Darwin and Modern Science (1909)
Edited by A.C. Seward
II. DARWIN'S PREDECESSORS.
By J. ARTHUR THOMSON
Professor of Natural History in the University of Aberdeen.
n seeking to discover Darwin's relation to his predecessors it is useful
to distinguish the various services which he rendered to the theory of
organic evolution.
(I) As everyone knows, the general idea of the Doctrine of Descent is that
the plants and animals of the present-day are the lineal descendants of
ancestors on the whole somewhat simpler, that these again are descended
from yet simpler forms, and so on backwards towards the literal "Protozoa"
and "Protophyta" about which we unfortunately know nothing. Now no one
supposes that Darwin originated this idea, which in rudiment at least is as
old as Aristotle. What Darwin did was to make it current intellectual
coin. He gave it a form that commended itself to the scientific and public
intelligence of the day, and he won wide-spread conviction by showing with
consummate skill that it was an effective formula to work with, a key which
no lock refused. In a scholarly, critical, and pre-eminently fair-minded
way, admitting difficulties and removing them, foreseeing objections and
forestalling them, he showed that the doctrine of descent supplied a modal
interpretation of how our present-day fauna and flora have come to be.
(II) In the second place, Darwin applied the evolution-idea to particular
problems, such as the descent of man, and showed what a powerful organon it
is, introducing order into masses of uncorrelated facts, interpreting
enigmas both of structure and function, both bodily and mental, and, best
of all, stimulating and guiding further investigation. But here again it
cannot be claimed that Darwin was original. The problem of the descent or
ascent of man, and other particular cases of evolution, had attracted not a
few naturalists before Darwin's day, though no one (except Herbert Spencer
in the psychological domain (1855)) had come near him in precision and
thoroughness of inquiry.
(III) In the third place, Darwin contributed largely to a knowledge of the
factors in the evolution-process, especially by his analysis of what occurs
in the case of domestic animals and cultivated plants, and by his
elaboration of the theory of Natural Selection, which Alfred Russel Wallace
independently stated at the same time, and of which there had been a few
previous suggestions of a more or less vague description. It was here that
Darwin's originality was greatest, for he revealed to naturalists the many
different forms—often very subtle—which natural selection takes, and with
the insight of a disciplined scientific imagination he realised what a
mighty engine of progress it has been and is.
(IV) As an epoch-marking contribution, not only to Aetiology but to
Natural History in the widest sense, we rank the picture which Darwin gave
to the world of the web of life, that is to say, of the inter-relations and
linkages in Nature. For the Biology of the individual—if that be not a
contradiction in terms—no idea is more fundamental than that of the
correlation of organs, but Darwin's most characteristic contribution was
not less fundamental,—it was the idea of the correlation of organisms.
This, again, was not novel; we find it in the works of naturalist like
Christian Conrad Sprengel, Gilbert White, and Alexander von Humboldt, but
the realisation of its full import was distinctively Darwinian.
AS REGARDS THE GENERAL IDEA OF ORGANIC EVOLUTION.
While it is true, as Prof. H.F. Osborn puts it, that "'Before and after
Darwin' will always be the ante et post urbem conditam of biological
history," it is also true that the general idea of organic evolution is
very ancient. In his admirable sketch "From the Greeks to Darwin"
("Columbia University Biological Series", Vol. I. New York and London,
1894. We must acknowledge our great indebtness to this fine piece of
work.), Prof. Osborn has shown that several of the ancient philosophers
looked upon Nature as a gradual development and as still in process of
change. In the suggestions of Empedocles, to take the best instance, there
were "four sparks of truth,—first, that the development of life was a
gradual process; second, that plants were evolved before animals; third,
that imperfect forms were gradually replaced (not succeeded) by perfect
forms; fourth, that the natural cause of the production of perfect forms
was the extinction of the imperfect." (Op. cit. page 41.) But the
fundamental idea of one stage giving origin to another was absent. As the
blue Aegean teemed with treasures of beauty and threw many upon its shores,
so did Nature produce like a fertile artist what had to be rejected as well
as what was able to survive, but the idea of one species emerging out of
another was not yet conceived.
