Stoic Logic from the Theory of Mental Models

Abstract

An essential point about Stoic philosophy is why certain arguments and rules are basic in their logic. That is the case of the indemonstrables and the themata. It has been proposed that assuming the theory of mental models, one can think that the five indemonstrables and two of the themata are easy to understand for the human mind. This can explain why those arguments and rules are essential components in Stoic logic. In addition, it is relevant because, given that the theory of mental models tries to capture the real way people reason, it can show that Stoic logic is closer to the manner individuals naturally make inferences than modern propositional calculus. The present paper is intended to move forward in this direction. It has two aims: one of them is to give an account from the theory of mental models of all of the themata. The other one is to argue that a simple schema that is correct in modern propositional calculus, and which, however, is not deemed as a true syllogism in Stoic logic, is difficult for people according to the theory of mental models. Those are further pieces of evidence that Stoic logic describes the way human beings think to a greater extent than modern logic.