ntrol, individual and public, is developed later than the
emotional form, or, at any rate, is not at first independent of it.

The origin of mental impressionability seems to lie then, not in one,
but in the two general regions of activity--that connected with the
struggle for food and that connected with reproduction. The strain
on the attention in the food and conflict side of life involves
the development of mental impressionability, particularly of an
impressionability on the side of cognition. But in addition we have
the impressionability growing out of sexual life which has been in
question above, and which is more closely related to appreciation than
to cognition. And of these two aspects of impressionability--the one
growing out of conflict and the one growing out of reproduction--the
latter has more social possibilities than the former, because it
implies a sympathetic rather than an antagonistic organic attitude. It
is certainly in virtue of susceptibility to the opinion of others that
society works--through public opinion, fashion, tradition, reproof,
encouragement, precept, and doctrine--to bring the individual
under control and make him a member of society; and it is doubtful
whether this could have been accomplished if a peculiar attitude
of responsiveness to opinion had not arisen in sexual relations,
reinforcing the more general and cognitive impressionability.
Without this capacity to be influenced the individual would be in the
condition of the hardened criminal, and society would be impossible.

This sex-susceptibility, which was originally developed as an
accessory of reproduction and had no social meaning whatever, has
thus, in the struggle of society to obtain a hold on the individual,
become a social factor of great importance, and together with another
product of sexual life--the love of offspring--it is, I suspect, the
most immediate source of our sympathetic attitudes in general, and an
important force in the development of the ideal, moral, and aesthetic
sides of life.

Morality, sympathy, and altruism are of tribal origin, and have their
roots in (1) the love of offspring, (2) the sensitivity connected
with courtship, and (3) the comradeship which arises among men in
prosecuting vital interests in common. The history of society on the
moral and aesthetic sides is in great part the history of the attempt
to make the sympathetic attitude prevail over the more antagonistic.
But how far we are