If then begging the point at issue is proving by means of itself what is not clear by means of itself, in other words failing to prove when the failure is due to the thesis to be proved and that through which it is proved being equally uncertain, either because predicates which are identical belong to the same subject, or because the same predicate belongs to subjects which are identical, the point at issue may be begged in the middle and third figures in both ways, though, if the deduction is affirmative, only in the third and first figures.