the nature of objects, while the assertion that an
event must have a necessary antecedent affirms that such an
antecedent must exist, but gives no clue to its specific
nature. Compare "But the existence of phenomena cannot be
known _a priori_, and although we could be led in this way to
infer the fact of some existence, we should not know this
existence determinately, i. e. we could not anticipate the
respect in which the empirical perception of it differed from
that of other existences". (B. 221, M. 134). Kant seems to
think that the fact that the dynamical principles relate to
the existence of objects is a sufficient justification of
their name.

It needs but little reflection to see that the distinctions
which Kant draws between the mathematical and the dynamical
principles must break down.

These two groups of principles are not, as their names might suggest,
principles within mathematics and physics, but presuppositions of
mathematics and physics respectively. Kant also claims appropriateness
for the special terms used of each minor group to indicate the kind of
principles in question, viz. 'axioms', 'anticipations', 'analogies',
'postulates'. But it may be noted as an indication of the
artificiality of the scheme that each of the first two groups contains
only one principle, although Kant refers to them in the plural as
axioms and anticipations respectively, and although the existence of
three categories corresponding to each group would suggest the
existence of three principles.

The axiom of perception is that 'All perceptions are extensive
quantities'. The proof of it runs thus:

"An extensive quantity I call that in which the representation of the
parts renders possible the representation of the whole (and therefore
necessarily precedes it). I cannot represent to myself any line,
however small it may be, without drawing it in thought, that is,
without generating from a point all its parts one after another, and
thereby first drawing this perception. Precisely the same is the case
with every, even the smallest, time.... Since the pure perception in
all phenomena is either time or space, every phenomenon as a
perception is an extensive quantity, because it can be known in
apprehension only by a successive synthesis (of part with part). All
phenomena, therefore, are already perceived as aggregates (groups of
previously given parts), which is not the c