in the rough, but gradually in
more and more minute detail. This adaptation, brought about by chance,
gives _the impression_ of intelligent creative purpose.

In Darwin this fundamental mode of naturalistic interpretation took, under
the influence of the social-economic theories of Malthus, the special form
of natural selection by means of the struggle for existence, in
association with the assumption of unlimited and fluctuating variability
in the forms of life. All living beings have a tendency to increase in
number without limit. But the means of subsistence and other conditions of
existence do not increase at the same rate; they are relatively constant.
Thus competition must come about. Any organism that is, by fortuitous
variation, more favourably equipped than its fellows maintains itself and
reproduces itself; the less favoured perish. For all things living are
exposed to enemies, to untoward circumstances, and the like. Every
individual favoured above its rivals persists, and can transmit to its
descendants its own more favourable, more differentiated, more highly
equipped character. Thus evolution is begun, and is forced on into the
ever more diverse and ever "higher."

To Darwin this struggle for existence and this selection according to
utility seemed, at any rate, the chief factor in progress. He did, indeed,
make some concessions to the Lamarckian principle that new characters may
be acquired by increased use, and to other "secondary" principles. But
these are of small importance as compared with his main factor.

Differences of Opinion As To the Factors In Evolution.

The theory of natural selection in the struggle for existence rapidly
gained wide acceptance, but from the first it was called in question from
many sides. Bronn, who translated Darwin's works into German, was and
remained loyal to the idea of a "developmental law"--that there is within
the organism an innate tendency towards self-differentiation and progress,
thus a purely teleological principle.(34) Similarly, von Baer emphasised
the idea of an endeavour to realise an aim; von Koelliker, that of
"heterogenesis"; Naegeli, that of an impulse towards perfection--all three
thus recognising the theory of evolution, but dissenting from the view
that the struggle for existence is the impelling factor and actual guide
in the process. Very soon, in another direction, antagonism became
pronounced between the strictly Darwinian elements of