res their applicability in
the field of experience, at the same time limit them to this sphere. The
schematism makes the immanent use of the categories, and thus a metaphysics
of phenomena, possible, but the transcendent use of them, and consequently
the metaphysics of the suprasensible, impossible. The case would be
different if our intuition were intellectual instead of sensuous, or,
which is the same thing, if our understanding were intuitive instead of
discursive; then the objects which we think would not need to be given us
from another source (through sensuous intuition), but would be themselves
produced in the act by which we thought them. The divine spirit may be such
an archetypal, creative understanding (_intellectus archetypus_), which
generates objects by its thought; the human spirit is not such, and
therefore is confined, with its knowledge, within the circle of possible
perception.--The conception of "intellectual intuition" leads to a
distinction in regard to things in themselves: in its negative meaning
noumenon denotes a thing in so far as it is _not_ the object of our
_sensuous_ intuition, in its positive meaning a thing which is the
object of a _non-sensuous_ intuition. The positive thing in itself is a
problematical concept; its possibility depends on the existence of an
intuitive understanding, something about which we are ignorant. The
negative thing in itself cannot be known, indeed, but it can be thought;
and the representation of it is a possible concept, one which is not
self-contradictory[2] (a principle which is of great importance for
practical philosophy). Still further, it is an indispensable concept, which
shows that the boundary where our intuition ends is not the boundary of
the thinkable as well; and even if it affords no positive extension of
knowledge[3] it is, nevertheless, very useful, since it sets bounds to the
use of the understanding, and thus, as it were, negatively extends our
knowledge. That which lies beyond the boundary, the "how are they possible"
_(Wiemoeglichkeit)_ of things in themselves is shrouded in darkness, but the
boundary itself, _i.e._, the "that they are possible" _(Dassmoeglichkeit)_,
of things in themselves, and the unknowableness of their nature, belongs to
that which is within the boundary and lies in the light. In this way Kant
believed that the categories of causality and substance might be applied to
the relation of things in themselves to phenomena witho