Chapter 13
Let then the genera about which, and from which, arguments subsist be defined, as we have stated before, but the instruments by which we shall be well provided with syllogisms are four; one to assume propositions, the second to be able to distinguish in how many ways each thing is predicated, the third to discover differences, and the fourth the consideration of the similar. In a certain way indeed there are three propositions of these, since it is possible to make a proposition as to each of them, as that the beautiful, or the sweet, or the profitable is eligible, and that sense differs from science, in that he who loses the latter may regain it; but this is impossible with the other, and that the wholesome has the same relation to health as what produces good constitutional habit, to a good habit of constitution. Now the first proposition is derived from that which is predicated in many ways, but the second from differences, and the third from similars.
Chapter 14
Propositions then must be selected in as many ways as there has been definition about proposition, either choosing the opinions of all, or those of most, or those of the wise, and of these either of all, or of most, or of the most celebrated, or opinions contrary to the apparent, and whatever are according to arts. Yet it is necessary to propose according to contradiction those which are contrary to the apparently probable, as we observed before; but it is useful to produce them by selecting, not only those which are probable, but those also which are like these, as that there is the same sense of contraries, (for there is the same science,) and that we see by admitting, not by emitting, somewhat, as it is thus also with the other senses, since we
