is given a priori, the law of causality which brings about the empirical perception. Not only are both right, but we can also see quite directly that a contradiction lies in the assertion that a thing is known as it is in and for itself, i.e., outside of knowledge. For all knowing is, as we have said, essentially a perceiving of ideas; but my perception of ideas, just because it is mine, can never be identical with the inner nature of the thing outside of me. The being in and for itself, of everything, must necessarily be subjective; in the idea of another, however, it exists just as necessarily as objective – a difference which can never be fully reconciled. For by it the whole nature of its existence is fundamentally changed; as objective it presupposes a foreign subject, as whose idea it exists, and, moreover, as Kant has shown, has entered forms which are foreign to its own nature, just because they belong to that foreign subject, whose knowledge is only possible by means of them. If I, absorbed in this reflection, perceive, let us say lifeless bodies, of easily surveyed magnitude and regular, comprehensible form, and now attempt to conceive this spatial existence, in its three dimensions, as their being in itself, consequently as the existence which to the things is subjective, the impossibility of the thing is at once apparent to me, for I can never think those objective forms as the being which to the things is subjective, rather I become directly conscious that what I there perceive is only a picture produced in my brain, and existing only for me as the knowing subject, which cannot constitute the ultimate, and therefore subjective, being in and for itself of even these lifeless bodies. But, on the other hand, I must not assume that even these lifeless bodies exist only in my idea, but, since they have inscrutable qualities, and, by virtue of these, activity, I must concede to them a being in itself of some kind. But this very inscrutableness of the properties, while, on the one hand, it certainly points to something which exists independently of our knowledge, gives also, on the other hand, the empirical proof that our knowledge, because it
