f their relation to perception, an answer is
readily forthcoming. We need only reverse the original argument and
appeal directly to the phenomenal character of space and time and of
what is contained in them. Objects in space and time, being
appearances, must conform to the laws according to which we have
appearances; and since space and time are only ways in which we
perceive, or have appearances, mathematical laws, which constitute the
general nature of space and time, are the laws according to which we
have appearances. Mathematical laws, then, constitute the general
structure of appearances, and, as such, enter into the very being
of objects in space and time. But the case is otherwise with the
conceptions and principles underlying natural science. For the law of
causality, for instance, is a law not of our perceiving but of our
thinking nature, and consequently it is not presupposed in the
presentation to us of objects in space and time. Objects in space
and time, being appearances, need conform only to the laws of our
perceiving nature. We have therefore to explain the possibility of
saying that a law of our thinking nature must be valid for objects
which, as conditioned merely by our perceiving nature, are independent
of the laws of our thinking; for phenomena might be so constituted as
not to correspond to the necessities of our thought.'

[8] B. 120-1, M. 73-4.

No doubt Kant's _solution_ of this problem in the _Analytic_ involves
an emphatic denial of the central feature of this statement of it,
viz. that phenomena may be given in perception without any help from
the activity of the understanding.[9] Hence it may be urged that this
passage merely expresses a temporary aberration on Kant's part, and
should therefore be ignored. Nevertheless, in spite of this
inconsistency, the view that phenomena may be given in perception
without help from the activity of the understanding forms the basis
of the difference of treatment which Kant thinks necessary for the
vindication of the judgements underlying natural science and for that
of the judgements of mathematics.

[9] Cf. B. 137-8, M. 85, and B. 160 note, M. 98 note.

We may now consider how Kant 'discovers' the categories or conceptions
which belong to the understanding as such.[10] His method is sound in
principle. He begins with an account of the understanding in general.
He then determines its essential differentiations. Finally, he argues
that each