By space and time Kant does not mean the abstract ideas of coexistence and succession; nor does he call them, as some critics used incorrectly to suppose, forms of thought, but forms of intuition. We do not build them up with the help of muscular or other feelings, but are conscious of them in a way not admitting of any further analysis. The parts of space, no doubt, are coexistent, but they are also connected and continuous; more than this, positions in space do not admit of mutual substitution; the right hand and left hand glove are perfectly symmetrical, but the one cannot be superimposed on the other. Besides, all particular spaces are contained in universal space, not as particular conceptions are contained in a general conception, but as parts of that which extends to infinity, and where each has an individual place of its own, repeating all the characters of space in general except its illimitable extension. And the same is true of time, with this further distinction from abstract succession, that succession may be reversed; whereas the order of past, present, and future is irreversibly maintained. The contemporary school of Reid in Scotland, and the subsequent Eclectic school of Victor Cousin in France, would agree with Kant in maintaining that sensuous experience will not account for our knowledge of space and time. But they would protest, in the name {91} of common sense, against the reduction of these apparently fundamental elements to purely subjective forms. They would ask, with the German critic Trendelenburg, Why cannot space and time be known intuitively and yet really exist? Kant furnishes no direct answer to the question, but he has suggested one in another connection. Mathematical truth is concerned with spatial and temporal relations, and for that truth to be above suspicion and exception we must assume that the objects with which it deals are wholly within our grasp--that our knowledge of them is exhaustive. But there could be no such assurance on the supposition that, besides the space and time of our sensuous experience, another space and time existed independently of our consciousness as attributes of things in themselves--possibly differing in important respects from ours--as, for example, a finite, or a non-continuous, or a four-dimensional space, and a time with a circular instead of a progressive movement.