Aristotle's views of Nature (See G.J. Romanes, "Aristotle as a Naturalist",
"Contemporary Review", Vol. LIX. page 275, 1891; G. Pouchet "La Biologie
Aristotelique", Paris, 1885; E. Zeller, "A History of Greek Philosophy",
London, 1881, and "Ueber die griechischen Vorganger Darwin's", "Abhandl.
Berlin Akad." 1878, pages 111-124.) seem to have been more definitely
evolutionist than those of his predecessors, in this sense, at least, that
he recognised not only an ascending scale, but a genetic series from polyp
to man and an age-long movement towards perfection. "It is due to the
resistance of matter to form that Nature can only rise by degrees from
lower to higher types." "Nature produces those things which, being
continually moved by a certain principle contained in themselves, arrive at
a certain end."
To discern the outcrop of evolution-doctrine in the long interval between
Aristotle and Bacon seems to be very difficult, and some of the instances
that have been cited strike one as forced. Epicurus and Lucretius, often
called poets of evolution, both pictured animals as arising directly out of
the earth, very much as Milton's lion long afterwards pawed its way out.
Even when we come to Bruno who wrote that "to the sound of the harp of the
Universal Apollo (the World Spirit), the lower organisms are called by
stages to higher, and the lower stages are connected by intermediate forms
with the higher," there is great room, as Prof. Osborn points out (op. cit.
page 81.), for difference of opinion as to how far he was an evolutionist
in our sense of the term.
The awakening of natural science in the sixteenth century brought the
possibility of a concrete evolution theory nearer, and in the early
seventeenth century we find evidences of a new spirit—in the embryology of
Harvey and the classifications of Ray. Besides sober naturalists there
were speculative dreamers in the sixteenth and seventeenth centuries who
had at least got beyond static formulae, but, as Professor Osborn points
out (op. cit. page 87.), "it is a very striking fact, that the basis of our
modern methods of studying the Evolution problem was established not by the
early naturalists nor by the speculative writers, but by the Philosophers."
He refers to Bacon, Descartes, Leibnitz, Hume, Kant, Lessing, Herder, and
Schelling. "They alone were upon the main track of modern thought. It is
evident that they were groping in the dark for a working theory of the
Evolution of life, and it is remarkable that they clearly perceived from
the outset that the point to which observation should be directed was not
the past but the present mutability of species, and further, that this
mutability was simply the variation of individuals on an extended scale."
Bacon seems to have been one of the first to think definitely about the
mutability of species, and he was far ahead of his age in his suggestion of
what we now call a Station of Experimental Evolution. Leibnitz discusses
in so many words how the species of animals may be changed and how
intermediate species may once have linked those that now seem
discontinuous. "All natural orders of beings present but a single
chain"..."All advances by degrees in Nature, and nothing by leaps."
Similar evolutionist statements are to be found in the works of the other
"philosophers," to whom Prof. Osborn refers, who were, indeed, more
scientific than the naturalists of their day. It must be borne in mind
that the general idea of organic evolution—that the present is the child
of the past—is in great part just the idea of human history projected upon
the natural world, differentiated by the qualification that the continuous
"Becoming" has been wrought out by forces inherent in the organisms
themselves and in their environment.
A reference to Kant (See Brock, "Die Stellung Kant's zur
Deszendenztheorie," "Biol. Centralbl." VIII. 1889, pages 641-648. Fritz
Schultze, "Kant und Darwin", Jena, 1875.) should come in historical order
after Buffon, with whose writings he was acquainted, but he seems, along
with Herder and Schelling, to be best regarded as the culmination of the
evolutionist philosophers—of those at least who interested themselves in
scientific problems. In a famous passage he speaks of "the agreement of so
many kinds of animals in a certain common plan of structure"...an "analogy
of forms" which "strengthens the supposition that they have an actual
blood-relationship, due to derivation from a common parent." He speaks of
"the great Family of creatures, for as a Family we must conceive it, if the
above-mentioned continuous and connected relationship has a real
foundation." Prof. Osborn alludes to the scientific caution which led
Kant, biology being what it was, to refuse to entertain the hope "that a
Newton may one day arise even to make the production of a blade of grass
comprehensible, according to natural laws ordained by no intention." As
Prof. Haeckel finely observes, Darwin rose up as Kant's Newton. (Mr Alfred
Russel Wallace writes: "We claim for Darwin that he is the Newton of
natural history, and that, just so surely as that the discovery and
demonstration by Newton of the law of gravitation established order in
place of chaos and laid a sure foundation for all future study of the
starry heavens, so surely has Darwin, by his discovery of the law of
natural selection and his demonstration of the great principle of the
preservation of useful variations in the struggle for life, not only thrown
a flood of light on the process of development of the whole organic world,
but also established a firm foundation for all future study of nature"
("Darwinism", London, 1889, page 9). See also Prof. Karl Pearson's
"Grammar of Science" (2nd edition), London, 1900, page 32. See Osborn, op.
