  Theophrastus distinguished three figures of these syllogisms, depending on the position of the indefinite term (also called ‘middle term’) in the prosleptic premise; for example (1) produces a third figure syllogism, (2) a first figure syllogism. The number of prosleptic syllogisms was presumably equal to that of types of prosleptic sentences: with Theophrastus’ concept of the first figure these would be sixty-four (i.e. 32 + 16 + 16). Theophrastus held that certain prosleptic premises were equivalent to certain categorical sentences, e.g. (1) to ‘A is predicated of all B’. However, for many, including (2), no such equivalent can be found, and prosleptic syllogisms thus increased the inferential power of Peripatetic logic.