The Republic · ¶164

In attempting to prove that the soul has three separate faculties, Plato takes occasion to discuss what makes difference of faculties. And the criterion which he proposes is difference in the working of the faculties. The same faculty cannot produce contradictory effects. But the path of early reasoners is beset by thorny entanglements, and he will not proceed a step without first clearing the ground. This leads him into a tiresome digression, which is intended to explain the nature of contradiction. First, the contradiction must be at the same time and in the same relation. Secondly, no extraneous word must be introduced into either of the terms in which the contradictory proposition is expressed: for example, thirst is of drink, not of warm drink. He implies, what he does not say, that if, by the advice of reason, or by the impulse of anger, a man is restrained from drinking, this…

Plato · translated by Benjamin Jowett · composite transcription based on the 1888 third edition
Benjamin Jowett, revised third edition (1888), with Stephanus numbering from the 1908 edition; composite transcription, Project Gutenberg #55201
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