Abstract

In Part I, I argue that deductive reasoning is a crucial area of interest both for the new cognitive psychology and for a series of philosophical problems. I lay down criteria for judging descriptive adequacy and psychological reality for a theory of reasoning. ;In Part II, I consider the mental logic hypothesis and the mental model hypothesis. I critically discuss their history, their structures, and the evidence for them. Contrarily to the general opinion, I conclude that the mental model hypothesis is deeply flawed and does not solve the philosophical problems it supposedly solves. In part III I argue that at least for propositional reasoning the mental logic hypothesis can be considered psychologically real. I discuss the consequences of this conclusion for the language of thought hypothesis, for the syntactic theory of mind, and for the problem of rationality