h themselves. The ideal would be a society
always in progress and always in equilibrium, but this ideal is perhaps
unrealizable: the two characteristics that would fain complete each
other, which do complete each other in their embryonic state, can no
longer abide together when they grow stronger. If one could speak,
otherwise than metaphorically, of an impulse toward social life, it
might be said that the brunt of the impulse was borne along the line of
evolution ending at man, and that the rest of it was collected on the
road leading to the hymenoptera: the societies of ants and bees would
thus present the aspect complementary to ours. But this would be only a
manner of expression. There has been no particular impulse towards
social life; there is simply the general movement of life, which on
divergent lines is creating forms ever new. If societies should appear
on two of these lines, they ought to show divergence of paths at the
same time as community of impetus. They will thus develop two classes of
characteristics which we shall find vaguely complementary of each other.

So our study of the evolution movement will have to unravel a certain
number of divergent directions, and to appreciate the importance of what
has happened along each of them--in a word, to determine the nature of
the dissociated tendencies and estimate their relative proportion.
Combining these tendencies, then, we shall get an approximation, or
rather an imitation, of the indivisible motor principle whence their
impetus proceeds. Evolution will thus prove to be something entirely
different from a series of adaptations to circumstances, as mechanism
claims; entirely different also from the realization of a plan of the
whole, as maintained by the doctrine of finality.

* * * * *

That adaptation to environment is the necessary condition of evolution
we do not question for a moment. It is quite evident that a species
would disappear, should it fail to bend to the conditions of existence
which are imposed on it. But it is one thing to recognize that outer
circumstances are forces evolution must reckon with, another to claim
that they are the directing causes of evolution. This latter theory is
that of mechanism. It excludes absolutely the hypothesis of an original
impetus, I mean an internal push that has carried life, by more and more
complex forms, to higher and higher destinies. Yet this impetus is
evident, and a m