A Class Room Logic / Deductive and Inductive, with Special Application to the Science and Art of Teaching

by George Hastings McNair

∴ This substance is nourishing.

(c) Thieves should be imprisoned,

This man has taken what does not belong to him,

∴ This man should be imprisoned.

In the “four-term” fallacies, observe that the four terms occur in the premises. When a fourth term is introduced in the conclusion, the material fallacy of non sequitur has been committed.

(2) Amphibology (or amphiboly).

Amphibology is a fallacy resulting from an ambiguousproposition rather than from the ambiguity of any particular term. The fallacy of amphibology is committed when the spoken or written proposition conveys more than one meaning. The ancient oracles indulged in this sort of fallacy, the reason for such indulgence being obvious; the oracles were not too positive as to the outcome of their prognostications, and therefore were especially careful to cover every emergency.

A careless use of relative clauses and prepositional phrases often results in the fallacy of amphibology.

ILLUSTRATIONS OF THE FALLACY OF AMPHIBOLOGY.

(a) “You the enemy will slay.”