by 'the length of S, which does not have a
constant function as its sense.
Some philosophers have thought that descriptions, in English, are ambiguous, that sometimes they non-rigidly designate, in each world, the object
(if any) satisfying the description, while sometimes they rigidly designate the
object actually satisfying the description. (Others, inspired by Donnellan, say
the description sometimes rigidly designates the object thought or presupposed
to satisfy the description.) I find any such alleged ambiguities dubious. I know

60
I hope the idea of fixing the reference as opposed to actually
defining one term as meaning the other is somewhat clear.
There is really not enough time to go into everything in great
detail. I think, even in cases where the notion of rigidity versus
accidentality of designation cannot be used to make out the
difference in question, some things called definitions really
intend to fix a reference rather than to give the meaning of a
phrase, to give a synonym. Let me give an example. a is
supposed to be the ratio of the circumference of a circle to its
diameter. Now, it's something that I have nothing but a vague
intuitive feeling to argue for: It seems to me that here this
Greek letter is not being used as short for the phrase 'the ratio
of the circumference of a circle to its diameter' nor is it even
used as short for a cluster of alternative definitions of t, whatever that might mean. It is used as a name for a real number,
which in this case is necessarily the ratio of the circumference
of a circle to its diameter. Note that here both 't' and 'the ratio
of the circumference of a circle to its diameter'
are rigid
designators, so the arguments given in the metric case are
inapplicable. (Well, if someone doesn't see this, or thinks it's
wrong, it doesn't matter.)
Let me return to the question about names which I raised.
As I said, there is a popular modern substitute for the theory of
Frege and Russell; it is adopted even by such a strong critic of
many views of Frege and Russell, especially the latter, as
of no clear evidence for them which cannot be handled either by Russell's
notion of scope or by the considerations alluded to in footnote 3, p. 25.
If the ambiguity does exist, then in the supposed rigid sense of the length of
S', 'one meter' and 'the length of S' designate the same thing in all possible
worlds and have the same (functional) sense.
In the formal semantics of intensional logic, suppose we take a definite
description to designate, in each world, the object satisfying the description.
It is indeed useful to have an operator which transforms cach description into
a term which rigidly designates the object actually satisfying the description.
David Kaplan has proposed such an operator and calls it 'Dthat.
6I
Strawson." The substitute is that, although a name is not a
disguised description it either abbreviates, or anyway its
reference is determined by, some cluster of descriptions. The
question is whether this is true. As I also said, there are stronger
and weaker versions of this. The stronger version would say
that the name is simply defined, synonymously, as the cluster of
descriptions. It will then be necessary, not that Moses had any
particular property in this cluster, but that he had the disjunction of them. There couldn't be any counterfactual situation in which he didn't do any of those things. I think it's clear
that this is very implausible. People have said it—or maybe they
haven't been intending to say that, but were using 'necessary'
in some other sense. At any rate, for example, in Searle's article
on proper names:
To put the same point differently, suppose we ask, 'why do we have
proper names at all?' Obviously to refer to individuals. "Yes but
descriptions could do that for us'. But only at the cost of specifying
identity conditions every time reference is made: Suppose
agree to drop 'Aristotle' and use, say, 'the teacher of Alexander',
then it is a necessary truth that the man referred to is Alexander's
teacher-but it is a contingent fact that Aristotle ever went into
pedagogy (though I am suggesting that it is a necessary fact that
Aristotle has the logical sum, inclusive disjunction, of properties
commonly attributed to him)."
Such a suggestion, if 'necessary' is used in the way I have been
using it in this lecture, must clearly be false. (Unless he's got
me very interesting essential property commonly attribute
› Aristotle.) Most of the things commonly attributed t
Aristotle are things that Aristotle might not have done at all.
In a situation in which he didn't do them, we would describe
that as a situation in which Aristotle didn't do them. This is not
a distinction of scopc, as happens sometimes in the case of
*3 P. F. Strawson, Individuals, Methuen, London, 1959, Ch. 6.
"Searle, op. cit. in Caton, Philosophy and Ordinary Language, p. 160.

62
descriptions, where someone might say that the man who
taught Alexander might not have taught Alexander; though it
could not have been true that: the man who taught Alexander
didn't teach Alexander. This is Russell's distinction of scope. (I
won't go into it.) It seems to me clear that this is not the case
here. Not only is it true of the man Aristotle that he might not
have gone into pedagogy; it is also true that we use the term
"Aristotle' in such a way that, in thinking of a counterfactual
situation in which Aristotle didn't go into any of the fields and
do any of the achievements we commonly attribute to him,
still we would say that was a situation in which Aristotle did not
do these things.?5 Well there are some things like the date, the
period he lived in, that might be more imagined as necessary.
Maybe those are things we commonly attribute to him. There
are exceptions. Maybe it's hard to imagine how he could have
lived soo years later than he in fact did. That certainly raises at
least a problem. But take a man who doesn't have any idea of
the date. Many people just have some vague cluster of his
most famous achievements. Not only each of these singly, but
the possession of the entire disjunction of these properties,
is just a contingent fact about Aristotle; and the statement
25 The facts that 'the teacher of Alexander' is capable of scope distinctions
in modal contexts and that it is not a rigid designator are both illustrated when
one observes that the teacher of Alexander might not have taught Alexander
(and, in such circumstances, would not have been the teacher of Alexander).
On the other hand, it is not true that Aristotle might not have been Aristotle,
although Aristotle might not have been called 'Aristotle', just as 2 × 2 might
not have been called 'four'. (Sloppy, colloquial speech, which often confuses
use and mention, may, of course, express the fact that someone might have
been called, or not have been called, 'Aristotle' by saying that he might have
been, or not have been, Aristotlc. Occasionally, I have heard such loose usages
adduced as counterexamples to the applicability of the present theory to
ordinary language. Colloquialisms like these seem to me to create as little
problem for my theses as the success of the 'impossible Missions Force' creates
for the modal law that the impossible does not happen.) Further, although
under certain circumstances Aristotle would not have taught Alexander, these
are not circumstances under which he would not have been Aristore
63
that Aristotle had this disjunction of properties is a contingent
truth.
A man might know it a priori in some sense, if he in fact fixes
the reference of Aristotle as the man who did one of these
things. Still it won't be a necessary truth for him. So this sort of
example would be an example where a prioricity would not
necessarily imply necessity, if the cluster theory of names were
right. The case of fixing the reference of 'one meter' is a very
clear example in which someone, just because he fixed the
reference in this way, can in some sense know a priori that the
length of this stick is a meter without regarding it as a necessary
truth. Maybe the thesis about a prioricity implying necessity
can be modified. It does appear to state some insight which
might be important, and truc, about epistemology. In a way
an example like this may seem like a trivial counterexample
which is not really the point of what some people think when
they think that only necessary truths can be known a priori.
Well, if the thesis that all a priori truth is necessary is to be
immune from this sort of counterexample, it needs to be
modified in some way. Unmodified it leads to confusion about
the nature of reference. And I myself have no idea how it
should be modified or restated, or if such a modification or
restatement is possible.2
26 If someone fixes a meter as "the length of stick S at lo', then in some sense
he knows a priori that the length of stick S at 1, is one meter, even though he
uses this statement to express a contingent truth. But, merely by fixing a
system of measurement, has he thereby learned some (contingent) information
about the world, some new fact that he did not know before? It seems plausible
that in some sense he did not, even though it is undeniably a contingent fact
that S is one meter long. So there may be a case for reformulating the thesis
that everything a priori is necessary so as to save it from this type of counterexample. As I said, I don't know how such a reformulation would go; the
reformulation should not be such as to make the thesis trivial (e.g., by defining
a priori as known to be necessary (instead of truc) independently of experience);
and the converse thesis would still be false.
Since I will not attempt such a reformulation, I shall consistently use the

64
Let me state then what the cluster concept theory of names
is. (It really is a nice theory. The only defect I think it has is
probably common to all philosophical theories. It's wrong.
You may suspect me of proposing another theory in its place;
but I hope not, because I'm sure it's wrong too if it is a theory.)
The theory in question can be broken down into a number of
theses, with some subsidiary theses if you want to see how it
handles the problem of existence statements, identity statements, and so on. There are more theses if you take it in the
stronger version as a theory of meaning. The speaker is A.
(1) To every name or designating expression 'X', there
corresponds a cluster of properties, namely the family
of properties a such that A believes pX'.
This thesis is true, because it can just be a definition. Now, of
course, some people might think that not everything the
speaker believes about X has anything to do with determining the reference of 'X'. They might only be interested in a
subset. But we can handle this later on by modifying some of
the other theses. So this thesis is correct, by definition. The
theses that follow, however, are all, I think, false.
(2)
One of the properties, or some conjointly, are believed by A to pick out some individual uniquely.
This doesn't say that they do pick out something uniquely,
just that A believes that they do. Another thesis is that he is
correct.
(3) If most, or a weighted most, of the o's are satisfied by
one unique object y, then y is the referent of 'X'.
Well, the theory says that the referent of 'X' is supposed to be
the thing satisfying, if not all the properties, 'enough of them.
term 'a priori" in the text so as to make statements whose truth follows from a
referenco-fixing 'definition' a priori.
65
Obviously A could be wrong about some things about X. You
take some sort of a vote. Now the question is whether this vote
should be democratic or have some inequalities among the
properties. It seems more plausible that there should be some
weighting, that some properties are more important than
others. A theory really has to specify how this weighting goes.
I believe that Strawson, to my surprise, explicitly states that
democracy should rule here, so the most trivial properties are
of equal weight with the most crucial." Surely it is more
plausible to suppose that there is some weighting. Let's say
democracy doesn't necessarily rule. If there is any property
that's completely irrelevant to the reference we can disenfranchise it altogether, by giving it weight O. The properties can
be regarded as members of a corporation. Some have more
stock than others; some may even have only non-voting stock.
If the vote yields no unique object, 'X' does not refer.
(5) The statement, To eques ben has es no refere.
ø's' is known a priori by the speaker.
(б)
The statement, 'If X exists, then X has most of the
p's' expresses a necessary truth (in the idiolect of the
speaker).
(6) need not be a thesis of the theory if someone doesn't think
that the cluster is part of the meaning of the name. He could
think that though he determines the reference of "Aristotle' as
the man who had most of the o's, still there are certainly
possible situations in which Aristotle wouldn't have had most
of the o's.
As I indicated, there are some subsidiary theses, though I
won't go into them in detail. These would give the analyses of
singular existential statements like, '"Moses exists" means
# Strawson, op. cit., pp. I91-92. Strawson actually considers the case of
everal speakers, pools their properties, and takes a democratic (equally
weighted) vote. He requires only a sufficiently plurality, not a majority.

66
"enough of the properties o are satisfied"'. Even the man who
doesn't use the theory as a theory of meaning has some of these
theses. For example, subsidiary to thesis 4, we should say that
it is a priori true for the speaker that, if not cnough of the o's
are satisfied, then X does not exist. Only if he holds the view
as a theory of meaning, rather than of reference, would it also
be necessarily true that, if not enough of the o's are satisfied, X
does not exist. In any case it will be something he knows a
priori. (At least he will know it a priori provided he knows the
proper theory of names.) Then there is also an analysis of
identity statements along the same lines.
The question is, are any of these true? If true, they give a
nice picture of what's going on. Preliminary to discussing these
thescs, let me mention that, often, when people specify which
properties o are relevant, they seem to specify them wrongly.
That's just an incidental defect, though it is closcly related to
the arguments against the theory that I will give presently.
Consider the example from Wittgenstein. What does he say
the relevant properties are? 'When one says "Moses does not
exist",
, this may mean various things. It may mean: the
Israelites did not have a single Icader when they withdrew from
Egypt-or: their leader was not called Moses-or: there cannot
have been anyone who accomplished all that the Bible relates
of Moses...' The gist of all this is that we know a priori that,
if the Biblical story is substantially false, Moses did not exist. I
have already argued that the Biblical story does not give
necessary properties of Moses, that he might have lived without
doing any of these things. Here I ask whether we know a priori
that if Moses existed, he in fact did some or most of them. Is
this rcally the cluster of properties that we should use here?
Surely there is a distinction which is neglected in these kinds of
remarks. The Biblical story might have been a complete
legend, or it might have been a substantially false account of a
real person. In the latter case, it seems to me that a scholar
67
could say that he supposes that, though Moses did exist, the
things said of him in the Bible are substantially false. Such
things occur in this very field of scholarship. Suppose that
someone says that no prophet ever was swallowed by a big
fish or a whale. Does it follow, on that basis, that Jonah did
not exist? There still seems to be the question whether the
Biblical account is a legendary account of no person or a
legendary account built on a real person. In the latter case, it's
only natural to say that, though Jonah did exist, no one did the
things commonly related to him. I choose this case because
while Biblical scholars generally hold that Jonah did exist, the
account not only of his being swallowed by a big fish but even
going to Nineveh to preach or anything else that is said in the
Biblical story is assumed to be substantially false. But nevertheless there are reasons for thinking this was about a real prophet.
If I had a suitable book along with me I could start quoting out
of it: 'Jonah, the son of Amittai, was a real prophet, however
such and such and such'. There are independent reasons for
thinking this was not a pure legend about an imaginary
character but one about a rcal character.28
28 Sce, for example, H. L. Ginsberg, The Five Megilloth and Jonah, The
Jewish Publication Society of America, 1969, p. 114: "The "hero" of this tale,
the prophet Jonah the son of Amittai, is a historical personage ... (but) this
book is not history but fiction.' The scholarly consensus regards all details about
Jonah in the book as legendary and not even based on a factual substratum,
excepting the bare statement that he was a Hebrew prophet, which is hardly
uniquely identifying. Nor need he have been called "Jonah' by the Hebrews;
the 'J' sound does not exist in Hebrew, and Jonah's historical existence is
independent of whether we know his original Hebrew name or not. The fact
that we call him Jonah cannot be used to single him out without circularity.
The evidence for the historicity of Jonah comes from an independent reference
to him in II Kings; but such evidence could have been available in the absence
of any such other references-e.g., evidence that all Hebrew legends were
about actual personages. Further, the statement that Jonah is a legend about a
real person might have been true, even if there were no evidence for it. One
may say, 'The Jonah of the book never existed,' as one may say, 'The Hitler
of Nazi propaganda never existed.' As the quotation above shows, this usage

68
These examples could be modified. Maybe all we believe is
that the Bible relates of him that such and such. This gives us
another problem, because how do we know whom the Bible
is referring to? The question of our reference is thrown back
to the question of reference in the Bible. This leads to a condition which we ought to put in explicitly.
(C) For any successful theory, the account must not be circular. The
properties which are used in the vote must not themselves involve
the notion of reference in a way that it is ultimately impossible to
eliminatc.
Let me give an example where the noncircularity condition is
clearly violated. The following theory of proper names is due
to William Kneale in an article called 'Modality, De Dicto
and De Re'.2 It contains, I think, a clear violation of noncircularity conditions.
Ordinary proper names of people are not, as John Stuart Mill
supposed, signs without sense. While it may be informative to tell
a man that the most famous Greek philosopher was called Socrates,
it is obviously trifing to tell him that Socrates was called Socrates;
and the reason is simply that he cannot understand your use of the
word 'Socrates' at the beginning of your statement unless he already
knows that 'Socrates' means "The individual called "Socrates" ' 30
Jere we have a theory of the reference of proper names
Socrates' just means 'the man called "Socrates"! Actually, of
course, maybe not just one man can be called 'Socrates', and
need not coincide with the historian's view of whether Jonah ever existed.
Ginsberg is writing for the lay reader, who, he assumes, will find his statement
intelligible.
* In Ernest Nagel, Patrick Suppes, and Alfred Tarski, Logic, Methodology
and the Philosophy of Science: Proceedings of the 1960 International Congress,
Stanford University Press, 1962, 622-33.
30 Loc. cit., pp. 629-30.
69
some may call him "Socrates' while others may not. Certainly
that is a condition which under some circumstances is uniquely
satisfied. Maybe only one man was called 'Socrates' by me on
a certain occasion.
Kneale says it's trifling to tell someone that Socrates was
called 'Socrates'. That isn't trifling on any view. Maybe the
Greeks didn't call him 'Socrates'. Let's say that Socrates is
called 'Socrates' by us—-by me anyway. Suppose that's trifling.
(I find it surprising that Kneale uses the past tense here; it is
dubious that the Greeks did call him "Socrates'-at least, the
Greek name is pronounced differently. I will check the accuracy
of the quotation for the next lecture.)
Kneale gives an argument for this theory. 'Socrates' must
be analyzed as 'the individual called "Socrates"', because how
else can we explain the fact that it is trifling to be told that
Socrates is called 'Socrates? In some cases that's rather trifling.
In the same sense, I suppose, you could get a good theory of
the meaning of any expression in English and construct a
dictionary. For example, though it may be informative to tell
someone that horses are used in races, it is trifling to tell him
that horses are called 'horses'. Therefore this could only be the
case because the term 'horse', means in English 'the things
called "horses". Similarly with any other expression which
might be used in English. Since it's trifling to be told that
sages are called "sages', "sages' just means 'the people called
"sages"'. Now plainly this isn't really a very good argument,
nor can it therefore be the only explanation of why it's trifling
to be told that Socrates is called 'Socrates'. Let's not go into
exactly why it's trifling. Of course, anyone who knows the
use of 'is called' in English, even without knowing what the
statement means, knows that if 'quarks' means something
hen 'quarks are called "quarks"" will express a truth. He may
not know what truth it expresses, because he doesn't know
what a guark is. But his knowledge that it expresses a truth

70
does not have much to do with the meaning of the term
'quarks".
We could go into this actually at great length. There are
interesting problems coming out of this sort of passage. But
the main rcason I wanted to introduce it here is that as a theory
of reference it would give a clear violation of the noncircularity
condition. Somcone uses the name 'Socrates'. How are we
supposed to know to whom he refers? By using the description
which gives the sense of it. According to Kncalc, the description
is 'the man called "Socrates"'. And here, (presumably, since
this is supposed to be so trifling!) it tells us nothing at all.
Taking it in this way it seems to be no theory of reference at all.
Weask, 'To whom does he refer by "Socrates"?' And then the
answer is given, 'Well, he refers to the man to whom he refers.
If this were all there was to the meaning of a proper name, then
no reference would get off the ground at all.
So there's a condition to be satisfied; in the case of this particular theory it's obviously unsatisfied. The paradigm,
amazingly enough, is even sometimes used by Russell as the
descriptive sense, namely: 'the man called "Walter Scott"'.
Obviously if the only descriptive senses of names we can
think of are of the form 'the man called such and such', 'the
then willed Vice so in i raily sens."
the reference and not any description like 'the man called
"Socrates" .
LECTURE II: JANUARY 22, 1970
Last time we ended up talking about a theory of naming which
is given by a number of theses here on the board.
I) To every name or designating expression 'X', there
corresponds a cluster of properties, namely the family
of those propertics o such that A believes oX'.
One of the propertics, or some conjointly, are believed by A to pick out some individual uniquely.
(3)
If most, or a weighted most, of the o's are satisfied by
one unique object y, then y is the referent of 'X'.
(4)
(s)
If the vote yields no unique object, 'X' does not refer.
The statement, 'If X exists, then X has most of the p's'
is known a priori by the speaker.
(6)
The statement, 'If X exists, then X has most of the
o's expresses a necessary truth (in the idiolect of the
spcaker).
(C) For any successful theory, the account must not be
circular. The properties which are used in the vote
must not themsclves involve the notion of reference
in such a way that it is ultimately impossible to
eliminate.
(C) is not a thesis but a condition on the satisfaction of the other
theses. In other words, Theses (1) -(6) cannot be satisfied in a
way which leads to a circle, in a way which does not lead to
any independent determination of reference. The example I

72
gave last time of a blatantly circular attempt to satisfy these
conditions was a theory of names mentioned by William
Kneale. I was a little surprised at the statement of the theory
when I was reading what I had copied down, so I looked it up
again. I looked it up in the book to see if I'd copied it down
accurately. Kneale did use the past tense. He said that though
it is not trifling to be told that Socrates was the greatest
philosopher of ancient Greece, it is trifling to be told that
Socrates was called 'Socrates'. Therefore, he concludes, the
name "Socrates' must simply
mean 'the individual called
"Socrates"'. Russell, as I've said, in some places gives a similar
analysis. Anyway, as stated using the past tense, the condition
wouldn't be circular, because one certainly could decide to
use the term "Socrates' to refer to whoever was called 'Socrates'
by the Greeks. But, of course, in that sense it's not at all trifling
to be told that Socrates was called 'Socrates'. If this is any kind
of fact, it might be false. Perhaps we know that we call him
"Socrates'; that hardly shows that the Greeks did so. In fact, of
course, they may have pronounced the name differently. It
may be, in the case of this particular name, that transliteration
from the Greek is so good that the English version is not
pronounced very differently from the Greek. But that won't
be so in the general case. Certainly it is not trifling to be told
that Isaiah was called "Isaiah'. In fact, it is false to be told that
Isaiah was called 'Isaiah'; the prophet wouldn't have recognized
this name at all. And of course the Greeks didn't call their
country anything like 'Greece'. Suppose we amend the thesis
so that it reads: it's trifling to be told that Socratcs is called
'Socrates' by us, or at least, by me, the speaker. Then in some
sense this is fairly trifling. I don't think it is necessary or analytic.
In the same way, it is trifling to be told that horses are called
"horses', without this leading to the conclusion that the word
'horse' simply means 'the animal called a "horse"'. As a theory
of the reference of the name 'Socrates' it will lead immediately
73
to a vicious circle. If one was determining the referent of a
name like 'Glunk' to himself and made the following decision,
'I shall use the term "Glunk" to refer to the man that I call
"Glunk"", this would get one nowhere. One had better have
some independent determination of the referent of 'Glunk'.
This is a good example of a blatantly circular determination.
Actually sentences like 'Socrates is called "Socrates"' are very
interesting and one can spend, strange as it may seem, hours
talking about their analysis. I actually did, once, do that. I
won't do that, however, on this occasion. (See how high the
seas of language can rise. And at the lowest points too.) Anyway
this is a useful example of a violation of the noncircularity
condition. The theory will satisfy all of these statements,
perhaps, but it satisfies them only because there is some
independent way of determining the reference independently
of the particular condition: being the man called 'Socrates'.
I have already talked about, in the last lecture, Thesis (6).
Theses (s) and (6), by the way, have converses. What I said for
Thesis (5) is that the statement that if X exists, X has most of
the p's, is a priori true for the speaker. It will also be true under
the given theory that certain converses of this statement hold
true also a priori for the speaker, namely: if any unique thing
has most of the properties o in the properly weighted sense,
it is X. Similarly a certain converse to this will be necessarily
true, namely: if anything has most of the properties o in the
properly weighted sense, it is X. So really one can say that it is
both a priori and necessary that something is X if and only if it
uniquely has most of the properties o. This really comes from
the previous Theses (I)-(4), I supposc. And (s) and (6) really
just say that a sufficiently reflective speaker grasps this theor!
of proper names. Knowing this, he therefore sces that (s) and
(6) are true. The objections to Theses (s) and (6) will not be
that some speakers are unaware of this theory and therefore
don't know these things.

