The semantic method of extension and intension and the four criteria of the conditional described by Sextus Empiricus

Abstract

In this paper an analysis is conducted of the debate about the most suitable way to understand the conditional, which took place in the 4th century B.C. This is done using the extension and intension method provided by Rudolf Carnap to study the meaning of expressions. The results seem to show that, according to Sextus Empiricus, although the debate was about four different criteria to understand the conditional, three of those criteria actually appear to be the same and have a very clear common logical form under Carnap’s framework.