Institutio Oratoria

Quintilian

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

The following type of argument on the other hand is more serviceable in questions turning

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on definition or quality. [*]( See iii. 6. passim. )
If strength is good for the body, health is no less good.
If theft is a crime, sacrilege is a greater crime.
If abstinence is a virtue, so is self-control.
If the world is governed by providence, the state also requires a government.
If a house cannot be built without a plan, what of a whole city?
If naval stores require careful supervision, so also do arms.

I am content to treat this type of argument as a genus without going further; others however divide it into species. For we may argue from several things to one or from one thing to several; hence arguments such as

What has happened once may happen often.
We may also argue from a part to a whole, from genus to species, from that which contains to that which is contained, from the difficult to the easy, from the remote to the near, and similarly from the opposites of all these to their opposites.

Now all these arguments deal with the greater or the less or else with things that are equal, and if we follow up such fine distinctions, there will be no limit to our division into species. For the comparison of things is infinite; things may be more pleasant, more serious, more necessary, more honourable, more useful. I say no more for fear of falling into that very garrulity which I deprecate.

The number of examples of these arguments which I might quote is likewise infinite, but I will only deal with a very few. As an example of argument from something greater take the following example from the pro Caecina [*](XV. 43.)

Shall we suppose that that which alarms whole armies caused no alarm to a peaceful company of lawyers?
As an instance of argument from something easier, take this passage
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from the speech against Clodius and Curio: [*]( A lost speech of Cicero to which reference is made in III. vii. 2. )
Consider whether it would have been easy for you to secure the praetorship, when he in whose favour you withdrew failed to secure election?