74
What I talked about in the last lecture is Thesis (6). It's been
observed by many philosophers that, if the cluster of properties
associated with a proper name is taken in a very narrow sense,
so that only one propcrty is given any weight at all, let's say one
definite description to pick out the referent—for example,
Aristotle was the philosopher who taught Alexander the
Great-then certain things will seem to turn out to be necessary
truths which are not necessary truths—in this case, for example,
that Aristotle taught Alexander the Great. But as Searle said,
it is not a necessary truth but a contingent one that Aristotle
ever went into pedagogy. Therefore, he concludes that one
must drop the original paradigm of a single description and
turn to that of a cluster of descriptions.
To summarize some things that I argued last tinie, this is not
the correct answer (whatever it may be) to this problem about
necessity. For Searle goes on to say,
Suppose we agree to drop "Aristotle' and use, say, 'the teacher of
Alexander', then it is a necessary truth that the man referred to is
Alexander's teacher—-but it is a contingent fact that Aristotle ever
went into pedagogy, though I am suggesting that it is a necessary
fact that Aristotle has the logical sum, inclusive disjunction, of
properties commonly attributed to him... 31
This is what is not so. It just is not, in any intuitive sense of
necessity, a necessary truth that Aristotle had the properties
conmonly attributed to him. There is a certain theory, perhaps
popular in some views of the philosophy of history, which
might both be deterministic and yet at the same time assign a
great role to the individual in history. Perhaps Carlyle would
associate with the meaning of the name of a great man his
achievements. According to such a view it will be necessary,
once a certain individual is born, that he is destined to perform
31 Searle, 'Proper Names, in Caton, op. cit., p. 160.
75
various great tasks and so it will be part of the very nature of
Aristotle that he should have produced ideas which had a great
influence on the western world. Whatever the merits of such
a view may be as a view of history or the nature of great men,
it does not seem that it should be trivially true on the basis of a
theory of proper names. It would seem that it's a contingent
fact that Aristotle ever did any of the things commonly
attributed to him today, any of these great achievements that
we so much admire. I must say that there is something to this
fecling of Searle's. When I hear the name 'Hitler', I do get an
illusory 'gut feeling' that it's sort of analytic that that man was
evil. But really, probably not. Hitler might have spent all his
days in quiet in Linz. In that case we would not say that then
this man would not have been Hitler, for we use the name
'Hitler' just as the name of that man, even in describing other
possible worlds. (This is the notion which I called a rigid
designator in the previous talk.) Suppose we do decide to pick
out the reference of 'Hitler', as the man who succeeded in
having more Jews killed than anyone else managed to do in
history. That is the way we pick out the reference of the
name; but in another counterfactual situation where some one
else would have gained this discredit, we wouldn't say that in
that case that other man would have been Hitler. If Hitler had
never come to power, Hitler would not have had the property
which I am supposing we use to fix the reference of his name.
Similarly, even if we define what a meter is by reference to
the standard meter stick, it will be a contingent truth and not a
necessary one that that particular stick is one meter long. If it
had been stretched, it would have been longer than one meter.
And that is because we use the term
'one meter' rigidly to
designate a certain length. Even though we fix what length
we are designating by an accidental property of that length,
just as in the case of the name of the man we may pick the man
out by an accidental property of the man, still we use the name

76
to designate that man or that length in all possible worlds. The
property we use need not be one which is regarded in any way
as necessary or essential. In the case of a yard, the original way
this length was picked out was, I think, the distance when
the arm of King Henry I of England was outstretched from
the tip of his finger to his nose. If this was the length of a yard,
it nevertheless will not be a necessary truth that the distance
between the tip of his finger and his nose should be a yard.
Maybe an accident might have happened to foreshorten his
arm; that would be possible. And the reason that it's not a
necessary truth is not that there might be other criteria in a
"cluster concept' of yardhood. Even a man who strictly uses
King Henry's arm as his one standard of length can say,
counterfactually, that if certain things had happened to the
King, the exact distance between the end of one of his fingers
and his nose would not have been exactly a yard. He need not
be using a cluster as long as he uses the term 'yard' to pick
out a certain fixed reference to be that length in all possible
worlds.
These remarks show, I think, the intuitive bizarreness of a
good deal of the literature on 'transworld identification' and
counterpart theory'. For many theorists of these sorts, believing, as they do, that a 'possible world' is given to us only
qualitatively, argue that Aristotle is to be "identified in other
possible worlds', or alternatively that his counterparts are to be
identified, with those things in other possible worlds who most
closcly resemble Aristotle in his most important properties.
(Lewis, for example, says: "Your counterparts ... resemble
you.
..in important respects... more closely than do
the other things in their worlds... weighted by the importance of the various respects and by the degrees of the similarities.'32) Some may equate the important properties with those
33 D. Lewis, op. cit., pp. 114-IS.
77
properties used to identify the object in the actual world.
Surely these notions are incorrect. To me Aristotle's most
important properties consist in his philosophical work, and
Hitler's in his murderous political role; both, as I have said,
might have lacked these properties altogether. Surely there
was no logical fate hanging over either Aristotle or Hitler
which made it in any sense inevitable that they should have
possessed the properties we regard as important to thens; they
could have had careers completely different from their actual
ones. Important properties of an object need not be essential,
unless "importance' is used as a synonym for essence; and an
object could have had properties very different from its most
striking actual properties, or from the properties we use to
identify it.
To clear up one thing which some people have asked me:
When I say that a designator is rigid, and designates the same
thing in all possible worlds, I mean that, as used in our language,
it stands for that thing, when we talk about counterfactual
situations. I don't mean, of course, that there mightn't be
counterfactual situations in which in the other possible worlds
people actually spoke a different language. One doesn't say
that 'two plus two equals four' is contingent because people
might have spoken a language in which 'two plus two equals
four' meant that seven is even. Similarly, when we speak of a
counterfactual situation, we speak of it in English, even if it is
part of the description of that counterfactual situation that we
were all speaking German in that counterfactual situation. We
say, 'suppose we had all been speaking German' or 'suppose we
had been using English in a nonstandard way. Then we are
describing a possible world or counterfactual situation in which
people, including oursclves, did speak in a certain way different
from the way we speak. But still, in describing that world, we
use English with our meanings and our references. It is in this
sense that I speak of a rigid designator as having the same

78
reference in all possible worlds. I also don't mean to imply
that the thing designated exists in all possible worlds, just that
the name refers rigidly to that thing. If you say 'suppose Hitler
had never been born' then 'Hitler' refers here, still rigidly, to
something that would not exist in the counterfactual situation
described.
Given these remarks, this means we must cross off Thesis (6)
as incorrect. The other theses have nothing to do with necessity
and can survive. In particular Thesis (s) has nothing to do with
necessity and it can survive. If I use the name 'Hesperus' to
refer to a certain planetary body when seen in a certain celestial
position in the evening, it will not therefore be a necessary
truth that Hesperus is ever seen in the evening. That depends
on various contingent facts about people being there to see
and things like that. So even if I should say to myself that I will
use 'Hesperus' to name the heavenly body I see in the evening
in yonder position of the sky, it will not be necessary that
Hesperus was ever seen in the evening. But it may be a priori
in that this is how I have determined the referent. If I have
determined that Hesperus is the thing that I saw in the evening
over therc, then I will know, just from making that determination of the referent, that if there is any Hesperus at all it's
the thing I saw in the evening. This at least survives as far as
the arguments we have given up to now go.
How about a theory where Thesis (6) is eliminated? Theses
(z), (3), and (4) turn out to have a large class of counterinstances. Even when Theses (2)-(4) are true, Thesis (s) is usually
false; the truth of Theses (3) and (4) is an empirical 'accident',
which the speaker hardly knows a priori. That is to say, other
principles rcally determine the speaker's reference, and the
fact that the referent coincides with that determined by (2)-(4)
is an 'accident', which we were in no position to know a priori.
Only in a rare class of cases, usually initial baptisins, are all of
(2)-(s) true.
79
What picture of naming do these Theses ((t)-(s)) give you?
The picture is this. I want to name an object. I think of some
way of describing it uniquely and then I go through, so to
speak, a sort of mental ceremony: By 'Cicero' I shall mean the
man who denounced Catiline; and that's what the reference of
'Cicero' will be. I will use "Cicero' to designate rigidly the
man who (in fact) denounced Catiline, so I can speak of
possible worlds in which he did not. But still my intentions are
given by first, giving some condition which uniquely determines an object, then using a certain word as a name for the
object determined by this condition. Now there may be
some cases in which we actually do this. Maybe, if you want
to stretch and call it description, when you say: I shall call that
heavenly body over there 'Hesperus. 33 That is really a case
where the theses not only are true but really even give a correct
picture of how the reference is determined. Another case, if
you want to call this a name, might be when the police in
London use the name 'Jack' or 'Jack the Ripper' to refer to the
man, whoever he is, who committed all these murders, or
most of them. Then they are giving the reference of the name
33 An even better case of determining the reference of a name by description,
as opposed to ostension, is the discovery of the planet Neptune. Neptune was
hypothesized as the planet which caused such and such discrepancies in the
orbits of certain other planets. If Lewerrier indeed gave the name 'Neptune"
to the planet before it was ever seen, then he fixed the reference of 'Neptune'
by means of the description just mentioned. At that time he was unable to
see the planet even through a telescope. At this stage, an a priori material
equivalence held between the statements "Neptune exists' and 'some one
planet perturbing the orbit of such and such other planets exists in such and
such a position", and also such statements as 'if such and such perturbations are
caused by a planet, they are caused by Neptune' had the status of a priori
truths. Nevertheless, they were not necessary truths, since "Neptune was
introduced as a name rigidly designating a certain planet. Leverrier could well
have believed that if Neptune had been knocked off its course one million
years earlier, it would have caused no such perturbations and even that some
other object might have caused the perturbations in its place.

80
by a description.3 But in many or most cases, I think the
theses are false. So let's look at them.35
Thesis (1), as I say, is a definition. Thesis (2) says that one of
the properties believed by A of the object, or some conjointly,
are believed to pick out some individual uniquely. A sort of
example people have in mind is just what I said: I shall use the
term "Cicero' to denote the man who denounced Catiline (or
first denounced him in public, to make it unique). This picks
out an object uniqucly in this particular reference. Even some
writers such as Ziff in Semantic Analysis, who don't believe that
names have meaning in any sense, think that this is a good
picture of the way reference can be determined.
Let's see if Thesis (2) is true. It seems, in some a priori way,
that it's got to be true, because if you don't think that the
properties you have in mind pick out anyone uniquely-let's
say they're all satisfied by two people-then how can you say
which one of them you're talking about? There seem to be no
grounds for saying you're talking about the one rather than
about the other. Usually the properties in question are supposed
to be some famous deeds of the person in question. For
example, Cicero was the man who denounced Catiline. The
average person, according to this, when he refers to Cicero, is
3 Following Donnellan's remarks on definite descriptions, we should add
that in some cases, an object may be identified, and the refcrence of a name
fixed, using a description which may turn out to be false of its object. The
case where the reference of 'Phosphorus' is determined as the 'morning star",
which later turns out not to be a star, is an obvious example. In such cases, the
description which fixes the reference clearly is in no sense known a priori to
hold of the object, though a more cautious substitute may be. If such a more
cautious substitute is available, it is really the substitute which fixes the
reference in the sense intended in the text.
36 Some of the theses are sloppily stated in respect of fussy matters like use
of quotation marks and related details. (For example, Theses (s) and (6), as
stated, presuppose that the speaker's language is English.) Since the purport of
the theses is clear, and they are false anyway, I have not bothered to set these
things straight.
8I
saying something like 'the man who denounced Catiline' and
thus has picked out a certain man uniquely. It is a tribute to
the education of philosophers that they have held this thesis
for such a long time. In fact, most people, when they think
of Cicero, just think of a famous Roman orator, without any
pretension to think either that there was only one famous
Roman orator or that one must know something else about
Cicero to have a referent for the name. Consider Richard
Feynman, to whom many of us are able to refer. He is a leading
contemporary theoretical physicist. Everyone here (I'm sure!)
can state the contents of one of Feynman's theories so as to
differentiate him from Gell-Mann. However, the man in the
street, not possessing these abilities, may still use the name
'Feynman'. When asked he will say: well he's a physicist or
something. He may not think that this picks out anyone
uniquely. I still think he uses the name "Feynman' as a name
for Feynman.
But let's look at some of the cases where we do have a
description to pick out someone uniquely. Let's say, for example, that we know that Cicero was the man who first
denounced Catiline. Well, that's good. That really picks
someone out uniquely. However, there is a problens, because
this description contains another name, namely 'Catiline'. We
must be sure that we satisfy the conditions in such a way as to
avoid violating the noncircularity condition here. In particular,
we must not say that Catiline was the man denounced by
Cicero. If we do this, we will really not be picking out anything
uniquely, we will simply be picking out a pair of objects A and
B, such that A denounced B. We do not think that this was
the only pair where such denunciations ever occurred; so
we had better add some other conditions in order to satisfy
the uniqueness condition.
If we say Einstein was the man who discovered the theory of
relativity, that certainly picks out someone uniquely. One can

82
be sure, as I said, that everyone here can make a compact and
independent statement of this theory and so pick out Einstein
uniquely; but many people actually don't know enough about
this stuff, so when asked what the theory of relativity is, they
will say: "Einstein's theory', and thus be led into the most
straightforward sort of vicious circle.
So Thesis (z), in a straightforward way, fails to be satisfied
when we say Feynman is a famous physicist without attributing
anything else to Feynman. In another way it may not be
satisfied in the proper way even when it is satisfied: If we say
Einstein was 'the man who discovered relativity theory', that
docs pick someone out uniquely; but it may not pick him out
in such a way as to satisfy the noncircularity condition, because
the theory of relativity may in turn be picked out as Einstein's
theory'. So Thesis (z) seenis to be falsc.
By changing the conditions o from those usually associated
with names by philosophers, one could try to improve the
theory. There have been various ways I've heard; maybe I'll
discuss these later on. Usually they think of famous achievements of the man named. Certainly in the case of famous
achievements, the theory doesn't work. Some student of mine
once said, 'Well, Einstein discovered the theory of relativity';
and he determined the reference of the theory of relativity'
independently by referring to an encyclopedia which would
give the details of the theory. (This is what is called a transcendental deduction of the existence of encyclopedias.) But it
seems to me that, even if someone has heard of encyclopedias,
it really is not essential for his reference that he should know
whether this theory is given in detail in any encyclopedia. The
reference might work even if there had been no encyclopedias
at all.
Let's go on to Thesis (3): If most of the p's, suitably weighted,
are satisfied by a unique object y, then y is the referent of the
name for the speaker. Now, since we have already established
83
that Thesis (z) is wrong, why should any of the rest work? The
whole theory depended on always being able to specify
unique conditions which are satisfied. But still we can look at
the other theses. The picture associated with the theory is that
only by giving some unique properties can you know who
someone is and thus know what the reference of your name is.
Well, I won't go into the question of knowing who someone
is. It's really very puzzling. I think you do know who Cicero is
if you just can answer that he's a famous Roman orator.
Strangely enough, if you know that Einstein discovered the
theory of relativity and nothing about that theory, you can
both know who Einstein is, namely the discoverer of the
theory of relativity, and who discovered the theory of relativity,
namely Einstein, on the basis of this knowledge. This seems to
be a blatant violation of some sort of noncircularity condition;
but it is the way we talk. It therefore would seem that a picture
which suggests this condition must be the wrong picture.
Suppose most of theo's are in fact satisfied by a unique object.
Is that object necessarily the referent of 'X' for A? Let's suppose
someone says that Gödel is the man who proved the incompleteness of arithmetic, and this man is suitably well educated
and is even able to give an independent account of the incompleteness theorem. He doesn't just say, 'Well, that's
Gödel's theoren', or whatever. He actually states a certain
theorem, which he attributes to Gödel as the discoverer. Is it
the case, then, that if most of the p's are satisfied by a unique
object y, then y is the referent of the name 'X' for A? Let's take
a simple case. In the case of Gödel that's practically the only
thing many people have heard about him—-that he discovered
the incompleteness of arithmetic. Does it follow that whoever
discovered the incompleteness of arithmetic is the referent of
'Gödel'?
Imagine the following blatantly fictional situation. (I hope
Professor Gödel is not present.) Suppose that Gödel was not in

84
fact the author of this theorem. A man named "Schmidt',
whose body was found in Vienna under mysterious circumstances many years ago, actually did the work in question. His
friend Gödel somehow got hold of the manuscript and it was
thereafter attributed to Gödel. On the view in question, then,
when our ordinary man uses the name 'Gödel", he really means
to refer to Schmidt, because Schmidt is the unique person
satisfying the description, 'the man who discovered the incompleteness of arithmetic'. Of course you might try changing
it to the man who published the discovery of the incompleteness
of arithmetic'. By changing the story a litile further one can
make even this formulation false. Anyway, most people might
not even know whether the thing was published or got
around by word of mouth. Let's stick to 'the man who
discovered the incompleteness of arithmetic. So, since the
man who discovered the incompleteness of arithnietic is in fact
Schmidt, we, when we talk about "Gödel", are in fact always
referring to Schmidt. But it seems to me that we are not. We
simply are not. One reply, which I will discuss later, might be:
You should say instead, 'the man to whom the incompleteness
of arithmetic is commonly attributed', or something like that.
Let's see what we can do with that later.
But it may seem to many of you that this is a very odd
example, or that such a situation occurs rarely. This also is a
tribute to the education of philosophers. Very often we use a
name on the basis of considerable misinformation. The case of
mathematics used in the fictive example is a good case in point.
What do we know about Peano? What many people in this
room may 'know' about Peano is that he was the discoverer of
certain axioms which characterize the sequence of natural
numbers, the so-called 'Peano axioms. Probably some people
can even state them. I have been told that these axioms were
not first discovered by Peano but by Dedekind. Peano was of
course not a dishonest man. I am told that his footnotes
85
include a credit to Dedekind. Somehow the footnote has been
ignored. So on the theory in question the term 'Peano', as we
use it, really refers to-now that you've heard it you see that
you were really all the time talking about--Dedekind. But
you were not. Such illustrations could be multiplied indefinitely.
Even worse misconceptions, of course, occur to the layman.
In a previous example I supposed people to identify Einstein
by reference to his work on relativity. Actually, I often used to
hear that Einstein's most famous achievement was the invention
of the atomic bomb. So when we refer to Einstein, we refer
to the inventor of the atomic bomb. But this is not so. Columbus was the first man to realize that the earth was round. He
was also the first European to land in the western hemisphere.
Probably none of these things are true, and therefore, when
people use the term 'Columbus' they really refer to some
Greek if they use the roundness of the earth, or to some
Norseman, perhaps, if they use the 'discovery of America'.
But they don't. So it does not seem that if most of the o's are
satisfied by a unique object y, then y is the referent of the name.
This seems simply to be falsc. 36
3 The cluster-of-descriptions theory of naming would make 'Peano discovered the axioms for number theory' express a trivial truth, not a misconception, and similarly for other misconceptions about the history of
science. Some who have conceded such cases to me have argued that there are
other uses of the same proper names satisfying the cluster theory. For example,
it is argued, if we say, 'Gödel proved the incompleteness of arithmetic,' we
are, of course, referring to Gödel, not to Schmidt. But, if we say, 'Gödel
relied on a diagonal argument in this step of the proof,' don't we here, perhaps,
refer to whoever proved the theorem? Similarly, if someone asks, 'What did
Aristotle (or Shakespeare) have in mind here?", isn't he talking about the
author of the passage in question, whoever he is? By analogy to Donnellan's
usage for descriptions, this might be called an "attributive' use of proper
names. If this is so, then assuming the Gödel-Schmidt story, the sentence
"Gödel proved the incompleteness theorem' is false, but 'Gödel used a diagonal
argument in the proof' is (at least in some contexts) true, and the reference of
the name "Gödel" is ambiguous. Since some counterexamples remain, the

86
Thesis (4): If the vote yields no unique object the name does
not refer. Really this case has been covered before—has been
covered in my previous examples. First, the vote may not
yield a unique object, as in the case of Cicero or Feynman.
Secondly, suppose it yields no object, that nothing satisfies
most, or cven any, substantial number, of the p's. Does that
mean the name doesn't refer? No: in the same way that you
may have false beliefs about a person which may actually be
true of someone else, so you may have false beliefs which are
true of absolutely no onc. And these may constitute the totality
of your beliefs. Supposc, to vary the example about Gödel, no
one had discovered the incompleteness of arithmetic-perhaps
the proof simply materialized by a random scattering of atoms
on a piece of paper-the man Gödel being lucky enough to
have been present when this improbable event occurred.
Further, suppose arithmetic is in fact complete. One wouldn't
really expect a random scattering of atoms to produce a correct
proof. A subtle crror, unknown through the decades, has still
been unnoticed-or perhaps not actually unnoticed, but the
friends of Gödel.... So even if the conditions are not satisfied
cluster-of-descriptions theory would still, in general, be false, which was my
main point in the text; but it would be applicable in a wider class of cases than I
thought. I think, however, that no such ambiguity need be postulated. It is,
perhaps, true that sometimes when someone uses the name 'Gödel", his main
interest is in whoever proved the theorem, and perhaps, in some sense, he
'refers' to him. I do not think that this case is diffcrent from the case of Smith
and Jones in n. 3, p. 25. If I mistake Jones for Smith, I may refer (in an appropriate sense) to Jones when I say that Smith is raking the leaves; nevertheless I
do not use 'Smith' ambiguously, as a name sometimes of Smith and sometimes
of Jones, but univocally as a name of Smith. Similarly, if I crroneously think
that Aristotle wrote such-and-such passage, I may perhaps sometimes use
'Aristotle' to refer to the actual author of the passage, even though there is no
ambiguity in my use of the name. In both cases, I will withdraw my original
statement, and my original use of the name, if apprised of the facts. Recall
that, in these lectures, 'referent' is used in the technical sense of the thing
named by a name (or uniquely satisfying a description), and there should be
no Contion.
87
by a unique object the name may still refer. I gave you the
case of Jonah last weck. Biblical scholars, as I said, think that
Jonah really existed. It isn't because they think that someone
ever was swallowed by a big fish or even went to Nineveh
to preach. These conditions may be true of no one whatsoever and yet the name 'Jonah' really has a referent. In the
case above of Einstein's invention of the bomb, possibly
no one really deserves to be called the 'inventor' of the
device.
Thesis s says that the statement "If X exists, then X has most
of the p's', is a priori true for A. Notice that even in a case
where (3) and (4) happen to be true, a typical speaker hardly
knows a priori that they are, as required by the theory. I think
that my belief about Gödel is in fact correct and that the
"Schmidt' story is just a fantasy. But the belief hardly constitutes a priori knowledge.
What's going on here? Can we rescue the theory??? First,
one may try and vary these descriptions-not think of the
famous achievements of a man but, let's say, of something
elsc, and try and use that as our description. Maybe by enough
futzing around someone might eventually get something out
" It has been suggested to me that someone might argue that a name is
associated with a 'referential' use of a description in Donnellan's sense. For
example, although we identify Gödel as the author of the incompleteness
theorem, we are talking about him even if he turns out not to have proved the
theorem. Theses (2)-(6) could then fail; but nevertheless each name would
abbreviate a description, though the role of description in naming would
differ radically from that imagined by Frege and Russell. As I have said above,
I am inclined to reject Donnellan's formulation of the notion of referential
definite description. Even if Donnellan's analysis is accepted, however, it is
clear that the present proposal should not be. For a referential definite description, such as 'the man drinking champagne', is typically withdrawn when the
speaker realizes that it does not apply to its object. If a Gödelian fraud were
exposed, Gödel would no longer be called 'the author of the incompleteness
theorem' but he would still be called 'Gödel". The name, therefore, does not
abbreviate the description.

