eft the greater part of
physics or the theory of existence to the metaphysicians. What they have
made of it does not concern us here, since the result has certainly not
been a science; indeed they have obscured the very notion that there
should be a science of all existence and that metaphysics, if it is more
than a name for ultimate physics, can be nothing but dialectic, which
does not look toward existence at all. But the prevalence of a mythical
physics, purporting to describe the structure of the universe in terms
quite other than those which scientific physics could use, has affected
this scientific physics and seriously confused it. Its core, in
mechanics, to be sure, could not be touched; and the detail even of
natural history and chemistry could not be disfigured: but the general
aspect of natural history could be rendered ambiguous in the doctrine of
evolution; while in psychology, which attempted to deal with that half
of the world which Descartes had not subjected to mechanism, confusion
could hold undisputed sway.

[Sidenote: Evolution by mechanism.]

There is a sense in which the notion of evolution is involved in any
mechanical system. Descartes indeed had gone so far as to describe, in
strangely simple terms, how the world, with all its detail, might have
been produced by starting any motion anywhere in the midst of a plenum
at rest. The idea of evolution could not be more curtly put forth; so
much so that Descartes had to arm himself against the inevitable charge
that he was denying the creation, by protesting that his doctrine was a
supposition contrary to fact, and that though the world _might_ have
been so formed, it was really created as Genesis recorded. Moreover, in
antiquity, every Ionian philosopher had conceived a gradual
crystallisation of nature; while Empedocles, in his magnificent oracles,
had anticipated Darwin's philosophy without Darwin's knowledge. It is
clear that if the forces that hold an organism together are mechanical,
and therefore independent of the ideal unities they subtend, those
forces suffice to explain the origin of the organism, and can have
produced it. Darwin's discoveries, like every other advance in physical
insight, are nothing but filling for that abstract assurance. They show
us how the supposed mechanism really works in one particular field, in
one stage of its elaboration. As earlier naturalists had shown us how
mechanical causes might produce the miracle of the