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To have considered in how many ways a thing may predicated, is useful for perspicuity, (as any one can better know what he admits, when it is clearly explained in how many ways it may be predicated,) and for the construction of syllogisms against the thing itself, and not (merely) against the name. For when it is dubious in how many ways it is predicated, he who answers, and he who questions, may possibly not direct their attention, to the same thing, but when it is explained in how many ways it is predicated and with what object a person admits it, the questioner would appear ridiculous if he did not frame his argument against this. But it is also useful that we may not be deceived (ourselves) by paralogism, and may deceive another by it, since when we know in how many ways predication occurs, we can never be deceived by paralogism, but we shall know if the questioner does not argue against the same thing, and we ourselves, when questioning, shall be able to deceive by paralogism, except the respondent happens to know, in how many ways predication occurs. Nevertheless, this is not possible in all cases, but when of things multifariously predicated, some are true, but others false; this mode however is not appropriate to dialectic, wherefore a thing of ​this kind, must be altogether avoided by dialecticians, viz. arguing against a name, unless any one should be otherwise incapable of discussing the proposition.

Notwithstanding, it is useful to discover differences, in order to (construct) syllogisms of the same, and of the different, and also to the knowledge of what each thing is. That it is useful for syllogisms about the same, and the different, is clear; for when we have discovered the difference of the things proposed, of whatever kind it may be, we shall have shown that they are not the same, (and it is useful) for the knowledge of what a thing is, because we are accustomed to separate the proper definition of the essence of each thing, by the peculiar differences of each.

On the other hand, speculation upon the similar, is useful for inductive reasons, and for hypothetical syllogisms, and for the statement of detinitions. For inductive reasons then, because by the induction of similar particulars, we deem it proper to infer the universal, since it is not easy to form induction, when we are ignorant of similars. (It is useful also) for hypothetical syllogisms, because it is probable that as a thing subsists in one of those which are similar, so also it does in the rest, so that in order that we may discuss any of them sufficiently, we should previously acknowledge, that as a thing is in these, so also is its condition in the subject proposed; but when we have demonstrated that, we shall also have proved the proposition by hypothesis, for we have framed a demonstration, upon the supposition that as a thing is in these, so it is also, in the case of what is proposed. Again, for the statement of definitions (it is useful), since being able to comprehend what in each thing is identical, we shall not be in doubt as to what genus the thing proposed ought to be referred, in definition; for of those which are common, what is especially predicated in (the question) what a thing is, will be the genus; in like manner in those which are vastly different from each other, the contemplation of the similar is useful for definitions, as that tranquillity in the sea, is the same thing as serenity in the air, (for each of them is quiet,) and that a point in a line (is ​ identical) with unity in number, for each is a principle. Wherefore by assigning the common genus in all things, we shall appear not to define in a manner foreign (from the subject), and indeed almost those who define, are accustomed thus to explain, for they say that unity is the principle of number, and that a point is the principle of a line; it is evident then that they refer the genus of both to what is common.

The instruments therefore by which syllogisms are constructed, are these; but the places, for which what we have said, is useful, are those (which follow).