sion in the alternately perceived states of A and B
as interacting. Moreover, there is really a change in the cases under
consideration. The case with which he begins, i. e. when he is
considering merely the reciprocal sequence of perceptions, is the
successive perceptions of two _bodies in space_ alternately, e. g. of
the moon and the earth, the nature of their states at the time of
perception not being in question. But the case with which he ends is
the successive perception of the _states of two bodies_ alternately,
e. g. of the states of the fire and of the lump of ice. Moreover, it
is only in the latter case that the objective relation apprehended is
that of coexistence in the proper sense, and in the sense which Kant
intends throughout, viz. that of being contemporaneous in distinction
from being successive. For when we say that two bodies, e. g. the moon
and the earth, coexist, we should only mean that both exist, and not,
as Kant means, that they are contemporaneous. For to a substance,
being as it is the substratum of changes, we can ascribe no temporal
predicates. That which changes cannot be said either to begin, or to
end, or to exist at a certain moment of time, or, therefore, to exist
contemporaneously with, or after, or before anything else; it cannot
even be said to persist through a portion of time or, to use the
phrase of the first analogy, to be permanent. It will be objected
that, though the cases are different, yet the transition from the one
to the other is justified, for it is precisely Kant's point that the
existence together of two substances in space can only be discovered
by consideration of their successive states under the presupposition
that they mutually determine one another's states. "Besides the mere
fact of existence there must be something by which A determines the
place in time for B, and conversely B the place for A, because only
under this condition can these substances be empirically represented
as coexistent."[56] The objection, however, should be met by two
considerations, each of which is of some intrinsic importance. In the
first place, the apprehension of a body in space in itself involves
the apprehension that it exists together with all other bodies in
space, for the apprehension of something as spatial involves the
apprehension of it as spatially related to, and therefore as existing
together with, everything else which is spatial. No process,
therefore, such as Kant descri