its special mode of conduct is just what nature has produced by
selection from among countless other forms of living which have not had
the same degree of biological utility. But man alone recognizes vaguely or
clearly the "why and wherefore" of his acts that are far more instinctive
than he supposes; he only is consciously aware of the bonds of kinship and
economic interdependence. He looks about for the authority which imposes
his duties and fashions his bonds, and conceives this authority as
something superhuman, until the comparative studies of evolutionary
phenomena reveal the true causes in uniform nature itself.

According to biological ethics, the fundamental obligations of all living
things are the same, even though the modes of discharging them may be
various. Every individual must lead an efficient personal life by
procuring food, but animals differ very much in their alimentary
apparatus; among other things they must respire, but some are so simply
organized that they do not need elaborate organs like the tufted gills of
a crustacean or the lungs of higher vertebrates. Every individual of
whatever grade must also provide in some way for the maintenance of the
species, but some, like a conger eel, produce enormous numbers of eggs
which are left uncared for, while others, like birds, bring forth only a
few young, which receive constant attention and protection until they are
able to shift for themselves. Nature has no place for even a human
community unless individual and racial interests are conserved, so that
the greatest duties are definitely formulated--all else is secondary and
less essential. Selfish action on the part of every unit is obligatory,
but it must always be antecedent to endeavor in the wider interests of the
race if the unit is a solitary individual; if it is a member of an
association of any grade, then it must serve its fellows in some way.
Egoism and altruism are natural essential guides to conduct; neither can
safely exclude the other, and their antithesis sets a problem for every
organism, which is to work out the proper compromise that will be most
satisfactory to nature. The Golden Rule is taught by biology because it is
demonstrated empirically, and not because it has any _a priori_ value as
an ideal ethical principle.

But utilitarian or natural ethics need not stop with the statement of
vague generalities like the foregoing. In human society, as in the life of
low animals, the wor