vism_ or _agnosticism_. The modesty of this doctrine does not, it
is true, strike very deep. For, although it disclaims knowledge of
ultimate reality, it also forbids anyone else to have any. Knowledge, it
affirms, can be of but one type, that which comprises the verifiable
laws governing nature. All questions concerning first causes are
futile, a stimulus only to excursions of fancy popularly mistaken for
knowledge. The superior certainty and stability which attaches to
natural science is to be permanently secured by the savant's steadfast
refusal to be led away after the false gods of metaphysics.

But though this is sufficient ground for an agnostic policy, it does
prove an agnostic theory. The latter has sprung from a closer analysis
of knowledge, though it fails to make a very brave showing for
thoroughness and consistency. The crucial point has already been brought
within our view. The general principles of naturalism require that
knowledge shall be reduced to sensations, or impressions of the
environment upon the organism. But the environment and the sensations do
not correspond. The environment is matter and motion, force and energy;
the sensations are of motions, to be sure, but much more conspicuously
of colors, sounds, odors, pleasures, and pains. Critically, this may be
expressed by saying that since the larger part of sense-perception is so
unmistakably subjective, and since all knowledge alike must be derived
from this source, knowledge as a whole must be regarded as dealing only
with appearances. There are at least three agnostic methods progressing
from this point. All agree that the inner or essential reality is
unfathomable. But, in the first place, those most close to the tradition
of materialism maintain that the most significant appearances, the
primary qualities, are those which compose a purely quantitative and
corporeal world. The inner essence of things may at any rate be
_approached_ by a monism of matter or of energy. This theory is
epistemological only to the extent of moderating its claims in the hope
of lessening its responsibility. Another agnosticism places all sense
qualities on a par, but would regard physics and psychology as
complementary reports upon the two distinct series of phenomena in which
the underlying reality expresses itself. This theory is epistemological
to the extent of granting knowledge, viewed as perception, as good a
standing in the universe as that which is accorded