88
of this; 3 however, most of the attempts that one tries are open
to counterexamples or other objections. Let me give an
example of this. In the case of Gödel one may say,
'Well,
"Gödel" doesn't mean "the man who proved the incompleteness of arithmetic"'. Look, all we really know is that most
people think that Gödel proved the incompleteness of arithmetic, that Gödel is the man to whom the incompleteness of
arithmetic is commonly attributed. So when I determine the
referent of the name 'Gödel", I don't say to myself, 'by "Gödel"
I shall mean "the man who proved the incompleteness of
arithmetic, whoever he is"'. That might turn out to be
Schmidt or Post. But instead I shall mean 'the man who most
people think proved the incompleteness of arithmetic'.
Is this right? First, it seems to nie that it's open to counterexamples of the same type as I gave before, though the counterexamples may be more recherché. Suppose, in the case of
Peano mentioned previously, unbeknownst to the speaker,
most people (at least by now) thoroughly realize that the
number-thcoretic axioms should not be attributed to him.
Most people don't credit them to Peano but now correctly
ascribe them to Deckind. So then even the man to whom this
thing is commonly attributed will still be Dedekind and not
Peano. Still, the speaker, having picked up the old outmoded
38 As Robert Nozick pointed out to me, there is a sense in which a description theory must be trivially true if any theory of the reference of names,
spelled out in terms independent of the notion of reference, is availabie. For if
such a theory gives conditions under which an object is to be the referent of
a name, then it of course uniquely satisfies these conditions. Since I am not
pretending to give any theory which eliminates the notion of reference in
this sense, i am not aware of any such trivial fulfillment of the description theory
and doubt that one exists. (A description using the notion of the reference of a
name is easily available but circular, as we saw in our discussion of Kneale.) If
any such trivial fulfilment were available, however, the arguments I have
given show that the description must be one of a completely different sort
from that supposed by Frege, Russell, Searle, Strawson and other advocates of
the description theory.
89
belief, may still be referring to Peano, and hold a false belief
about Peano, not a true belief about Dedekind.
But second, and perhaps more significantly, such a criterion
violates the noncircularity condition. How is this? It is true
that most of us think that Gödel proved the incompleteness of
arithmetic. Why is this so? We certainly say, and sincerely,
'Gödel proved the incompleteness of arithmetic. Does it
follow
from that that we believe that Gödel proved the
incompleteness
of arithmetic-that we
attribute the incompleteness of arithmetic to this man? No. Not just from
that. We have to be referring to Gödel when we say 'Gödel
proved the incompleteness of arithmetic'. If, in fact, we were
always referring to Schmidt, then we would be attributing the
incompleteness of arithmetic to Schmidt and not to Gödelif we used the sound 'Gödel' as the name of the man whom I
amn calling "Schmidt'.
But we do in fact refer to Gödel. How do we do this? Well,
not by saying to ourselves, 'By "Gödel" I shall mean the man
to whom
the incompleteness of arithmetic is commonly
attributed'. If we did that we would run into a circle. Here we
are all in this room. Actually in this institution some people
have met the man, but in many institutions this is not so. All
of us in the community are trying to determine the reference
by saying 'Gödel is to be the man to whom the incompleteness
of arithmetic is commonly attributed'. None of us will get
started with any attribution unless there is some independent
criterion for the reference of the name other than 'the man to
whom the incompleteness of arithmetic is commonly attributed'. Otherwise all we will be saying is,
'We attribute this
achievement to the man to whom we attribute it, without
saying who that man is, without giving any independent
criterion of the refcrence, and so the determination will be
circular. This then is a violation of the condition I have
30 Princeton University.

90
marked 'C', and cannot be used in any theory of refcrence.
Of course you might try to avoid circularity by passing the
buck. This is mentioned by Strawson, who says in his footnote
on these matters that one man's reference may derive from
another's.
The identifying description, though it must not include a reference
to the speaker's own reference to the particular in question, may
include a reference to another's reference to that particular. If a
putatively identifying description is of this latter kind, then, indeed,
the question, whether it is a genuinely identifying description, turns
on the question, whether the reference it refers to is itself a genuinely
identifying reference. So one reference may borrow its credentials,
as a genuinely identifying reference, from another; and that from
another. But this regress is not infinite.*
I may then say, 'Look, by "Gödel" I shall mean the man Joe
thinks proved the incompleteness of arithmetic'. Joe may then
pass the thing over to Harry. One has to be very careful that
this doesn't come round in a circle. Is one really sure that this
won't happen? If you could be sure yourself of knowing such
a chain, and that evcryone else in the chain is using the proper
conditions and so is not getting out of it, then maybe you could
get back to the man by referring to such a chain in that way,
borrowing the refcrences one by one. However, although in
general such chains do exist for a living man, you won't know
what the chain is. You won't be sure what descriptions the
other man is using, so the thing won't go into a circle, or
whether by appealing to Joe you won't get back to the right
man at all. So you cannot use this as your identifying description with any confidence. You may not even remember
from whom you heard of Gödel.
What is the true picture of what's going on? Maybe reference
doesn't really take place at all! After all, we don't really know
*° Strawson, op. cit., p. 182 n.
9I
that any of the properties we use to identify the man are right.
We don't know that they pick out a unique object. So what
does make my use of 'Cicero' into a name of him? The picture
which leads to the cluster-of-descriptions theory is something
like this: One is isolated in a room; the entire community of
other speakers, everything else, could disappear; and one
determines the reference for himself by saying—-'By "Gödel"
I shall mean the man, whoever he is, who proved the incompleteness of arithmetic'. Now you can do this if you want
to. There's nothing really preventing it. You can just stick to
that determination. If that's what you do, then if Schmidt
discovered the incompleteness of arithmetic you do refer to
him when you say 'Gödel did such and such'.
But that's not what most of us do. Someone, let's say, a baby,
is born; his parents call him by a certain name. They talk about
him to their friends. Other people meet him. Through various
sorts of talk the nane is spread from link to link as if by a chain.
A speaker who is on the far end of this chain, who has heard
about, say Richard Feynman, in the market place or elsewhere,
may be referring to Richard Feynman even though he can't
remember from whom he first heard of Feynman or from
whom he ever heard of Feynman. He knows that Feynman
is a famous physicist. A certain passage of communication
reaching ultimately to the man himself does reach the speaker.
He then is referring to Feynman even though he can't identify
him uniquely. He doesn't know what a Feynman diagram is,
he doesn't know what the Feynman theory of pair production
and annihilation is. Not only that: he'd have trouble distinguishing between Gell-Mann and Feynman. So he doesn't
have to know these things, but, instead, a chain of communication going back to Feynman himself has been established,
by virtue of his membership in a community which passed
the name on from link to link, not by a ceremony that
he makes in private in his study: "By "Feynman" I shall

92
mean the man who did such and such and such and such'.
How does this view differ from Strawson's suggestion,
mentioned before, that one identifying reference may borrow
its credentials from another? Certainly Strawson had a good
insight in the passage quoted; on the other hand, he certainly
shows a difference at least in emphasis from the picture I
advocate, since he confines the remark to a footnote. The
main text advocates the cluster-of-descriptions theory. Just
because Strawson makes his remark in the context of a description theory, his view therefore differs from mine in one
important respect. Strawson apparently requires that the
speaker must know from whom he got his reference, so that he
can say: 'By "Gödel" I mean the man Jones calls "Gödel"'. If
he does not remember how he picked up the reference, he
cannot give such a description. The present theory sets no such
requirement. As I said, I may well not remember from whom I
heard of Gödel, and I may think I remember from which
people I heard the name, but wrongly.
These considerations show that the view advocated here can
lead to consequences which actually diverge from those of
Strawson's footnote. Suppose that the speaker has heard the
name 'Cicero' from Smith and others, who use the name to
refer to a famous Roman orator. He later thinks, however,
that he picked up the name from Jones, who (unknown to the
speaker) uses 'Cicero' as the name of a notorious German spy
and has never heard of any orators of the ancient world. Then,
according to Strawson's paradigm, the speaker must determine
his reference by the resolution, I shall use "Cicero" to refer to
the man whom Jones calls by that name', while on the present
view, the referent will be the orator in spite of the speaker's
false impression about where he picked up the name. The
point is that Strawson, trying to fit the chain of communication
view into the description theory, relies on what the speaker
thinks was the source of his reference. If the speaker has for-
93
gotten his source, the description Strawson uses is unavailable
to him; if he misremembers it, Strawson's paradigm can give
the wrong results. On our view, it is not how the speaker
thinks he got the reference, but the actual chain of communication, which is relevant.
I think I said the other time that philosophical theories are
in danger of being false, and so I wasn't going to present an
alternative theory. Have I just done so? Well, in a way; but
my characterization has been far less specific than a real set of
necessary and sufficient conditions for reference would be.
Obviously the name is passed on from link to link. But of
course not every sort of causal chain reaching from me to a
certain man will do for me to make a reference. There may be
a causal chain from our use of the term "Santa Claus' to a
certain historical saint, but still the children, when they use
this, by this time probably do not refer to that saint. So other
conditions must be satisfied in order to make this into a really
rigorous theory of reference. I don't know that I'm going to
do this because, first, I'm sort of too lazy at the moment;
secondly, rather than giving a set of necessary and sufficient
conditions which will work for a term like reference, I want to
present just a better picture than ihe picture presented by the
received views.
Haven't I been very unfair to the description theory? Here
I have stated it very preciselymore precisely, perhaps, than
it has been stated by any of its advocates. So then it's easy to
refute. Maybe if I tried to state mine with sufficient precision
in the form of six or seven or eight theses, it would also turn
out that when you examine the theses one by one, they will
all be false. That might even be so, but the difference is this.
What I think the examples I've given show is not simply that
there's some technical crror here or some mistake there, but
that the whole picture given by this theory of how reference is
determined seems to be wrong from the fundamentals. It

94
seems to be wrong to think that we give ourselves some
properties which somehow qualitatively uniquely pick out an
object and determine our reference in that manner. What I am
trying to present is a better picture-a picture which, if more
details were to be filled in, might be refined so as to give more
exact conditions for reference to take place.
One might never reach a set of necessary and sufficient conditions. I don't know, I'm always sympathetic to Bishop
Butler's 'Everything is what it is and not another thing'-in
the nontrivial sense that philosophical analyses of some concept
like reference, in completely different terms which make no
mention of reference, are very apt to fail. Of course in any
particular case when one is given an analysis one has to look
at it and see whether it is true or false. One can't just cite this
maxim to oneself and then turn the page. But more cautiously,
I want to present a better picture without giving a set of
necessary and sufficient conditions for reference. Such conditions would be very complicated, but what is true is that it's
in virtue of our connection with other speakers in the community, going back to the referent himself, that we refer to a
certain man.
There may be some cases where the description picture is
true, where some man really gives a name by going into the
privacy of his room and saying that the referent is to be the
unique thing with certain identifying properties. Jack the
Ripper' was a possible example which I gave. Another was
'Hesperus'. Yet another case which can be forced into this
description is that of meeting someone and being told his
name. Except for a belief in the description theory, in its
importance in other cases, one probably wouldn't think that
that was a case of giving oneself a description, i.e., 'the guy
I'm just meeting now'. But one can put it in these terms if one
wishes, and if one has never heard the name in any other way.
Of course, if you're introduced to a man and told, 'That's
95
Einstein, you've heard of hi.i before, it may be wrong, and
so on.
But maybe in soine cases such a paradigm worksespecially for the man who first gives someone or something
a name. Or he points to a star and says,
That is to be Alpha
Centauri". So he can really make himself this ceremony: 'By
"Alpha Centauri" I shall mean the star right over there with
such and such coordinates'. But in general this picture fails. In
general our reference depends not just on what we think ourselves, but on other people in the community, the history of
how the name reached one, and things like that. It is by following such a history that one gets to the reference.
More exact conditions are very conplicated to give. They
seem in a way somehow different in the case of a famous man
and one who isn't so famous. For example, a teacher tells his
class that Newton was famous for being the first man to think
there's a force pulling things to the earth; I think that's what
little kids think Newton's greatest achievement was. I won't
say what the merits of such an achievement would be, but,
anyway, we may suppose that just being told that this was the
sole content of Newton's discovery gives the students a false
belief about Newton, even though they have never heard of
him before. If, on the other hand, " the teacher uses the name
'George Smith'-a man by that name is actually his next door
neighbor-and says that George Smith first squared the circle,
does it follow from this that the students have a false belief
about the teacher's neighbor? The teacher doesn't tell them
that Smith is his neighbor, nor does he believe Smith first
squared the circle. He isn't particularly trying to get any
belief about the neighbor into the students' heads. He tries to
inculcate the belief that there was a man who squared the
circle, but not a belief about any particular man—he just pulls
out the first name that occurs to him—as it happens, he uses
his neighbor's name. It doesn't seem clear in that case that the
"The essential points of this example were suggested by Richard Miller.

90
students have a false belief about the neighbor, even though
there is a causal chain going back to the neighbor. I am not sure
about this. At any rate more refinements need to be added to
make this even begin to be a set of necessary and sufficient
conditions. In that sense it's not a theory, but is supposed to
give a better picture of what is actually going on.
A rough statement of a theory might be the following: An
initial "baptism' takes place. Here the object may be named by
ostension, or the reference of the name may be fixed by a
description. 12 When the name is "passed from link to link',
the receiver of the name must, I think, intend when he learns
it to use it with the same reference as the man from whom he
heard it. If I hear the name 'Napoleon' and decide it would be
a nice name for my pet aardvark, I do not satisfy this condition. 43 (Perhaps it is some such failure to keep the reference
• A good example of a baptism whose reference was fixed by means of a
description was that of naming Neptune in n. 33, p. 79. The case of a baptism
by ostension can perhaps be subsumed under the description concept also.
Thus the primary applicability of the description theory is to cases of initial
baptism. Descriptions are also used to fix a reference in cases of designation
which are similar to naming except that the terms introduced are not usually
called 'names". The terms one meter", '100 degrees Centigrade', have already
been given as examples, and other examples will be given later in these
lectures. Two things should be emphasized concerning the case of introducing
a name via a description in an initial baptism. First, the description used is not
synonymous with the name it introduces but rather fixes its reference. Here
we differ from the usual description theorists. Second, most cases of initial
baptism are far from those which originally inspired the description theory.
Usually a baptizer is acquainted in some sense with the object he names and is
able to name it ostensively. Now the inspiration of the description theory lay
in the fact that we can often use names of famous figures of the past who are
long dead and with whom no living person is acquainted; and it is precisely
these cases which, on our view, cannot be correctly explained by a description
theory.
13 1 can transmit the name ot the aaravark to oner people. For cach ot these
people, as for me, there will be a certain sort of causal or historical connection
between my use of the name and the Emperor of the French, but not one of
the required type.
97
fixed which accounts for the divergence of present uses of
"Santa Claus' from the alleged original usc.)
Notice that the preceding outline hardly eliminates the notion
of reference; on the contrary, it takes the notion of intending
to use the same reference as a given. There is also an appeal to
an initial baptism which is explained in terms either of fixing a
reference by a description, or ostension (if ostension is not to be
subsumed under the other category).* (Perhaps there are other
possibilities for initial baptisms.) Further, the George Smith
case casts some doubt as to the sufficiency of the conditions.
Even if the teacher does refer to his neighbor, is it clear that he
has passed on his reference to the pupils? Why shouldn't their
belief be about any other man named 'George Smith'? If he
says that Newton was hit by an apple, somehow his task of
transmitting a reference is easier, since he has communicated a
common misconception about Newton.
To repeat, I may not have presented a theory, but I do think
that I have presented a better picture than that given by
description theorists.
I think the next topic I shall want to talk about is that of statements of identity. Are these necessary or contingent? The
matter has been in some dispute in recent philosophy. First,
" Once we realize that the description used to fix the reference of a name is
not synonymous with it, then the description theory can be regarded as presupposing the notion of naming or reference. The requirement I made that
the description used not itself involve the notion of reference in a circular
way is something else and is crucial if the description theory is to have any
value at all. The reason is that the description theorist supposes that each
speaker essentially uses the description he gives in an initial act of naming to
determine his reference. Clearly, if he introduces the name 'Cicero' by
the determination, 'By "Cicero" I shall refer to the man I call "Cicero",' he
has by this ceremony determined no reference at all.
Not all description theorists thought that they were eliminating the notion
of reference altogether. Perhaps some realized that some notion of ostension,
or primitive reference, is required to back it up. Certainly Russell did.

