forcibly and abruptly checked, a vague sense of dissatisfaction is
generally experienced.
It has often been assumed that animals were in the first place rendered
social, and that they feel as a consequence uncomfortable when
separated from each other, and comfortable whilst together; but it is a
more probable view that these sensations were first developed, in order
that those animals which would profit by living in society, should be
induced to live together, in the same manner as the sense of hunger and
the pleasure of eating were, no doubt, first acquired in order to
induce animals to eat. The feeling of pleasure from society is probably
an extension of the parental or filial affections, since the social
instinct seems to be developed by the young remaining for a long time
with their parents; and this extension may be attributed in part to
habit, but chiefly to natural selection. With those animals which were
benefited by living in close association, the individuals which took
the greatest pleasure in society would best escape various dangers,
whilst those that cared least for their comrades, and lived solitary,
would perish in greater numbers. With respect to the origin of the
parental and filial affections, which apparently lie at the base of the
social instincts, we know not the steps by which they have been gained;
but we may infer that it has been to a large extent through natural
selection. So it has almost certainly been with the unusual and
opposite feeling of hatred between the nearest relations, as with the
worker-bees which kill their brother drones, and with the queen-bees
which kill their daughter-queens; the desire to destroy their nearest
relations having been in this case of service to the community.
Parental affection, or some feeling which replaces it, has been
developed in certain animals extremely low in the scale, for example,
in star-fishes and spiders. It is also occasionally present in a few
members alone in a whole group of animals, as in the genus Forficula,
or earwigs.
The all-important emotion of sympathy is distinct from that of love. A
mother may passionately love her sleeping and passive infant, but she
can hardly at such times be said to feel sympathy for it. The love of a
man for his dog is distinct from sympathy, and so is that of a dog for
his master. Adam Smith formerly argued, as has Mr. Bain recently, that
the basis of sympathy lies in our strong retentiveness of former states
of pain or pleasure. Hence, the sight of another person enduring
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