and always infers something of prior matter. Now this has first escaped the notice of all those who use it, and they endeavour to show that demonstration about essence and the very nature of a thing is possible, so that they neither perceive that those who divide happen to syllogize, nor that it is possible in the manner we have said. In demonstrations therefore, when it is requisite to infer absolute presence, the middle term by which the syllogism is produced must always be less, and must not be universally predicated of the first extreme, but on the contrary, division takes the universal for the middle term. For let animal be A, mortal B, immortal C, and man of whom we ought to assume the definition D, every animal then comprehends either mortal or immortal, but this is that the whole of whatever may be A is either B or C. Again, he who divides man, admits that he is animal, so that he assumes A to be predicated of D, hence the syllogism is that every D is either B or C, wherefore it is necessary for man to be either mortal or immortal, yet it is not necessary that animal should be mortal, but this is desired to be granted, which was the very thing which ought to have been syllogistically inferred. Again, taking A for mortal animal, B for pedestrian, C without feet, and D for man, in the same manner it assumes A to be either with B or C, for every mortal animal is either pedestrian or without feet, and that A is predicated of D, for it has assumed that man is a mortal animal, so that it is necessary that man should be either a pedestrian
