[Footnote 1:  Kant’s conjectures concerning a common ground of material and mental phenomena, and those concerning the common root of sensibility and understanding, show the same tendency.  On the one hand, duality, on the other, unity.]

[Footnote 2:  “Phenomenon, which always has two sides, the one when the object in itself is considered (apart from the way in which it is intuited, and just because of which fact its character always remains problematical), the other when we regard the form of the intuition of this object, which must be sought not in the object in itself, but in the subject to whom the object appears, while it nevertheless actually and necessarily belongs to the phenomenon of this object.”  “This predicate “—­sc., spatial quality, extension—­“is attributed to things only in so far as they appear to us.”]

There is, then, a threefold distinction to be made:  (1) Things in themselves, which can never be the object of our knowledge, because our forms of intuition are not valid for them. (2) Phenomena, things for us, nature or the totality of that which either is or, at least, may be the object of our knowledge (here belong the possible inhabitants of the moon, the magnetic matter which pervades all bodies, and the forces of attraction and repulsion, though the first have never been observed, and the second is not perceptible on account of the coarseness of our senses, and the last, because forces in general are not perceptible; nature comprehends everything whose existence “is connected with our perceptions in a possible experience"[1]). (3) Our representations of phenomena, i.e., that of the latter which actually enters into the consciousness of the empirical individual.  In the realm of things in themselves there is no motion whatever, but at most an intelligible correlate of this relation; in the world of phenomena, the world of physics, the earth moves around the sun; in the sphere of representation the sun moves around the earth.  It is true, as has been said, that Kant sometimes ignores the distinction between phenomena as related to noumena and phenomena as related to representations; and, as a result of this, that the phenomenon is either completely volatilized into the representation[2] or split up into an objective half independent of us and a representative half dependent on us, of which the former falls into the thing in itself,[3] while the latter is resolved into subjective states of the ego.

[Footnote 1:  “Nothing is actually given to us but the perception and the empirical progress from this to other possible perceptions.”  “To call a phenomenon a real thing antecedent to perception, means ... that in the progress of experience we must meet with such a perception.”]

[Footnote 2:  Phenomena “are altogether in me,” “exist only in our sensibility as a modification of it.”  “There is nothing in space but that which is actually represented in it.”  Phenomena are “mere representations, which, if they are not given in us (in perception) nowhere exist.”]