820 THE AMERICAN JOURNAL OF SOCIOLOGY
complex developing series of phenomena. The genetic method and point of view must be adopted in the social sciences; the actual series of progressive stages observed in this case or that ; the psychology and biological fact carefully distinguished; and a comparative morphology of social groups gradually worked out. Each stage of social organization must be treated as what it is found to be, not what we expect it to be on our theories ; and only in the result will a general interpretation of social life be reached which will stand beside the corresponding interpretations of the biologist and the psychologist.'
Ill
Perhaps so much preliminary discussion of method may be found excessive, but it enables me at this point to proceed at once to a positive affirmation : to wit, that recent researches of the sort I have mentioned have shown that there has actually been a progressive evolution in social organization, a historical and racial movement. This has not been confined to human history, but has proceeded pari passu with the evolution of mind in the animal kingdom. We may recognize, indeed, in a preliminary way for our discussion, three modes of association or social grouping related, indeed, genetically to one another, but yet so different from one another, that we may consider them as clearly dis- tinguishable in type. I shall treat them under the following head- ings, first naming them, and then characterizing each with reference to the sort of solidarity which it shows.
These modes of "social" or collective life are: (i) the in- stinctive or gregarious; (2) the spontaneous or plastic; and (3) the reflective or social proper.
I. The Instinctive or Gregarious Group. The characters of this sort of group life are quite clearly expressed by the terms "instinctive" and "gregarious." The former term suggests their biological character, the latter their social character. In saying there is a form of association that is instinctive, we mean to sug-
• In a little book entitled Darwin and the Humanities (Review Pub. Co., Baltimore), I have endeavored to trace the precise influence of Darwinism in the mental and social sciences.
