sary that it be with a certain E, because an universal predication may be converted into a particular one.
Wherefore we must evidently regard what has been mentioned as to each part of every problem, since all syllogisms are from these; but in consequents, and the antecedents of each thing, we must look to first elements, and to those which are for the most part universal, as in the case of E we must look more to K F than only to F, but in the case of A more to K C than to C only. For if A is present with K C it is also present with F and with E, but if it is not consequent to this, yet it may be consequent to F; in like manner we must examine those which the thing itself is consequent to, for if it follows the primary, it also does those which are included under them, and if it does not follow these, yet it may those which are arranged under them.
Speculation then, plainly, consists of three terms and two propositions, and all syllogisms are through the above-mentioned figures; for A is shown present with every E, when of C and F something identical may be assumed. Now this will be the middle term, and A and E the extremes, and there is the first figure, but (presence with) a certain thing is shown when C and G are assumed identical, and this is the last figure, for G becomes the middle. Again, (presence with) none, when D and F are identical, but thus also the first figure and the middle are produced; the first, because A is with no F, (since a negative is converted,) but F is with every E; and the middle because D is with no A, but with every E. Not to be present also with a certain one, (is shown) when D and G are the same, and this is the last figure, for A will be with no G, and E with every G. Wherefore all syllogisms are evidently through the above-named figures, and we must not select those which are consequent to all, because no syllogism arises from them; as, in short, we cannot construct from con-
