at the same time', so that what appears is under these qualifications true. But perhaps for this reason those who argue thus not because they feel a difficulty but for the sake of argument, should say that this is not true, but true for this man. And as has been already said, they must make everything relative — relative to thought and perception, so that nothing either has come to be or will be without some one's first thinking so. But if things have come to be or will be,[1] evidently not all things will be relative to opinion. — Again, if a thing is one, it is in relation to one thing or to a definite number of things; and if the same thing is both half and equal, still the equal is not correlative to the double.[2] If, then, the same thing is a man, in relation to that which thinks, and is that which is thought, in relation to that which thinks, that which thinks will not be a man, but only that which is thought. Again, if each thing is to be relative to that which thinks, that which thinks will be relative to an infinity of specifically different things.
Let this, then, suffice to show (1) that the most indisputable of all beliefs is that contradictory statements are not at the same time true, and (2) what consequences follow from the denial of this belief, and (3) why people do deny it. Now since it is impossible that contradictories should be at the same time true of the same thing, obviously contraries also cannot belong at the same time to the same thing. For of the contraries, no less than of the contradictories, one is a privation — and a privation of substance ; and privation is the denial of a predicate to a determinate genus. If, then, it is impossible to affirm and deny truly at the same time, it is also impossible that contraries should belong to a subject at the same time, unless both belong to it in particular relations, or one in a particular relation and one without qualification.
Chapter 7
But on the other hand there cannot be an intermediate between contradictories, but of one subject we must either affirm or deny any one predicate. This is clear, in the first
