ndental aesthetic enunciated by Kant,
who first pointed out that there are elements, and those the most
necessary and universal, in the sense-presentation which bear the
character of ideality as fully as the most subjective efforts of our
ideative activity. More particularly do we illustrate the ideality of
Space as a cognition precedent to experience. It is because general laws
constantly operative regulate the transmutations which constitute the
individual's Presentment that it is possible for him to abstract from
and generalise the data of sense; and it is because the subjective
process of Ideation, by which we mean our representative mental activity
in its widest sense, consists also in transmutations under the same
general laws of the same portion of the energetic organism, that it is
possible to frame general ideas. These general laws of organic
transmutation are the _a priori_ conditions of the necessary
determination in time of all existences in the world of phenomena.

The form, therefore, of the phenomenon, in the language of Kant, is
constituted by the transmutations of the Energy immediately related to
consciousness; the matter of the phenomenon is constituted by the
varieties produced in these by the transmitted transmutations from the
Energy beyond--just as the musician may produce a constant variety of
harmonies upon his instrument, but all must be conditioned by the
relations fixed and established between the notes of which the
instrument is composed. Transmutations of the cerebral Energy may be
stimulated not only from without, but by subjective impulse from within;
but in either case the laws of these transmutations are the necessary
form of experience, and it is the possibility of transmutation upon an
internal and subjective impulse which makes possible the formation of
synthetical judgments _a priori_. It is as if the organ were not only
responsive to impressions upon its keyboard from without, but were also
automotive and could originate harmonies in its own notes; and as if,
moreover, it were endowed with consciousness so as to receive an
intuition of both classes of music. The former would correspond to
sensations, the latter to ideas; and we might imagine such an instrument
by presenting to itself its own system of notes, contriving thus to
frame _a priori_ a synthetical system of these general musical laws
which would constitute the necessary and universal form of its whole
musical experience.