admitted. A theory is overthrown, so soon as any fact out of harmony with it is accepted. These principles seem to be sure guides, whatever may be the object matter of thought, and whatever the stage of thought we have reached.
But it is not to be supposed that these are the only laws of thought, or that they have any special sanctions attaching to them. Even Aristotle did not recognize all the distinctions, gradations, evolutions of thought. The Hegelian way of viewing the nature of thought is important in this among other respects, that it emphasizes the difference of categories. According to it, while there is one thought in all things, this thought is protean. There is not one category only; there is a scale of categories. There is one law of thought, and yet it would be equally true to say, that there is an indefinite number of laws of thought. Being belongs to one plane of thought, the lowest; but there are higher planes represented by such conceptions as substance, cause, organism.
It would then be legitimate to say that, so long as we keep to the category of Being, we are bound by the laws of non-contradiction. But it is only so long as we keep to this category. Not that this law is violated; it is simply unable to express the procedure of thought, when it passes to higher relations. Being stands in abstract opposition to nothing: Α is not non-Α. Let the world, however, be recognized as a world of individual things, one thing is the negation of another. Yet the negation may be of a much less definite kind. The two things which refuse to surrender their individuality may yet be essentially the same. This oak-tree is not that oak-tree, but unless the identities of the two are recognized the surface of the facts has scarcely been touched. The negative is not a sheer negative. The relation is that of similarity, or it is one still closer. It is no longer, Α is not non-Α. The essence of Α and non-Α is one; and the thought which perceives this relation is a new thought, or has a new law.
Similarly the treatment of space by mathematical science involves the recognition of specific laws. The law of non-contradiction still holds: a triangle cannot be thought to be a
