f the same, distinct therefrom, if it
stands under a rule which distinguishes it from _every other_
apprehension, and renders necessary a mode of conjunction of the
manifold."[27] A representation, however, cannot be so related by a
rule to another representation, for the rule meant relates to
realities in nature, and, however much Kant may try to maintain the
contrary, two representations, not being realities in nature, cannot
be so related. Kant is in fact only driven to treat rules of nature as
relating to representations, because there is nothing else to which he
can regard them as relating. The result is that he is unable to
justify the very distinction, the implications of which it is his aim
to discover, and he is unable to do so for the very reason which would
have rendered Hume unable to justify it. Like Hume, he is committed to
a philosophical vocabulary which makes it meaningless to speak of
relations of objects at all in distinction from relations of
apprehensions. It has been said that for Kant the road to objectivity
lay through necessity.[28] But whatever Kant may have thought, in
point of fact there is no road to objectivity, and, in particular, no
road through necessity. No necessity in the relation between two
representations can render the relation objective, i. e. a relation
between objects. No doubt the successive acts in which we come to
apprehend the world are necessarily related; we certainly do not
suppose their order to be fortuitous. Nevertheless, their relations
are not in consequence a relation of realities apprehended.

[25] pp. 133-4; cf. pp. 180 and 230-1.

[26] Cf. p. 209, note 3, and p. 233.

[27] The italics are mine.

[28] Caird, i. 557.

Kant only renders his own view plausible by treating an apprehension
or representation as if it consisted in a sensation or an appearance.
A sensation or an appearance, so far from being the apprehension of
anything, is in fact a reality which can be apprehended, of the kind
called mental. Hence it can be treated as an object, i. e. something
apprehended or presented, though not really as an object in nature. On
the other hand, from the point of view of the thing in itself it can
be treated as only an apprehension, even though it is an unsuccessful
apprehension. Thus, for Kant, there is something which can with some
plausibility be treated as an object as well as an apprehension, and
therefore as capable of standing in both a su