It will be readily admitted that of all living writers Mr. Alfred
Russel Wallace is the one the peculiar turn of whose mind best fits
him to write on the subject of natural selection, or the
accumulation of fortunate but accidental variations through descent
and the struggle for existence. His mind in all its more essential
characteristics closely resembles that of the late Mr. Charles
Darwin himself, and it is no doubt due to this fact that he and Mr.
Darwin elaborated their famous theory at the same time, and
independently of one another. I shall have occasion in the course
of the following article to show how misled and misleading both
these distinguished men have been, in spite of their unquestionable
familiarity with the whole range of animal and vegetable phenomena.
I believe it will be more respectful to both of them to do this in
the most outspoken way. I believe their work to have been as
mischievous as it has been valuable, and as valuable as it has been
mischievous; and higher, whether praise or blame, I know not how to
give. Nevertheless I would in the outset, and with the utmost
sincerity, admit concerning Messrs. Wallace and Darwin that neither
can be held as the more profound and conscientious thinker; neither
can be put forward as the more ready to acknowledge obligation to
the great writers on evolution who had preceded him, or to place his
own developments in closer and more conspicuous historical
connection with earlier thought upon the subject; neither is the
more ready to welcome criticism and to state his opponent's case in
the most pointed and telling way in which it can be put; neither is
the more quick to encourage new truth; neither is the more genial,
generous adversary, or has the profounder horror of anything even
approaching literary or scientific want of candour; both display the
same inimitable power of putting their opinions forward in the way
that shall best ensure their acceptance; both are equally unrivalled
in the tact that tells them when silence will be golden, and when on
the other hand a whole volume of facts may be advantageously brought
forward. Less than the foregoing tribute both to Messrs. Darwin and
Wallace I will not, and more I cannot pay.
Let us now turn to the most authoritative exponent of latter-day
evolution--I mean to Mr. Wallace, whose work, entitled Darwinism,
though it should have been entitled Wallaceism, is still so far
Darwinistic that it develops the teaching of Mr. Darwin in the
direction given to it by Mr. Darwin himself--so far, indeed, as this
can be ascertained at all--and not in that of Lamarck. Mr. Wallace
tells us, on the first page of his preface, that he has no intention
of dealing even in outline with the vast subject of evolution in
general, and has only tried to give such an account of the theory of
natural selection as may facilitate a clear conception of Darwin's
work. How far he has succeeded is a point on which opinion will
probably be divided. Those who find Mr. Darwin's works clear will
also find no difficulty in understanding Mr. Wallace; those, on the
other hand, who find Mr. Darwin puzzling are little likely to be
less puzzled by Mr. Wallace. He continues:--
"The objections now made to Darwin's theory apply solely to the
particular means by which the change of species has been brought
about, not to the fact of that change."
But "Darwin's theory"--as Mr. Wallace has elsewhere proved that he
understands--has no reference "to the fact of that change"--that is
to say, to the fact that species have been modified in course of
descent from other species. This is no more Mr. Darwin's theory
than it is the reader's or my own. Darwin's theory is concerned
only with "the particular means by which the change of species has
been brought about"; his contention being that this is mainly due to
the natural survival of those individuals that have happened by some
accident to be born most favourably adapted to their surroundings,
or, in other words, through accumulation in the common course of
nature of the more lucky variations that chance occasionally
purveys. Mr. Wallace's words, then, in reality amount to this, that
the objections now made to Darwin's theory apply solely to Darwin's
theory, which is all very well as far as it goes, but might have
been more easily apprehended if he had simply said, "There are
several objections now made to Mr. Darwin's theory."
It must be remembered that the passage quoted above occurs on the
first page of a preface dated March, 1889, when the writer had
completed his task, and was most fully conversant with his subject.
Nevertheless, it seems indisputable either that he is still
confusing evolution with Mr. Darwin's theory, or that he does not
know when his sentences have point and when they have none.