98
everyone agrees that descriptions can be used to make contingent identity statements. If it is true that the man who
invented bifocals was the first Postmaster General of the United
States—-that these were one and the same—it's contingently
true. That is, it might have been the case that one man invented
bifocals and another was the first Postmaster General of the
United States. So certainly when you make identity statements
using descriptions—when you say 'the x such that ox and the
* such that x are one and the same —that can be a contingent
fact. But philosophers have been interested also in the question
of identity statements between names. When we say "Hesperus
is Phosphorus' or 'Cicero is Tully', is what we are saying
necessary or contingent? Further, they've been intercsted in
another type of identity statement, which comes from scientific
theory. We identify, for example, light with electromagnetic
radiation between certain limits of wavelengths, or with a
stream of photons. We identify heat with the motion of
molecules; sound with a certain sort of wave disturbance in
the air; and so on. Concerning such statements the following
thesis is commonly held. First, that these are obviously contingent identities: we've found out that light is a stream of
photons, but of course it might not have been a stream of
photons. Heat is in fact the motion of molecules; we found
that out, but heat might not have been the motion of molecules. Secondly, many philosophers feel damned lucky that
these examples are around. Now, why? These philosophers,
whose views are expounded in a vast literature, hold to a thesis
called 'the identity thesis' with respect to some psychological
concepts. They think, say, that pain is just a certain material
state of the brain or of the body, or what have you-say the
stimulation of C-fibers. (It doesn't matter what.) Some people
have then objected, 'Well, look, there's perhaps a correlation
between pain and these states of the body; but this must just be
a contingent correlation between two different things, because
99
it was an empirical discovery that this correlation ever held.
Therefore, by "pain" we must mean something different from
this state of the body or brain; and, therefore, they must be
two different things.
Then it's said, 'Ah, but you see, this is wrong! Everyone
knows that there can be contingent identities. First, as in the
bifocals and Postmaster General case, which I have mentioned
before. Second, in the case, believed closer to the present
paradigm, of theoretical identifications, such as light and a
stream of photons, or water and a certain compound of
hydrogen and oxygen. These are all contingent identities. They
might have been false. It's no surprise, therefore, that it can be
true as a matter of contingent fact and not of any necessity that
feeling pain, or seeing red, is just a certain state of the human
body. Such psychophysical identifications can be contingent
facts just as the other identities are contingent facts. And of
course there are widespread motivations—-ideological, or just
not wanting to have the 'nomological dangler' of mysterious
connections not accounted for by the laws of physics, one to
one correlations between two different kinds of thing, material
states, and things of an entirely different kind, which lead
people to want to believe this thesis.
I guess the main thing I'll talk about first is identity statements between names. But I hold the following about the
general case. First, that characteristic theoretical identifications
like 'Heat is the motion of molecules', are not contingent
truths but necessary truths, and here of course I don't mean just
physically necessary, but necessary in the highest degreewhatever that means. (Physical necessity, might turn out to be
necessity in the highest degree. But that's a question which I
don't wish to prejudge. At least for this sort of example, it
might be that when something's physically necessary, it always
is necessary tout court.) Second, that the way in which these
have turned out to be necessary truths does not seem to me to

NAMING AND NECFSSITY
be a way in which the mind-brain identities could turn out to
be either necessary or contingently true. So this analogy has to
go. It's hard to see what to put in its place. It's hard to see
therefore how to avoid concluding that the two are actually
Let me go back to the more mundane case about proper
names. This is already mysterious enough. There's a dispute
about this between Quine and Ruth Barcan Marcus. * Marcus
says that identities between names are necessary. If someone
thinks that Cicero is Tully, and really uses 'Cicero' and "Tully'
as names, he is thereby committed to holding that his belief is a
necessary truth. She uses the term 'mere tag'. Quine replies as
follows, 'We may tag the planet Venus, some fine evening,
with the proper name "Hesperus". We may tag the same
planet again, some day before sunrise, with the proper name
'Phosphorus". When we discover that we have tagged the
same planet twice our discovery is empirical. And not because
the proper names were descriptions. * First, as Quine says
when we discovered that we tagged the same planet twice, our
discovery was empirical. Another example I think Quine gives
in another book is that the same mountain sech from Nepal
and from Tibet, or somcthing like that, is from one angle
called 'Mt. Everest' (you've heard of that); from another it's
supposed to be called "Gaurisanker'. It can actually be an
empirical discovery that Gaurisanker is Everest. (Quine says
at the example is actually false. He got the example fror
rwin Schrödinger. You wouldn't think the inventor of wav
mechanics got things that wrong. I don't know where the
mistake is supposed to come from. One could certainly imagine
this situation as having been the case; and it's another
" Ruth Barcan Marcus, 'Modalities and Intensional Languages' (comments
by W. V. Quine, plus discussion) Boston Studies in the Philosophy of Science,
volume I, Reidel, Dordrecht, Holland, 1963, pp. 77-116.
• p. IOI.
IOI
good illustration of the sort of thing that Quine has in mind.)
What about it? I wanted to find a good quote on the other
side from Marcus in this hook but I am having trouble locating
one. Being present at that discussion, I remember" that she
advocated the view that if you really have names, a good
dictionary should be able to tell you whether they have the
same reference. So someone should be able, by looking in the
dictionary, to say that Hesperus and Phosphorus are the same.
Now this does not seem to be true. It does seem, to many
people, to be a consequence of the view that identities between
names are necessary. Therefore the view that identity statements between names are necessary has usually been rejected.
Russell's conclusion was somewhat different. He did think
there should never be any empirical question whether two
names have the same reference. This isn't satisfied for ordinary
names, but it is satisfied when you're naming your own sense
datum, or something like that. You say, 'Here, this, and that
(designating the same sense datum by both demonstratives)'
So you can tell without empirical investigation that you're
naming the same thing twice; the conditions are satisfied. Since
this won't apply to ordinary cases of naming, ordinary "names'
cannot be genuine names.
What should we think about this? First, it's true that someone
can use the name 'Cicero' to refer to Cicero and the name
"Tully' to refer to Cicero also, and not know that Cicero is
Tully. So it seems that we do not necessarily know a priori that
an identity statement between names is true. It doesn't follow
from this that the statement so expressed is a contingent one if
true. This is what I've emphasized in my first lecture. There is
a very strong feeling that leads one to think that, if you can't
know something by a priori ratiocination, then it's got to be
contingent: it might have turned out otherwise; but nevertheless I think this feeling is wrong.
'p. Its.

I02
Let's suppose we refer to the same heavenly body twice, as
'Hesperus' and 'Phosphorus'. We say: Hesperus is that star
over there in the evening; Phosphorus is that star over there
in the morning. Actually, Hesperus is Phosphorus. Are there
really circumstances under which Hesperus wouldn't have been
Phosphorus? Supposing that Hesperus is Phosphorus, let's try
to describe a possible situation in which it would not have
been. Well, it's easy. Someone goes by and he calls two
different stars 'Hesperus' and 'Phosphorus'. It may even be
under the same conditions as prevailed when we introduced
the names 'Hesperus' and 'Phosphorus'. But are those circumstances in which Hesperus is not Phosphorus or would not
have been Phosphorus? It seems to me that they are not.
Now, of course I'm committed to saying that they're not,
by saying that such terms as 'Hesperus and "Phosphorus,
when used as names, are rigid designators. They refer in every
possible world to the planet Venus. Therefore, in that possible
world too, the planet Venus is the planet Venus and it doesn't
matter what any other person has said in this other possible
world. How should we describe this situation? He can't have
pointed to Venus twice, and in the one case called it "Hesperus'
and in the other "Phosphorus', as we did. If he did so, then
'Hesperus is Phosphorus' would have been true in that situation
too. He pointed maybe neither time to the planet Venus-at
least one time he didn't point to the planet Venus, let's say
when he pointed to the body he called 'Phosphorus'. Then in
that case we can certainly say that the name "Phosphorus'
might not have referred to Phosphorus.
We can even say
that in the very position when viewed in the morning that
we found Phosphorus, it might have been the case that
Phosphorus was not there—-that something else was there, and
that even, under certain circumstances it would have been
called 'Phosphorus'. But that still is not a case in which Phosphorus was not Hesperus. There might be a possible world in
I03
which, a possible counterfactual situation in which, "Hesperus'
and 'Phosphorus' weren't names of the things they in fact are
names of. Someone, if he did determine their reference by
identifying descriptions, might even have used the very
identifying descriptions we used. But still that's not a case in
which Hesperus wasn't Phosphorus. For there couldn't have
been such a case, given that Hesperus is Phosphorus.
Now this seems very strange because in advance, we are
inclined to say, the answer to the question whether Hesperus
is Phosphorus might have turned out either way. So aren't
there really two possible worlds—-one in which Hesperus was
Phosphorus, the other in which Hesperus wasn't Phosphorus
—in advance of our discovering that these were the same?
First, there's one sense in which things might turn out either
way, in which it's clear that that doesn't imply that the way it
finally turns out isn't necessary. For example, the four color
theoren might turn out to be true and might turn out to be
false. It might turn out either way. It still doesn't mean that
the way it turns out is not necessary. Obviously, the "might'
here is purely 'epistemic'—it merely expresses our present state
of ignorance, or uncertainty.
But it seems that in the Hesperus-Phosphorus case, something
even stronger is true. The evidence I have before I know that
Hesperus is Phosphorus is that I see a certain star or a certain
heavenly body in the evening and call it "Hesperus', and in the
morning and call it 'Phosphorus'. I know these things. There
certainly is a possible world in which a man should have seen a
certain star at a certain position in the evening and called it
"Hesperus' and a certain star in the morning and called it
"Phosphorus'; and should have concluded—should have found
out by empirical investigation—that he names two different
stars, or two different heavenly bodies. At least one of these
stars or heavenly bodies was not Phosphorus, otherwise it
couldn't have come out that way. But that's true. And so it's

I04
true that given the evidence that someone has antecedent to
his empirical investigation, he can be placed in a sense in
exactly the same situation, that is a qualitatively identical
epistemic situation, and call two heavenly bodies 'Hesperus'
and "Phosphorus', without their being identical. So in that
sense we can say that it might have turned out either way. Not
that it might have turned out either way as to Hesperus's being
Phosphorus. Though for all we knew in advance, Hesperus
wasn't Phosphorus, that couldn't have turned out any other
way, in a sense. But being put in a situation where we have
exactly the same evidence, qualitatively speaking, it could
have turned out that Hesperus was not Phosphorus; that is, in
a counterfactual world in which 'Hesperus' and 'Phosphorus'
were not used in the way that we use them, as names of this
planet, but as names of some other objects, one could have had
qualitatively identical evidence and concluded that "Hesperus'
and 'Phosphorus' named two different objects, * But we, using
the names as we do right now, can say in advance, that if
Hesperus and Phosphorus are one and the same, then in no
other possible world can they be different. We use 'Hesperus'
as the name of a certain body and 'Phosphorus' as the name of
a certain body. We use them as names of those bodies in all
possible worlds. If, in fact, they are the same body, then in any
other possible world we have to use them as a name of that
object. And so in any other possible world it will be true that
Hesperus is Phosphorus. So two things are true: first, that we
do not know a priori that Hesporus is Phosphorus, and are in no
position to find out the answer excopt empirically. Second,
this is so because we could have evidence qualitatively indistinguishable from the evidence we have and determine the
reference of the two names by the positions of two planets in
the sky, without the planets being the same.
4 There is a more elaborate discussion of this point in the third lecture,
where its relation to a certain sort of counterpart theory is also mentioned.
IOS
Of course, it is only a contingent truth (not true in every
other possible world) that the star seen over there in the
evening is the star seen over there in the morning, because
there are possible worlds in which Phosphorus was not
visible in the morning. But that contingent truth shouldn't
be identified with the statement that Hesperus is Phosphorus.
It could only be so identified if you thought that it was a
necessary truth that Hesperus is visible over there in the evening
or that Phosphorus is visible over there in the morning. But
neither of those are necessary truths even if that's the way we
pick out the planet. These are the contingent marks by which
we identify a certain planet and give it a name.

LECTURE III: JANUARY 29, 1970
What's been accomplished, if anything, up to now? First, I've
argued that a popular view about how names get their reference
in general doesn't apply. It is in general not the case that the
reference of a name is determined by some uniquely identifying
marks, some unique properties satisfied by the referent and
known or believed to be true of that referent by the speaker.
First, the properties believed by the speaker need not be
uniquely specifying. Second, even in the case where they are,
they may not be uniquely true of the actual referent of the
speaker's use but of something else or of nothing. This is the
case where the speaker has erroneous beliefs about some person.
He does not have correct beliefs about another person, but
erroneous beliefs about a certain person. In these cases the
reference actually seems to be determined by the fact that the
speaker is a member of a community of speakers who use
the name. The name has been passed to him by tradition from
link to link.
Second, I've argued, even if in some special cases, notably
some cases of initial baptism, a referent is determined by a
description, by some uniquely identifying property, what that
property is doing in many cases of designation is not giving a
synonym, giving something for which the name is an abbreviation; it is, rather, fixing a reference. It fixes the reference by
some contingent marks of the object. The name denoting that
107
object is then used to refer to that object, even in referring to
counterfactual situations where the object doesn't have the
properties in question. An example was the case of a meter.
Finally, at the end of the talk last time we were talking about
statements of identity. Statements of identity should seem very
simple but they are somehow very puzzling to philosophers. I
cannot be sure in my own case whether I have all the possible
confusions that can be generated by this relation straightened
out. Some philosophers have found the relation so confusing
that they change it. It is, for example, thought that if you have
two names like 'Cicero' and "Tully' and say that Cicero is
Tully, you can't really be saying of the object which is both
Cicero and Tully that it is identical with itself. On the contrary, 'Cicero is Tully' can express an empirical discovery, as
we mentioned before. And so some philosophers, even Frege
at one early stage of his writing, have taken identity to be a
relation between names. Identity, so they say, is not the relation
between an object and itself, but is the relation which holds
between two names when they designate the same object.
This occurs even in the more recent literature. I didn't bring
the book along, but J. B. Rosser, the distinguished logician,
writes in his book, Logic for Mathematicians, *° that we say that
× = y if and only if 'x' and 'y' are names for the same object.
He remarks that the corresponding statement about the object
itself, that it in no way differs from itself, is of course trivial;
and so, presumably, cannot be what we mean. This is an
especially unusual paradigm of what the identity relationship
should be because it would apply very rarely. As far as I know,
outside the militant black nationalist movement no one has
ever been named 'x'. Seriously speaking, of course, "x' and 'y'
in the open sentence "x = y' are not names at all, they are
variables. And they can occur with identity as bound variables
in a closed sentence. If you say for cvery x and y, if x = y then
• New York, McGraw-Hill (1953), see Chapter VII, 'Equality'.

108
y = x, or something like that—no names occur in that statement at all, nor is anything said about names. This statement
would be true even though the human race had never existed
or, though it did exist, never produced the phenomenon of
names.
If anyone ever inclines to this particular account of identity,
let's suppose we gave him his account. Suppose identity were a
relation in English between the names. I shall introduce an
artificial relation called 'schmidentity' (not a word of English)
which I now stipulate to hold only between an object and
itself. 5° Now then the question whether Cicero is schmidentical
with Tully can arise, and if it does arise the same problems will
hold for this statement as were thought in the case of the
original identity statement to give the belief that this was a
relation between the names. If anyone thinks about this
seriously, I think he will see that therefore probably his
original account of identity was not necessary, and probably
not possible, for the problems it was originally meant to solve,
and that therefore it should be dropped, and identity should
just be taken to be the relation between a thing and itself. This
sort of device can be used for a number of philosophical
problems.
We have concluded that an identity statement between
names, when true at all, is necessarily true, even though one
may not know it a priori. Suppose we identify Hesperus as a
80 Of course, the device will fail to convince a philosopher who wants to
argue that an artificial language or concept of the supposed type is logically
impossible. In the present casc, some philosophers have thought that a relation,
being essentially two-termed, cannot hold between a thing and itself. This
position is plainly absurd. Someone can be his own worst enemy, his own
severest critic and the like. Some relations are reflexive such as the relation
'no richer than'. Identity or schmidentity is nothing but the smallest reflexive
relation.
I hope to elaborate on the utility of this device of imagining a hypothetical
language elsewhere.
100
certain star seen in the evening and Phosphorus as a certain
star, or a certain heavenly body, seen in the morning; then
there may be possible worlds in which two different planets
would have been seen in just those positions in the evening and
morning. However, at least one of them, and maybe both,
would not have been Hesperus, and then that would not have
been a situation in which Hesperus was not Phosphorus. It
might have been a situation in which the planet seen in this
position in the evening was not the planet seen in this position
in the morning; but that is not a situation in which Hesperus
was not Phosphorus. It might also, if people gave the names
'Hesperus' and 'Phosphorus' to these plancts, be a situation in
which some planet other than Hesperus was called 'Hesperus'.
But even so, it would not be a situation in which Hesperus
itself was not Phosphorus. 51
Some of the problems which bother people in these situations, as I have said, come from an identification, or as I would
put it, a confusion, between what we can know a priori in
advance and what is necessary. Certain statements-and the
identity statement is a paradigm of such a statement on my
view—if true at all must be necessarily true. One does know
a priori, by philosophical analysis, that if such an identity statement is true it is necessarily true.
One qualification: when I say "Hesperus is Phosphorus'
is necessarily true, I of course do not deny that situations
might have obtained in which there was no such planet as
Venus at all, and therefore no Hesperus and no Phosphorus.
In that casc, there is a question whether the identity statement
'Hesperus is Phosphorus' would be true, false, or neither true
" Recall that we describe the situation in our language, not the language
that the people in that situation would have used. Hence we must use the terms
"Hesperus' and 'Phosphorus' with the same reference as in the actual world.
The fact that people in that situation might or might not have used these
names for different planets is irrelevant. So is the fact that they might have
done so using the very same descriptions as we did to fix their references.

IIO
nor false. 52 And if we take the last option, is "Hesperus =
Phosphorus' necessary because it is never false, or should we
require that a necessary truth be true in all possible worlds? I
am leaving such problenis outside my considerations altogether.
If we wish to be somewhat more careful, we could replace the
statement 'Hesperus is Phosphorus' by the conditional, 'If
Hesperus exists then Hesperus is Phosphorus', cautiously taking
only the latter to be necessary. Unfortunately this conditional
involves us in the problem of singular attributions of existence,
one I cannot discuss here. In particular, philosophers sympathetic to the description theory of naming often argue that
one cannot ever say of an object that it exists. A supposed
statement about the existence of an object really is, so it's
argued, a statement about whether a certain description or
property is satisfied. As I have already said, I disagrce.
Anyway, I can't really go into the problems of existence
here.
I want to mention at this point that other considerations
about de re modality, about an object having essential properties,
can only be regarded correctly, in my view, if we recognize
the distinction between a prioricity and necessity. One night
very well discover essence empirically.
There are some examples of alleged essential properties in
an article by Timothy Sprigge.
The internalist [which means the believer that there are some
essential properties] says that the Queen must have been born of
royal blood. (He means that this person must have been of royal
blood.] The anti-essentialist says there would be no contradiction
in a news bulletin asserting that it had been established that the
Queen was not in fact the child of her supposed parents, but had
been secretly adopted by them, and therefore the proposition that
she is of royal blood is synthetic...
52 The same three options exist for "Hesperus is Hesperus', and the answer
must be the same as in the case of 'Hesperus is Phosphorus'.
III
For a time the anti-essentialist) is winning. Yet there comes a time
when his claims appear a trifle too far fetched. The internalist
suggests that we cannot imagine that particular we call the Queen
having the property of at no stage in her existence being human. If
the anti-internalist admits this, admits that it is logically inconceivable that the Queen should have had the property of, say,
always being a swan, then he admits that she has at least one
internal property. If on the other hand he says that it's only a
contingent fact that the Queen has ever been human, he says what
it is hard to accept. Can we really consider it as conceivable that she
should never have been human?sa
'At no stage in her existence' and 'always' are justifications
Sprigge presumably introduces to allow such possibilities as
her right now being changed into a swan—by a wicked witch,
I guess. (Or a benign witch.)
One confusion I find in this discussion is that in the first case
Sprigge talks about whether there would be any contradiction
in supposing that we had an announcement that the Queen was
born of parents different from the ones she actually had. And
in that there is no contradiction. Similarly, though, there is no
contradiction in an announcement that the Queen, this thing we
thought to be a woman, was in fact an angel in human form,
or an automaton cleverly constructed by the royal family, who
did not want the succession to pass to that bastard so-and-so, or
something. Neither of these announcements represent things
that we couldn't possibly discover, either. What is the question
we are asking when we ask whether it's necessary, concerning
this woman, that she should either have been of royal blood or
have been human? Royal blood is a little complicated, because
in order for it to be necessary for her to have been of royal
blood it has to be necessary that this particular family line at
some time attained to royal power; but the latter fact seems to
ss 'Internal and External Properties', Mind 7x (April, 1962), pp. 202-03.

NAMING AND NECESSILY
be contingent. Therefore I suppose it is contingent that her
blood should ever have been royal.
Let's try and refine the question a little bit. The question
really should be, let's say, could the Queen--could this woman
herself have been born of different parents from the parents
from whom she actually came? Could she, let's say, have been
the daughter instead of Mr. and Mrs. Truman? There would
be no contradiction, of course, in an announcement that (I hope
the ages do not make this impossible), fantastic as it may
sound, she was indeed the daughter of Mr. and Mrs. Truman.
I suppose there might even be no contradiction in the discovery
that—it seems very suspicious anyway that on either hypothesis
she has a sister called Margaret-that these two Margarets
were one and the same person flying back and forth in a clever
way. At any rate we can imagine discovering all of these
things.
But let us suppose that such a discovery is not in fact the
case. Let's suppose that the Queen really did come from these
parents. Not to go into too many complications here about
what a parent is, let's suppose that the parents are the people
whose body tissues are sources of the biological sperm and egg.
So you get rid of such recherché possibilities as transplants of
the sperm from the father, or the egg from the mother, into
other bodies, so that in one sense other people might have
been her parents. If that happened, in another sense her parents
were still the original king and queen. But other than that, can
we imagine a situation in which it would have happened that
this very woman came out of Mr. and Mrs. Truman? They
might have had a child resembling her in many properties.
Perhaps in some possible world Mr. and Mrs. Truman even
had a child who actually became the Queen of England and
was even passed off as the child of other parents. This still would
not be a situation in which this very woman whom we call
'Elizabeth II' was the child of Mr. and Mrs. Truman, or so it
111
seems to me. It would be a situation in which there was some
other woman who had many of the properties that are in fact
true of Elizabeth. Now, one question is, in this possible world,
was Elizabeth herself ever born? Let's suppose she wasn't ever
born. It would than be a situation in which, though Truman
and his wife have a child with many of the properties of
Elizabeth, Elizabeth herself didn't exist at all. One can only
become convinced of this by reflection on how you would
describe this situation. (That, I suppose, means in many cases
that you won't become convinced of this, at least not at the
moment. But it is something of which I personally have been
convinced.)
How could a person originating from different parents,
from a totally different sperm and egg, be this very woman?
One can imagine, given the woman, that various things in her
life could have changed: that she should have become a
pauper; that her royal blood should have been unknown, and
so on. One is given, let's say, a previous history of the world
up to a certain time, and from that time it diverges considerably
from the actual course. This seems to be possible. And so it's
possible that even though she were born of these parents she
never became queen. Even though she were born of these
parents, like Mark Twain's characters* she was switched off
with another girl. But what is harder to imagine is her being
born of different parents. It seems to me that anything coming
from a different origin would not be this object.
In the case of this table, ' we may not know what block of
wood the table came from. Now could this table have been
made from a completely different block of wood, or even of
water cleverly hardened into ice--water taken from the
Thames River? We could conceivably discover that, contrary
to what we now think, this table is indeed made of ice from
0 In The Prince and The Pauper.
" Of course I was pointing to a wooden table in the room.

