ion, results
which are greatly inferior.

The social phenomenon, in short, is not something which occurs in one
individual, or even in several individuals taken severally. It is
essentially an interaction of individuals, and as the capabilities of
any given individual are extraordinarily various and are only called
out, each by appropriate circumstances, it will be readily seen that the
nature of the interaction may itself bring forth new and perhaps
unexpected capacities, and elicit from the individuals contributing to
it forces which, but for this particular opportunity, might possibly
remain forever dormant. If this is so, sociology as a science is not the
same thing as either biology or psychology. It deals neither with the
physical capacities of individuals as such nor with their psychological
capacities as such. It deals rather with results produced by the play of
these forces upon one another, by the interaction of individuals under
the conditions imposed by their physical environment. The nature of the
forces and the point of these distinctions may be made clear by a very
simple instance.

The interplay of human motives and the interaction of human beings is
the fundamental fact of social life, and the permanent results which
this interaction achieves and the influence which it exercises upon the
individuals who take part in it constitute the fundamental fact of
social evolution. These results are embodied in what may be called,
generically, tradition. So understood, tradition--its growth and
establishment, its reaction upon the very individuals who
contribute to building it up, and its modifications by subsequent
interactions--constitutes the main subject of sociological inquiry.

Tradition is, in the development of society, what heredity is in the
physical growth of the stock. It is the link between past and future, it
is that in which the effects of the past are consolidated and on the
basis of which subsequent modifications are built up. We might push the
analogy a little further, for the ideas and customs which it maintains
and furnishes to each new generation as guides for their behavior in
life are analogous to the determinate methods of reaction, the inherited
impulses, reflexes, and instincts with which heredity furnishes the
individual. The tradition of the elders is, as it were, the instinct of
society. It furnishes the prescribed rule for dealing with the ordinary
occasions of life, which is for t