as successions in our
perception. Further, not only are we aware of this distinction in
general, but in particular cases we succeed in distinguishing a
succession of the one kind from a succession of the other. Yet from
Kant's standpoint it would be impossible to distinguish them in
particular cases, and even to be aware of the distinction in general.
For the distinction is possible only so long as a distinction is
allowed between our perceptions and the realities perceived. But for
Kant this distinction has disappeared, for in the end the realities
perceived are merely our perceptions; and time, if it be a
characteristic of anything, must be a characteristic only of our
perceptions.

CHAPTER VII

THE METAPHYSICAL DEDUCTION OF THE CATEGORIES

The aim of the _Aesthetic_ is to answer the first question of the
_Critique_ propounded in the Introduction, viz. 'How is pure
mathematics possible?'[1] The aim of the _Analytic_ is to answer the
second question, viz. 'How is pure natural science possible?' It has
previously[2] been implied that the two questions are only verbally of
the same kind. Since Kant thinks of the judgements of mathematics as
self-evident, and therefore as admitting of no reasonable doubt[3],
he takes their truth for granted. Hence the question, 'How is pure
mathematics possible?' means 'Granted the truth of mathematical
judgements, what inference can we draw concerning the nature of the
reality to which they relate?'; and the inference is to proceed from
the truth of the judgements to the nature of the reality to which
they relate. Kant, however, considers that the principles underlying
natural science, of which the law of causality is the most prominent,
are not self-evident, and consequently need proof.[4] Hence, the
question, 'How is pure natural science possible?' means 'What
justifies the assertion that the presuppositions of natural science
are true?' and the inference is to proceed from the nature of the
objects of natural science to the truth of the _a priori_ judgements
which relate to them.

[1] B. 20, M. 13.

[2] pp. 23-5.

[3] Cf. p. 24, note 1.

[4] Cf. p. 24, notes 2 and 3.

Again, as Kant rightly sees, the vindication of the presuppositions
of natural science, to be complete, requires the discovery upon a
definite principle of _all_ these presuppositions. The clue to this
discovery he finds in the view that, just as the perceptions of space
and time orig