In his Topics Aristotle sets up the theory of dialectic, which he seems not to use in his other works. This must be accounted for. Irwin assumes that there is a distinction in dialectic: pure and strong. But in my opinion Aristotle’s theory of dialectic has undergone development from an inchoate one into a revised one: the former is found in Topics while the latter in Rhetoric. The theory of dialectic in Topics is not full-blown. To explain. Aristotle there asserts that there are four predicables: definition, property, genus, accident and that a set of the predicables, which are mutually exclusive, is exhaustive. However, per se accident does not fall under any of these. Traditionally per se accident has been interpreted to be a sort of pr...