cit. Page 100.))
The scientific renaissance brought a wealth of fresh impressions and some
freedom from the tyranny of tradition, and the twofold stimulus stirred the
speculative activity of a great variety of men from old Claude Duret of
Moulins, of whose weird transformism (1609) Dr Henry de Varigny
("Experimental Evolution". London, 1892. Chap. 1. page 14.) gives us a
glimpse, to Lorenz Oken (1799-1851) whose writings are such mixtures of
sense and nonsense that some regard him as a far-seeing prophet and others
as a fatuous follower of intellectual will-o'-the-wisps. Similarly, for De
Maillet, Maupertuis, Diderot, Bonnet, and others, we must agree with
Professor Osborn that they were not actually in the main Evolution
movement. Some have been included in the roll of honour on very slender
evidence, Robinet for instance, whose evolutionism seems to us extremely
dubious. (See J. Arthur Thomson, "The Science of Life". London, 1899.
Chap. XVI. "Evolution of Evolution Theory".)
The first naturalist to give a broad and concrete expression to the
evolutionist doctrine of descent was Buffon (1707-1788), but it is
interesting to recall the fact that his contemporary Linnaeus (1707-1778),
protagonist of the counter-doctrine of the fixity of species (See Carus
Sterne (Ernest Krause), "Die allgemeine Weltanschauung in ihrer
historischen Entwickelung". Stuttgart, 1889. Chapter entitled
"Bestandigkeit oder Veranderlichkeit der Naturwesen".), went the length of
admitting (in 1762) that new species might arise by intercrossing.
Buffon's position among the pioneers of the evolution-doctrine is weakened
by his habit of vacillating between his own conclusions and the orthodoxy
of the Sorbonne, but there is no doubt that he had a firm grasp of the
general idea of "l'enchainement des etres."
Erasmus Darwin (1731-1802), probably influenced by Buffon, was another firm
evolutionist, and the outline of his argument in the "Zoonomia" ("Zoonomia,
or the Laws of Organic Life", 2 vols. London, 1794; Osborn op. cit. page
145.) might serve in part at least to-day. "When we revolve in our minds
the metamorphoses of animals, as from the tadpole to the frog; secondly,
the changes produced by artificial cultivation, as in the breeds of horses,
dogs, and sheep; thirdly, the changes produced by conditions of climate and
of season, as in the sheep of warm climates being covered with hair instead
of wool, and the hares and partridges of northern climates becoming white
in winter: when, further, we observe the changes of structure produced by
habit, as seen especially in men of different occupations; or the changes
produced by artificial mutilation and prenatal influences, as in the
crossing of species and production of monsters; fourth, when we observe the
essential unity of plan in all warm-blooded animals,—we are led to
conclude that they have been alike produced from a similar living
filament"..."From thus meditating upon the minute portion of time in which
many of the above changes have been produced, would it be too bold to
imagine, in the great length of time since the earth began to exist,
perhaps millions of years before the commencement of the history of
mankind, that all warm-blooded animals have arisen from one living
filament?"..."This idea of the gradual generation of all things seems to
have been as familiar to the ancient philosophers as to the modern ones,
and to have given rise to the beautiful hieroglyphic figure of the proton
oon, or first great egg, produced by night, that is, whose origin is
involved in obscurity, and animated by Eros, that is, by Divine Love; from
whence proceeded all things which exist."
