said to be instances of a transcendental
determination of time, the fact that the latter agrees with
the corresponding category by being universal and _a priori_
does not constitute it homogeneous with the category, in the
sense required for subsumption, viz. that it is an instance
of or a species of the category.

"The schema is in itself always a mere product of the imagination.
But since the synthesis of the imagination has for its aim no single
perception, but merely unity in the determination of the sensibility,
the schema should be distinguished from the image. Thus, if I place
five points one after another, . . . . . this is an image of the
number five. On the other hand, if I only just think a number in
general--no matter what it may be, five or a hundred--this thinking
is rather the representation of a method of representing in an image
a group (e. g. a thousand), in conformity with a certain conception,
than the image itself, an image which, in the instance given, I should
find difficulty in surveying and comparing with the conception. Now
this representation of a general procedure of the imagination to
supply its image to a conception, I call the schema of this
conception."

"The fact is that it is not images of objects, but schemata, which lie
at the foundation of our pure sensuous conceptions. No image could
ever be adequate to our conception of a triangle in general. For it
would not attain the generality of the conception which makes it valid
for all triangles, whether right-angled, acute-angled, &c., but would
always be limited to one part only of this sphere. The schema of the
triangle can exist nowhere else than in thought, and signifies a rule
of the synthesis of the imagination in regard to pure figures in
space. An object of experience or an image of it always falls short of
the empirical conception to a far greater degree than does the schema;
the empirical conception always relates immediately to the schema of
the imagination as a rule for the determination of our perception in
conformity with a certain general conception. The conception of 'dog'
signifies a rule according to which my imagination can draw the
general outline of the figure of a four-footed animal, without being
limited to any particular single form which experience presents to me,
or indeed to any possible image that I can represent to myself _in
concreto_. This schematism of our understanding in regard to phe