Institutio Oratoria

III. Conjecture is followed by definition. For the man who cannot assert that he has done nothing, must needs take refuge in the assertion that lie has not committed the act which is alleged against him. Consequently the laws which govern definition are for the most part the same as those which govern conjecture, the only difference lying in the method to be employed in defence in cases such as those concerned with theft, deposits or adultery. For just as we say,

I have not committed theft, I never received a deposit, I am not guilty of adultery,

This is not theft, this is not a deposit, this is not adultery.

Sometimes we may pass from quality to definition, as in actions concerned with lunacy, cruelty and offences against the State. In such cases if it is impossible to assert that the acts alleged were right, we are left with such pleas as,

To use bad language to one's wife does not amount to cruelty.

As I have already said, [*](V. x. 55.) it consists mainly in the statement of genus, species, difference and property. For example, if you wish to define a horse (for I will take a familiar example), the genus is animal, the species mortal, the diffrence irrational (since man also is mortal) and the properly neighing. Definition is employed by the orator for a number of different reasons.

For sometimes, though there may be no doubt as to a term, there is a question as to what it includes, or, on the other hand, there may be no doubt about the thing, but no agreement as to the term to be applied to it. When the term is agreed, but the thing doubtful, conjecture may sometimes come into play, as, for instance, in the question,

What is god?

For the man who denies that god is a spirit permeating all things, assuredly asserts that the epithet

divine

Sometimes again we have recourse to quality, as in the question,

What is

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rhetoric? Is it the power to persuade or the science of speaking well?

There is a different type of question where the dispute is concerned with the term to be applied, which depends on the letter of the law: it is a form of question which can only arise in the courts from the actual words on which the dispute turns. Take as examples the questions, whether suicide is a form of homicide, or whether the man who forces a tyrant to kill himself can be considered a tyrannicide, or whether magical incantations are equivalent to the crime of poisoning. In all these cases there is no doubt about the facts, for it is well known that there is a difference between killing oneself and killing another, between slaying a tyrant and forcing him to suicide, between employing incantations and administering a deadly draught, but we enquire whether we are justified in calling them by the same name.

Though I hardly like to differ from Cicero, [*](cp. III. vi. 31. ) who follows many authorities in saying that definition is concerned with identity and difference (since he who denies the applicability of one term must always produce another term which he regards as preferable), for my own part I consider that definition falls into three types, which I may perhaps call species.

For at times it is convenient merely to

Thirdly, there are times when the question concerns things which are different in species, and we ask whether two different things are to be called by the same name, in spite of the fact that each has a special name of its own: for example, is tile same name applicable both to a love-potion and a poison? [*](cp. VIII. V. 31. ) But in all disputes of this kind the question is whether one thing is another thing as well, since the name in doubt does without question apply to something else. It is sacrilege to steal a sacred object from a temple; is it also sacrilege to steal private property from a temple? It is adultery to lie with another man's wile in one's own house; is it adultery to do so in a brothel? It is tyrannicide to slay a tyrant; is it tyrannicide to force him to slay himself?

Consequently the syllogism, to which I shall return later, is virtually a weaker form of definition, since while definition seeks to determine whether one thing has the same name as another, syllogism seeks to determine whether one thing is to be regarded as identical with another.

There is moreover great variety in definitions. For instance, persons will give different verbal expression to

Definition is sometimes required to explain rare or obscure words such as clarigatio [*](A formal demand for redress under threat of war.) or erctum citum, [*](An undivided inheritance.) or again to explain familiar words such as penus [*](Store of provisions.) or litus. [*]( Shore, see v. xiv. 34, where its derivation is explained as qua fiuctus eludit. ) This variety in definition has caused some writers to include it under conjecture, others under quality and others again under legal questions.

Some, on the other hand, entirely reject the elaborate and formal methods of reasoning employed by dialectic, regarding such ingenuity as suited rather to quibbles over words in philosophical discussions than as likely to carry much weight in the performance of the duties of an orator. For though in dialogue definition may serve to fetter the person who has got to reply in chains of his own making, or may force him to silence, or even to reluctant confession of a point which tells against himself, it is of less use in forensic cases.

For there we have to persuade the judge, who, even though he may be tied and bound with our words, will still dissent in silence, unless he is brought really into touch with the actual facts. And what need has a pleader for such precision of definition? Even if I do not say that man is an animal, mortal and rational, surely I shall still be able, by setting forth the numerous properties of his

Again, may not the same thing be defined in more than one way, as Cicero does when he says,

What do we mean when we say' commonly ': surely we mean 'by all men'?

if we make a mistake in a single word, we are like to lose our whole case, and consequently the compromise adopted by Cicero in the pro Caecina [*](XV. 42.) is the safest course to follow; this consists in setting forth the facts without running any risks over the exactness of our terminology. These are his words:

Judges, the violence which threatens our lives and persons is not the only kind of violence: there is a much more serious form which by the threat of death fills our minds with panic and often turns them from their natural condition of stability.

Or again, we may prove before we define, as Cicero does in the Philippics, [*](IX. iii. 7.) where he proves that Servius Sulpicius was killed by Antony and introduces his definition at the conclusion in the following terms:—

For assuredly the murderer was he who was the cause of his death.

The order to be followed in definition is invariable. We first ask what a thing is, and then, whether it is this. [*](i. e. the thing under consideration. ) And there is generally more difficulty in the establishment than in the application of a definition. In determining what a thing is, there are two things which require to be done: we must establish our own definition and destroy that of our opponent. Consequently in the schools,

where we ourselves imagine our opponent's reply, we have to introduce two definitions, which should suit the respective sides of the case as well as it is in our power to make them. But in the courts we must give careful consideration to the question whether our definition may not be superfluous and irrelevant or ambiguous or inconsistent or even of no less service to our opponents than to ourselves, since it will be the fault of the pleader if any of these errors occur. On the other hand, we shall ensure the right definition,