Lamarck (1744-1829) seems to have become an evolutionist independently of
Erasmus Darwin's influence, though the parallelism between them is
striking. He probably owed something to Buffon, but he developed his
theory along a different line. Whatever view be held in regard to that
theory there is no doubt that Lamarck was a thorough-going evolutionist.
Professor Haeckel speaks of the "Philosophie Zoologique" as "the first
connected and thoroughly logical exposition of the theory of descent."
(See Alpheus S. Packard, "Lamarck, the Founder of Evolution, His Life and
Work, with Translations of his writings on Organic Evolution". London,
1901.)
Besides the three old masters, as we may call them, Buffon, Erasmus Darwin,
and Lamarck, there were other quite convinced pre-Darwinian evolutionists.
The historian of the theory of descent must take account of Treviranus
whose "Biology or Philosophy of Animate Nature" is full of evolutionary
suggestions; of Etienne Geoffroy St Hilaire, who in 1830, before the French
Academy of Sciences, fought with Cuvier, the fellow-worker of his youth, an
intellectual duel on the question of descent; of Goethe, one of the
founders of morphology and the greatest poet of Evolution—who, in his
eighty-first year, heard the tidings of Geoffroy St Hilaire's defeat with
an interest which transcended the political anxieties of the time; and of
many others who had gained with more or less confidence and clearness a new
outlook on Nature. It will be remembered that Darwin refers to thirty-four
more or less evolutionist authors in his Historical Sketch, and the list
might be added to. Especially when we come near to 1858 do the numbers
increase, and one of the most remarkable, as also most independent
champions of the evolution-idea before that date was Herbert Spencer, who
not only marshalled the arguments in a very forcible way in 1852, but
applied the formula in detail in his "Principles of Psychology" in 1855.
(See Edward Clodd, "Pioneers of Evolution", London, page 161, 1897.)
It is right and proper that we should shake ourselves free from all
creationist appreciations of Darwin, and that we should recognise the
services of pre-Darwinian evolutionists who helped to make the time ripe,
yet one cannot help feeling that the citation of them is apt to suggest two
fallacies. It may suggest that Darwin simply entered into the labours of
his predecessors, whereas, as a matter of fact, he knew very little about
them till after he had been for years at work. To write, as Samuel Butler
did, "Buffon planted, Erasmus Darwin and Lamarck watered, but it was Mr
Darwin who said 'That fruit is ripe,' and shook it into his lap"...seems to
us a quite misleading version of the facts of the case. The second fallacy
which the historical citation is a little apt to suggest is that the
filiation of ideas is a simple problem. On the contrary, the history of an
idea, like the pedigree of an organism, is often very intricate, and the
evolution of the evolution-idea is bound up with the whole progress of the
world. Thus in order to interpret Darwin's clear formulation of the idea
of organic evolution and his convincing presentation of it, we have to do
more than go back to his immediate predecessors, such as Buffon, Erasmus
Darwin, and Lamarck; we have to inquire into the acceptance of evolutionary
conceptions in regard to other orders of facts, such as the earth and the
solar system (See Chapter IX. "The Genetic View of Nature" in J.T. Merz's
"History of European Thought in the Nineteenth Century", Vol. 2, Edinburgh
and London, 1903.); we have to realise how the growing success of
scientific interpretation along other lines gave confidence to those who
refused to admit that there was any domain from which science could be
excluded as a trespasser; we have to take account of the development of
philosophical thought, and even of theological and religious movements; we
should also, if we are wise enough, consider social changes. In short, we
must abandon the idea that we can understand the history of any science as
such, without reference to contemporary evolution in other departments of
activity.
