transcendental conception of phenomena in space is a critical admonition, that, in general, nothing which is intuited in space is a thing in itself, and that space is not a form which belongs as a property to things; but that objects are quite unknown to us in themselves, and what we call outward objects, are nothing else but mere representations of our sensibility, whose form is space, but whose real correlate, the thing in itself, is not known by means of these representations, nor ever can be, but respecting which, in experience, no inquiry is ever made.
SECTION II. Of Time.
§ 5. Metaphysical Exposition of this Conception.
1. Time is not an empirical conception. For neither co-existence nor succession would be perceived by us, if the representation of time did not exist as a foundation a priori. Without this presupposition we could not represent to ourselves that things exist together at one and the same time, or at different times, that is, contemporaneously, or in succession.
2. Time is a necessary representation, lying at the foundation of all our intuitions. With regard to phenomena in general, we cannot think away time from them, and represent them to ourselves as out of and unconnected with time, but we can quite well represent to ourselves time void of phenomena. Time is therefore given a priori. In it alone is all reality of phenomena possible. These may all be annihilated in thought, but time itself, as the universal condition of their possibility, cannot be so annulled.
3. On this necessity a priori is also founded the possibility of apodeictic principles of the relations of time, or axioms of time in general, such as, "Time has only one dimension," "Different times are not co-existent but successive," (as different spaces are not successive but co-existent). These principles cannot be derived from experience, for it would give neither strict universality, nor apodeictic certainty. We should only be able to say, "so common experience teaches us," but not it must be so. They are valid as rules, through which, in general, experience is possible; and they instruct us respecting experience, and not by means of it.
