the first, and arises from
the fact that Kant speaks of space not only as a form of _perception_,
but also as the form of _phenomena_ in opposition to sensation as
their matter. "That which in the phenomenon corresponds to[4] the
sensation I term its matter; but that which effects that the manifold
of the phenomenon can be arranged under certain relations I call the
form of the phenomenon. Now that in which alone our sensations can be
arranged and placed in a certain form cannot itself be sensation.
Hence while the matter of all phenomena is only given to us _a
posteriori_, their form [i. e. space] must lie ready for them all
together _a priori_ in the mind."[5] Here Kant is clearly under the
influence of his theory of perception.[6] He is thinking that, given
the origination of sensations in us by the thing in itself, it is the
business of the mind to arrange these sensations spatially in order to
attain knowledge of the spatial world.[7] Space being, as it were,
a kind of empty vessel in which sensations are arranged, is said
to be the form of phenomena.[8] Moreover, if we bear in mind that
ultimately bodies in space are for Kant only spatial arrangements
of sensations,[9] we see that the assertion that space is the form
of phenomena is only Kant's way of saying that all bodies are
spatial.[10] Now Kant, in thus asserting that space is the form of
phenomena, is clearly confusing this assertion with the assertion that
space is a form of perception, and he does so in consequence of the
first confusion, viz. that between a capacity of perceiving and an
actual perception of empty space. For in the passage last quoted he
continues thus: "I call all representations[11] _pure_ (in the
transcendental sense) in which nothing is found which belongs to
sensation. Accordingly there will be found _a priori_ in the mind the
pure form of sensuous perceptions in general, wherein all the manifold
of phenomena is perceived in certain relations. This pure form of
sensibility will also itself be called _pure perception_. Thus,
if I abstract from the representation of a body that which the
understanding thinks respecting it, such as substance, force,
divisibility, &c., and also that which belongs to sensation, such as
impenetrability, hardness, colour, &c., something is still left over
for me from this empirical perception, viz. extension and shape. These
belong to pure perception, which exists in the mind _a priori_, even
without an act