Whatever the thing-in-itself may be, Kant is right in his conclusion that time, space, and causality (which we afterwards found to be forms of the principle of sufficient reason, the general expression of the forms of the phenomenon) are not its properties, but come to it only after, and so far as, it has become idea. That is, they belong only to its phenomenal existence, not to itself. For since the subject fully understands and constructs them out of itself, independently of all object, they must be dependent upon _existence as idea_ as such, not upon that which becomes idea. They must be the form of the idea as such; but not qualities of that which has assumed this form. They must be already given with the mere antithesis of subject and object (not as concepts but as facts), and consequently they must be only the more exact determination of the form of knowledge in general, whose most universal determination is that antithesis itself. Now, that in the phenomenon, in the object, which is in its turn conditioned by time, space and causality, inasmuch as it can only become idea by means of them, namely _multiplicity_, through co-existence and succession, _change_ and _permanence_ through the law of causality, _matter_ which can only become idea under the presupposition of causality, and lastly, all that becomes idea only by means of these,—all this, I say, as a whole, does not in reality belong to that which appears, to that which has passed into the form of idea, but belongs merely to this form itself. And conversely, that in the phenomenon which is not conditioned through time, space and causality, and which cannot be referred to them, nor explained in accordance with them, is precisely that in which the thing manifested, the thing-in-itself, directly reveals itself. It follows from this that the most complete capacity for being known, that is to say, the greatest clearness, distinctness, and susceptibility of exhaustive explanation, will necessarily belong to that which pertains to knowledge _as such_, and thus to the _form_ of knowledge; but not to that which in itself is not idea, not object, but which has become knowledge only through entering these forms; in other words, has become idea, object. Thus only that which depends entirely upon being an object of knowledge, upon existing as idea in general and _as such_ (not upon that which _becomes_ known, and has only _become_ idea), which therefore belongs without distinction to everything that is known, and which, on that account, is found just as well if we start from the subject as if we start from the object,—this alone can afford us without reserve a sufficient, exhaustive knowledge, a knowledge which is clear to the very foundation. But this consists of nothing but those forms of all phenomena of which we are conscious _a priori_, and which may be generally expressed as the principle of sufficient reason. Now, the forms of this principle which