Jaakko Hintikka, ‘Cogito Ergo Sum: Inference or Performance?’ Philosophical Review 71 (1962) 3-32. Katz never mentions Hintikka, an odd omission in view of the fact that his article is a landmark in the history of attempts to lay bare the formal structure of the Cogito. And although, unlike Katz, Hintikka maintains that cogito and sum are not related to one another as the premiss and the conclusion of an argument, like Katz, he maintains that that relation is different from any that the logicians have standardly recognised.

A joke heard by my daughter Nicole: a flight attendant asks ‘tea or coffee, sir?’ Descartes replies ‘I think not’ and promptly disappears.