reground, naturally promoted attempts to
discover in them the chief key to the growth of civilisation. Comte had
expressly denounced the notion that the biological methods of Lamarck
could be applied to social man. Buckle had taken account of natural
influences, but had relegated them to a secondary plane, compared with
psychological factors. But the Darwinian theory made it tempting to
explain the development of civilisation in terms of "adaptation to
environment," "struggle for existence," "natural selection," "survival
of the fittest," etc. (Recently O. Seeck has applied these principles to
the decline of Graeco-Roman civilisation in his "Untergang der antiken
Welt", 2 volumes, Berlin, 1895, 1901.)

The operation of these principles cannot be denied. Man is still an
animal, subject to zoological as well as mechanical laws. The dark
influence of heredity continues to be effective; and psychical
development had begun in lower organic forms,--perhaps with life itself.
The organic and the social struggles for existence are manifestations of
the same principle. Environment and climatic influence must be called in
to explain not only the differentiation of the great racial sections of
humanity, but also the varieties within these sub-species and, it may
be, the assimilation of distinct varieties. Ritter's "Anthropogeography"
has opened a useful line of research. But on the other hand, it is urged
that, in explaining the course of history, these principles do not take
us very far, and that it is chiefly for the primitive ultra-prehistoric
period that they can account for human development. It may be said
that, so far as concerns the actions and movements of men which are
the subject of recorded history, physical environment has ceased to act
mechanically, and in order to affect their actions must affect their
wills first; and that this psychical character of the causal relations
substantially alters the problem. The development of human societies, it
may be argued, derives a completely new character from the dominance
of the conscious psychical element, creating as it does new conditions
(inventions, social institutions, etc.) which limit and counteract the
operation of natural selection, and control and modify the influence of
physical environment. Most thinkers agree now that the chief clews to
the growth of civilisation must be sought in the psychological
sphere. Imitation, for instance, is a principle which is probably