eal _in time_,
that of cause the _succession_ of the manifold, in so far as that
succession is subjected to a rule, that of interaction the
_coexistence_ of the determinations or accidents of one substance
with those of another according to a universal rule.[18] Again, the
schemata of possibility, of actuality and of necessity are said to be
respectively the accordance of the synthesis of representations with
the conditions of time in general, existence in a determined time, and
existence of an object in all time.

[18] The italics are mine.

The main confusion pervading the chapter is of course that between
temporal relations which concern the process of apprehension and
temporal relations which concern the realities apprehended. Kant is
continually referring to the former as if they were the latter. The
cause of this confusion lies in Kant's reduction of physical realities
to representations. Since, according to him, these realities are only
our representations, all temporal relations are really relations of
our representations, and these relations have to be treated at one
time as relations of our apprehensions, and at another as relations of
the realities apprehended, as the context requires.

CHAPTER XI

THE MATHEMATICAL PRINCIPLES

As has been pointed out,[1] the aim of the second part of the
_Analytic of Principles_ is to determine the _a priori_ principles
involved in the use of the categories under the necessary sensuous
conditions. These principles Kant divides into four classes,
corresponding to the four groups of categories, and he calls
them respectively 'axioms of perception', 'anticipations of
sense-perception', 'analogies of experience', and 'postulates of
empirical thought'. The first two and the last two classes are grouped
together as 'mathematical' and 'dynamical' respectively, on the ground
that the former group concerns the perception of objects, i. e. their
nature apprehended in perception, while the latter group concerns
their existence, and that consequently, since assertions concerning
the existence of objects presuppose the realization of empirical
conditions which assertions concerning their nature do not, only the
former possesses an absolute necessity and an immediate evidence such
as is found in mathematics.[2]

[1] p. 246.

[2] The assertion that all perceptions (i. e. all objects of
perception) are extensive quantities relates, according to
Kant, to