SS 18.
In Cognition, its Application to Objects of Experience is the
only legitimate use of the Category.
To think an object and to cognize an object are by no means the same
thing. In cognition there are two elements: firstly, the conception,
whereby an object is cogitated (the category); and, secondly, the
intuition, whereby the object is given. For supposing that to the
conception a corresponding intuition could not be given, it would
still be a thought as regards its form, but without any object, and no
cognition of anything would be possible by means of it, inasmuch as,
so far as I knew, there existed and could exist nothing to which my
thought could be applied. Now all intuition possible to us is
sensuous; consequently, our thought of an object by means of a pure
conception of the understanding, can become cognition for us only in
so far as this conception is applied to objects of the senses.
Sensuous intuition is either pure intuition (space and time) or
empirical intuition— of that which is immediately represented in space
and time by means of sensation as real. Through the determination of
pure intuition we obtain a priori cognitions of objects, as in
mathematics, but only as regards their form as phenomena; whether
there can exist things which must be intuited in this form is not
thereby established. All mathematical conceptions, therefore, are
not per se cognition, except in so far as we presuppose that there
exist things which can only be represented conformably to the form
of our pure sensuous intuition. But things in space and time are given
only in so far as they are perceptions (representations accompanied
with sensation), therefore only by empirical representation.
Consequently the pure conceptions of the understanding, even when they
are applied to intuitions a priori (as in mathematics), produce
cognition only in so far as these (and therefore the conceptions of
the understanding by means of them) can be applied to empirical
intuitions. Consequently the categories do not, even by means of
pure intuition afford us any cognition of things; they can only do
so in so far as they can be applied to empirical intuition. That is to
say, the, categories serve only to render empirical cognition
possible. But this is what we call experience.
Consequently, in
cognition, their application to objects of experience is the only
legitimate use of the categories.
