There is another fallacy which appears to me to pervade the so-called
"ethics of evolution." It is the notion that because, on the whole,
animals and plants have advanced in perfection of organization by
means of the struggle for existence and the consequent "survival of the
fittest"; therefore men in society, men as ethical beings, must look to
the same process to help them towards perfection. I suspect that this
fallacy has arisen out of the unfortunate ambiguity of the phrase
"survival of the fittest." "Fittest" has a connotation of "best"; and
about "best" there hangs a moral flavour. In cosmic nature, however,
what is "fittest" depends upon the conditions. Long since, I ventured to
point out that if our hemisphere were to cool again, the survival of
the fittest might bring about, in the vegetable kingdom, a population
of more and more stunted and humbler and humbler organisms, until the
"fittest" that survived might be nothing but lichens, diatoms, and such
microscopic organisms as those which give red snow its colour; while, if
it became hotter, the pleasant valleys of the Thames and Isis might
be uninhabitable by any animated beings save those that flourish in a
tropical jungle. They, as the fittest, the best adapted to the changed
conditions, would survive.