concluded, yet not always, nor entirely, but when those which are under the middle so subsist as either to be the same, or as a whole to a part: otherwise it is impossible, for the propositions will by no means be either contrary or contradictory.
In the third figure there will never be an affirmative syllogism from opposite propositions, for the reason alleged in the first figure; but there will be a negative, both when the terms are and are not universal. For let science be B and C, and medicine A, if then a person assumes that all medicine is science, and that no medicine is science, he would assume B present with every A, and C with no A, so that a certain science will not be science. Likewise, if the proposition A B is not taken as universal, for if a certain medicine is science, and again no medicine is science, it results that a certain science is not science. But the propositions are contrary, the terms being universally taken, if however one of them is particular, they are contradictory.
We must however understand that it is possible thus to assume opposites as we have said, that every science is good, and again, that no science is good, or that a certain science is not good, which does not usually lie concealed. It is also possible to conclude either (of the opposites), through other interrogations, or as we have observed in the Topics, to assume it. Since however the oppositions of affirmations are three, it results that we may take opposites in six ways, either with every and with none, or with every and not with every individual, or with a certain and with no one; and to convert
