Aristotle, Rhetoric
J. H. Freese, Ed.

[23] In regard to the future, it is clear that one can argue in the same way; for if we are able and wish to do a thing, it will be done; and so too will those things which desire, anger, and reasoning urge us to do, if we have the power. For this reason also, if a man has an eager desire, or intention, of doing a thing, it will probably be done; since, as a rule, things that are about to happen are more likely to happen than those which are not. [24] And if all the natural antecedents have happened; for instance, if the sky is cloudy, it will probably rain. [25] And if one thing has been done with a view to another, it is probable that the latter will also be done; for instance, if a foundation has been laid, a house will probably be built.

[26] What we have previously said clearly shows the nature of the greatness and smallness of things, of the greater and less, and of things great and small generally. For, when treating of deliberative rhetoric,¹ we spoke of greatness of goods, and of the greater and less generally. Therefore, since in each branch of Rhetoric the end set before it is a good, such as the expedient, the noble, or the just, it is evident that all must take the materials of amplification from these. [27] To make any further inquiry as to magnitude and superiority absolutely would be waste of words; for the particular has more authority than the general for practical purposes.
Let this suffice for the possible and impossible; for the question whether a thing has happened, or will happen, or not; and for the greatness or smallness of things.

20. It remains to speak of the proofs common to all branches of Rhetoric, since the particular proofs have been discussed. These common proofs are of two kinds, example and enthymeme （for the maxim is part of an enthymeme）. [2] Let us then first speak of the example; for the example resembles induction, and induction is a beginning.²

There are two kinds of examples; namely, one which consists in relating things that have happened before, and another in inventing them oneself. The latter are subdivided into comparisons or fables, [3] such as those of Aesop and the Libyan.³ It would be an instance of the historical kind of example, if one were to say that it is necessary to make preparations against the Great King and not to allow him to subdue Egypt; for Darius did not cross over to Greece until he had obtained possession of Egypt;