on, indicating the degree of reality) the schema of limitation.
Permanence in time is the sign for the application of the category of
substance;[1] regular succession, for the application of the concept of
cause; the coexistence of the determinations of one substance with those of
another, the signal for their subsumption under the concept of reciprocity.
The schemata of possibility, actuality, and necessity, finally, are
existence at any time whatever (whensoever), existence at a definite time,
and existence at all times. By such schematic syntheses the pure concept
is brought near to the empirical intuition, and the way is prepared for an
application of the former to the latter, or, what is the same thing, for
the subsumption of the latter under the former.

[Footnote 1: This determination is important for psychology. Since
the inner sense shows nothing constant, but everything in a continual
flux,--for the permanent subject of our thoughts is an identical activity
of the understanding, not an intuitable object,--the concept of substance
is not applicable to psychical phenomena. Representations of a permanent
(material substances) exist, indeed, but not permanent representations. The
abiding self (ego, soul) which we posit back of internal phenomena is, as
the Dialectic will show, a mere Idea, which, or, rather, the object of
which, maybe "thought" as substance, it is true, but cannot be "given" in
intuition, hence cannot be "known."]

As a result of the fact that the schematism permits a presentation of the
categories in time intuition antecedent to all experience, the possibility
is given of synthetic judgments _a priori_ concerning objects of possible
experience. Such judgments, in so far as they are not based on higher
and more general cognitions, are termed "principles," and the system of
them--to be given, with the table of the categories as a guide, in
the _Analytic of Principles_ or the Doctrine of the Faculty of
Judgment--furnishes the outlines of "pure natural science." When thus
the rules of the subsumption to be effected have been found in the pure
concepts, and the conditions and criteria of the subsumption in the
schemata, it remains to indicate the principles which the understanding,
through the aid of the schemata, actually produces _a priori_ from its
concepts.

The principle of quantity is the _Axiom of Intuition_, the principle of
quality the _Anticipation of Perception_; the principles of relation