the river. But let us suppose that it is not. Then, though we can
imagine making a table out of another block of wood or even
from ice, identical in appearance with this one, and though we
could have put it in this very position in the room, it seems to
me that this is not to imagine this table as made of wood or ice,
but rather it is to imagine another table, resembling this one in
all external details, inade of another block of wood, or even
of ice. 50, 52
50 A principle suggested by these examples is: If a material object has its origin
from a certain hunk of matter, it could not have had its origin in any other matter.
Some qualifications might have to be stated (for example, the vagueness of the
notion of hunk of matter leads to some problems), but in a large class of cases
the principle is perhaps susceptible of something like proof, using the principle
of the necessity of identity for particulars. Let 'B' be a name (rigid designator)
of a table, let 'A' name the piece of wood from which it actually came. Let
'C' name another piece of wood. Then suppose B were made from A, as in
the actual world, but also another table D were simultaneously made from C.
(We assume that there is no relation between A and C which makes the
possibility of making a table from one dependent on the possibility of making
a table from the other.) Now in this situation B ÷ D; hence, even if D were
made by itself, and no table were made from A, D would not be B. Strictly
speaking, the "proof' uses the necessity of distinctness, not of identity. However, the same types of considerations that can be used to establish the latter
can be used to establish the former. (Suppose X‡ Y; if Xand Y were both
identical to some object Z in another possible world, then X = Z, Y= Z,
hence X = Y.) Alternatively, the principle follows from the necessity of
identity plus the "Brouwersche' axiom, or, equivalently, symmetry of the
accessibility rclation between possible worlds. In any event, the argument
applies only if the making of D from C does not affect the possibility of
making B from A, and vice-versa.
57 In addition to the principle that the origin of an object is essential to it,
another principle suggested is that the substance of which it is made is essential.
Several complications exist here. First, one should not confuse the type of
essence involved in the question 'What properties must an object retain if it is
not to cease to exist, and what properties of the object can change while the
object endures?", which is a temporal question,
with the question What
(timeless) properties could the object not have failed to have, and what
properties could it have lacked while still (timelessly) existing?, which
concerns necessity and not time and which is our topic here. Thus the question
of whether the table could have changed into ice is irrelevant here. The question
IIS
These are only examples of essential properties.58 I won't
whether the table could originally have been made of anything other than wood
is relevant. Obviously this question is related to the necessity of the origin of
the table from a given block of wood and whether that block, too, is essentially
wood (even wood of a particular kind). Thus it is ordinarily impossible to
imagine the table made from any substance other than the one of which it is
actually made without going back through the entire history of the universe,
a mind-boggling feat. (Other possibilities of the table not having been wooden
originally have been suggested to me, including an ingenious suggestion of
Slote's, but I find none of them really convincing. I cannot discuss them here.)
A full discussion of the problems of essential properties of particulars is
impossible here, but I will mention a few other points: (1) Ordinarily when
we ask intuitively whether something might have happened to a given object,
we ask whether the universe could have gone on as it actually did up to a
certain time, but diverge in its history from that point forward so that the
vicissitudes of that object would have been different from that time forth.
Perhaps this feature should be erected into a general principle about essence.
Note that the time in which the divergence from actual history occurs may be
sometime before the object itself is actually created. For example, I might have
been deformed if the fertilized egg from which I originated had been damaged
in certain ways, even though I presumably did not yet exist at that time. (2) I
am not suggesting that only origin and substantial makeup are essential. For
example, if the very block of wood from which the table was made had
instead been made into a vase, the table never would have existed. So (roughly)
being a table seems to be an essential property of the table. (3) Just as the
question whether an object actually has a certain property (e.g. baldness) can
be vaguc, so the question whether the object essentially has a certain property
can be vague, even when the question whether it actually has the property is
decided. (4) Certain counterexamples to the origin principle appear to exist
in ordinary parlance. I am convinced that they are not genuine counterexamples, but their exact analysis is difficult. I cannot discuss this here.
58 Peter Geach has advocated (in Mental Acts, Routledge and Kegan Paul,
London, 1957, Section 16, and elsewhere) a notion of "nominal essence'
different from the type of essential property considered here. According to
Geach, since any act of pointing is ambiguous, someone who baptizes an
object by pointing to it must apply a sortal property to disambiguate his
reference and to ensure correct criteria of identity over time-for example,
someone who assigns a reference to 'Nixon' by pointing to him must say. "I
use "Nixon" as a name of that man', thus removing his hearer's temptations
to take him to be pointing to a nose or a time-slice. The sortal is then in some
sense part of the meaning of the name; names do have a (partial) sense after all,
though their senses may not be complete enough to determine their references,

IIO
dwell on them further because I want to go on to the more
general casc, which I mentioned in the last lecture, of some
identitics betwen terms for substances, and also the properties
of substances and of natural kinds. Philosophers have, as I've
said, been very interested in statements expressing theoretical
identifications; among them, that light is a stream of photons,
that water is HO, that lightning is an electrical discharge, that
gold is the element with the atomic number 79.
To get clear about the status of these statements we must
first maybe have some thoughts about the status of such substances as gold. What's gold? I don't know if this is an example
which has particularly interested philosophers. Its interest in
financial circles is diminishing because of increased stability of
currencies. ° Even so gold has interested many people. Here
as they are in description and cluster-of-descriptions theories. If I understand
Geach correctly, his nominal essence should be understood in terms of a
prioricity, not necessity, and thus is quite different from the kind of essence
advocated here (perhaps this is part of what he means when he says he is
dealing with 'nominal", not "real", essences). So 'Nixon is a man', 'Dobbin
is a horse', and the like would be a priori truths.
I need not take a position on this view here. But I would briefly mention
the following: (1) Even if a sortal is used to disambiguate an ostensive reference,
surely it need not be held a priori to be true of the object designated. Couldn't
Dobbin turn out to belong to a species other than horses (though superficially
he looked like a horse), Hesperus to be a planet rather than a star, or Lot's
guests, even if he names them, to be angels rather than men? Perhaps Geach
should stick to more cautious sortals. (2) Waiving the objection in (I), surely
there is a substantial gap between premise and conclusion. Few speakers do in
fact learn the reference of a given name by ostension; and, even if they picked
up the name by a chain of communication leading back to an ostension, why
should the sortal allegedly used in the ostension be, in any sense, part of the
"sense' of the name for them? No argument is offered here. (An extreme case:
A mathematician's wife overhears her husband muttering the name 'Nancy".
She wonders whether Nancy, the thing to which her husband referred, is a
woman or a Lie group. Why isn't her use of "Nancy" a case of naming? If it
isn't, the reason is not indefiniteness of her reference.)
5 I may have spoken too soon. That is what some financial pages said when
these lectures were delivered, January, 1970.
117
is what Immanuel Kant says about gold. (He was a wealthy
spcculator who kept his possessions under his bed.) Kant is introducing the distinction between analytic and synthetic judgements, and he says: "All analytic judgements depend wholly
on the law of contradiction, and are in their nature a priori
cognitions, whether the concepts that supply them with matter
be empirical or not. For the predicate of an affirmative analytic
judgement is already contained in the concept of the subject,
of which it cannot be denied without contradiction...
For this very reason all analytic judgements are a priori even
when the concepts are empirical, as, for example,
"Gold is a
yellow metal"; for to know this I require no experience beyond my concept of gold as a yellow metal. It is, in fact, the
very concept, and I need only analyze it without looking
beyond it. "6° I should have looked at the German. 'It is in fact
the very concept' sounds as if Kant is saying here that "gold'
just means 'yellow metal'. If he says that, then it's especially
strange, so let's suppose that that is not what he's saying. At
least Kant thinks it's a part of the concept that gold is to be a
yellow metal. He thinks we know this a priori, and that we
could not possibly discover this to be empirically false.
Is Kant right about this? First, what I would have wanted to
do would have been to discuss the part about gold being a
metal. This, however, is complicated because first, I don't
know too much chemistry. Investigating this a few days ago
in just a couple of references, I found in a more phenomenological account of metals the statement that it's very difficult to
say what a metal is. (It talks about malleability, ductility, and
the like, but none of these exactly work.) On the other hand,
something about the periodic table gave a description of
80 Prolegomena to Any Future Metaphysics, Preamble Section z.b. (Prussian
Academy edition, p. 267). My impression of the passage was not changed by a
subsequent cursory look at the German, though I can hardly lay claim to any
real competence here.

II8
elements as metals in terms of their valency properties. This
may make some people think right away that there are really
two concepts of metal operating here, a phenomenological
one and a scientific one which then replaces it. This I reject,
but since the move will tempt many, and can be refuted only
after I devclop my own views, it will not be suitable to use
'Gold is a metal' as an example to introduce these views.
But let's consider something casier-the question of the
yellowness of gold. Could we discover that gold was not in
fact yellow? Suppose an optical illusion were prevalent, due to
peculiar properties of the atmosphere in South Africa and
Russia and certain other arcas where gold mines are common.
Suppose there were an optical illusion which made the substance appear to be yellow; but, in fact, once the peculiar
properties of the atmosphere were removed, we would see
that it is actually blue. Maybe a demon even corrupted the
vision of all those entering the gold mines (obviously their
souls were already corrupt, and thus made them believe that
this substance was yellow, though it is not. Would there on
this basis be an announcement in the newspapers: "It has
turned out that there is no gold. Gold does not exist. What
we took to be gold is not in fact gold."? Just imagine the world
financial crisis under these conditions! Here we have an undrcant of source of shakiness in the monetary system.
It seems to me that there would be no such announcement.
On the contrary, what would be announced would be that
though it appeared that gold was yellow, in fact gold has
turned out not to be yellow, but blue. The reason is, I think,
that we usc 'gold' as a term for a certain kind of thing. Others
have discovered this kind of thing and we have heard of it.
We thus as part of a community of speakers have a certain
connection between ourselves and a certain kind of thing. The
kind of thing is thought to have certain identifying marks. Some
of these marks may not really be true of gold. We might
1I9
discover that we are wrong about them. Further, there might
be a substance which has all the identifying marks we commonly attributed to gold and used to identify it in the first
place, but which is not the same kind of thing, which is not
the same substance. We would say of such a thing that though
it has all the appearances we initially used to identify gold, it is
not gold. Such a thing is, for example, as we well know, iron
pyrites or fool's gold. This is not another kind of gold. It's a
completely different thing which to the uninitiated person
looks just like the substance which we discovered and called
gold. We can say this not because we have changed the meaning
of the term gold, and thrown in some other criteria which
distinguished gold from pyrites. It seems to me that that's not
true. On the contrary, we discovered that certain properties
were true of gold in addition to the initial identifying marks
by which we identified it. These propertics, then,
being
characteristic of gold and not true of iron pyrites, show that
the fool's gold is not in fact gold.
We should look at this in another example. It says somewhere in here:® 'I say "The word "tiger' has meaning in
English.
.. If I am then asked "What is a tiger?" I might
reply "A tiger is a large carnivorous quadrupedal feline, tawny
yellow in color with blackish transverse stripes and white
belly," (derived from the entry under "tiger" in the Shorter
Oxford English Dictionary.)' And now suppose someone says
'You have just said what the word "tiger" means in English'
And Ziff asks, 'Is that so?' and he says, correctly, 'I think not.'
fis example is, Suppose in a jungle clearing one says "look, :
hree-legged tiger!
must one be confused? The phrase "a
three-legged tiger" is not a contradictio in adjecto. But if "tiger"
in English meant, among other things, either quadruped or
quadrupedal, the phrase "a three-legged tiger" could only be a
• Paul Ziff, Semantic Analysis, Ithaca, Cornell University Press, 1960, PP.
184-85.

I20
contradictio in adjecto.' So, his example shows that if it is part of
the concept of tiger that a tiger has four legs, there couldn't be
a three-legged tiger. This is the sort of case which many
philosophers tend to explain as a "cluster concept'. Is it even a
contradiction to suppose that we should discover that tigers
never have four legs? Suppose the explorers who attributed
these properties to tigers were deceived by an optical illusion,
and that the animals they saw were from a three-legged species,
would we then say that there turned out to be no tigers after
all? I think we would say that in spite of the optical illusion
which had deceived the explorers, tigers in fact have three legs.
Further, is it true that anything satisfying this description in
the dictionary is necessarily a tiger? It seems to me that it is
not. Suppose we discover an animal which, though having all
external appearances of a tiger as described herc, has an internal
structure completely different from that of the tiger. Actually
the word 'felinc' was put in here, so it is not entirely fair. Let's
suppose it were left out, for this example. That a tiger belongs
to any particular biological family, anyway, was something
we discovered. If 'feline' means just having the appearance of a
cat, let's suppose that it does have the appearance of a big cat.
We night find animals in some part of the world which,
though they look just like a tiger, on examination were discovered not even to be mammals. Let's say they were in fact
very peculiar looking reptiles. Do we then conclude on the
basis of this description that some tigers are reptiles? We don't.
We would rather conclude that these animals, though they
have the external marks by which we originally identified
tigers, are not in fact tigers, because they are not of the same
species as the species which we called 'the species of tigers'. Now
this, I think, is not because, as some people would say, the old
concept of tiger has been replaced by a new scientific definition.
I think this is true of the concept of tiger before the internal
structure of tigers has been investigated. Even though we don't
I2I
knou the internal structure of tigers, we suppose—-and let us
suppose that we are right-that tigers form a certain species or
natural kind. We then can imagine that there should be a
creature which, though having all the external appearance of
tigers, differs from them internally enough that we should say
that it is not the same kind of thing. We can imagine it without
knowing anything about this internal structure-what this
internal structure is. We can say in advance that we use the
term "tiger' to designate a species, and that anything not of
this species, even though it looks like a tiger, is not in fact a tiger.
Just as something may have all the properties by which we
originally identified tigers and yet not be a tiger, so we might
also find out tigers had none of the properties by which we
originally identified them. Perhaps none are quadrupedal, nonc
tawny yellow, none carnivorous, and so on; all these properties
turn out to be based on optical illusions or other errors, as in
the case of gold. So the term "tiger", like the term 'gold", does
not mark out a "cluster concept' in which most, but perhaps
not all, of the properties used to identify the kind must be
satisfied. On the contrary, possession of most of these properties need not be a necessary condition for membership in
the kind, nor need it be a sufficient condition.
Since we have found out that tigers do indeed, as we
suspected, form a single kind, then something not of this kind
is not a tiger. Of course, we may be mistaken in supposing
that there is such a kind. In advance, we suppose that they
probably do form a kind. Past experience has shown that
usually things like this, living together, looking alike, mating
together, do form a kind. If there are two kinds of tigers that
have something to do with each other but not as much as we
thought, then maybe they form a larger biological family. I€
they have absolutely nothing to do with each other, then there
are really two kinds of tigers. This all depends on the history
and on what we actually find out.

The philosopher I find most to recognize this sort of consideration (our thoughts on these matters developed independently) is Putnam. In an article called 'It Ain't Necessarily
So' 82 he says of statements about species, that they are "less
necessary' (as he cautiously says) than statements like "bachelors
aren't married'. The example he gives is "cats are animals.
Cats might turn out to be automata, or strange demons (not
his example) planted by a magician. Suppose they turned out
to be a species of demons. Then on his view, and I think also
my view, the inclination is to say, not that there turned out to
be no cats, but that cats have turned out not to be animals as
we originally supposed. The original concept of cat is: that
kind of thing, where the kind can be identified by paradigmatic
instances. It is not something picked out by any qualitative
dictionary definition. However, Putnam's conclusion is that
statements like "cats are animals' are 'less necessary' than statements like "bachelors are unmarried'. Certainly I agree that
the argument indicates that such statements are not known a
priori, and hence are not analytic; ® whether a given kind is a
" Journal of Philosophy, 59, No. 22 (October 25, 196z), Pp. 658-71. In
subsequent work on natural kinds and physical properties, which I have not
had a chance to see at the time of this writing, Putnam has done further work,
which (I gather) has many points of contact with the viewpoint expressed
here. As I mentioned in the text, there are some divergencies between Putnam's approach and mine; Putnam does not base his considerations on the
apparatus of necessary versus a priori truths which I invoke.
In his earlier
paper, "The Analytic and the Synthetic", Minnesota Studies in the Philosophy of
Science, 'vol. III, pp. 358-97, he seems closer to the 'cluster concept' theory in
some respects, suggesting, for example, that it applies to proper names.
I should emphasize again that it was an example of Rogers Albritton which
called my attention to this complex of problems, though Albritton probably
would not accept the theories I have developed on the basis of the example.
*3 I am presupposing that an analytic truth is one which depends on meanings
in the strict sense and therefore is necessary as well as a priori. If statements
whose a priori truth is known via the fixing of a reference are counted as
analytic, then some analytic truths are contingent; this possibility is excluded
in the notion of analyticity adopted here. The ambiguity in the notion of
123
species of animals is a matter for empirical investigation.
Perhaps this episteinological sense is what Putnam means by
'necessary'. The question remains whether such statements are
necessary in the non-epistemological sense advocated in these
lectures. So the next thing to investigate is (using the concept
of necessity that I talked about): are such statements as "cats
are animals, or such statements as "gold is a yellow metal",
necessary?
So far I've only been talking about what we could find out.
I've been saying we could find out that gold was not in fact
yellow, contrary to what we thought. If one went in more
detail into the concept of metals, let's say in terms of valency
properties, one could certainly find out that though one took
gold to be a metal, gold is not in fact a metal. Is it necessary or
contingent that gold be a metal? I don't want to go into detail
on the concept of a metal-as I said, I don't know enough
about it. Gold apparently has the atomic number 79. Is it a
necessary or a contingent property of gold that it has the atomic
number 79? Certainly we could find out that we were mistaken. The whole theory of protons, of atomic numbers, the
whole theory of molecular structure and of atomic structure,
on which such views are based, could all turn out to be false.
Certainly we didn't know it from time immemorial. So in that
sense, gold could turn out not to have atomic number 79.
Given that gold does have the atomic number 79, could
something be gold without having the atomic number 79?
analyticity of course arises from the ambiguity in the usual uses of such terms
as "definition' and 'sense'. I have not attempted to deal with the delicate
problems regarding analyticity in these lectures, but I will say that some
(though not all) of the cases often adduced to discredit the analytic-synthetic
distinction, especially those involving natural phenomena and natural kinds,
should be handled in terms of the apparatus of fixing a reference invoked here.
Note that Kant's example, 'gold is a yellow metal", is not even a priori, and
whatever necessity it has is established by scientific investigation; it is thus
far from analytic in any sense.

I24
Let us suppose the scientists have investigated the nature of
gold and have found that it is part of the very nature of this
substance, so to speak, that it have the atomic number 79.
Suppose we now find some other yellow metal, or some other
yellow thing, with all the properties by which we originally
identified gold, and many of the additional ones that we have
discovered later. An example of one with many of the initial
properties is iron pyrites, 'fool's gold.' As I have said, we
wouldn't say that this substance is gold. So far we are speaking
of the actual world. Now consider a possible world. Consider
a counterfactual situation in which, let us say, fool's gold or
iron pyrites was actually tound in various mountains in the
United States, or in areas of South Africa and the Soviet Union.
Suppose that all the areas which actually contain gold now,
contained pyrites instead, or some other substance which
counterfeited the superficial properties of gold but lacked its
atomic structure.6* Would we say, of this counterfactual
situation, that in that situation gold would not even have been
an element (because pyrites is not an element)? It seems to me
that we would not. We would instead describe this as a situation
in which a substance, say iron pyrites, which is not gold,
would have been found in the very mountains which actually
contain gold and would have had the very propertics by which
we commonly identify gold. But it would not be gold; it
would be something else. One should not say that it would
still be gold in this possible world, though gold would then
lack the atomic number 79. It would be some other stuff,
some other substance. (Once again, whether people counterfactually would have called it 'gold' is irrelevant. We do not
describe it as gold.) And so, it seems to me, this would not
be a case in which possibly gold might not have been an
" Even better pairs of ringers exist; for example, some pairs of elements of a
single column in the periodic table which resemble each other closely but
nevertheless are different elements.
I2S
element, nor can there be such a case (except in the epistemic
sense of possible'). Given that gold is this element, any other
substance, even though it looks like gold and is found in the
very places where we in fact find gold, would not be gold. It
would be some other substance which was a counterfeit for
gold. In any counterfactual situation where the same geographical areas were filled with such a substance, they would
not have been filled with gold. They would have been filled
with something else.
So if this consideration is right, it tends to show that such
statements representing scientific discoveries about what this
stuff is are not contingent truths but necessary truths in the
strictest possible sense. It's not just that it's a scientific law, but
of course we can imagine a world in which it would fail. Any
world in which we imagine a substance which does not have
these properties is a world in which we imagine a substance
which is not gold, provided these properties form the basis of
what the substance is. In particular, then, present scientific
theory is such that it is part of the nature of gold as we have it
to be an element with atomic number 79. It will therefore be
necessary and not contingent that gold be an element with
atomic number 79. (We may also in the same way, then,
investigate further how color and metallic properties follow
from what we have found the substance gold to be: to the
extent that such properties follow from the atomic structure of
gold, they are necessary properties of it, even though they unquestionably are not part of the meaning of 'gold' and were
not known with a priori certainty.)
Putnam's example "cats are animals comes under the same
sort of heading. We have in fact made a very surprising discovery in this case. We have in fact found nothing to go
against our belief. Cats are in fact animals! Then is this truth a
necessary truth or a contingent one? It seems to me that it is
necessary. Consider the counterfactual situation in which in

126
place of these creatures-these animals--we have in fact little
demons which when they approached us brought bad luck
indeed. Should we describe this as a situation in which cats
were demons? It seems to me that these demons would not be
cats. They would be demons in a cat-like form. We could
have discovered that the actual cats that we have are demons.
Once we have discovered, however, that they are not, it is part
of their very nature that, when we describe a counterfactual
world in which there were such demons around, we must say
that the demons would not be cats. It would be a world
containing demons masquerading as cats. Although we could
say cats might turn out to be demons, of a certain species, given
that cats are in fact animals, any cat-like being which is not an
animal, in the actual world or in a counterfactual onc, is not
a cat. The same holds even for aninials with the appearance of
cats but reptilic internal structure. Were such to exist, they
would not be cats, but 'fool's cats.
This has some relation also to the essence of a particular
object. The molecular theory has discovered, let's say, that
this object here is composed of molecules. This was certainly
an important cipirical discovery. It was something we didn't
know in advance; maybe this might have been composed, for
all we knew, of some ethercal entelechy. Now imagine an
object occupying this very position in the room which was ar
ethcreal entclechy. Would it be this very object here? It might
have all the appearance of this object, but it seems to me that
it could not ever be this thing. The vicissitudes of this thing might
have been very different from its actual history. It might have
been transported to the Kremlin. It might have already been
hewn into bits and no longer exist at the present time. Various
things might have happened to it. But whatever we imagine
counterfactually having happened to it other than what actually
did, the one thing we cannot imagine happening to this thing
is that it, given that it is composed of molecules, should still
I27
have existed and not have been composed of molecules. We
can imagine having discovered that it wasn't composed of
molecules. But once we know that this is a thing composed of
molecules-that this is the very nature of the substance of
which it is made-we can't then, at least if the way I see it is
correct, imagine that this thing might have failed to have been
composed of molecules.
According to the view I advocate, then, terms for natural
kinds are much closer to proper names than is ordinarily
supposed. The old term "common name' is thus quite appropriate for predicates marking out species or natural kinds, such
as 'cow' or 'tiger'. My considerations apply also, however, to
certain mass terms for natural kinds, such as gold', 'water',
and the like. It is interesting to compare my views to those of
Mill. Mill counts both predicates like 'cow', definite descriptions, and proper names as names. He says of 'singular' names
that they are connotative if they are definite descriptions but
non-connotative if they are proper names. On the other hand,
Mill says that all "general' names are connotative; such a
predicate as 'human being' is defined as the conjunction of
certain properties which give necessary and sufficient conditions
for humanity-rationality, animality, and certain physical
features. & The modern logical tradition, as represented by
Frege and Russell, seems to hold that Mill was wrong about
singular names, but right about general names. More recent
philosophy has followed suit, except that, in the case of both
proper names and natural kind terms, it often replaces the
notion of defining properties by that of a cluster of properties,
only some of which need to be satisfied in each particular case.
My own view, on the other hand, regards Mill as more-or-less
right about 'singular' names, but wrong about 'general' names.
Perhaps some "general' names ('foolish', 'fat', 'yellow') express
" Mill, op. cit.

