TITLE: Is there a general effective method to solve Smullyan style Knights and Knaves problems? Is the truth table method the most appropriate one?
QUESTION [8 upvotes]: Below, an attempt at solving a knight/knave puzzle using the truth table method. 
Are there other methods? 
Source : https://en.wikipedia.org/wiki/Knights_and_Knaves

REPLY [3 votes]: As others have noted, truth tables always work for "classify the participants based on their statements" puzzles; if you work through Smullyan's books of course not all puzzles are of this sort, even at the beginning. For example, there will puzzles like "so and so then answered my question and I knew blah; what question did I ask?" These questions requires a little more thinking, but often can be checked via truth tables once you have some ideas.
In this particular case you can arrive at the answer faster by observing this key fact:

No knight ever claims to be a knave.

"We are both knaves" is a claim to be a knave, and therefore we can immediately reject all the truth-table columns that suggest that John is a knight. By eliminating half the possibilities immediately, you can simplify this sort of problem.