Institutio Oratoria

I now turn to arguments, the name under which we comprise the ἐνθυμήματα, ἐπιχειρήματα, and ἀποδείξεις of the Greeks, terms which, in spite of their difference, have much the same meaning. For the enthymeme (which we translate by commentun or commentatio, there being no alternative, though we should be wiser to use the Greek name) has three meanings: firstly it means anything conceived in the mind (this is not however the sense of which I am now speaking);

secondly it signifies a proposition with a reason, and thirdly a conclusion of an argument drawn either from denial of consequents or from incompatibles [*](v. viii. 5; xiv. 2. n.) ; although there is some controversy on this point. For there are some who style a conclusion from consequents an epicheireme, while it will be found that the majority hold the view that an epicheireme is a conclusion from incompatibles: [*](See v. xiv. 2, VIII. v. 9.) wherefore Cornificius styles it a contrarium or argument from contraries. Some again call it a rhetorical

syllogism, others an incomplete syllogism, because its parts are not so clearly defined or of the same number as those of the regular syllogism, since such

that is an attempt. It would however, in my opinion, be truer to say that it is not our handling of the subject, but the thing itself which we attempt which should be called an ἐπιχείρημα, that is to say the argument by which we try to prove something and which, even if it has not yet been stated in so many words, has been clearly conceived by the mind.

Others regard it not as an attempted or imperfect proof, but a complete proof, falling under the most special [*]( The last or lowest species. p. § 56 and VII. i. 23. ) species of proof; consequently, according to its proper and most generally received appellation it must be understood in the sense of a definite conception of some thought consisting of at least three parts. [*](i.e. the major and minor premisses and the conclusion. See v. xiv. 6 sqq. ) Some call an ἐπιχείρημα a reason,

but Cicero [*](de Inv. . xxxi. 34. ) is more correct in calling it a reasoning, although he too seems to derive this name from the syllogism rather than anything else; for he calls the syllogistic basis [*](See III. vi. 43, 46, 51.) a ratiocinative basis and quotes philosophers to support him. And since there is a certain kinship between a syllogism and an epicheireme, it may be thought that he was justified in his use of the latter term.

An ἀπόδεξις is a clear proof; hence the use of the term γραμμικαὶ ἀποδείξεις,

linear demonstrations

But all authorities, however much they may differ on other points, define both in the same way, in so far as they call both a method of proving what is not certain by means of what is certain. Indeed this is the nature of all arguments, for what is certain cannot be proved by what is uncertain. To all these forms of argument the Greeks give the name of πίστεις , a term which, though the literal translation is fides

a warrant of credibility,

proof.

For the plots of plays composed for acting in the theatre are called arguments, while Pedianus, when explaining the themes of the speeches of Cicero, says The argument is as follows. Cicero [*](In some letter now lost.) himself in writing to Brutus says, Fearing that I might transfer something from that source to my Cato, although the argument is quite different. It is thus clear that all subjects for writing are so called.

Nor is this to be wondered at, since the term is also in common use among artists; hence the Vergilian phrase A mighty argument. [*](Aen. vii. 791, with Reference to the design on the shield of Turnus. ) Again a work which deals with a number of different themes is called

rich in argument.

For proof and credibility are not merely the result of logical processes, but may equally be secured by inartificial arguments. Now I have already [*](v. ix. 2.) distinguished signs or, as he prefers to call them, indications from arguments. Consequently, since an argument is a process of reasoning

Otherwise there will be nothing by which we can prove anything; there must be something which either is or is believed to be true, by means of which doubtful things may be rendered credible. We may regard as certainties, first, those things which we perceive by the senses, things for instance that we hear or see, such as signs or indications; secondly, those things about which there is general agreement, such as the existence of the gods or the duty of loving one's parents;

thirdly, those things which are established by law or have passed into current usage, if not throughout the whole world, at any rate in the nation or state where the case is being pleaded—there are for instance many rights which rest not on law, but on custom; finally, there are the things which are admitted by either party, and whatever has already been proved or is not disputed by our adversary.

Thus for instance it may be argued that since the world is governed by providence, the state should similarly be governed by some controlling power: it follows that the state must be so governed, once it is clear that the world is governed by providence.

Further, the man who is to handle arguments correctly must know the nature and meaning of everything and their usual effects. For it is thus that we arrive at probable arguments or εἰκότα as the Greeks call them.

With regard to credibility there are three degrees. First, the highest, based on what usually happens, as for instance the assumption that children are loved by

Consequently Aristotle in the second book of his Rhetoric has made a careful examination of all that commonly happens to things and persons, and what things and persons are naturally adverse or friendly to other things or persons, as for instance, what is the natural result of wealth or ambition or superstition, what meets with the approval of good men, what is the object of a soldier's or a farmer's desires, and by what means everything is sought or shunned.

For my part I do not propose to pursue this subject. It is not merely a long, but an impossible or rather an infinite task; moreover it is within the compass of the common understanding of mankind. If, however, anyone wishes to pursue the subject, I have indicated where he may apply.

But all credibility, and it is with credibility that the great majority of arguments are concerned, turns on questions such as the following: whether it is credible that a father has been killed by his son, or that a father has committed incest with his daughter, or to take questions of an opposite character, whether it is credible that a stepmother has poisoned her stepchild, or that a man of luxurious life has committed adultery; or again whether a crime has been openly committed, or false evidence given for a small bribe, since each of these crimes is the result of a special cast of character as a rule, though not always; if it were

Let us now turn to consider the

places