nt which is of its
kind--direct demonstration being out of the question--quite
unequalled. Because, in the third place, he broke down the opposition
which the most scientific had felt to the seductive modal formula of
evolution by bringing forward a more plausible theory of the process
than had been previously suggested. Nor can one forget, since
questions of this magnitude are human and not merely academic, that he
wrote so that all men could understand.

_As Regards the Factors of Evolution_

It is admitted by all who are acquainted with the history of biology
that the general idea of organic evolution as expressed in the
Doctrine of Descent was quite familiar to Darwin's grandfather and to
others before and after him, as we have briefly indicated. It must
also be admitted that some of these pioneers of evolutionism did more
than apply the evolution-idea as a modal formula of becoming, they
began to inquire into the factors in the process. Thus there were
pre-Darwinian theories of evolution, and to these we must now briefly
refer.[15]

In all biological thinking we have to work with the categories
Organism--Function--Environment, and theories of evolution may be
classified in relation to these. To some it has always seemed that the
fundamental fact is the living organism,--a creative agent, a striving
will, a changeful Proteus, selecting its environment, adjusting itself
to it, self-differentiating and self-adaptive. The necessity of
recognising the importance of the organism is admitted by all
Darwinians who start with inborn variations, but it is open to
question whether the whole truth of what we might call the Goethian
position is exhausted in the postulate of inherent variability.

To others it has always seemed that the emphasis should be laid on
Function,--on use and disuse, on doing and not doing. Practice makes
perfect; _c'est a force de forger qu'on devient forgeron_. This is one
of the fundamental ideas of Lamarckism; to some extent it met with
Darwin's approval; and it finds many supporters to-day. One of the
ablest of these--Mr. Francis Darwin--has recently given strong reasons
for combining a modernised Lamarckism with what we usually regard as
sound Darwinism.[16]

To others it has always seemed that the emphasis should be laid on the
Environment, which wakes the organism to action, prompts it to change,
makes dints upon it, moulds it, prunes it, and finally, perhaps, kills it.
It is again impo