and objective knowledge. Kant considers intuitive forms to be a priori, because he confuses mathematical space and time, which are concepts, with sensible space and time; whereas they contain a material element irreducible to pure formal and mathematical relations.[1] This must not be taken to mean that either geometry or mechanics, taking, as they do, sensible data as the basis of their concepts, are of purely empirical and contingent value. The activity of thought elaborates the impressions of the senses in accordance with its own laws, and thus transforms and completes them till they correspond to its need of unity and universality; and this logical reconstruction is neither arbitrary nor violent, but answers to their nature, whose source, as we have already pointed out, is identical with that of thought.
8. Criticism of Riehl’s Philosophy. — There can be no
question that Riehl’s conception more nearly succeeds in
placing science on a firm basis than does neo-Kantism;
but it has the serious drawback of being founded, just
as is the transfigured realism of Spencer, upon a
metaphysical doctrine against which human thought rebels,
i.e. on the hypothesis of that unknowable entity which
nothing but a miracle could bring within the range of
thought. Kiehl not only admits its reality, but credits
it with being the common cause of the two series,
that is to say, with standing in certain functional
relations thereto, thus implicitly assuming it not to be
beyond the forms of our thought. How indeed could it
be so without losing the character of reality? Can we
conceive of anything real which cannot be translated
more or less definitely into terms of thought? Biehl
rightly insists upon the necessity of admitting the
existence of a cause producing our sensations, but
differing from them, since between the stimulus and the
fact of consciousness there is a series of processes which
physiology has described to us in all its stages;[2] but
the fact that we conceive this cause proves it to be already
known to a certain extent. Monism based upon the