I should perhaps explain to some readers that Mr. Darwin did not
modify the main theory put forward, first by Buffon, to whom it
indisputably belongs, and adopted from him by Erasmus Darwin,
Lamarck, and many other writers in the latter half of the eighteenth
century and the earlier years of the nineteenth. The early
evolutionists maintained that all existing forms of animal and
vegetable life, including man, were derived in course of descent
with modification from forms resembling the lowest now known.
Mr. Darwin went as far as this, and farther no one can go. The
point at issue between him and his predecessors involves neither the
main fact of evolution, nor yet the geometrical ratio of increase,
and the struggle for existence consequent thereon. Messrs. Darwin
and Wallace have each thrown invaluable light upon these last two
points, but Buffon, as early as 1756, had made them the keystone of
his system. "The movement of nature," he then wrote, "turns on two
immovable pivots: one, the illimitable fecundity which she has
given to all species: the other, the innumerable difficulties which
reduce the results of that fecundity." Erasmus Darwin and Lamarck
followed in the same sense. They thus admit the survival of the
fittest as fully as Mr. Darwin himself, though they do not make use
of this particular expression. The dispute turns not upon natural
selection, which is common to all writers on evolution, but upon the
nature and causes of the variations that are supposed to be selected
from and thus accumulated. Are these mainly attributable to the
inherited effects of use and disuse, supplemented by occasional
sports and happy accidents? Or are they mainly due to sports and
happy accidents, supplemented by occasional inherited effects of use
and disuse?
The Lamarckian system has all along been maintained by Mr. Herbert
Spencer, who, in his Principles of Biology, published in 1865,
showed how impossible it was that accidental variations should
accumulate at all. I am not sure how far Mr. Spencer would consent
to being called a Lamarckian pure and simple, nor yet how far it is
strictly accurate to call him one; nevertheless, I can see no
important difference in the main positions taken by him and by
Lamarck.
The question at issue between the Lamarckians, supported by Mr.
Spencer and a growing band of those who have risen in rebellion
against the Charles-Darwinian system on the one hand, and Messrs.
Darwin and Wallace with the greater number of our more prominent
biologists on the other, involves the very existence of evolution as
a workable theory. For it is plain that what Nature can be supposed
able to do by way of choice must depend on the supply of the
variations from which she is supposed to choose. She cannot take
what is not offered to her; and so again she cannot be supposed able
to accumulate unless what is gained in one direction in one
generation, or series of generations, is little likely to be lost in
those that presently succeed. Now variations ascribed mainly to use
and disuse can be supposed capable of being accumulated, for use and
disuse are fairly constant for long periods among the individuals of
the same species, and often over large areas; moreover, conditions
of existence involving changes of habit, and thus of organization,
come for the most part gradually; so that time is given during which
the organism can endeavour to adapt itself in the requisite
respects, instead of being shocked out of existence by too sudden
change. Variations, on the other hand, that are ascribed to mere
chance cannot be supposed as likely to be accumulated, for chance is
notoriously inconstant, and would not purvey the variations in
sufficiently unbroken succession, or in a sufficient number of
individuals, modified similarly in all the necessary correlations at
the same time and place to admit of their being accumulated. It is
vital therefore to the theory of evolution, as was early pointed out
by the late Professor Fleeming Jenkin and by Mr. Herbert Spencer,
that variations should be supposed to have a definite and persistent
principle underlying them, which shall tend to engender similar and
simultaneous modification, however small, in the vast majority of
individuals composing any species. The existence of such a
principle and its permanence is the only thing that can be supposed
capable of acting as rudder and compass to the accumulation of
variations, and of making it hold steadily on one course for each
species, till eventually many havens, far remote from one another,
are safely reached.
