 Three features of this text are important to note from the point of view of the history of logic. First, as the schema above shows, arguments are put into a canonical form. While we have no record that semantic ascent had taken place, there is no doubt from the arguments are intended to satisfy a certain form. Second, the sentences of the argument are logically related. The author takes for granted that the sentences assented to are inconsistent, corresponding to an instance of the following inconsistent propositional schemata of \(\alpha\), \(\neg \beta\), \(\alpha \rightarrow \beta\). He also takes it for granted that it is wrong to hold inconsistent propositions. And he finally presupposes that, if a sentence corresponding to propositional schema \(\alpha \rightarrow \beta\) is true, then the sentence corresponding to the propositional schema \(\neg \beta \rightarrow \neg \alpha\) is also true; that is, he presupposes the natural language counterpart to one direction of the equivalence of a conditional and its contrapositive. (See Ganeri 2001 for the most recent attempt to explicate the dialectic implicit in the text.)