Epicheirema

Among the tools of logic in persuasive rhetoric, the Epicheireme (singular, pronounced eh puh kai' reem) is another kind of chain argument, or compound syllogism, similar to the sorites. An epicheirema, like a sorites, is an abridged polysyllogism; but unlike a sorites, it is of formally limited length, and the movement of thought is partly backward and partly forward. Epicheirema (plural, pronounced eh puh kai reem' uh) are categorical syllogisms in which at least one of the premises contains causal propositions. A causal proposition is a proposition or the reasons for believing the proposition to be true and along with the form (figure and mood) of the argument being valid and the deductive inference as a whole to be sound.

Basic form

The casual proposition is usually introduced by the words for, since, or because. An example of an epicheireme is as follows:

All waiters are beneficent because they cater to the needs of their customers.

Darryl is a waiter.

Therefore, Darryl is beneficent.

Three kinds of epicheirema

There are three kinds of epicheirema in accordance with which premise (or premises) contain the causal proposition.

First Order Epicheirema

All M is P, since r

All S is a M

Therefore, S is P

(where r is the reason or proof of the proposition that precedes it)

Note that the causal proposition is in the major premise.

Second Order Epicheirema

All M is P

All S is a M, since r

Therefore, S is P

Note that the causal proposition is in the minor premise.

Third Order Epicheirema

All M is P, since r₁

All S is a M, since r₂

Therefore, S is P

Third Order epicheirema are compounds of First and Second Order epicheirema in which there are causal propositions in both the major and minor premises. For example:

All waiters are beneficent because they cater to the needs of their customers.

Darryl is a waiter since Darryl serves tables at Chez Casimir

Therefore, Darryl is beneficent.

Like the enthymeme, parts of epicheirema (of which its premises are in fact enthymemes) may be heard in common speech when reasoning one's point and attempting to prove one's idea to a fellow interlocutor is indeed sound.

References

• M. Cothran. Traditional Logic II:Advanced Formal Logic. Memoria Press. p. 75. ISBN 978-1-61538-874-5.
• Sister Miriam Joseph, C.S.C., Ph.D. The Trivium - The Liberal Arts of Logic, Grammar, and Rhetoric. Paul Dry Books. p. 145. ISBN 978-0967967509.{{cite book}}: CS1 maint: multiple names: authors list (link)
• J. Maritain. Formal Logic. Sheed & Ward. p. 253. ASIN B0007F0HL0.