It is obvious that the having fatally impaired the theory of his
predecessors could not warrant Mr. Darwin in claiming, as he most
fatuously did, the theory of evolution. That he is still generally
believed to have been the originator of this theory is due to the
fact that he claimed it, and that a powerful literary backing at
once came forward to support him. It seems at first sight
improbable that those who too zealously urged his claims were
unaware that so much had been written on the subject, but when we
find even Mr. Wallace himself as profoundly ignorant on this subject
as he still either is, or affects to be, there is no limit
assignable to the ignorance or affected ignorance of the kind of
biologists who would write reviews in leading journals thirty years
ago. Mr. Wallace writes:--
"A few great naturalists, struck by the very slight difference
between many of these species, and the numerous links that exist
between the most different forms of animals and plants, and also
observing that a great many species do vary considerably in their
forms, colours and habits, conceived the idea that they might be all
produced one from the other. The most eminent of these writers was
a great French naturalist, Lamarck, who published an elaborate work,
the Philosophie Zoologique, in which he endeavoured to prove that
all animals whatever are descended from other species of animals.
He attributed the change of species chiefly to the effect of changes
in the conditions of life--such as climate, food, etc.; and
especially to the desires and efforts of the animals themselves to
improve their condition, leading to a modification of form or size
in certain parts, owing to the well-known physiological law that all
organs are strengthened by constant use, while they are weakened or
even completely lost by disuse. . . .
"The only other important work dealing with the question was the
celebrated Vestiges of Creation, published anonymously, but now
acknowledged to have been written by the late Robert Chambers."
None are so blind as those who will not see, and it would be waste
of time to argue with the invincible ignorance of one who thinks
Lamarck and Buffon conceived that all species were produced from one
another, more especially as I have already dealt at some length with
the early evolutionists in my work Evolution, Old and New, first
published ten years ago, and not, so far as I am aware, detected in
serious error or omission. If, however, Mr. Wallace still thinks it
safe to presume so far on the ignorance of his readers as to say
that the only two important works on evolution before Mr. Darwin's
were Lamarck's Philosophie Zoologique and the Vestiges of Creation,
how fathomable is the ignorance of the average reviewer likely to
have been thirty years ago, when the Origin of Species was first
published? Mr. Darwin claimed evolution as his own theory. Of
course, he would not claim it if he had no right to it. Then by all
means give him the credit of it. This was the most natural view to
take, and it was generally taken. It was not, moreover, surprising
that people failed to appreciate all the niceties of Mr. Darwin's
"distinctive feature" which, whether distinctive or no, was
assuredly not distinct, and was never frankly contrasted with the
older view, as it would have been by one who wished it to be
understood and judged upon its merits. It was in consequence of
this omission that people failed to note how fast and loose Mr.
Darwin played with his distinctive feature, and how readily he
dropped it on occasion.
It may be said that the question of what was thought by the
predecessors of Mr. Darwin is, after all, personal, and of no
interest to the general public, comparable to that of the main
issue--whether we are to accept evolution or not. Granted that Buff
on, Erasmus Darwin, and Lamarck bore the burden and heat of the day
before Mr. Charles Darwin was born, they did not bring people round
to their opinion, whereas Mr. Darwin and Mr. Wallace did, and the
public cannot be expected to look beyond this broad and indisputable
fact.
The answer to this is, that the theory which Messrs. Darwin and
Wallace have persuaded the public to accept is demonstrably false,
and that the opponents of evolution are certain in the end to
triumph over it. Paley, in his Natural Theology, long since brought
forward far too much evidence of design in animal organization to
allow of our setting down its marvels to the accumulation of
fortunate accident, undirected by will, effort and intelligence.
Those who examine the main facts of animal and vegetable
organization without bias will, no doubt, ere long conclude that all
animals and vegetables are derived ultimately from unicellular
organisms, but they will not less readily perceive that the
evolution of species without the concomitance and direction of mind
and effort is as inconceivable as is the independent creation of
every individual species. The two facts, evolution and design, are
equally patent to plain people. There is no escaping from either.
According to Messrs. Darwin and Wallace, we may have evolution, but
are on no account to have it as mainly due to intelligent effort,
guided by ever higher and higher range of sensations, perceptions,
and ideas. We are to set it down to the shuffling of cards, or the
throwing of dice without the play, and this will never stand.