128
properties. In a significant sense, such general names as "cow'
and 'tiger' do not, unless being a cow counts trivially as a
property. Certainly 'cow' and "riger' are not short for the
conjunction of properties a dictionary would take to define
them, as Mill thought. Whether science can discover empirically that certain properties are necessary of cows, or of
tigers, is another question, which I answer affirmatively.
Let's consider how this applies to the types of identity statements expressing scientific discoveries that I talked about
before-say, that water is HO. It certainly represents a
discovery that water is HO. We identified water originally
by its characteristic feel, appearance and perhaps taste, (though
the taste may usually be due to the impurities). If there were a
substance,
even actually, which had a completely different
atomic structure from that of water, but resembled water in
these respects, would we say that some water wasn't H,O? I
think not. We would say instead that just as there is a fool's
gold there could be a fool's water; a substance which, though
having the properties by which we originally identified water,
would not in fact be water. And this, I think, applies not only
to the actual world but even when we talk about counterfactual situations. If there had been a substance, which was a
fool's water, it would then be fool's water and not water. On
the other hand if this substance can take another form-such
" I am not going to give any criterion for what I mean by a 'pure property
r Fregean intension. It is hard to find unquestionable examples of what i
meant. Yellowness certainly expresses a manifest physical property of an
object and, relative to the discussion of gold above, can be regarded as a
property in the required sense. Actually, however, it is not without a certain
referential element of its own, for on the present view yellowness is picked
out and rigidly designated as that external physical property of the object
which we sense by means of the visual impression of yellowness. It does in this
respect resemble the natural kind terms. The phenomenological quality of the
sensation itself, on the other hand, can be regarded as a quale in some pure
sense. Perhaps I am rather vague about these questions, but further precision
seems unnecessary here.
129
as the polywater allegedly discovered in the Soviet Union,
with very different identifying marks from that of what we
now call water—it is a form of water because it is the same
substance, even though it doesn't have the appearances by
which we originally identified water.
Let's consider the statement "Light is a stream of photons' or
'Heat is the motion of molecules. By referring to light, of
course, I mean something which we have some of in this room.
When I refer to heat, I refer not to an internal sensation that
someone may have, but to an external phenomenon which
we perceive through the sense of feeling; it produces a characteristic sensation which we call the sensation of heat. Heat is
the motion of molecules. We have also discovered that increasing heat corresponds to increasing motion of molecules,
or, strictly speaking, increasing average kinetic energy of
molecules. So temperature is identified with mean molecular
kinetic energy. However I won't talk about temperature
because there is the question of how the actual scale is to be set.
It might just be set in terms of the mean molecular kinetic
energy.® But what represents an interesting phenomenological
discovery is that when it's hotter the molecules are moving
faster. We have also discovered about light that light is a stream
of photons; alternatively it is a form of electromagnetic
radiation. Originally we identified light by the characteristic
internal visual impressions it can produce in us, that make us
able to see. Heat, on the other hand, we originally identified
by the characteristic effect on one aspect of our nerve endings
or our sense of touch.
Imagine a situation in which human beings were blind or
their eyes didn't work. They were unaffected by light. Would
that have been a situation in which light did not exist? It seems
• Of course, there is the question of the relation of the statistical mechanical
notion of temperature to, for example, the thermodynamic notion. I wish to
leave such questions aside in this discussion.

I30
to me that it would not. It would have been a situation in
which our eyes were not sensitive to light. Some creatures may
have eyes not sensitive to light. Among such creatures are
unfortunately some people, of course; they are called "blind'.
Even if all people had had awful vestigial growths and just
couldn't see a thing, the light might have been around; but it
would not have been able to affect people's eyes in the proper
way. So it seems to me that such a situation would be a
situation in which there was light, but people could not see it.
So, though we may identify light by the characteristic visual
impressions it produces in us, this seems to be a good example
of fixing a reference. We fix what light is by the fact that it is
whatever, out in the world, affects our eyes in a certain way.
But now, talking about counterfactual situations in which
let's say, people were blind, we would not then say that since,
in such situations, nothing could affect their eyes, light would
not exist; rather we would say that that would be a situation
in which light-the thing we have identified as that which in
fact enables us to see-existed but did not manage to help us
see due to some defect in us.
Perhaps we can imagine that, by some miracle, sound waves
somehow enabled some creature to see. I mean, they gave him
visual impressions just as we have, maybe exactly the same
color sense. We can also imagine the same creature to be
completely insensitive to light (photons). Who knows what
subtle undreamt of possibilities there may be? Would we say
that in such a possible world, it was sound which was light,
that these wave motions in the air were light? It seems to me
that, given our concept of light, we should describe the
situation differently. It would be a situation in which certain
creatures, maybe even those who were called people and
inhabited this planet, were sensitive not to light but to sound
waves, sensitive to them in exactly the same way that we are
sensitive to light. If this is so, once we have found out what
I3I
light is, when we talk about other possible worlds we are
talking about this phenomenon in the world, and not using
'light' as a phrase synonymous with 'whatever gives us the visual
impression—whatever helps us to see'; for there might have
been light and it not helped us to see; and even something else
might have helped us to see. The way we identified light fixed
a reference.
And similarly for other such phrases, such as "hear'. Here heat
is something which we have identified (and fixed the reference
of its name) by its giving a certain sensation, which we call 'the
sensation of heat.
We don't have a special name for this
sensation other than as a sensation of heat. It's interesting that
the language is this way. Whereas you might suppose it, from
what I an saying, to have been the other way. At any rate, we
identify heat and are able to sense it by the fact that it produces
in us a sensation of heat. It might here be so important to the
concept that its reference is fixed in this way, that if someone
else detects heat by some sort of instrument, but is unable to
feel it, we might want to say, if we like, that the concept of
heat is not the same even though the referent is the same.
Nevertheless, the term "heat' doesn't mean 'whatever gives
people these sensations'. For first, people might not have been
sensitive to heat, and yet the heat still have existed in the
external world. Secondly, let us suppose that somehow light
rays, because of some difference in their nerve endings, did give
them these sensations. It would not then be heat but light which
gave people the sensation which we call the sensation of heat.
Can we then imagine a possible world in which heat was not
molecular motion? We can imagine, of course, having discovered that it was not. It seems to me that any case which
someone will think of, which he thinks at first is a case in which
heat—-contrary to what is actually the case—-would have been
something other than molecular motion, would actually be a
case in which some creatures with different nerve endings from

132
ours inhabit this planet (maybe even we, if it's a contingent
fact about us that we have this particular neural structure), and
in which these creatures were sensitive to that something else,
say light, in such a way that they felt the same thing that we
feel when we fcel heat. But this is not a situation in which, say,
light would have been heat, or even in which a stream of
photons would have been heat, but a situation in which a
stream of photons would have produced the characteristic
sensations which we call 'sensations of heat'.
Similarly for many other such identifications, say, that
lightning is electricity. Flashes of lightning are flashes of
electricity. Lightning is an electrical discharge. We can imagine,
of course, I suppose, other ways in which the sky might be
illuminated at night with the same sort of flash without any
electrical discharge being present. Here too, I am inclined to
say, when we imagine this, we imagine something with all the
visual appearances of lightning but which is not, in fact,
lightning. One could be told: this appeared to be lightning
but it was not. I suppose this might even happen now. Someone
might, by a clever sort of apparatus, produce some phenomenon in the sky which would fool people into thinking that
there was lightning even though in fact no lightning was
present. And you wouldn't say that that phenomenon, because
it looks like lightning, was in fact lightning. It was a different
phenomenon from lightning, which is the phenomenon of
an electrical discharge; and this is not lightning but just something that deceives us into thinking that there is lightning.
What characteristically goes on in these cases of, let's say,
"heat is molecular motion'? There is a certain referent which
we have fixed, for the real world and for all possible worlds,
by a contingent property of it, namely the property that it's
able to produce such and such sensations in us. Let's say it's a
contingent property of heat that it produces such and such
sensations in people. It's after all contingent that there should
133
ever have been people on this planet at all. So one doesn't
know a priori what physical phenomenon, described in other
terms—in basic terms of physical theory—is the phenomenon
which produces these sensations. We don't know this, and
we've discovered eventually that this phenomenon is in fact
molecular motion. When we have discovered this, we've discovered an identification which gives us an essential property of this phenomenon. We have discovered a phenomenon
which in all possible
worlds will be molecular motionwhich could not have failed to be molecular motion, because
that's what the phenomenon is.® On the other hand, the
property by which we identify it originally, that of producing
such and such a sensation in us, is not a necessary property but
a contingent one.
This very phenomenon could have existed,
but due to differences in our neural structures and so on, have
failed to be felt as heat. Actually, when I say our neural structures, as those of human beings, I'm really hedging a point
which I made earlier; because of course, it might be part of
the very nature of human beings that they have a neural
structure which is sensitive to heat. Therefore this too could
turn out to be necessary if enough investigation showed it.
This I'm just ignoring,
for the purpose of simplifying the
discussion. At any rate it's not necessary, I suppose, that this
" Some people have been inclined to argue that although certainly we
cannot say that sound waves 'would have been heat' if they had been felt by
the sensation which we feel when we feel heat, the situation is different with
respect to a possible phenomenon, not present in the actual world, and distinct
from molecular motion. Perhaps, it is suggested, there might be another form
of heat other than 'our heat", which was not molecular motion; though no
actual phenomenon other than molecular motion, such as sound,
would
qualify. Similar claims have been made for gold and for light. Although I am
disinclined to accept these views, they would make relatively little difference
to the substance of the present lectures. Someone who is inclined to hold
these views can simply replace the terms "light", "heat", 'pain', etc., in the
examples by 'our light", 'our heat", 'our pain' and the like. I therefore will not
take the space to discuss this issue here.

134
planet should have been inhabited by creatures sensitive to
heat in this way.
I will conclude with some remarks about the application of
the foregoing considerations to the debate over the mind-body
identity thesis. Before I do so, however, I wish to recapitulate
the views I have developed, and perhaps add a point or two.
First, my argument implicitly concludes that certain general
terms, those for natural kinds, have a greater kinship with
proper names than is generally realized. This conclusion holds
for certain for various species names, whether they are count
nouns, such as 'cat", 'tiger', 'chunk of gold', or mass termis such
as "gold', 'water', 'iron pyrites'. It also applies to certain terms
for natural phenomena, such as 'heat', "light', "sound", 'lightning', and, presumably, suitably elaborated, to corresponding
adjectives— hot, 'loud, red".
Mill, as I have recalled, held that although some singular
names, the definite descriptions, have both denotation and
connotation, others, the genuine proper names, had denotation
but not connotation. Mill further maintained that "general
names", or general terms, had connotation. Such terms as
'cow' or "human' are defined by the conjunction of certain
properties which pick out their extension—a human being, for
example, is a rational animal with certain physical characteristics. The hoary tradition of definition by genus and differentia
is of a piece with such a conception. If Kant did, indeed,
suppose that 'gold' could be defined as 'yellow metal", it may
well be this tradition which led him to the definition. ("Metal'
would be the genus, 'yellow' the differentia. The differentia
could hardly include "being gold' without circularity.)
The modern logical tradition, as represented by Frege and
Russell, disputed Mill on the issue of singular names, but endorsed him on that of general names. Thus all terms, both
singular and general, have a "connotation' or Fregean sense.
More recent theorists have followed Frege and Russell, modi-
135
fying their views only by replacing the notion of a sense as
given by a particular conjunction of properties with that of a
sense as given by a 'cluster' of properties, only enough of which
need apply. The present view, directly reversing Frege and
Russell, (more or less) endorses Mill's view of singular terms, but
disputes his view of general terms.
Second, the present view asserts, in the case of species terms
as in that of proper names, that one should bear in mind the
contrast between the a priori but perhaps contingent properties
carried with a term, given by the way its reference was fixed,
and the analytic (and hence necessary) properties a term may
carry, given by its meaning. For species, as for proper nanes,
the way the reference of a term is fixed should not be regarded
as a synonym for the term. In the case of proper names, the
reference can be fixed in various ways. In an initial baptism it
is typically fixed by an ostension or a description. Otherwise,
the reference is usually determined by a chain, passing the
name from link to link. The same observations hold for such
a general term as 'gold'. If we imagine a hypothetical (admittedly somewhat artificial) baptism of the substance, we
must imagine it picked out as by some such 'definition' as,
"Gold is the substance instantiated by the items over there, or
at any rate, by almost all of them'. Several features of this
baptism are worthy of note. First, the identity in the 'definition'
does not express a (completely) necessary truth: though each
of these items is, indeed, essentially (necessarily) gold," gold
might have existed even if the items did not. The definition
does,
however, express an a priori truth, in the same sense
as (and with the same qualifications applied as) "I meter =
length of S': it fixes a reference. I believe that, in general,
• Assuming, of course, that they are all gold; as I say below, some may be
fool's gold. We know in advance, a priori, that it is not the case that the items
are typically fool's gold; and all those items which are actually gold are, of
course, essentially gold.

136
terms for natural kinds (e.g., animal, vegetable, and chemical
kinds) get their reference fixed in this way; the substance is
defined as the kind instantiated by (almost all of) a given
sample. The 'almost all' qualification allows that some fools'
gold may be present in the sample. If the original sample has a
small number of deviant items, they will be rejected as not
really gold. If, on the other hand, the supposition that there is
one uniform substance or kind in the initial sample proves
more radically in error, reactions can vary: sometimes we may
declare that there are two kinds of gold, sometimes we may
drop the term 'gold'. (These pessibilities are not supposed to
be exhaustive.) And the alleged new kind may prove illusory
for other reasons. For example, suppose some items (let the
set of them be I) are discovered and are believed to belong to
a new kind K. Suppose that later it is discovered that the items
in I are indeed of a single kind; however, they belong to a
previously known kind, L. Observational error led to the
false initial belief that the items in I possessed sume characteristic
C excluding them from L. In this case we would surely say
that the kind K does not exist, in spite of the fact that it was
defined by reference to a uniform initial sample. (Note that
if L had not previously been identified, we might well have
said that the kind K did exist, but that we were in error in supposing it to be associated with the characteristic C!) To the
extent that the notion 'same kind' is vaguc, so is the original
notion of gold. Ordinarily, the vagueness doesn't matter in
practice.
In the case of a natural phenomenon perceptible to the
senses, the way the reference is picked out is simple: 'Heat =
that which is sensed by sensation S'. Once again, the identity
fixes a reference: it therefore is a priori, but not necessary,
since heat might have existed, though we did not. 'Heat', like
'gold, is a rigid designator, whose reference is fixed by its
"definition'. Other natural phenomena, such as clectricity, are
I37
originally identified as the causes of certain concrete experimental effects. I do not attempt to give exhaustive characterizations here, only examples.
Third, in the case of natural kinds, certain properties, believed to be at least roughly characteristic of the kind and
believed to apply to the original sample, are used to place new
itens, outside the original sample, in the kind. ("Properties' is
used here in a broad sense, and may include larger kinds: for
example animality and felinity, for tigers.) These properties
need not hold a priori of the kind; later empirical investigation
may establish that some of the properties did not belong to the
original sample, or that they were peculiarities of the original
sample, not to be generalized to the kind as a whole. (Thus the
yellowness of gold may be an optical illusion; or, more
plausibly, though the gold originally observed was indeed
yellow, it could turn out that some gold is white.) On the
other hand, an item may possess all the characteristics originally
used and fail to belong to the kind. Thus an animal may look
just like a tiger, and fail to be a tiger, as mentioned above;
distinct clements in the same column of the periodic table
may resemble each other rather closely. Such failures are the
exception; but, as in the periodic table, they do arise. (Sometimes a failure of the initial sample to have the characteristics
associated with it may lead us to repudiate the species, as in
the I-K-L case above. But this phenomenon is not typical, let
alone universal; see the remarks on the yellowness of gold, or
whether cats are animals.) A priori, all we can say is that it is
at empirical matter whether the characteristics originally
associated with the kind apply to its members universally, or
even ever, and whether they are in fact jointly sufficient for
membership in the kind. (The joint sufficiency is extremely
unlikely to be necessary, but it may be true. In fact, any animal
looking just like a tiger is a tiger—as far as I know—-though it
is (metaphysically) possible that there should have been animals

138
that resenbled tigers but were not tigers. The universal applicability, on the other hand, may well be necessary, if true.
"Cats are animals' has turned out to be a necessary truth. Indeed
of many such statements, especially those subsuming one
species under another, we know a priori that, if they are true
at all, they are necessarily true.)
Fourth, scientific investigation generally discovers characteristics of gold which are far better than the original set. For
example, it turns out that a material object is (pure) gold if and
only if the only element contained therein is that with atomic
number 79. Here, the 'if and only if' can be taken to be strict
(necessary). In general, science attempts, by investigating basic
structural traits, to find the nature, and thus the essence (in the
philosophical sense) of the kind. The case of natural phenomena
is similar; such theoretical identifications as 'heat is molecular
motion' are necessary, though not a priori. The type of property
identity used in science seems to be associated with necessity,
not with a prioricity, or analyticity: For all bodies x and y, x is
hotter than y if and only if * has higher mean molecular
kinetic energy than y. Here the coextensiveness of the predicates
is necessary, but not a priori. The philosophical notion of
attribute, on the other hand, seems to demand a priori (and
analytic) coextensiveness as well as necessary coextensiveness.
Note that on the present view, scientific discoveries of species
essence do not constitute a 'change of meaning'; the possibility
of such discoveries was part of the original enterprise. We
need not even assume that the biologist's denial that whales
are fish shows his "concept of fishhood' to be different from
that of the layman; he simply corrects the layman, discovering
that 'whales are mammals, not fish' is a necessary truth. Neither
'whales are mammals' nor 'whales are fish' was supposed to be
a priori or analytic in any case.
Fifth, and independently of the scientific investigations just
mentioned, the 'original sample' gets augmented by the dis-
139
covery of new items." (In the case of gold, men applied
tremendous effort to the task. Those who doubt the natural
scientific curiosity of Man should consider this case. Only such
anti-scientific fundamentalists as Bryan cast aspersions on the
effort.) More important, the species-name may be passed from
link to link, exactly as in the case of proper names, so that
many who have seen little or no gold can still use the term.
Their reference is determined by a causal (historical) chain,
not by use of any items. I will make even less effort here
to spell out an exact theory than in the case of proper
names.
Usually, when a proper name is passed from link to link,
the way the reference of the name is fixed is oflittle importance
to us. It matters not at all that different speakers may fix the
reference of the name in different ways, provided that they
give it the same referent. The situation is probably not very
different for species names, though the temptation to think
that the metallurgist has a different concept of gold from the
man who has never seen any may be somewhat greater. The
interesting fact is that the way the reference is fixed seems overwhelmingly important to us in the case of sensed phenomena:
a blind man who uses the term "light', even though he uses it
as a rigid designator for the very same phenomenon as we,
seens to us to have lost a great deal, perhaps enough for us to
declare that he has a different concept. ('Concept' here is used
non-technically!) The fact that we identify light in a certain
way seems to us to be crucial, even though it is not necessary;
the intimate connection may create an illusion of necessity. I
think that this observation, together with the remarks on
property-identity above, may well be essential to an under-
10 Obviously, there are also artificialities in this whole account. For example,
it may be hard to say which items constitute the original sample. Gold may
have been discovered independently by various people at various times. I do
not feel that any such complications will radically alter the picture.

