if they be in any degree profitable to the individuals of a
species, in their infinitely complex relations to other organic beings,
and to their physical conditions of life, will tend to the preservation
of such individuals and will generally be inherited by the offspring.
The offspring also will thus have a better chance of surviving, for of
the many individuals of any species which are periodically born, but a
small number can survive. I have called this principle by which each
slight variation, if useful, is preserved, by the term, "natural
selection." Mr. Darwin adds that his meaning would be more accurately
expressed by a phrase of Mr. Spencer's coinage, "Survival of the
Fittest."

It may be observed that neither "natural selection" nor "survival of
the fittest" gives very accurate expression to the idea which Darwin
seems to wish to convey. Natural selection is at best a metaphorical
description of a process, and "survival of the fittest" describes the
result of that process. Nor shall we find the moving principle of
evolution in individual variability unless we choose to regard chance
as an efficient agency. Consequently, the only efficient principle
conceivably connected with the process is the "struggle for existence;"
and even this has only a purely negative function in the origination of
species or of adaptations. For, the "surviving fittest" owe nothing
more to the struggle for existence than our pensioned veterans owe to
the death-dealing bullets which did _not_ hit them. Mr. Darwin has,
however, obviated all difficulty regarding precision of terms by the
remark that he intended to use his most important term, "struggle for
existence" in "a large and metaphorical sense."

We have now seen the second element of Darwinism, namely, the "struggle
for life." The theory of natural selection, then, postulates the
accumulation of minute "fortuitions" individual modifications, which
are useful to the possessor of them, by means of a struggle for life of
such a sanguinary nature and of such enormous proportions as to result
in the destruction of the overwhelming majority of adult individuals.
These are the correlative factors in the process of natural selection.

In view of the popular identification of Darwinism with the doctrine of
evolution, on the one hand, and with the theory of struggle for life,
on the other hand, it is necessary to insist on the Darwinian
conception of small, fluctuating, useful variations