positions it is necessary that a part of essence should be essence, yet this is not concluded through the assumptions, but the propositions are wanting. Again, if because man exists, it is necessary that animal should be, and animal existing, that there should be essence; then, because man exists, essence must necessarily be; but this is not yet syllogistically inferred, for the propositions do not subsist as we have said they should; but we are deceived in such, because something necessary happens from the things laid down, and because also a syllogism is something necessary. The necessary, however, is more extensive than the syllogism, for every syllogism is necessary, but not every thing necessary is a syllogism; so that if any thing occurs from certain positions, we must not immediately endeavour to reduce, but first assume two propositions, then we must divide them into terms, in this manner, that term we must place as the middle which is said to be in both propositions, for the middle must necessarily exist in both, in all the figures. If then the middle predicates, and is predicated of, or if it indeed predicates, but another thing is denied of it, there will be the first figure, but if it predicates, and is denied by something, there will be the middle figure, and if other things are predicated of it, and one thing is denied, but another is predicated, there will be the last figure; thus the middle subsists in each figure. In a similar manner also, if the propositions should not be universal, for the determination of the middle is the same, wherefore it is evident, that in discourse, where the same thing is not asserted more than once, a syllogism does not subsist, since the middle is not assumed. As, however, we know what kind of problem is deduced in each figure, in what the universal, and in what the particular, it is clear that we must not regard all the figures, but that one which is appropriate to each problem, and whatever things are deduced in many figures, we may ascertain the figure of by the position of the middle.
