Potentiality and Possibility in Θ3

In Θ3, Aristotle presents four arguments against the Megarians who maintained that there is no potentiality prior to actuality and that each thing is able to do something only when it is acting and doing it, and not before that. In the fourth argument, 1047a10-14, he uses αδυνατον which means either not-potential or impossible. If it means the latest, his argument would be: It is impossible for whatever lacks potentiality to become, and it cannot be said that it becomes or will become, and this is the denial of motion. But how can Aristotle, in this argument, pass from potentiality to possibility? Moreover in 1047a24-26, he explicitly relates potentiality to possibility. This paper explains the relation between potentiality and possibility. Aristotle’s analysis of motion pushes him into the notion of potentiality, and then he notices that potentiality implies possibility. He first explains potentiality independently, and then explains it on the basis of possibility. His words in Θ3 and Θ4 may indicate that he has a temporal notion of modality, but as is argued, temporal interpretation cannot cover what he means. Although Aristotle has some uses of temporal expressions in order to explain possibility, impossibility and necessity, this might be due to his approach to the problem here. That is, here he speaks of modality in relation to potentiality and motion.