  All we know about the so-called founder of the so-called Dialectical school, Clinomachus of Thurii, is that he was the first who wrote about predicates (katêgorêmata) and propositions (axiômata) and the like (DL 2.112). Our evidence for Diodorus and Philo confirms that they, too, conceived of logic as a logic of propositions. It was the Stoics who systematically developed a logic of propositions and devised subtle classifications of predicates. (By contrast, Aristotle's logic had been a logic of terms, where subject and predicate terms were in principle interchangeable.) The logic of the Dialectical school thus was a precursor of Stoic logic.