TITLE: Deducing "Some are " from "All are"?
QUESTION [8 upvotes]: In classical symbolic logic, Can we conclude "Some are Italian" from "All are Italian"?

All are Italian.
  Therefore, Some are Italian.

Apparently, Modern logicians argue that it is invalid since we cannot drop "all" to from "All are Italian" to derive "Someone is Italian". I'm looking to know the views of Classical and modern logic on this if it is true.

REPLY [3 votes]: There is an absolutely masterly treatment of the relation between Aristotelian logic and modern quantificational logic by Timothy Smiley in his paper "Syllogism and Quantification" Journal of Symbolic Logic 1962, pp. 58-72. This now classic paper is still not as well-known as it should be: it is a must-read for anyone who wants to know about the issue and really should be on any student reading-list.
Take a many-sorted predicate calculus, i.e. with sorted variables which run over different domains of quantification -- and NB, as with the standard modern single-sorted calculus, domains are non-empty. And now add sortal predicates corresponding to the domains. Thus corresponding to the sorted variable $a$ there is a sortal $A$ such that $\forall aAa$. Then Smiley's headline news is that the traditional syllogistic translates neatly into this many sorted framework -- preserving the traditional rule that All A are B implies Some A are B, for this goes over to $\forall aBa$ implies $\exists aBa$. For all the details, see Smiley.
What this shows is that the issue about existential import has little to do with the traditional vs post-Fregean quantifier/variable treatment of quantification, and a lot more to do with a decision early on the development of modern logic to privilege single-sorted calculi, and then implement sorted quantifiers artificially by the use of restricting predicates. (This decision was for logicians' convenience rather than for mathematical utility --  mathematicians use sorted informal quantifiers all the time.)