s so large a bulk of details expressly social in their character
and value, virtually compels us to scrutinize the history of the economic
and other interrelationships maintained by the human constituents of
civilized, barbarous, and savage communities. Language has been treated as
an individual mental product, and so have the arts of life and of
pleasure; but all of these things find their greatest utility in their
social usage,--in their value as bonds which hold together the few or many
human beings composing groups of lower or higher grade. Without
discovering any other reasons we would be impelled to take up social
evolution, for this process is inextricably bound up with the origin and
development of all departments of human thought and action.

If now this new field is actually to be included within the scope of the
laws controlling the rest of nature's evolution, two general conclusions
must be established. Although no formal order need be followed, it must at
some time be shown that human social relations are biological relations,
to be best explained only through their comparison with the far simpler
modes of association found by the biologist among lower orders of beings;
and in the second place it must be demonstrated that identical biological
laws, uniform in their operation everywhere in the organic world, have
controlled the origin and establishment of even the most complex societies
of men. So far no reason has been discovered by science for believing that
evolution has been discontinuous, holding true only for the merely
physical characteristics of humanity as a whole; and furthermore, the
impersonal student of nature finds ample positive evidences showing that
the basic laws of associations of whatever grade are exactly the same. For
these laws we are to seek.

Heretofore the doctrine of organic evolution has been discussed with
reference to the single individual organism viewed as a natural object
whose history and vital relations require elucidation. Both in the general
arguments of the first few chapters and in the fifth and sixth chapters
dealing with the single case of the human species, the proof has been
given that all of the structural and physiological characters of any and
every organic type fall within the scope of the principles of evolution,
by which alone they can be reasonably interpreted. It has been unjust in a
sense to ignore completely the importance of the organic relations of a
soc