Institutio Oratoria

Quintilian

Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.

Great ingenuity may be exercised with regard to properties and differences, as for instance in the question whether a person assigned to his creditor for debt, [*](cp. III. vi. 25. )

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who is condemned by the law to remain in a state of servitude until he has paid his debt, is actually a slave. One party will advance the following definition,
A slave is one who is legally in a state of servitude.
The other will produce the definition,
A slave is one who is in a state of servitude on the same terms as a slave (or, to use the older phrase, 'who serves as a slave').
This definition, though it differs considerably from the other, will be quite useless unless it is supported by properties and differences.

For the opponent will say that the person in question is actually serving as a slave or is legally in a state of servitude. We must therefore look for properties and differences, to which in passing I devoted a brief discussion in my fifth book. [*](V. x. 60.) A slave when manumitted becomes a freedman: a man who is assigned for debt becomes a free man on the restoration of his liberty. A slave cannot acquire his freedom without the consent of his master: a man assigned for debt can acquire it by paying his debt without the consent of his master being necessary. A slave is outside the law; a man assigned for debt is under the law. Turning to properties, we may note the following which are possessed by none save the free, the three names (praenomen, nomen and cognomen) and membership of a tribe, all of which are possessed by the man assigned for debt.

By settling what a thing is we have come near to determining its identity, for our purpose is to produce a definition that is applicable to our case. Now the most important element in a definition is provided by quality, as, for example, in the question whether love be a form of madness. To this point

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in our procedure belong those proofs which according to Cicero [*](Top. xxiii. 88. ) are peculiar to definition, that is, proofs drawn from antecedents, consequents, adjuncts, contraries, causes, effects and similarities, with the nature of which I have already dealt. [*](V. x. 73.)

I will, however, quote a passage from the pro Caecina [*](XV. 44.) in which Cicero includes brief proofs drawn from origins, causes, effects, antecedents and consequents:

Why then did they fly? Because they were afraid. What were they afraid of? Obviously of violence. Can you then deny the beginning, when you have admitted the end?
But he also argued from similarity: [*](XV. 43.)
Shall not that which is called violence in war be called violence in peace as well
Arguments may also be drawn from contraries, as for instance in the question whether a love-potion can be a poison, in view of the fact that a poison is not a love-potion. In order that my young students (and I call them mine, because the young student is always dear to me) may form a clearer conception of this second kind of definition, I will once more quote a fictitious controversial theme.