While there were many evolutionists before Darwin, few of them were expert
naturalists and few were known outside a small circle; what was of much
more importance was that the genetic view of nature was insinuating itself
in regard to other than biological orders of facts, here a little and there
a little, and that the scientific spirit had ripened since the days when
Cuvier laughed Lamarck out of court. How was it that Darwin succeeded
where others had failed? Because, in the first place, he had clear
visions—"pensees de la jeunesse, executees par l'age mur"—which a
University curriculum had not made impossible, which the "Beagle" voyage
made vivid, which an unrivalled British doggedness made real—visions of
the web of life, of the fountain of change within the organism, of the
struggle for existence and its winnowing, and of the spreading genealogical
tree. Because, in the second place, he put so much grit into the
verification of his visions, putting them to the proof in an argument which
is of its kind—direct demonstration being out of the question—quite
unequalled. Because, in the third place, he broke down the opposition
which the most scientific had felt to the seductive modal formula of
evolution by bringing forward a more plausible theory of the process than
had been previously suggested. Nor can one forget, since questions of this
magnitude are human and not merely academic, that he wrote so that all 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. (See Prof. W.A. Locy's "Biology and
its Makers". New York, 1908. Part II. "The Doctrine of Organic
Evolution".
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 a 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. (Presidential Address to the British Association meeting at Dublin in
1908.)
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 (See in particular Samuel Butler, "Evolution Old
and New", London, 1879; J.L. de Lanessan, "Buffon et Darwin", "Revue
Scientifique", XLIII. pages 385-391, 425-432, 1889.) 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 (op. cit. page 136.):
"Le cours ordinaire de la nature vivante, est en general toujours constant,
toujours le meme; son mouvement, toujours regulier, roule sur deux points
inebranlables: l'un, la fecondite sans bornes donnee a toutes les especes;
l'autre, les obstacles sans nombre qui reduisent cette fecondite a une
mesure determinee et ne laissent en tout temps qu'a peu pres la meme
quantite d'individus de chaque espece"..."Les especes les moins parfaites,
les plus delicates, les plus pesantes, les moins agissantes, les moins
armees, etc., ont deja disparu ou disparaitront."
Erasmus Darwin (See Ernst Krause and Charles Darwin, "Erasmus Darwin",
London, 1879.) 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." (Osborn
op. cit. page 142.)
Lamarck (1744-1829) (See E. Perrier "La Philosophie Zoologique avant
Darwin", Paris, 1884; A. de Quatrefages, "Darwin et ses Precurseurs
Francais", Paris, 1870; Packard op. cit.; also Claus, "Lamarck als
Begrunder der Descendenzlehre", Wien, 1888; Haeckel, "Natural History of
Creation", English translation London, 1879; Lang "Zur Charakteristik der
Forschungswege von Lamarck und Darwin", Jena, 1889.) 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
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 (1776-1837) (See Huxley's article "Evolution in Biology",
"Encyclopaedia Britannica" (9th edit.), 1878, pages 744-751, and Sully's
article, "Evolution in Philosophy", ibid. pages 751-772.), 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 (1749-1832) (See Haeckel, "Die Naturanschauung von Darwin, Goethe
und Lamarck", Jena, 1882.), 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. Etienne Geoffroy Saint-Hilaire (1772-1844), 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." ("Origin of
Species" (6th edition), page xvii.) 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." ("The Life and Letters of Charles
Darwin", Vol. 1. page 83. London, 1887.)
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." (A.R.
Wallace, "My Life, A Record of Events and Opinions", London, 1905, Vol. 1.
page 232.) 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 average than that of
more civilized peoples. It then occurred to me that these causes or their
equivalents are continually acting in the case of animals also; and as
animals usually breed much more rapidly than does mankind, the destruction
every year from these causes must be enormous in order to keep down the
numbers of each species, since they evidently do not increase regularly
from year to year, as otherwise the world would long ago have been densely
crowded with those that breed most quickly. Vaguely thinking over the
enormous and constant destruction which this implied, it occurred to me to
ask the question, Why do some die and some live? And the answer was
clearly, that on the whole the best fitted live. From the effects of
disease the most healthy escaped; from enemies the strongest, the swiftest,
or the most cunning; from famine the best hunters or those with the best
digestion; and so on. Then it suddenly flashed upon me that this self-
acting process would necessarily improve the race, because in every
generation the inferior would inevitably be killed off and the superior
would remain—that is, the fittest would survive." (Ibid. Vol. 1. page
361.) We need not apologise for this long quotation, it is a tribute to
Darwin's magnanimous colleague, the Nestor of the evolutionist camp,—and
it probably indicates the line of thought which Darwin himself followed.
