Institutio Oratoria

Quintilian

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

As examples of necessary conclusions on the other hand I may cite the following:

If wisdom makes a man good, a good man must needs be wise
; and again,
It is the part of a good man to act honourably, of a bad man to act dishonourably,
or
Those who act honourably are considered good, those who act dishonourably are considered bad men.
In these cases the conclusion is correct. On the other hand,
though exercise generally makes the body robust, not everyone who is robust is given to exercise, nor is everyone that is addicted to exercise robust. Nor again, because courage prevents our fearing death, is every man who has no fear of death to be regarded as a brave man; nor is the sun useless to man because it sometimes gives him a headache.

Arguments such as the following belong in the main to the hortative department of oratory:—

Virtue brings renown, therefore it should be pursued; but the pursuit of pleasure brings ill-repute, therefore it should be shunned.
But the warning that we should not necessarily search for the originating cause is just: an example of such error is provided by the speech of Medea [*]( The opening of Ennius' translation of the Medea of Euripides. ) beginning

Ah! would that never there in Pelion's grove,
as though her misery or guilt were due to the fact that there
  1. The beams of fir had fallen to the ground
    ;
or I might cite the words addressed by Philoctetes to Paris, [*]( From the Philoctetes of Accius, Ribbeck fr. 178. )
  1. Hadst thou been other than thou art, then I
  2. Had ne'er been plunged in woe.
v4-6 p.249
By tracing back causes on lines such as these we may arrive anywhere.

But for the fact that Cicero [*](Top. iii. 12. ) has done so, I should regard it as absurd to add to these what is styled the conjugate argument, such as

Those who perform a just act, act justly,
a self-evident fact requiring no proof; or again,
Every man has a common right to send his cattle to graze in a common pasture.

Some call these arguments derived from causes or efficients by the Greek name ἐκβάσεις that is, results; for in such cases the only point considered is how one thing results from another. Those arguments which prove the lesser from the greater or the greater from the less or equals from equals are styled apposite or comparative.