Cogitations: A Study of the Cogito in Relation to the Philosophy of Logic and Language and a Study of Them in Relation to the Cogito

Descartes's cogito ergo sum is at once one of the simplest and most puzzling of philosophical arguments. Although most philosophers agree that the argument is valid, they do not agree about why it is valid. And the most generally accepted account, on which the inference becomes a standard logical argument once a missing premise is supplied, contradicts Descartes's own statements about the cogito.