of directions. People do not tend
to fall in love with those who are in racial respects a contrast to
themselves; they do not tend to fall in love with foreigners; they do
not tend to be attracted to the ugly, the diseased, the deformed. All
these things may happen, but they are the exception and not the rule.
These limitations to the roving impulses of love, while very real, to
some extent vary at different periods in accordance with the ideals
which happen to be fashionable. In more remote ages they have been still
more profoundly modified by religious and social ideas; polygamy and
polyandry, the custom of marrying only inside one's own caste, or only
outside it, all these various and contradictory plans have been easily
accepted at some place and some time, and have offered no more conscious
obstacle to the free play of love than among ourselves is offered by the
prohibition against marriage between near relations.

Those simple-minded people who talk about the blind and irresistible
force of passion are themselves blind to very ordinary psychological
facts. Passion--when it occurs--requires in normal persons cumulative
and prolonged forces to impart to it full momentum.[157] In its early
stages it is under the control of many influences, including influences
of reason. If it were not so there could be no sexual selection, nor any
social organization.[158]

The eugenic ideal which is now developing is thus not an artificial
product, but the reasoned manifestation of a natural instinct, which has
often been far more severely strained by the arbitrary prohibitions of
the past than it is ever likely to be by any eugenic ideals of the
future. The new ideal will be absorbed into the conscience of the
community, whether or not like a kind of new religion,[159] and will
instinctively and unconsciously influence the impulses of men and women.
It will do all this the more surely since, unlike the taboos of savage
societies, the eugenic ideal will lead men and women to reject as
partners only the men and women who are naturally unfit--the diseased,
the abnormal, the weaklings--and conscience will thus be on the side of
impulse.

It may indeed be pointed out that those who advocate a higher and more
scientific conscience in matters of mating are by no means plotting
against love, which is for the most part on their side, but rather
against the influences that do violence to love: on the one hand, the
reckless and thoughtles