According to the older men, cards did indeed count for much, but
play counted for more. They denied the teleology of the time--that
is to say, the teleology that saw all adaptation to surroundings as
part of a plan devised long ages since by a quasi-anthropomorphic
being who schemed everything out much as a man would do, but on an
infinitely vaster scale. This conception they found repugnant alike
to intelligence and conscience, but, though they do not seem to have
perceived it, they left the door open for a design more true and
more demonstrable than that which they excluded. By making their
variations mainly due to effort and intelligence, they made organic
development run on all-fours with human progress, and with
inventions which we have watched growing up from small beginnings.
They made the development of man from the amoeba part and parcel of
the story that may be read, though on an infinitely smaller scale,
in the development of our most powerful marine engines from the
common kettle, or of our finest microscopes from the dew-drop.
The development of the steam-engine and the microscope is due to
intelligence and design, which did indeed utilize chance
suggestions, but which improved on these, and directed each step of
their accumulation, though never foreseeing more than a step or two
ahead, and often not so much as this. The fact, as I have elsewhere
urged, that the man who made the first kettle did not foresee the
engines of the Great Eastern, or that he who first noted the
magnifying power of the dew-drop had no conception of our present
microscopes--the very limited amount, in fact, of design and
intelligence that was called into play at any one point--this does
not make us deny that the steam-engine and microscope owe their
development to design. If each step of the road was designed, the
whole journey was designed, though the particular end was not
designed when the journey was begun. And so is it, according to the
older view of evolution, with the development of those living
organs, or machines, that are born with us, as part of the
perambulating carpenter's chest we call our bodies. The older view
gives us our design, and gives us our evolution too. If it refuses
to see a quasi-anthropomorphic God modelling each species from
without as a potter models clay, it gives us God as vivifying and
indwelling in all His creatures--He in them, and they in Him. If it
refuses to see God outside the universe, it equally refuses to see
any part of the universe as outside God. If it makes the universe
the body of God, it also makes God the soul of the universe. The
question at issue, then, between the Darwinism of Erasmus Darwin and
the neo-Darwinism of his grandson, is not a personal one, nor
anything like a personal one. It not only involves the existence of
evolution, but it affects the view we take of life and things in an
endless variety of most interesting and important ways. It is
imperative, therefore, on those who take any interest in these
matters, to place side by side in the clearest contrast the views of
those who refer the evolution of species mainly to accumulation of
variations that have no other inception than chance, and of that
older school which makes design perceive and develop still further
the goods that chance provides.
But over and above this, which would be in itself sufficient, the
historical mode of studying any question is the only one which will
enable us to comprehend it effectually. The personal element cannot
be eliminated from the consideration of works written by living
persons for living persons. We want to know who is who--whom we can
depend upon to have no other end than the making things clear to
himself and his readers, and whom we should mistrust as having an
ulterior aim on which he is more intent than on the furthering of
our better understanding. We want to know who is doing his best to
help us, and who is only trying to make us help him, or to bolster
up the system in which his interests are vested. There is nothing
that will throw more light upon these points than the way in which a
man behaves towards those who have worked in the same field with
himself, and, again, than his style. A man's style, as Buffon long
since said, is the man himself. By style, I do not, of course, mean
grammar or rhetoric, but that style of which Buffon again said that
it is like happiness, and vient de la douceur de l'ame. When we
find a man concealing worse than nullity of meaning under sentences
that sound plausibly enough, we should distrust him much as we
should a fellow-traveller whom we caught trying to steal our watch.
We often cannot judge of the truth or falsehood of facts for
ourselves, but we most of us know enough of human nature to be able
to tell a good witness from a bad one.
