bjects, and the _a priori_ character of our
apprehension of space lies, as before, in the supposed fact that
in order to apprehend objects in space we must begin with the
apprehension of empty space.

The examination of Kant's arguments for the _perceptive_ character
of our apprehension of space is a more complicated matter. By way of
preliminary it should be noticed that they presuppose the possibility
in general of distinguishing features of objects which belong to the
perception of them from others which belong to the conception of them.
In particular, Kant holds that our apprehension of a body as a
substance, as exercising force and as divisible, is due to our
understanding as conceiving it, while our apprehension of it as
extended and as having a shape is due to our sensibility as perceiving
it.[18] The distinction, however, will be found untenable in
principle; and if this be granted, Kant's attempt to distinguish in
this way the extension and shape of an object from its other features
can be ruled out on general grounds. In any case, it must be conceded
that the arguments fail by which he seeks to show that space in
particular belongs to perception.

[18] B. 35, M. 22 (quoted p. 39). It is noteworthy (1) that
the passage contains no _argument_ to show that extension and
shape are not, equally with divisibility, _thought_ to belong
to an object, (2) that impenetrability, which is here said
to belong to sensation, obviously cannot do so, and (3) that
(as has been pointed out, p. 39) the last sentence of the
paragraph in question presupposes that we have a perception
of empty space, and that this is a _form_ of perception.

There appears to be no way of distinguishing perception and conception
as the apprehension of different realities[19] except as the
apprehension of the individual and of the universal respectively.
Distinguished in this way, the faculty of perception is that in virtue
of which we apprehend the individual, and the faculty of conception is
that power of reflection in virtue of which a universal is made the
explicit object of thought.[20] If this be granted, the only test for
what is perceived is that it is individual, and the only test for what
is conceived is that it is universal. These are in fact the tests
which Kant uses. But if this be so, it follows that the various
characteristics of objects cannot be divided into those which are
perceived and those which