as the cause of sensation
is thought of as a physical body. For the problem 'How do we,
beginning with mere sensation, come to know a spatial and temporal
world?' is only a problem so long as it is supposed that the cause of
sensation is a spatial and temporal world or a part of it, and that
this world is what we come to know. If the cause of sensation, as
being beyond the mind, is held to be unknowable and so not known to be
spatial or temporal, the problem has disappeared. Corroboration is
given by certain passages[11] in the _Critique_ which definitely
mention 'the senses', a term which refers to bodily organs, and by
others[12] to which meaning can be given only if they are taken to
imply that the objects which affect our sensibility are not unknown
things in themselves, but things known to be spatial. Even the use of
the plural in the term 'things in themselves' implies a tendency to
identify the unknowable reality beyond the mind with bodies in space.
For the implication that different sensations are due to different
things in themselves originates in the view that different sensations
are due to the operation of different spatial bodies.

[11] E. g. B. 1 init., M. 1 init., and B. 75 fin., M. 46,
lines 12, 13 [for 'the sensuous faculty' should be
substituted 'the senses'].

[12] E. g. B. 42, lines 11, 12; M. 26, line 13; A. 100, Mah.
195 ('even in the absence of the object'). Cf. B. 182-3, M.
110-1 (see pp. 257-8, and note p. 257), and B. 207-10, M.
126-8 (see pp. 263-5).

It is now necessary to consider how the distinction between the
sensibility and the understanding contributes to articulate the
problem 'How are _a priori_ synthetic judgements possible?' As has
been pointed out, Kant means by this question, 'How is it possible
that the mind is able, in virtue of its own powers, to make universal
and necessary judgements which anticipate its experience of objects?'
To this question his general answer is that it is possible and only
possible because, so far from ideas, as is generally supposed, having
to conform to things, the things to which our ideas or judgements
relate, viz. phenomena, must conform to the nature of the mind. Now,
if the mind's knowing nature can be divided into the sensibility and
the understanding, the problem becomes 'How is it possible for the
mind to make such judgements in virtue of its sensibility and its
understanding?' And the answer will be that it is