It is interesting also to recall the fact that in 1852, when Herbert
Spencer wrote his famous "Leader" article on "The Development Hypothesis"
in which he argued powerfully for the thesis that the whole animate world
is the result of an age-long process of natural transformation, he wrote
for "The Westminster Review" another important essay, "A Theory of
Population deduced from the General Law of Animal Fertility", towards the
close of which he came within an ace of recognising that the struggle for
existence was a factor in organic evolution. At a time when pressure of
population was practically interesting men's minds, Darwin, Wallace, and
Spencer were being independently led from a social problem to a biological
theory. There could be no better illustration, as Prof. Patrick Geddes has
pointed out, of the Comtian thesis that science is a "social phenomenon."
Therefore, as far more important than any further ferreting out of vague
hints of Natural Selection in books which Darwin never read, we would
indicate by a quotation the view that the central idea in Darwinism is
correlated with contemporary social evolution. "The substitution of Darwin
for Paley as the chief interpreter of the order of nature is currently
regarded as the displacement of an anthropomorphic view by a purely
scientific one: a little reflection, however, will show that what has
actually happened has been merely the replacement of the anthropomorphism
of the eighteenth century by that of the nineteenth. For the place vacated
by Paley's theological and metaphysical explanation has simply been
occupied by that suggested to Darwin and Wallace by Malthus in terms of the
prevalent severity of industrial competition, and those phenomena of the
struggle for existence which the light of contemporary economic theory has
enabled us to discern, have thus come to be temporarily exalted into a
complete explanation of organic progress." (P. Geddes, article "Biology",
"Chambers's Encyclopaedia".) It goes without saying that the idea
suggested by Malthus was developed by Darwin into a biological theory which
was then painstakingly verified by being used as an interpretative formula,
and that the validity of a theory so established is not affected by what
suggested it, but the practical question which this line of thought raises
in the mind is this: if Biology did thus borrow with such splendid results
from social theory, why should we not more deliberately repeat the
experiment?
Darwin was characteristically frank and generous in admitting that the
principle of Natural Selection had been independently recognised by Dr W.C.
Wells in 1813 and by Mr Patrick Matthew in 1831, but he had no knowledge of
these anticipations when he published the first edition of "The Origin of
Species". Wells, whose "Essay on Dew" is still remembered, read in 1813
before the Royal Society a short paper entitled "An account of a White
Female, part of whose skin resembles that of a Negro" (published in 1818).
In this communication, as Darwin said, "he observes, firstly, that all
animals tend to vary in some degree, and, secondly, that agriculturists
improve their domesticated animals by selection; and then, he adds, but
what is done in this latter case 'by art, seems to be done with equal
efficacy, though more slowly, by nature, in the formation of varieties of
mankind, fitted for the country which they inhabit.'" ("Origin of Species"
(6th edition) page xv.) Thus Wells had the clear idea of survival
dependent upon a favourable variation, but he makes no more use of the idea
and applies it only to man. There is not in the paper the least hint that
the author ever thought of generalising the remarkable sentence quoted
above.
Of Mr Patrick Matthew, who buried his treasure in an appendix to a work on
"Naval Timber and Arboriculture", Darwin said that "he clearly saw the full
force of the principle of natural selection." In 1860 Darwin wrote—very
characteristically—about this to Lyell: "Mr Patrick Matthew publishes a
long extract from his work on "Naval Timber and Arboriculture", published
in 1831, in which he briefly but completely anticipates the theory of
Natural Selection. I have ordered the book, as some passages are rather
obscure, but it is certainly, I think, a complete but not developed
anticipation. Erasmus always said that surely this would be shown to be
the case some day. Anyhow, one may be excused in not having discovered the
fact in a work on Naval Timber." ("Life and Letters" II. page 301.)
