to the method of evolution, none the less,
as a process sufficient to explain all biological phenomena, all
differentiations of life into widely diverse species, families, and even
kingdoms, evolution is flatly accepted. Likewise has been accepted its
law of development: _That_, _in the struggle for existence_, _the strong
and fit and the progeny of the strong and fit have a better opportunity
for survival than the weak and less fit and the progeny of the weak and
less fit_.

It is in the struggle of the species with other species and against all
other hostile forces in the environment, that this law operates; also in
the struggle between the individuals of the same species. In this
struggle, which is for food and shelter, the weak individuals must
obviously win less food and shelter than the strong. Because of this,
their hold on life relaxes and they are eliminated. And for the same
reason that they may not win for themselves adequate food and shelter,
the weak cannot give to their progeny the chance for survival that the
strong give. And thus, since the weak are prone to beget weakness, the
species is constantly purged of its inefficient members.

Because of this, a premium is placed upon strength, and so long as the
struggle for food and shelter obtains, just so long will the average
strength of each generation increase. On the other hand, should
conditions so change that all, and the progeny of all, the weak as well
as the strong, have an equal chance for survival, then, at once, the
average strength of each generation will begin to diminish. Never yet,
however, in animal life, has there been such a state of affairs. Natural
selection has always obtained. The strong and their progeny, at the
expense of the weak, have always survived. This law of development has
operated down all the past upon all life; it so operates today, and it is
not rash to say that it will continue to operate in the future--at least
upon all life existing in a state of nature.

Man, preeminent though he is in the animal kingdom, capable of reacting
upon and making suitable an unsuitable environment, nevertheless remains
the creature of this same law of development. The social selection to
which he is subject is merely another form of natural selection. True,
within certain narrow limits he modifies the struggle for existence and
renders less precarious the tenure of life for the weak. The extremely
weak, diseased, and ineffici