I40
standing of the traditional disputes over primary and secondary
qualities."
Let us return to the question of theoretical identification.
Theoretical identities, according to the conception I advocate,
are generally identities involving two rigid designators and
therefore are examples of the necessary a posteriori. Now in
spite of the arguments I gave before for the distinction between
necessary and a priori truth, the notion of a posteriori necessary
truth may still be somewhat puzzling. Someone may well be
inclined to argue as follows: 'You have admitted that heat
might have turned out not to have been molecular motion,
and that gold might have turned out not to have been the
element with the atomic number 79. For that matter, you also
* To understand this dispute, it is especially important to realize that
yellowness is not a dispositional property, although it is related to a disposition.
Many philosophers for want of any other theory of the meaning of the term
"yellow", have been inclined to regard it as expressing a dispositional property.
At the same time, I suspect many have been bothered by the 'gut feeling' that
yellowness is a manifest property, just as much right out there as hardness or
spherical shape. The proper account, on the present conceprion is, of course,
that the reference of "yellowness' is fixed by the description "that (manifest)
property of objects which causes them, under normal circumstances, to be
seen as yellow (i.e., to be sensed by certain visual impressions)'; "yellow", of
course, does not mean 'tends to produce such and such a sensation'; if we had
had different neutral structures, if atmospheric conditions had been different,
if we had been blind, and so on, then yellow objects would have done no such
thing. If one tries to revise the definition of 'yellow' to be, 'tends to produce
such and such visual impressions under circumstances C*, then one will find
that the specification of the circumstances C either circularly involves yellowness or plainly makes the alleged definition into a scientific discovery rather
than a synonymy. If we take the 'fixes a reference' view, then it is up to the
physical scientist to identify the property so marked out in any more fundamental physical terms that he wishes.
Some philosophers have argued that such terms as "sensation of yellow',
"sensation of heat", 'sensation of pain', and the like, could not be in the language
unless they were identifiable in terms of external observable phenomena, such
as heat, yellowness, and associated human behavior. I think that this question
is independent of any view argued in the text.
I4I
have acknowledged that Elizabeth Il might have turned out
not to be the daughter of George VI, or even to originate in
the particular sperm and egg we had thought, and this table
might have turned out to be made from ice made from water
from the Thames. I gather that Hesperus might have turned
out not to be Phosphorus. What then can you mean when you
say that such eventualities are impossible? If Hesperus might
have turned out not to be Phosphorus, then Hesperus might
not have been Phosphorus. And similarly for the other cases: if
the world could have turned out otherwise, it could have been
otherwise. To deny this fact is to deny the self-evident modal
principle that what is entailed by a possibility must itself be
possible. Nor can you evade the difficulty by declaring the
"might have" of "might have turned out otherwise" to be
merely epistemic, in the way that "Fermat's Last Theorem
might turn out to be true and might turn out to be false"
merely expresses our present ignorance, and "Arithmetic might
have turned out to be complete» signals our former ignorance.
In these mathematical cases, we may have been ignorant, but
it was in fact mathematically impossible for the answer to turn
out other than it did. Not so in your favorite cases of essence
and of identity between two rigid designators: it really is
logically possible that gold should have turned out to be a
compound, and this table might really have turned out not to
be made of wood, let alone of a given particular block of wood.
The contrast with the mathematical case could not be greater
and would not be alleviated even if, as you suggest, there may
be mathematical truths which it is impossible to know a priori.
Perhaps anyone who has caught the spirit of my previous
remarks can give my answer himself, but there is a clarification
of my previous discussion which is relevant here. The objector
is correct when he argues that if I hold that this table could not
have been made of ice, then I must also hold that it could not
have turned out to be made of ice; it could have turned out that P

....
I42
entails that P could have been the case. What, then, does the
intuition that the table might have turned out to have been
made of ice or of anything else, that it might even have turred
out not to be made of molecules, amount to? I think that it
means simply that there might have been a table looking and
feeling just like this one and placed in this very position in the
room, which was in fact made of ice. In other words, I (or
some conscious being) could have been qualitatively in the same
epistemic situation that in fact obtains, I could have the same
sensory evidence that I in fact have, about a table which was
made of ice. The situation is thus akin to the one which inspired
the counterpart theorists; when I speak of the possibility of
the table turning out to be made of various things, I am
speaking loosely. This table itself could not have had an origin
different from the one it in fact had, but in a situation qualitatively identical to this one with respect to all the evidence I had
in advance, the room could have contained a table made of ice in
place of this one. Something like counterpart theory is thus
applicable to the situation, but it applies only because we are
not interested in what might have been true of this particular
table, but in what might or might not be true of a table given
certain evidence. It is precisely because it is not true that this
table might have been made of ice from the Thames that we
must tun here to qualitative descriptions and counterparts. To
apply these notions to genuine de re modalities is, from the
present standpoint, perverse.
The general answer to the objector can be stated, then, as
follows: Any necessary truth, whether a priori or a posteriori,
could not have turned out otherwise. In the case of some
necessary a posteriori truths, however, we can say that under
appropriate qualitatively identical evidential situations,
an
appropriate corresponding qualitative statement might have
been false. The loose and inaccurate statement that gold might
have turned out to be a compound should be replaced (roughly)
143
by the statement that it is logically possible that there should
have been a compound with all the properties originally known
to hold of gold. The inaccurate statement that Hesperus might
have turned out not to be Phosphorus should be replaced by
the true contingency mentioned earlier in these lectures: two
distinct bodies might have occupied, in the morning and the
evening, respectively, the very positions actually occupied by
Hesperus-Phosphorus-Venus.' The reason the example of
Fermat's Last Theorem gives a different impression is that
here no analogue suggests itself, except for the extremely
general statement that, in the absence of proof or disproof, it is
possible for a mathematical conjecture to be either true or false.
I have not given any general paradigm for the appropriate
corresponding qualitative contingent statement. Since we are
concerned with how things might have turned out otherwise,
our general paradigm is to redescribe both the prior evidence
and the statement qualitatively and claim that they are only
contingently related. In the case of identities, using two rigid
designators, such as the Hesperus-Phosphorus case above, there
is a simpler paradigm which is often usable to at least approximately the same effect. Let "R,' and 'R,' be the two rigid
designators which flank the identity sign. Then 'R, = Ro' is
necessary if true. The references of "R,' and 'R', respectively,
may well be fixed by nonrigid designators 'D,' and 'D?', in the
Hesperus and Phosphorus cases these have the form 'the
heavenly body in such-and-such position in the sky in the
evening (morning)". Then although 'R, = Rs' is necessary,
" Some of the statements I myself make above may be loose and inaccurate
in this sense. If I say, 'Gold might turn out not to be an element,' I speak
correctly; 'might' here is epistemic and expresses the fact that the evidence does
not justify a priori (Cartesian) certainty that gold is an element. I am also
strictly correct when I say that the clementhood of gold was discovered a
posteriori. If I say, 'Gold might have turned out not to be an element,' I scem to
mean this metaphysically and my statement is subject to the correction noted
in the text.

-..
144
'D, = D,' may well be contingent, and this is often what leads
to the erroneous view that 'R, = R¿' might have turned out
otherwise.
I finally turn to an all too cursory discussion of the application
of the foregoing considerations to the identity thesis. Identity
theorists have been concerned with several distinct types of
identifications: of a person with his body, of a particular
sensation (or event or state of having the sensation) with a
particular brain state (Jones's pain at 06 : 00 was his C-fiber
stimulation at that time), and of types of mental states with the
corresponding types of physical states (pain is the stimulation of
C-fibers). Each of these, and other types of identifications in
the literature, present analytical problems, rightly raised by
Cartesian critics, which cannot be avoided by a simple appeal
to an alleged confusion of synonymy with identity. I should
mention that there is of course no obvious bar, at least (I say
cautiously) none which should occur to any intelligent thinker
on a first reflection just before bedtime, to advocacy of some
identity theses while doubting or denying others. For example,
some philosophers have accepted the identity of particular
sensations with particular brain states while denying the possibility ofidentities between mental and physical types? I will
concern myself primarily with the type-type identities, and the
philosophers in question will thus be immune to much of the
discussion; but I will mention the other kinds ofidentities briefly.
Descartes, and others following him, argued that a person or
mind is distinct from his body, since the mind could exist without the body. He might equally well have argued the same
* Thomas Nagel and Donald Davidson are notable examples. Their views
are very interesting, and I wish I could discuss them in further detail. It is
doubtful that such philosophers wish to call themselves 'materialists'. Davidson,
in particular, bases his case for his version of the identity theory on the supposed impossibility of correlating psychological properties with physical ones.
The argument against token-token identification in the text does apply to
these views.
145
conclusion from the premise that the body could have existed
without the mind." Now the one response which I regard as
plainly inadmissible is the response which cheerfully accepts
the Cartesian premise while denying the Cartesian conclusion.
Let 'Descartes' be a name, or rigid designator, of a certain
person, and let 'B' be a rigid designator of his body. Then if
Descartes were indeed identical to B, the supposed identity,
being an identity between two rigid designators, would be
necessary, and Descartes could not exist without B and B could
not exist without Descartes. The case is not at all comparable to
the alleged analogue, the identity of the first Postmaster
General with the inventor of bifocals. True, this identity
obtains despite the fact that there could have been a first
Postmaster General even though bifocals had never been
invented. The reason is that 'the inventor of bifocals' is not a
rigid designator; a world in which no one invented bifocals is
not ipso facto a world in which Franklin did not exist. The
alleged analogy therefore collapses; a philosopher who wishes
76 Of course, the body does exist without the mind and presumably without
the person, when the body is a corpse. This consideration, if accepted, would
already show that a person and his body are distinct. (See David Wiggins, 'On
Being at the Same Place at the Same Time', Philosophical Review, Vol. T7
(1968), pp. go-s.) Similarly, it can be argued that a statue is not the hunk of
matter of which it is composed. In the latter case, however, one might say
instead that the former is 'nothing over and above' the latter; and the same
device might be tried for the relation of the person and the body. The difficulties in the text would not then arise in the same form, but analogous difficulties
would appear. A theory that a person is nothing over and above his body in
the way that a statue is nothing over and above the matter of which it is
composed, would have to hold that (necessarily) a person exists if and only if
his body exists and has a certain additional physical organization. Such a thesis
would be subject to modal difficulties similar to those besetting the ordinary
identity thesis, and the same would apply to suggested analogues replacing the
identification of mental states with physical states. A further discussion of this
matter must be left for another place. Another view which I will not discuss,
although I have little tendency to accept it and am not even certain that it has
been set out with genuine clarity, is the so-called functional state view of
psychological concepts.

I46
to refute the Cartesian conclusion must refute the Cartesian
premise, and the latter task is not trivial.
Let 'A' name a particular pain sensation, and let 'B' name
the corresponding brain state, or the brain state some identity
theorist wishes to identify with A. Prima facie, it would seem
that it is at least logically possible that B should have existed
(Jones's brain could have been in exactly that state at the time
in question) without Jones feeling any pain at all, and thus
without the presence of A. Once again, the identity theorist
cannot admit the possibility cheerfully and proceed from there;
consistency, and the principle of the necessity of identities
using rigid designators, disallows any such course. If A and B
were identical, the identity would have to be necessary. The
difficulty can hardly be evaded by arguing that although B
could not exist without A, being a pain is merely a contingent
property of A, and that therefore the presence of B without
pain does not imply the presence of B without A. Can any
case of essence be more obvious than the fact that being a pain is
a necessary property of each pain? The identity theorist who
wishes to adopt the strategy in question must even argue that
being a sensation is a contingent property of A, for prima facie it
would seem logically possible that B could exist without any
sensation with which it might plausibly be identified. Consider
a particular pain, or other sensation, that you once had. Do you
find it at all plausible that that very sensation could have existed
without being a sensation, the way a certain inventor (Franklin)
could have existed without being an inventor?
I mention this strategy because it seems to me to be adopted
by a large number of identity theorists. These theorists, believing as they do that the supposed identity of a brain state
with the corresponding mental state is to be analyzed on the
paradigm of the contingent identity of Benjamin Franklin
with the inventor of bifocals, realize that just as his contingent
activity made Benjamin Franklin into the inventor of bifocals,
147
so some contingent property of the brain state must make it
into a pain. Generally they wish this property to be one
statable in physical or at least 'topic-neutral' language, so that
the materialist cannot be accused of positing irreducible nonphysical properties. A typical view is that being a pain, as a
property of a physical state, is to be analyzed in terms of the
'causal role' of the state,? in terms of the characteristic stimuli
(e.g., pinpricks) which cause it and the characteristic behavior
it causes. I will not go into the details of such analyses, even
though I usually find them faulty on specific grounds in
addition to the general modal considerations I argue here. All
I need to observe here is that the "causal role' of the physical
state is regarded by the theorists in question as a contingent
property of the state, and thus it is supposed to be a contingent
property of the state that it is a mental state at all, let alone that
it is something as specific as a pain. To repeat, this notion seems
to me self-evidently absurd. It amounts to the view that the
very pain I now have could have existed without being a mental
state at all.
I have not discussed the converse problem, which is closer to
the original Cartesian consideration—namely, that just as it
seems that the brain state could have existed without any pain,
so it seems that the pain could have existed without the
corresponding brain state. Note that being a brain state is
evidently an essential property of B (the brain state). Indeed,
even more is true: not only being a brain state, but even being
a brain state of a specific type is an essential property of B. The
configuration of brain cells whose presence at a given time
constitutes the presence of B at that time is essential to B, and
in its absence B would not have existed. Thus someone who
76 For example, David Armstrong, A Materialist Theory of the Mind, London
and New York, 1968, see the discussion review by Thomas Nagel, Philosophical
Review 79 (1970), PP. 394-403; and David Lewis, 'An Argument for the
Identity Theory, The Journal of Philosophy, pp. 17-25.

148
wishes to claim that the brain state and the pain are identical
must argue that the pain A could not have existed without a
quite specific type of configuration of molecules. If A = B,
then the identity of A with B is necessary, and any essential
property of one must be an essential property of the other.
Someone who wishes to maintain an identity thesis cannot
simply accept the Cartesian intuitions that A can exist without
B, that B can exist without A, that the correlative presence of
anything with mental properties is merely contingent to B,
and that the correlative presence of any specific physical
properties is merely contingent to A. He must explain these
intuitions away, showing how they are illusory. This task
may not be impossible; we have seen above how some things
which appear to be contingent turn out, on closer examination,
to be necessary. The task, however, is obviously not child's
play, and we shall see below how difficult it is.
The final kind of identity, the one which I said would get the
closest attention, is the type-type sort of identity exemplified
by the identification of pain with the stimulation of C-fibers.
These identifications are supposed to be analogous with such
scientific type-type identifications as the identity of heat with
molecular motion, of water with hydrogen hydroxide, and
the like. Let us consider, as an example, the analogy supposed
to hold between the materialist identification and that of heat
with molecular motion; both identifications identify two types
of phenomena. The usual view holds that the identification of
heat with molecular motion and of pain with the stimulation
of C-fibers are both contingent. We have seen above that
since 'heat' and "molecular motion' are both rigid designators,
the identification of the phenomena they name is necessary.
What about 'pain' and 'C-fiber stimulation'? It should be clear
from the previous discussion that "pain' is a rigid designator of
the type, or phenomenon, it designates: if something is a pain
it is essentialiy so, and it seems absurd to suppose that pain
149
could have been some phenomenon other than the one it is.
The same holds for the term 'C-fiber stimulation', provided
that 'C-fibers' is a rigid designator, as I will suppose here. (The
supposition is somewhat risky, since I know virtually nothing
about C-fibers, except that the stimulation of them is said to
be correlated with pain.?" The point is unimportant; if 'C-
fibers' is not a rigid designator, simply replace it by one which
is, or suppose it used as a rigid designator in the present
context.) Thus the identity of pain with the stimulation of
C-fibers, if true, must be necessary.
So far the analogy between the identification of heat with
molecular motion and pain with the stimulation of C-fibers
has not failed; it has merely turned out to be the opposite of
what is usually thought-both, if true, must be necessary. This
means that the identity theorist is committed to the view that
there could not be a C-fiber stimulation which was not a pain
nor a pain which was not a C-fiber stimulation. These consequences are certainly surprising and counterintuitive, but let
us not dismiss the identity theorist too quickly. Can he perhaps
show that the apparent possibility of pain not having turned out
to be C-fiber stimulation, or of there being an instance of one of
" I have been surprised to find that at least one able listener took my use of
such terms as "correlated with', "corresponding to', and the like as already
begging the question against the identity thesis. The identity thesis, so he said,
is not the thesis that pains and brain states are correlated, but rather that they
are identical. Thus my entire discussion presupposes the anti-materialist
position that I set out to prove. Although I was surprised to hear an objection
which concedes so little intelligence to the argument, I have tried especially to
avoid the term 'correlated' which seeins to give rise to the objection. Nevertheless, to obviate misunderstanding, I shall explain my usage. Assuming, at
least arguendo, that scientific discoveries have turned out so as not to refute
materialism from the beginning, both the dualist and the identity theorist
agree that there is a correlation or correspondence between mental states and
physical states. The dualist holds that the "correlation' relation in question is
irreflexive; the identity theorist holds that it is simply a special case of the
identity relation. Such terms as 'correlation' and 'correspondence' can be used
neutrally without prejudging which side is correct.

Iso
the phenomena which is not an instance of the other, is an
illusion of the same sort as the illusion that water might not
have been hydrogen hydroxide, or that heat might not have
been molecular motion? If so, he will have rebutted the
Cartesian, not, as in the conventional analysis, by accepting
his premise while exposing the fallacy of his argument,
but
rather by the reverse-while the Cartesian argument, given
its premise of the contingency of the identification, is granted
to yield its conclusion, the premise is to be exposed as superficially plausible but false.
Now I do not think it likely that the identity theorist will
succeed in such an endeavor. I want to argue that, at least, the
case cannot be interpreted as analogous to that of scientific
identification of the usual sort, as exemplified by the identity of
heat and molecular motion. What was the strategy used above
to handle the apparent contingency of certain cases of the
necessary a posteriori? The strategy was to argue that although
the statement itself is necessary, somcone could, qualitatively
speaking, be in the same epistemic situation as the original,
and in such a situation a qualitatively analogous statement could
be false. In the case of identities between two rigid designators,
the strategy can be approximated by a simpler one: Consider
how the references of the designators are determined; if these
coincide only contingently, it is this fact which gives the
original statement its illusion of contingency. In the case of
heat and molecular motion, the way these two paradigms
work out is simple. When someone says, inaccurately, that
heat might have turned out not to be molecular motion, what
is true in what he says is that someone could have sensed a
phenomenon in the same way we sense heat, that is, feels it by
means of its production of the sensation we call 'the sensation
of heat' (call it "S'), even though that phenomenon was not
molecular motion. He means, additionally, that the planet
might have been inhabited by creatures who did not get S
ISI
when they were in the presence of molecular motion, though
perhaps getting it in the presence of something else. Such
creatures would be, in some qualitative sense, in the same
pistemic situation as we are, they could use a rigid designator
for the phenomenon that causes sensation S in them (the rigid
designator could even be "heat'), yet it would not be molecular
motion (and therefore not heat!), which was causing the
Now can something be said analogously to explain away
the feeling that the identity of pain and the stimulation of
C-fibers, if it is a scientific discovery, could have turned out
otherwise? I do not see that such an analogy is possible. In the
case of the apparent possibility that molecular motion might
have existed in the absence of heat, what seemed really possible
is that molecular motion should have existed without being
felt as heat, that is, it might have existed without producing
the sensation S, the sensation of heat. In the appropriate
sentient beings is it analogously possible that a stimulation of
C-fibers should have existed without being felt as pain? If this
is possible, then the stimulation of C-fibers can itself exist
without pain, since for it to exist without being felt as pain is
for it to exist without there being any pain. Such a situation
would be in flat out contradiction with the supposed necessary
identity of pain and the corresponding physical state, and the
analogue holds for any physical state which might be identified
with a corresponding mental state. The trouble is that the
identity theorist does not hold that the physical state merely
produces the mental state, rather he wishes the two to be identical
and thus a fortiori necessarily co-occurrent. In the case of
molecular motion and heat there is something, namely, the
sensation of heat,
which is an intermediary between
the
external phenomenon and the observer. In the mentalphysical case no such intermediary is possible, since here the
physical phenomenon is supposed to be identical with the

I§2
internal phenomenon itself. Someone can be in the same
epistemic situation as he would be if there were heat, even in
the absence of heat, simply by feeling the sensation of heat;
and even in the presence of heat, he can have the same evidence
as he would have in the absence of heat simply by lacking the
sensation S. No such possibility exists in the case of pain and
other mental phenomena. To be in the same epistemic situation
that would obtain if one had a pain is to have a pain; to be in
the same epistemic situation that would obtain in the absence
of a pain is not to have a pain. The apparent contingency of
the connection between the mental state and the corresponding brain state thus cannot be explained by some sort of
qualitative analogue as in the case of heat.
We have just analyzed the situation in terms of the notion of
a qualitatively identical epistemic situation. The trouble is that
the notion of an epistemic situation qualitatively identical to
one in which the observer had a sensation S simply is one in
which the observer had that sensation. The same point can be
made in terms of the notion of what picks out the reference of
a rigid designator. In the case of the identity of heat with
molecular motion the important consideration was that although 'heat' is a rigid designator, the reference of that
designator was determined by an accidental property of the
referent, namely the property of producing in us the sensation
S. It is thus possible that a phenomenon should have been
rigidly designated in the same way as a phenomenon of heat,
with its reference also picked out by means of the sensationS,
without that phenomenon being heat and therefore without
its being molecular motion. Pain, on the other hand, is not
picked out by one of its accidental properties; rather it is
picked out by the property of being pain itself, by its immediate phenomenological quality. Thus pain, unlike heat, is
not only rigidly designated by 'pain' but the reference of the
designator is determined by an essential property of the
153
referent. Thus it is, not possible to say that although pain is
necessarily identical with a certain physical state, a certain
phenomenon can be picked out in the same way we pick out
pain without being correlated with that physical state. If any
phenomenon is picked out in exactly the same way that we
pick out pain, then that phenomenon is pain.
Perhaps the same point can be made more vivid without
such specific reference to the technical apparatus in these
lectures. Suppose we imagine God creating the world; what
does He need to do to make the identity of heat and molecular
motion obtain? Here it would seem that all He needs to do is
to create the heat, that is, the molecular motion itself. If the
air molecules on this earth are sufficiently agitated, if there is a
burning fire, then the earth will be hot even if there are no
observers to see it. God created light (and thus created streams
of photons, according to present scientific doctrine) before He
created human and animal observers; and the same presumably holds for heat. How then does it appear to us that the
identity of molecular motion with heat is a substantive scientific
fact, that the mere creation of molecular motion still leaves God
with the additional task of making molecular motion into
heat? This feeling is indeed illusory, but what is a substantive
task for the Deity is the task of making molecular motion felt
as heat. To do this He must create some sentient beings to
insure that the molecular motion produces the sensation S in
them. Only after he has done this will there be beings who can
Icarn that the sentence 'Heat is the motion of molecules' expresses an a posteriori truth in precisely the same way that we do.
What about the case of the stimulation of C-fibers? To create
this phenomenon, it would seem that God need only create
beings with C-fibers capable of the appropriate type of physical
stimulation; whether the beings are conscious or not is
irrelevant here. It would seem, though, that to make the C-fiber
stimulation correspond to pain, or be felt as pain, God must

