They therefore replied, “To say that, were He not endowed with these attributes—hearing, sight, and speech—while still being living, He would necessarily possess their opposites, can only be verified after we have first clarified what is meant by the two contraries and set out their various kinds.

We say: Two propositions are called ‘contraries’ when they cannot coexist in the same subject from the same perspective. Such contrariety may take one of two forms: either it is impossible for both propositions to be simultaneously true or simultaneously false, or this impossibility applies to only one of the two sides.

The first type is the opposition of affirmation and negation, which is contradiction. Contradiction is the divergence of two propositions, one affirming and the other denying, in such a way that—by their very nature—they can neither both be true nor both be false. An example is the pair: “Zayd is an animal” and “Zayd is not an animal.” One of the distinctive features of this type is the impossibility of their simultaneous occurrence.