188 HERBERT SPENCER
and fullness of life, and has doubtless done so, yet
until we come to its highest forms in subjective and
finally rational selection, it works not towards an ideal
but towards a relative fitness to present conditions.
And this may spell degeneration, as in parasites,
when an extrinsic standard is used. Tapeworms
may be just as fit to survive as golden eagles. Again,
the process of elimination does not necessarily mean
that the handicapped variants come at once to a violent
end, as when rat devours rat, or the cold decimates a
flock of birds in a single night; it often simply means
that the less fit die before the average time, and are
less successful than their neighbours as regards pair-
ing and having offspring. Moreover, although the
selective process is primarily eliminative or destructive,
like thinning turnips or pruning fruit-trees, we can-
not separate its positive and negative aspects. That
nothing succeeds like success is continually verifiable
in nature, the fit variant gets a start just as surely as
the unfit variant is handicapped; there is favouring
and fostering just because there is sifting and singling.
Given variations and given some mode of selection
in the manifold struggle for existence, the argument
continues, then the result will be in Spencer's phrase
" the survival of the fittest.'* And since many varia-
tions are transmitted from generation to generation,
and may, through the pairing of similar or suitable
mates, be gradually increased in amount and stability,
the eliminative or selective process works towards
the establishment of new adaptations and the origin
of new species.
Darwin thought chiefly of the struggle between
individuals—either between fellows of the same kin