the only immediate experience is inner experience, from which we reach
outer experience by inference alone, argues that, conversely, it is only
through outer experience, which is immediate experience proper, that inner
experience--as the consciousness of my own existence in time--is possible.
For all time determination presupposes something permanent in perception,
and this permanent something cannot be in me (the mere representation of an
external thing), but only actually existing things which I perceive without
me. There is, further, a chapter on the "Ground of the Distinction of all
Objects in general into Phenomena and Noumena," with an appendix on the
Amphiboly (ambiguity) of the Concepts of Reflection. The latter shows
that the concepts of comparison: identity and difference, agreement and
opposition, the internal and the external, matter and form, acquire
entirely different meanings when they relate to phenomena and to things in
themselves (in other words, to things in their relation to the sensibility,
and in relation to the understanding merely); and further, in a criticism
of the philosophy of Leibnitz, reproaches him with having intellectualized
phenomena, while Locke is said to have sensationalized the concepts of the
understanding.

The chapter on the distinction between phenomena and noumena very much
lessens the hopes, aroused, perchance, by the establishment of the
non-empirical origin of the categories, for an application of these not
confined to any experience. Although the categories, that is, are in their
origin entirely independent of all experience (so much so that they first
make experience possible), they are yet confined in their application
within the bounds of possible experience. They "serve only to spell
phenomena, that we may be able to read them as experience," and when
applied to things in themselves lose all significance.[1] Similarly the
principles which spring from them are "nothing more than principles of
possible experience," and can be referred to phenomena alone, beyond which
they are arbitrary combinations without objective reality. Things in
themselves may be thought, but they can never be known; for knowledge,
besides the empty thought of an object, implies intuitions which must be
subsumed under it or by which the object must be determined. In themselves
the pure concepts relate to all that is thinkable, not merely to that which
can be experienced, but the schemata, which assu