When Kant compared his work in philosophy to that of the men who introduced construction into geometry, and experimentation into physics and chemistry, the point of his remarks depends upon taking the _a priori_ worth of thought in a regulative, directive, controlling sense, thought as consciously, intentionally, making an experience _different_ in a _determinate_ sense and manner. But the point of his answer to Hume consists in taking the _a priori_ in the other sense, as something which is _already_ immanent in _any_ experience, and which accordingly makes no determinate difference to any one experience as compared with any other, or with any past or future form of itself. The concept is treated first as that which makes an experience actually different, controlling its evolution towards consistency, coherency, and objective reliability; then, it is treated as that which has already effected the organization of any and every experience that comes to recognition at all. The fallacy from which he never emerges consists in vibrating between the definition of a concept as a rule of constructive synthesis in a _differential_ sense, and the definition of it as a static endowment lurking in “mind,” and giving automatically a hard and fixed law for the determination of every experienced object. The _a priori_ conceptions of Kant as immanent fall, like the rain, upon the just and the unjust; upon error, opinion, and hallucination. But Kant slides into these _a priori_ functions the preferential values exercised by empirical reflective thought. The concept of triangle, taken geometrically, means doubtless a determinate method of construing space elements; but to Kant it also means something that exists in the mind _prior_ to all such geometrical constructions and that unconsciously lays down the law not only for their conscious elaboration, but also for any space perception, even for that which takes a rectangle to be a triangle. The first of the meanings is intelligible, and marks a definite contribution to the logic of science. But it is not “objective idealism”; it is a contribution to a revised empiricism. The second is a dark saying. That organization of some sort exists in every experience I make no doubt. That isolation, discrepancy, the fragmentary, the incompatible, are brought to recognition and to logical function only with reference to some prior existential mode of organization seems clear. And it seems equally clear that reflection goes on with profit only because the materials with which it deals have already some degree of organization, or exemplify various relationships. As against Hume, or even Locke, we may be duly grateful to Kant for enforcing acknowledgment of these facts. But the acknowledgment means simply an improved and revised empiricism.