The Descent of Man

of the same species. This fact is not more surprising
than that the fears of many animals
should be directed against special enemies.
Species which are not social, such as lions and
tigers, no doubt feel sympathy for the suffering
of their own young, but not for that of any other
animal. With mankind, selfishness, experience,
and imitation, probably add, as Mr. Bain
has shewn, to the power of sympathy; for we
are led by the hope of receiving good in return
to perform acts of sympathetic kindness to others;
and sympathy is much strengthened by
habit. In however complex a manner this feeling
may have originated, as it is one of high
importance to all those animals which aid and
defend one another, it will have been increased
through natural selection; for those communities,
which included the greatest number of the
most sympathetic members, would flourish
best, and rear the greatest number of offspring.