(for all things which at any time may be given to our senses), but only for these, not for things as they are in themselves.  They have “empirical reality, but, at the same time, transcendental ideality.”  As external phenomena all things are beside one another in space, and all phenomena whatever are in time and of necessity under temporal relations; in regard to all things which can occur in our experience, and in so far as they can occur, space and time are objectively, therefore empirically, real.  But they do not possess absolute reality (neither subsistent reality nor the reality of inherence); for if we abstract from our sensuous intuition both vanish, and, apart from the subject (N.B., the transcendental subject, concerning which more below), they are naught.  It is only from man’s point of view that we can speak of space, and of extended, moveable, changeable things; for we can know nothing concerning the intuitions of other thinking beings, we have no means of discovering whether they are bound by the same conditions which limit our intuitions, and which for us are universally valid. (3) Nothing which is intuited in space is a thing in itself.  What we call external objects are nothing but mere representations of our sensibility, whose true correlative, the thing in itself, cannot be known by ever so deep penetration into the phenomenon; such properties as belong to things in themselves can never be given to us through the senses.  Similarly nothing that is intuited in time is a thing in itself, so that we intuit ourselves only as we appear to ourselves, and not as we are.

The merely empirical reality of space and time, the limitation of their validity to phenomena, leaves the certainty of knowledge within the limits of experience intact; for we are equally certain of it, whether these forms necessarily belong to things in themselves, or only to our intuitions of things.  The assertion of their absolute reality, on the other hand, involves us in sheer absurdities (that is, it necessitates the assumption of two infinite nonentities which exist, but without being anything real, merely in order to comprehend all reality, and on one of which even our own existence would be dependent), in view of which the origin of so peculiar a theory as the idealism of Berkeley appears intelligible.  The critical theory of space and time is so far from being identical with, or akin to, the theory of Berkeley, that it furnishes the best and only defense against the latter.  If anyone assumes the absolute or transcendental reality of these forms, it is impossible for him to prevent everything, including even our own existence, from being changed thereby into mere illusion.  But the critical philosopher is far from degrading bodies to mere illusion; external phenomena are just as real for him as internal phenomena, though only as phenomena, it is true, as (possible) representations.