According to what has been said, the object of the categories is for Kant, not indeed the thing in itself, but yet most closely akin to it. It is the _object in itself_; it is an object that requires no subject; it is a particular thing, and yet not in space and time, because not perceptible; it is an object of thought, and yet not an abstract conception. Accordingly Kant really makes a triple division: (1.) the idea; (2.) the object of the idea; (3.) the thing in itself. The first belongs to the sensibility, which in its case, as in that of sensation, includes the pure forms of perception, space and time. The second belongs to the understanding, which thinks it through its twelve categories. The third lies beyond the possibility of all knowledge. (In support of this, _cf._ Critique of Pure Reason, first edition, p. 108 and 109.) The distinction of the idea from the object of the idea is however unfounded; this had already been proved by Berkeley, and it appears from my whole exposition in the first book, especially chap. i. of the supplements; nay, even from Kant’s own completely idealistic point of view in the first edition. But if we should not wish to count the object of the idea as belonging to the idea and identify it with the idea, it would be necessary to attribute it to the thing in itself: this ultimately depends on the sense which is attached to the word object. This, however, always remains certain, that, when we think clearly, nothing more can be found than idea and thing in itself. The illicit introduction of that hybrid, the object of the idea, is the source of Kant’s errors; yet when it is taken away, the doctrine of the categories as conceptions _a priori_ also falls to the ground; for they bring nothing to the perception, and are not supposed to hold good of the thing in itself, but by means of them we only think those “objects of the ideas,” and thereby change ideas into experience. For every empirical perception is already experience; but every perception which proceeds from sensation is empirical: this sensation is related by the understanding, by means of its sole function (knowledge _a priori_ of the law of causality), to its cause, which just on this account presents itself in space and time (forms of pure perception) as object of experience, material object, enduring in space through all time, yet as such always remains idea, as do space and time themselves. If we desire to go beyond this idea, then we arrive at the question as to the thing in itself, the answer to which is the theme of my whole work, as of all metaphysics in general. Kant’s error here explained is connected with his mistake, which we condemned before, that he gives no theory of the origin of empirical perception, but, without saying more, treats it as _given_, identifying it with the mere sensation, to which he only adds the forms of intuition or perception, space and time, comprehending both under the name sensibility. But from