probable is so, since none of those which are called probable has entirely the superficial image (of probability), as happens to be the case about the principles of contentious arguments, since immediately, and for the most part, the nature of the false in them is evident even to those who have small perception. Let then the first of the syllogisms called contentious, be also called a syllogism, but let the other be a contentious syllogism, yet not a syllogism (simply), since it appears indeed to draw an inference, but does not collect one.
Besides all the above-named syllogisms, there are paralogisms, which consist of things peculiar to certain sciences, as happens to be the case in geometry, and those (sciences) allied to it. For this mode seems to differ from the syllogisms enumerated, since he who describes falsely, neither syllogizes from the true and primary, nor from the probable, for he does not fall into definition, since he neither assumes things which appear to all men, nor those which appear to the greater number, nor to the wise, and to these neither to all, nor to the greater part, nor to the most famous; but he makes a syllogism from assumptions, appropriate indeed to science, yet not from the true, as either by describing semicircles not as they ought to be, or by drawing certain lines not as they ought to be drawn, he produces a paralogism.
Let then the species of syllogisms, to comprehend them summarily, be those which I have stated, and in a word, to sum up all that have been spoken of, and those which shall be mentioned hereafter, let our definition be so far given, because we do not propose to deliver an accurate description of any of these, but wish merely to run through them briefly, thinking it quite sufficient according to the proposed method, in some way or other to be able to know each of them.
Chapter 2
It will be consequent upon what we have stated to describe to what an extent and for what subjects
