Institutio Oratoria

Quintilian

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

This major premise is either an admitted fact as in the last example or requires

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to be proved as in the following:
He who wishes to live a happy life, must be a philosopher
: for this is not an acknowledged truth, and the premises must be established before we can arrive at the conclusion. Sometimes again the minor premise is an admitted fact, as for instance,
But all men wish to live a happy life,
while sometimes it requires to be proved, as for example the statement quoted above,
That which is dissolved into its elements is devoid of feeling,
since it is doubtful whether the soul is immortal after its release from the body or only continues to exist for a time. Some call this a minor premise, some a reason.

There is no difference between the epicheireme and the syllogism, except that the latter has a number of forms and infers truth from truth, whereas the epicheireme is frequently concerned with statements that are no more than credible. For if it were always possible to prove controversial points from admitted premises, the orator would have little to do in this connexion.

For what skill does it require to say,

The property is mine, for I am the only son of the deceased,
or
I am the sole heir, since possession of the testator's estate is given by the law of property in accordance with the terms of his will: the property therefore belongs to me
?

But when the reason given is itself disputable, we must establish the certainty of the premises by which we are proposing to prove what is uncertain. For example, if our opponent says

You are not his son
or
You are illegitimate
or
You are not his only son
; or, again,
You are not his heir
or
The will is invalid
or
You are not entitled to inherit
or
You have co-heirs,
we must prove the validity
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of the reason on which we base our claim that the property should be adjudicated to us.