However this may be, and whatever we may think of judging systems by
the directness or indirectness of those who advance them,
biologists, having committed themselves too rashly, would have been
more than human if they had not shown some pique towards those who
dared to say, first, that the theory of Messrs. Darwin and Wallace
was unworkable; and secondly, that even though it were workable it
would not justify either of them in claiming evolution. When
biologists show pique at all they generally show a good deal of
pique, but pique or no pique, they shunned Mr. Spencer's objection
above referred to with a persistency more unanimous and obstinate
than I ever remember to have seen displayed even by professional
truth-seekers. I find no rejoinder to it from Mr. Darwin himself,
between 1865 when it was first put forward, and 1882 when Mr. Darwin
died. It has been similarly "ostrichized" by all the leading
apologists of Darwinism, so far at least as I have been able to
observe, and I have followed the matter closely for many years. Mr.
Spencer has repeated and amplified it in his recent work The Factors
of Organic Evolution, but it still remains without so much as an
attempt at serious answer, for the perfunctory and illusory remarks
of Mr. Wallace at the end of his Darwinism cannot be counted as
such. The best proof of its irresistible weight is that Mr. Darwin,
though maintaining silence in respect to it, retreated from his
original position in the direction that would most obviate Mr.
Spencer's objection.
Yet this objection has been repeatedly urged by the more prominent
anti-Charles-Darwinian authorities, and there is no sign that the
British public is becoming less rigorous in requiring people either
to reply to objections repeatedly urged by men of even moderate
weight, or to let judgment go by default. As regards Mr. Darwin's
claim to the theory of evolution generally, Darwinians are beginning
now to perceive that this cannot be admitted, and either say with
some hardihood that Mr. Darwin never claimed it, or after a few
saving clauses to the effect that this theory refers only to the
particular means by which evolution has been brought about, imply
forthwith thereafter none the less that evolution is Mr. Darwin's
theory. Mr. Wallace has done this repeatedly in his recent
Darwinism. Indeed, I should be by no means sure that on the first
page of his preface, in the passage about "Darwin's theory," which I
have already somewhat severely criticized, he was not intending
evolution by "Darwin's theory," if in his preceding paragraph he had
not so clearly shown that he knew evolution to be a theory of
greatly older date than Mr. Darwin's.
The history of science--well exemplified by that of the development
theory--is the history of eminent men who have fought against light
and have been worsted. The tenacity with which Darwinians stick to
their accumulation of fortuitous variations is on a par with the
like tenacity shown by the illustrious Cuvier, who did his best to
crush evolution altogether. It always has been thus, and always
will be; nor is it desirable in the interests of Truth herself that
it should be otherwise. Truth is like money--lightly come, lightly
go; and if she cannot hold her own against even gross
misrepresentation, she is herself not worth holding.
Misrepresentation in the long run makes Truth as much as it mars
her; hence our law courts do not think it desirable that pleaders
should speak their bona fide opinions, much less that they should
profess to do so. Rather let each side hoodwink judge and jury as
best it can, and let truth flash out from collision of defence and
accusation. When either side will not collide, it is an axiom of
controversy that it desires to prevent the truth from being
elicited.
Let us now note the courses forced upon biologists by the
difficulties of Mr. Darwin's distinctive feature. Mr. Darwin and
Mr. Wallace, as is well known, brought the feature forward
simultaneously and independently of one another, but Mr. Wallace
always believed in it more firmly than Mr. Darwin did. Mr. Darwin
as a young man did not believe in it. He wrote before 1839,
"Nature, by making habit omnipotent and its effects hereditary, has
fitted the Fuegian for the climate and productions of his country,"
{259a} a sentence than which nothing can coincide more fully with
the older view that use and disuse were the main purveyors of
variations, or conflict more fatally with his own subsequent
distinctive feature. Moreover, as I showed in my last work on
evolution, {259b} in the peroration to his Origin of Species, he
discarded his accidental variations altogether, and fell back on the
older theory, so that the body of the Origin of Species supports one
theory, and the peroration another that differs from it toto coelo.
Finally, in his later editions, he retreated indefinitely from his
original position, edging always more and more continually towards
the theory of his grandfather and Lamarck. These facts convince me
that he was at no time a thoroughgoing Darwinian, but was throughout
an unconscious Lamarckian, though ever anxious to conceal the fact
alike from himself and from his readers.
