Evolution in Modern Thought | Page 5

men could understand.
As Regards the Factors of Evolution
It is admitted by all who are acquainted with the history of biology that
the general idea of organic evolution as expressed in the Doctrine of
Descent was quite familiar to Darwin's grandfather and to others before
and after him, as we have briefly indicated. It must also be admitted
that some of these pioneers of evolutionism did more than apply the
evolution-idea as a modal formula of becoming, they began to inquire
into the factors in the process. Thus there were pre-Darwinian theories
of evolution, and to these we must now briefly refer.[15]
In all biological thinking we have to work with the categories
Organism--Function--Environment, and theories of evolution may be
classified in relation to these. To some it has always seemed that the
fundamental fact is the living organism,--a creative agent, a striving
will, a changeful Proteus, selecting its environment, adjusting itself to it,
self-differentiating and self-adaptive. The necessity of recognising the
importance of the organism is admitted by all Darwinians who start
with inborn variations, but it is open to question whether the whole
truth of what we might call the Goethian position is exhausted in the
postulate of inherent variability.
To others it has always seemed that the emphasis should be laid on

Function,--on use and disuse, on doing and not doing. Practice makes
perfect; c'est à force de forger qu'on devient forgeron. This is one of
the fundamental ideas of Lamarckism; to some extent it met with
Darwin's approval; and it finds many supporters to-day. One of the
ablest of these--Mr. Francis Darwin--has recently given strong reasons
for combining a modernised Lamarckism with what we usually regard
as sound Darwinism.[16]
To others it has always seemed that the emphasis should be laid on the
Environment, which wakes the organism to action, prompts it to change,
makes dints upon it, moulds it, prunes it, and finally, perhaps, kills it. It
is again impossible to doubt that there is truth in this view, for even if
environmentally induced "modifications" be not transmissible,
environmentally induced "variations" are; and even if the direct
influence of the environment be less important than many enthusiastic
supporters of this view--may we call them Buffonians--think, there
remains the indirect influence which Darwinians in part rely on,--the
eliminative process. Even if the extreme view be held that the only
form of discriminate elimination that counts is inter-organismal
competition, this might be included under the rubric of the animate
environment.
In many passages Buffon[17] definitely suggested that environmental
influences--especially of climate and food--were directly productive of
changes in organisms, but he did not discuss the question of the
transmissibility of the modifications so induced, and it is difficult to
gather from his inconsistent writings what extent of transformation he
really believed in. Prof. Osborn says of Buffon: "The struggle for
existence, the elimination of the least-perfected species, the contest
between the fecundity of certain species and their constant destruction,
are all clearly expressed in various passages." He quotes two of
these:[18]
"Le cours ordinaire de la nature vivante, est en général toujours
constant, toujours le même; son mouvement, toujours régulier, roule
sur deux points inébranlables: l'un, la fécondité sans bornes donnée à
toutes les espèces; l'autre, les obstacles sans nombre qui réduisent cette

fécondité à une mesure déterminée et ne laissent en tout temps qu'à peu
près la même quantité d'individus de chaque espèce" ... "Les espèces
les moins parfaites, les plus délicates, les plus pesantes, les moins
agissantes, les moins armées, etc., ont déjà disparu ou disparaîtront.".
Erasmus Darwin[19] had a firm grip of the "idea of the gradual
formation and improvement of the Animal world," and he had his
theory of the process. No sentence is more characteristic than this: "All
animals undergo transformations which are in part produced by their
own exertions, in response to pleasures and pains, and many of these
acquired forms or propensities are transmitted to their posterity." This
is Lamarckism before Lamarck, as his grandson pointed out. His
central idea is that wants stimulate efforts and that these result in
improvements which subsequent generations make better still. He
realised something of the struggle for existence and even pointed out
that this advantageously checks the rapid multiplication. "As Dr.
Krause points out, Darwin just misses the connection between this
struggle and the Survival of the Fittest."[20]
Lamarck[21] (1744-1829) seems to have thought out his theory of
evolution without any knowledge of Erasmus Darwin's which it closely
resembled. The central idea of his theory was the cumulative
inheritance of functional modifications. "Changes in environment bring
about changes in the habits of animals. Changes in their wants
necessarily bring about parallel changes in their habits. If new wants
become constant or very lasting, they form new habits, the new habits
involve the use of