It is to be observed that the interest in historical research implied
by this conception need not be that of Comte. In the Positive
Philosophy history is part of sociology; the interest in it is to
discover the sociological laws. In the view of which I have just
spoken, history is permitted to be an end in itself; the
reconstruction of the genetic process is an independent interest. For
the purpose of the reconstruction, sociology, as well as physical
geography, biology, psychology, is necessary; the sociologist and the
historian play into each other's hands; but the object of the former
is to establish generalisations; the aim of the latter is to trace in
detail a singular causal sequence.

14. The success of the evolutional theory helped to discredit the
assumption or at least the invocation of transcendent causes.
Philosophically of course it is compatible with theism, but historians
have for the most part desisted from invoking the naive conception of
a "god in history" to explain historical movements. A historian may be
a theist; but, so far as his work is concerned, this particular belief
is otiose. Otherwise indeed (as was remarked above) history could not
be a science; for with a _deus ex machina_ who can be brought on the
stage to solve difficulties scientific treatment is a farce. The
transcendent element had appeared in a more subtle form through the
influence of German philosophy. I noticed how Ranke is prone to refer
to ideas as if they were transcendent existences manifesting
themselves in the successive movements of history. It is intelligible
to speak of certain ideas as controlling, in a given period,--for
instance, the idea of nationality; but from the scientific point of
view, such ideas have no existence outside the minds of individuals
and are purely psychical forces; and a historical "idea," if it does
not exist in this form, is merely a way of expressing a synthesis of
the historian himself.

15. From the more general influence of Darwinism on the place of
history in the system of human knowledge, we may turn to the influence
of the principles and methods by which Darwin explained development.
It had been recognised even by ancient writers (such as Aristotle and
Polybius) that physical circumstances (geography, climate) were
factors conditioning the character and history of a race or society.
In the sixteenth century Bodin emphasised these factors, and many
subsequent writers took them into a