9HMKJM - The Complete Work of Charles Darwin Online

24
DARWINIANA.
facts to such assumption, and also to adduce instances
explicable by it and inexplicable by the received view,
so perhaps winning our assent to the doctrine, through
its competency to harmonize all the facts, even though
the cause of the assumed variation remain as occult as
that of the transformation of tadpoles into frogs, or
that of Coryne into Sarzia.
The first line of proof, successfully carried out,
would establish derivation as a true physical theory ;
the second, as a sufficient hypothesis.
Lamarck mainly undertook the first line,
theory which has been so assailed by
in a
ridicule that it
rarely receives the credit for ability to which in its day
it was entitled. But he assigned partly unreal, partly
insufficient causes ; and the attempt to account for a
progressive change in species through the direct influence
of physical agencies, and through the appetencies
and habits of animals reacting upon their
structure, thus causing the production and the succes-
sive modification of organs, is a conceded and total
failure. The shadowy author of the " Yestiges of the
Natural History of Creation " can hardly be said to
have undertaken either line, in a scientific way. He
would explain the whole progressive evolution of Na-
ture by virtue of an inherent tendency to development,
thus giving us an idea or a word in place of a
natural cause, a restatement of the proposition instead
of an explanation. Mr. Darwin attempts both lines
of proof, and in a strictly scientific spirit ; but the
stress falls mainly upon the first, for, as he does assign
real causes, he is bound to prove their adequacy.
It should be kept in mind that, while all direct