De Quatrefages and De Varigny have maintained that the botanist Naudin
stated the theory of evolution by natural selection in 1852. He explains
very clearly the process of artificial selection, and says that in the
garden we are following Nature's method. "We do not think that Nature has
made her species in a different fashion from that in which we proceed
ourselves in order to make our variations." But, as Darwin said, "he does
not show how selection acts under nature." Similarly it must be noted in
regard to several pre-Darwinian pictures of the struggle for existence
(such as Herder's, who wrote in 1790 "All is in struggle...each one for
himself" and so on), that a recognition of this is only the first step in
Darwinism.
Profs. E. Perrier and H.F. Osborn have called attention to a remarkable
anticipation of the selection-idea which is to be found in the speculations
of Etienne Geoffroy St Hilaire (1825-1828) on the evolution of modern
Crocodilians from the ancient Teleosaurs. Changing environment induced
changes in the respiratory system and far-reaching consequences followed.
The atmosphere, acting upon the pulmonary cells, brings about
"modifications which are favourable or destructive ('funestes'); these are
inherited, and they influence all the rest of the organisation of the
animal because if these modifications lead to injurious effects, the
animals which exhibit them perish and are replaced by others of a somewhat
different form, a form changed so as to be adapted to (a la convenance) the
new environment."
Prof. E.B. Poulton ("Science Progress", New Series, Vol. I. 1897. "A
Remarkable Anticipation of Modern Views on Evolution". See also Chap. VI.
in "Essays on Evolution", Oxford, 1908.) has shown that the anthropologist
James Cowles Prichard (1786-1848) must be included, even in spite of
himself, among the precursors of Darwin. In some passages of the second
edition of his "Researches into the Physical History of Mankind" (1826), he
certainly talks evolution and anticipates Prof. Weismann in denying the
transmission of acquired characters. He is, however, sadly self-
contradictory and his evolutionism weakens in subsequent editions—the only
ones that Darwin saw. Prof. Poulton finds in Prichard's work a recognition
of the operation of Natural Selection. "After enquiring how it is that
'these varieties are developed and preserved in connection with particular
climates and differences of local situation,' he gives the following very
significant answer: 'One cause which tends to maintain this relation is
obvious. Individuals and families, and even whole colonies, perish and
disappear in climates for which they are, by peculiarity of constitution,
not adapted. Of this fact proofs have been already mentioned.'" Mr
Francis Darwin and Prof. A.C. Seward discuss Prichard's "anticipations" in
"More Letters of Charles Darwin", Vol. I. page 43, and come to the
conclusion that the evolutionary passages are entirely neutralised by
others of an opposite trend. There is the same difficulty with Buffon.
Hints of the idea of Natural Selection have been detected elsewhere. James
Watt (See Prof. Patrick Geddes's article "Variation and Selection",
"Encyclopaedia Britannica (9th edition) 1888.), for instance, has been
reported as one of the anticipators (1851). But we need not prolong the
inquiry further, since Darwin did not know of any anticipations until after
he had published the immortal work of 1859, and since none of those who got
hold of the idea made any use of it. What Darwin did was to follow the
clue which Malthus gave him, to realise, first by genius and afterwards by
patience, how the complex and subtle struggle for existence works out a
natural selection of those organisms which vary in the direction of fitter
adaptation to the conditions of their life. So much success attended his
application of the Selection-formula that for a time he regarded Natural
Selection as almost the sole factor in evolution, variations being pre-
supposed; gradually, however, he came to recognise that there was some
validity in the factors which had been emphasized by Lamarck and by Buffon,
and in his well-known summing up in the sixth edition of the "Origin" he
says of the transformation of species: "This has been effected chiefly
through the natural selection of numerous successive, slight, favourable
variations; aided in an important manner by the inherited effects of the
use and disuse of parts; and in an unimportant manner, that is, in relation
to adaptive structures, whether past or present, by the direct action of
external conditions, and by variations which seem to us in our ignorance to
arise spontaneously."
To sum up: the idea of organic evolution, older than Aristotle, slowly
developed from the stage of suggestion to the stage of verification, and
the first convincing verification was Darwin's; from being an a priori
anticipation it has become an interpretation of nature, and Darwin is still
the chief interpreter; from being a modal interpretation it has advanced to
the rank of a causal theory, the most convincing part of which men will
never cease to call Darwinism.
Home Page |
Further Reading |
Site Map |
Send Feedback
