Evolution in Modern Thought | Page 6

new parts, or a different use of old parts, which
results finally in the production of new organs and the modification of
old ones." He differed from Buffon in not attaching importance, as far
as animals are concerned, to the direct influence of the environment,
"for environment can effect no direct change whatever upon the
organisation of animals," but in regard to plants he agreed with Buffon
that external conditions directly moulded them.
Treviranus[22] (1776-1837), whom Huxley ranked beside Lamarck,
was on the whole Buffonian, attaching chief importance to the
influence of a changeful environment both in modifying and in

eliminating, but he was also Goethian, for instance in his idea that
species like individuals pass through periods of growth, full bloom, and
decline. "Thus, it is not only the great catastrophes of Nature which
have caused extinction, but the completion of cycles of existence, out
of which new cycles have begun." A characteristic sentence is quoted
by Prof. Osborn: "In every living being there exists a capability of an
endless variety of form-assumption; each possesses the power to adapt
its organisation to the changes of the outer world, and it is this power,
put into action by the change of the universe, that has raised the simple
zoophytes of the primitive world to continually higher stages of
organisation, and has introduced a countless variety of species into
animate Nature."
Goethe[23] (1749-1832), who knew Buffon's work but not Lamarck's,
is peculiarly interesting as one of the first to use the evolution-idea as a
guiding hypothesis, e.g. in the interpretation of vestigial structures in
man, and to realise that organisms express an attempt to make a
compromise between specific inertia and individual change. He gave
the finest expression that science has yet known--if it has known it--of
the kernel-idea of what is called "bathmism," the idea of an "inherent
growth-force"--and at the same time he held that "the way of life
powerfully reacts upon all form" and that the orderly growth of form
"yields to change from externally acting causes."
Besides Buffon, Erasmus Darwin, Lamarck, Treviranus, and Goethe,
there were other "pioneers of evolution," whose views have been often
discussed and appraised. Étienne Geoffroy Saint-Hilaire (1772-1884),
whose work Goethe so much admired, was on the whole Buffonian,
emphasising the direct action of the changeful milieu. "Species vary
with their environment, and existing species have descended by
modification from earlier and somewhat simpler species." He had a
glimpse of the selection idea, and believed in mutations or sudden
leaps--induced in the embryonic condition by external influences. The
complete history of evolution-theories will include many instances of
guesses at truth which were afterwards substantiated, thus the
geographer von Buch (1773-1853) detected the importance of the
Isolation factor on which Wagner, Romanes, Gulick and others have

laid great stress, but we must content ourselves with recalling one other
pioneer, the author of the Vestiges of Creation (1844), a work which
passed through ten editions in nine years and certainly helped to harrow
the soil for Darwin's sowing. As Darwin said, "it did excellent service
in this country in calling attention to the subject, in removing prejudice,
and in thus preparing the ground for the reception of analogous
views."[24] Its author, Robert Chambers (1802-1871) was in part a
Buffonian--maintaining that environment moulded organisms
adaptively, and in part a Goethian--believing in an inherent progressive
impulse which lifted organisms from one grade of organisation to
another.
As Regards Natural Selection
The only thinker to whom Darwin was directly indebted, so far as the
theory of Natural Selection is concerned, was Malthus, and we may
once more quote the well-known passage in the Autobiography: "In
October, 1838, that is, fifteen months after I had begun my systematic
enquiry, I happened to read for amusement 'Malthus on Population,'
and being well prepared to appreciate the struggle for existence which
everywhere goes on from long-continued observation of the habits of
animals and plants, it at once struck me that under these circumstances
favourable variations would tend to be preserved, and unfavourable
ones to be destroyed. The result of this would be the formation of new
species."[25]
Although Malthus gives no adumbration of the idea of Natural
Selection in his exposition of the eliminative processes which go on in
mankind, the suggestive value of his essay is undeniable, as is
strikingly borne out by the fact that it gave to Alfred Russel Wallace
also "the long-sought clue to the effective agent in the evolution of
organic species."[26] One day in Ternate when he was resting between
fits of fever, something brought to his recollection the work of Malthus
which he had read twelve years before. "I thought of his clear
exposition of 'the positive checks to increase'--disease, accidents, war,
and famine--which keep down the population of savage races to so
much lower an