154
do something in addition to the mere creation of the C-fiber
stimulation; He must let the creatures feel the C-fiber stimulation as pain, and not as a tickle, or as warmth, or as nothing, as
apparently would also have been within His powers. If these
things in fact are within His powers, the relation between the
pain God creates and the stimulation of C-fibers cannot be
identity. For if so, the stimulation could exist without the pain;
and since 'pain' and 'C-fiber stimulation' are rigid, this fact
implies that the relation between the two phenomena is not
that of identity. God had to do some work, in addition to
making the man himself, to make a certain man be the inventor
of bifocals; the man could well exist without inventing any
such thing. The same cannot be said for pain; if the phenomenon exists at all, no further work should be required to
make it into pain.
In sum, the correspondence between a brain state and a
mental state seems to have a certain obvious element of contingency. We have seen that identity is not a relation which
can hold contingently between objects. Therefore, if the
identity thesis were correct, the element of contingency would
not lie in the relation between the mental and physical states.
It cannot lie, as in the case of heat and molecular motion, in
the relation between the phenomenon (= heat = molecular
motion) and the way it is felt or appears (sensation S), since in
the case of mental phenomena there is no 'appearance' beyond
the mental phenomenon itself.
Here I have been emphasizing the possibility, or apparent
possibility, of a physical state without the corresponding mental
state. The reverse possibility, the mental state (pain) without
the physical state (C-fiber stimulation) also presents problems
for the identity theorists which cannot be resolved by appeal
to the analogy of heat and molecular motion.
I have discussed similar problems more briefly for views
equating the self with the body, and particular mental events
ISS
with particular physical events, without discussing possible
countermoves in the same detail as in the type-type case.
Suffice it to say that I suspect that the considerations given
indicate that the theorist who wishes to identify various
particular mental and physical events will have to face problems
fairly similar to those of the type-type theorist; he too will be
unable to appeal to the standard alleged analogues.
That the usual moves and analogies are not available to solve
the problems of the identity theorist is, of course, no proof
that no moves are available. I certainly cannot discuss all the
possibilities here. I suspect, however, that the present considerations tell heavily against the usual forms of materialism.
Materialism, I think, must hold that a physical description of
the world is a complete description of it, that any mental facts
are 'ontologically dependent' on physical facts in the straightforward sense of following from them by necessity. No
identity theorist seems to me to have made a convincing
argument against the intuitive view that this is not the case."
"Having expressed these doubts about the identity theory in the text, I
should emphasize two things: first, identity theorists have presented positive
arguments for their view, which I certainly have not answered here. Some of
these arguments seem to me to be weak or based on idcological prejudices, but
others strike me as highly compelling arguments which I am at present unable
to answer convincingly. Second, rejection of the identity thesis does not imply
acceptance of Cartesian dualism. In fact, my view above that a person could
not have come from a different sperm and egg from the ones from which he
actually originated implicitly suggests a rejection of the Cartesian picture. If
we had a clear idea of the soul or the mind as an independent, subsistent,
spiritual entity, why should it have to have any necessary connection with
particular material objects such as a particular sperm or a particular egg? A
convinced dualist may think that my views on sperms and eggs beg the
question against Descartes. I would tend to argue the other way; the fact that
it is hard to imagine me coming from a sperm and egg different from my
actual origins seems to me to indicate that we have no such clear conception
of a soul or self. In any event, Descartes' notion seems to have been rendered
dubious ever since Hume's critique of the notion of a Cartesian self. I regard
the mind-body problem as wide open and extremely confusing.

ADDENDA
These addenda represent certain amplifications of the original
text which I have added either in response to questions or for
the sake of clarification or sketchy amplification.
(a) Unicorns, pp. 23-4. In the light of the remarks on natural
kinds made in the third lecture, I shall try to give a brief
explanation of the strange view of unicorns advocated in the
text. There were two theses: first, a metaphysical thesis that no
counterfactual situation is properly describable as one in which
there would have been unicorns; second, an epistemological
thesis that an archeological discovery that there were animals
with all the features attributed to unicorns in the appropriate
myth would not in and of itself constitute proof that there
were unicorns.
As to the metaphysical thesis, the argument basically is the
following. Just as tigers are an actual species, so the unicorns
are a mythical species. Now tigers, as I argue in the third
lecture, cannot be defined simply in terms of their appearance;
it is possible that there should have been a different species
with all the external appearances of tigers but which had a
different internal structure and therefore was not the species of
tigers. We may be misled into thinking otherwise by the fact
that actually no such 'fool's tigers' exist, so that in practice
external appearance is sufficient to identify the species. Now
there is no actual species of unicorns, and regarding the several
I57
distinct hypothetical species, with different internal structures
(some reptilic, some mammalian, some amphibious), which
would have the external appearances postulated to hold of
unicorns in the myth of the unicorn, one cannot say which of
these distinct mythical species would have been the unicorns.
If we suppose, as I do, that the unicorns of the myth were
supposed to be a particular species, but that the myth provides
insufficient information about their internal structure to
determine a unique species, then there is no actual or possible
species of which we can say that it would have been the species
of unicorns.
The epistemological thesis is more casily argued. If a story
is found describing a substance with the physical appearance of
gold, one cannot conclude on this basis that it is talking about
gold; it may be talking about fools gold'. What substance is
eing discussed must be determined as in the case of proper
names: by the historical connection of the story with a certain
substance. When the connection is traced, it may well turn
out that the substance dealt with was gold, 'fools' gold", or
something else. Similarly, the mere discovery of animals with
the properties attributed to unicorns in the nyth would by no
means show that these were the animals the myth was about:
perhaps the myth was spun out of whole cloth, and the fact
that animals with the same appearance actually existed was
mere coincidence. In that casc, we cannot say that the unicorns
of the myth really existed; we must also establish a historical
connection that shows that the myth is about these animals.
I hold similar views regarding fictional proper names. The
mere discovery that there was indeed a detective with exploits
like those of Sherlock Holmes would not show that Conan
Doyle was writing about this man; it is theoretically possible,
though in practice fantastically unlikcly, that Doyle was
writing pure fiction with only a coincidental resemblance to the
actual man. (See the characteristic disclaimer: "The characters

158
in this work are fictional, and any resemblance to anyone,
living or dead, is purely coincidental.') Similarly, I hold the
metaphysical view that, granted that there is no Sherlock
Holmes, one cannot say of any possible person that he would
have been Sherlock Holmes, had he existed. Several distinct
possible people, and even actual ones such as Darwin or Jack
the Ripper, might have performed the exploits of Holmes,
but there is none of whom we can say that he would have been
Holmes had he performed these exploits. For if so, which one?
I thus could no longer write, as I once did, that Holmes does
not exist, but in other states of affairs, he would have existed.'
(See my 'Semantical Considerations on Modal Logic', Acta
Philosophica Fennica, Vol. 16 (1963) PP. 83-94; reprinted in L.
Linsky (ed.), Reference and Modality, Oxford University Press,
(1971; p. 65 in the Linsky reprint.) The quoted assertion gives
the erroneous impression that a fictional name such as 'Holmes'
names a particular possible-but-not-actual individual. The substantive point I was trying to make, however, remains and is
independent of any linguistic theory of the status of nanies in
fiction. The point was that, in other possible worlds "some
actually existing individuals may be absent while new individuals ... may appear' (ibid, p. 6s), and that if in an open
formula A (x) the free variable is assigned a given individual as
value, a problem arises as to whether (in a model-theoretic
treatment of modal logic) a truth-value is to be assigned to the
formula in worlds in which the individual in question does not
exist.
I am aware that the cryptic brevity of these remarks dininishes whatever persuasiveness they may otherwise possess. I
expect to elaborate on then elsewhere, in a forthcoming work
discussing the problems of existential statements, empty names,
and fictional entities.
(b) Can to must, first paragraph of p. 35. An unpublished
paper by Barry I. Stroud has called my attention to the fact
I59
that Kant himself. makes a closely related mistake. Kant
says,
'Experince teaches us that a thing is so and so, but
not that it cannot be otherwise. First, then, if we have a
proposition which in being thought is thought as necessary,
it is an a priori judgement... Necessity and strict universality
are thus sure criteria of a priori knowledge'. (Critique of
Pure Reason B3-4, pp. 43-4 in the Kemp Smith translation,
Macmillan, 1956.) Kant thus appears to hold that if a proposition is known to be necessary, the mode of knowledge not
only can be a priori but must be. On the contrary, one can
learn a mathematical truth a posteriori by consulting a computing machine, or even by asking a mathematician. Nor can
Kant argue that experience can tell us that a mathematical
proposition is true, but not that it is necessary; for the peculiar
character of mathematical propositions (like Goldbach's conjecture) is that one knows (a priori) that they cannot be
contingently true; a mathematical statement, if true, is
necessary.
All the cases of the necessary a posteriori advocated in the text
have the special character attributed to mathematical statements: Philosophical analysis tells us that they cannot be
contingently true, so any empirical knowledge of their truth is
automatically empirical knowledge that they are necessary.
This charactcrization applies, in particular, to the cases of
identity statements and of essence. It may give a clue to a
general characterization of a posteriori knowledge of necessary
truths.
I should mention that if the possibility of knowing a mathematical truth by consulting a computer were the only objection
to Kant offered, it would still be open to him to hold: (1) that
every necessary truth is knowable a priori; or, more weakly,
(2) that every necessary truth, if known at all, must be knowable a priori. Both (1) and (2) involve the obscure notion of the
possibility of a priori knowledge, but to the extent that the

Ібо
notion is clarified by restricting it to a priori knowledge of a
standard human sort, I argue against both (1) and (2) in the
text. In fact, of course, I hold that propositions that contemporary philosophers would properly count as 'empirical
can be neccssary and be known to be such.
Perhaps I should mention also that I have been unable to
find the characterization of a priori truth as truth which can be
known independently of experince in Kant; as far as 1 can
sec, Kant refers only to a priori knowiedge of particular statements, which does not involve the extra modality. (In the text,
I incautiously ascribed this common characterization of a
priori truth to Kant.) And, of course, when Kant uses "necessary'
for a type of proposition and 'a priori' for a mode of knowledge
he cannot possibly be guilty of the common contemporary
practice of treating the two terms as interchangeable synonyms.
It is clear from the opening pages of the Critique that he regards
the thesis that knowledge that something is necessary must be
a priori knowledge as an important, though obvious, substantive thesis.
(c) Some remarks that I have heard lead me to suppose that
the noncircularity condition could use further clarification.
First, my remark on p. 68 has been misunderstood to say
that a definition such as "Jonah is the man referred to by that
name in the Bible' necessarily violates the noncircularity
condition. It does not, provided that the description theory can
give an account of the Biblical authors' reference which is
independent of our own. When I discuss Strawson, I explicitly
acknowledge that a speaker may use a description of this sort
which "passes the buck' and that the procedure is noncircular
provided that the other speaker's description does not ultimately
involve the references made by the original speaker. Thus I
can say, 'Let "Glumph" be a name of the thing Jones calls
"Glumph", provided that Jones does not simultaneously say,
Let "Glumph" be a name of the thing Kripke calls "Glumph"!
ıбI
The objection to such noncircular determinations of reference
as Let "Glumph" be the man Jones calls "Glumph" and,
Let Gödel be the man to whom the experts attribute the
incompleteness theorem' (said by a layman) is otherwise: In
general, a speaker cannot be sure from whom he picked up
his reference; and as far as he knows 'the experts' may well
realize that Schmidt, not Gödel, proved the incompleteness
theorem even though the inexpert speaker still attributes it to
Gödel. Thus such determinations of the referent may well give
the wrong result, and the speaker surely cannot be said to
know a priori (as in Thesis s) that they do not. (See my criticisms
of Strawson in the text.) If, on the other hand, the speaker
attempts to avoid the possibility of such error by using his
own reference as the paradigm, as in such determinations as
'Let Glumph be the man I call "Glumph" (now)' or 'Let
Gödel be the man I believe to have proved the incompleteness
theorem,' the determination of the reference is circular (unless
the speaker has already determined his reference in some other
way, in which case that is the determining condition and not
the one stated). Often the determination of the reference risks
falling afoul both of circularity and of vulnerability to error,
for the speaker may not know whether those others to whom
he 'passes the buck' may not in turn pass the buck to him.
Blatant cases of vulnerability to both types of criticisms is to be
found in such determinations as, 'Let "Glumph" denote the
man all of us in Community C call "Glumph"; or 'Let
"Gödel" denote the man presently generally believed in
Community C to have proved the incompleteness theorem,'
if this determination is supposed to be the one used throughout
Community C. For an individual speaker may err in such a
determination if the community in gencral has been apprised
of the Gödel-Schmidt fraud but the speaker has not; and even
if the possibility of error is waived, the determination will be
circular if it is supposed that all, or even the large majority, of

162
the speakers of Community C use it to determine their
reference.
All these points are stated in the text, but misunderstandings
have led me to believe that a summary restatement could
conceivably do some good. Quite a different way of deterinining the reference would be, 'Let "Glumph" denote the man
called "Glumph" by the people from whom I got it (whoever
they are), provided that my present determination of the
reference satisfies the conditions sketched in
"Naming and
Necessity" and whatever other conditions need be satisfied'.
As I said in footnote 38, such a determination would constitute
a trivial fulfillment of the description theory in terms of the
present view if only the present view were not somewhat
loose and did not already involve the notion of the speaker's
own reference (in terms of his intention to agree in reference
with those from whom he picked up the name). Even if both
these problems were surmounted, the resulting description
would hardly be one of the type which occurs to a speaker
when he is asked such a question as, 'Who is Napoleon?, as
the description theorists intended. It would occur only to those
speakers who have mastered a complex theory of reference,
and it would be this theory, of course, and not the speaker s
knowledge of a description, which gave the true picture of
how the reference was determined.
(d) Initial baptism', p. g6. In footnote 70 on natural kind
terms, I mention that the notion of an initial sample appealed
to there gives an oversimplified picture of the case. Analogously
for proper names, of course I recognize that there need not
always be an identifiable initial baptism; so the picture is
oversimplified. Of course I also think, analogously to footnote
70, that such complications will not radically alter the picture.
It is probably true, however, that in the case of proper names,
examples with no identifiable initial baptism are rarer than in
the species case.
163
(e) Santa Claus, p. 93 and pp. 96-7. Gareth Evans has pointed
out that similar cases of reference shifts arise where the shit is
not from a real entity to a fictional one, but from one real
entity to another of the same kind. According to Evans,
'Madagascar' was a native name for a part of Africa; Marco
Polo, erroneously thinking that he was following native usage,
applied the name to an island. (Evans uses the example to
support the description theory; I, of course, do not.) Today
the usage of the name as a name for an island has become so
widespread that it surely overrides any historical connection
with the native name. David Lewis has pointed out that the
same thing could have happened even if the natives had used
'Madagascar' to designate a mythical locality. So real reference
can shift to another real reference, fictional reference can shift
to real, and real to fictional. In all these cases, a present intention
to refer to a given entity (or to refer fictionally) overrides the
original intention to preserve reference in the historical chain
of transmission. The matter deserves extended discussion. But
the phenomenon is perhaps roughly explicable in terns of the
predominantly social character of the use of proper names
emphasized in the text: we use names to communicate with
other speakers in a common language. This character dictates
ordinarily that a speaker intend to use a name the same way as
it was transmitted to him; but in the 'Madagascar' case this
social character dictates that the present intention to refer to
an island overrides the distant link to native usage. (Probably
Miller's case, 'George Smith' vs. 'Newton' is similarly explicable.) To state all this with any precision undoubtedly
requires more apparatus than I have developed here; in particular, we must distinguish a present intention to use a name
for an object from a mere present belief that the object is the
only one having a certain property, and clarify this distinction.
I leave the problem for further work.
(f) I perhaps should mention (amplifying p. 23 n. 2) that

164
the historical acquisition picture of naming advocated here is
apparently very similar to views of Keith Donnellan. (Charles
Chastain also made similar suggestions, but they had a greater
admixture of the old description theory.) David Kaplan's
investigation of 'Dthat', mentioned in footnote 22, has been
extended to a 'logic of demonstratives' in which, he says, a
good deal of the argument of this paper can be given a formal
representation. Indeed a good deal of this paper suggests a
certain formal apparatus, though the present presentation is
informal.
(g) The third lecture suggests that a good deal of what contemporary philosophy regards as mere physical necessity is
actually necessary tout court. The question how far this can be
pushed is one I leave for further work.
INDEX
Albritton, Rogers, 23n, 122n
Alpha Centauri, 95
Analytic truth, 34, 39, són, I17,
I22, 135
A posteriori truth, see A priori
truth, Necessary a posteriori
truth
A priori truth (a prioricity), as
epistemological notion, 34-9,
63, 122-3, 158-60; Kant's
views on, 34, I17, I58-60;
see also Contingent a priori
truth, Necessary a posteriori
truth
Aristotle, 6-14, 29-30, 57, 61-3,
65,74-s
Armstrong, David, 147n
Atomic number, 116, 123-S,
138,I40; see also Gold
Attribute, 138
"Baptism', initial, 78, 96-7, 106,
135-40, 162
"Bare particulars, 18, 52
Bifocals, the inventor of, 98,
145-6,154
Brain state, see Mind-body
identity thesis
Cartesian dualism, Issn
Catiline, 79-81
Cats, 122-3, 125-6, 134
Causal chain (in reference), see
Chain of communication
Causal role (of mental states), 147
Certainty, 34, 39
C-fibers, 98, 144, 148-54
Chain of communication (in
reference), 8n, s9n, 9I-7, 106,
тІбп, І3S, 139, I57, 163-4;
and shift of reference, 93-7,
163-4
Chastain, Charles, 23n, 164
Cicero, 20, 79-81, 92, 97n, 98,
I00-1, 107-8
Cluster concept, ssn, 6o, 76,
I20-I, 122n
'Cluster of descriptions' theory
of proper names, see Description theory of proper names
Columbus, C., 85
Connotation (Mill), 26, 127, 134
Contingent a priori truth, I4-IS,
54-7, 63, 66, 75-6, 78-9, 80-
91 passim, gón, 135-8; see also
Fixing the reference of a term,
Rigid designators

166
INDEX
78-97, 106-7
76-7,142
48-9
6I-2
129
Gold
101, 164
properties
ISS
propertics
Everest, 100
143
I34-S
INDEX
167
Gaurisanker, 100
Geach, Peter, 23n, II Sn
Gell-Mann, Murray 81, 91
General term, 127-8, 134-40;
see also Natural kinds, Natural
phenomena
Gilbert, Margaret, I
Ginsberg, H. L., 67n
'Glumph', 'Glunk', 73, 160-2
God, 26-7, 153-4
Gödel, K., 37, 83-92, 161
Gold, 39, 116-19, 123-S, 127,
134-40, 142-3, 157; fool's, see
Iron pyrites
Goldbach's conjecture, 36-8, 159
Hadleyburg, the man who corrupted, 24,28
Heat, 98-2, 129, 131-4, 136, 138,
140,148-54
Henry 1, 76
Hesperus, 20, 28-9, 57-8, 78-9,
94,98, 100-5, 108-10, IIOn
Hilbert, D., 37
Historical connection (of term
with referent), see Chain of
communication
Hitler, A., 75, 77-8
H,O, 99, 116, 128-9, 134, 148,
150; see also Water
Holmes, Sherlock, 157-8
Holy Roman Empire, The, 26
Humphrey, H., 45n, 48-9
Identifying marks (properties) of
a natural kind, original, I18-
122, 124-6, 128-2, 137-8, 156
Identity, 'across possible worlds',
see "Transworld identification;
criterion of, 17, 42-53, 1ISn;

168
INDEX
139, IS3
, 116, 126-31, 134.
SO-I
135
128, 134-S
thesis
INDEX
I09
39-53
properties
Nancy', riốn
Tigers, etc.
Light
IISn, I40-2
тт, бо
Peano, G., 84-s, 88-»
Person, and identity with body,

170
Person-cont.
144-6; see also Mind-body
identity thesis
Phosphorus (pianet), 20, 28-9,
80n, 98, 100-s, 108-10
Photons, 98-9, 116, 129, 130,
132,153
Physical phenomena, see Natural
phenomena
INDEX
proper names
duals, 158
137-8, 156
stipwated, not discovered, 44,
49
Postmaster General of the
Unites States, first, 98-2, 145
Proper names, correct picture of
ary, 140
reference of, 91-7,98-164
passim; description theory of,
see Description theory of
proper names; in epistemic
contexts, 20-1; in fiction and
legend, 66-7,93,96-7, 157-8,
163: "homonymous, 7-10;
and identity statements, see
Identity, necessity of; as
rigid designators, see Rigid
designators; and scope distinctions, 10-14, 6I-2; shift of
reference of, 93-7, 163-4; and
sortals, 11gn; and terms for
850, 87n
6I-2
171
20-1
54-6, 96л
IS0-7
148-55

172
Unicorns, 24, 157-8
United Nations, The, 26
Venus, 28, 100-s; see also
Hesperus
Water, boiling temperature of,
54-6, gon; molecular structure
of, 99, 116, 126-9, 134, 148,
ISO
INDEX
Whales, 138
Wiggins, David, 3, I450
Wittgenstein, Ludwig, 31, 33,
54,66
Yard, 76
Yellow, 118-19, 128n, 134, 140n
Ziff, Paul, 32, 80, 119-20