all powers have
developed in reciprocity with extendal conditions. Knowledge is here
considered from the practical point of view, as a weapon in the
struggle for life, as an "organon" which has been continuously in use
for generations. In recent years the economic or pragmatic
epistemology, as developed by Avenarius and Mach in Germany, and by
James in America, points in the same direction. Science, it is said,
only maintains those principles and presuppositions which are
necessary to the simplest and clearest orientation be applied to
experience and to practical work, will successively be eliminated.

In these views a striking and important application is made of the
idea of struggle for life to the development of human thought. Thought
must, as all other things in the world, struggle for life. But this
whole consideration belongs to psychology, not to the theory of
knowledge (epistemology), which is concerned only with the validity of
knowledge, not with its historical origin. Every hypothesis to explain
the origin of knowledge must submit to cross-examination by the theory
of knowledge, because it works with the fundamental forms and
principles of human thought. We cannot go further back than these
forms and principles, which it is the aim of epistemology to ascertain
and for which no further reason can be given.[202]

But there is another side of the problem which is, perhaps, of more
importance and which epistemology generally overlooks. If new
variations can arise, not only in organic but perhaps also in
inorganic nature, new tasks are placed before the human mind. The
question is, then, if it has forms in which there is room for the new
matter? We are here touching a possibility which the great master of
epistemology did not bring to light. Kant supposed confidently that no
other matter of knowledge could stream forth from the dark source
which he called "the thing-in-itself," than such as could be
synthesised in our existing forms of knowledge. He mentions the
possibility of other forms than the human, and warns us against the
dogmatic assumption that the human conception of existence should be
absolutely adequate. But he seems to be quite sure that the
thing-in-itself works constantly, and consequently always gives us
only what our powers can master. This assumption was a consequence of
Kant's rationalistic tendency, but one for which no warrant can be
given. Evolutionism and systematism are opposing tendenci