Not so with Mr. Wallace, who was both more outspoken in the first
instance, and who has persevered along the path of Wallaceism just
as Mr. Darwin with greater sagacity was ever on the retreat from
Darwinism. Mr. Wallace's profounder faith led him in the outset to
place his theory in fuller daylight than Mr. Darwin was inclined to
do. Mr. Darwin just waved Lamarck aside, and said as little about
him as he could, while in his earlier editions Erasmus Darwin and
Buffon were not so much as named. Mr. Wallace, on the contrary, at
once raised the Lamarckian spectre, and declared it exorcized. He
said the Lamarckian hypothesis was "quite unnecessary." The giraffe
did not "acquire its long neck by desiring to reach the foliage of
the more lofty shrubs, and constantly stretching its neck for this
purpose, but because any varieties which occurred among its
antitypes with a longer neck than usual at once secured a fresh
range of pasture over the same ground as their shorter-necked
companions, and on the first scarcity of food were thus enabled to
outlive them." {260}
"Which occurred" is evidently "which happened to occur" by some
chance of accident unconnected with use and disuse. The word
"accident" is never used, but Mr. Wallace must be credited with this
instance of a desire to give his readers a chance of perceiving that
according to his distinctive feature evolution is an affair of luck,
rather than of cunning. Whether his readers actually did understand
this as clearly as Mr. Wallace doubtless desired that they should,
and whether greater development at this point would not have helped
them to fuller apprehension, we need not now inquire. What was
gained in distinctness might have been lost in distinctiveness, and
after all he did technically put us upon our guard.
Nevertheless, he too at a pinch takes refuge in Lamarckism. In
relation to the manner in which the eyes of soles, turbots, and
other flat-fish travel round the head so as to become in the end
unsymmetrically placed, he says:--
"The eyes of these fish are curiously distorted in order that both
eyes may be upon the upper side, where alone they would be of any
use. . . . Now if we suppose this process, which in the young is
completed in a few days or weeks, to have been spread over thousands
of generations during the development of these fish, those usually
surviving _whose eyes retained more and more of the position into
which the young fish tried to twist them_ [italics mine], the change
becomes intelligible." {261} When it was said by Professor Ray
Lankester--who knows as well as most people what Lamarck taught--
that this was "flat Lamarckism," Mr. Wallace rejoined that it was
the survival of the modified individuals that did it all, not the
efforts of the young fish to twist their eyes, and the transmission
to descendants of the effects of those efforts. But this, as I said
in my book Evolution, Old and New, is like saying that horses are
swift runners, not by reason of the causes, whatever they were, that
occasioned the direct line of their progenitors to vary towards ever
greater and greater swiftness, but because their more slow-going
uncles and aunts go away. Plain people will prefer to say that the
main cause of any accumulation of favourable modifications consists
rather in that which brings about the initial variations, and in the
fact that these can be inherited at all, than in the fact that the
unmodified individuals were not successful. People do not become
rich because the poor in large numbers go away, but because they
have been lucky, or provident, or more commonly both. If they would
keep their wealth when they have made it they must exclude luck
thenceforth to the utmost of their power and their children must
follow their example, or they will soon lose their money. The fact
that the weaker go to the wall does not bring about the greater
strength of the stronger; it is the consequence of this last and not
the cause--unless, indeed, it be contended that a knowledge that the
weak go to the wall stimulates the strong to exertions which they
would not otherwise so make, and that these exertions produce
inheritable modifications. Even in this case, however, it would be
the exertions, or use and disuse, that would be the main agents in
the modification. But it is not often that Mr. Wallace thus
backslides. His present position is that acquired (as distinguished
from congenital) modifications are not inherited at all. He does
not indeed put his faith prominently forward and pin himself to it
as plainly as could be wished, but under the heading "The Non-
Heredity of Acquired Characters," he writes as follows on p. 440 of
his recent work in reference to Professor Weismann's Theory of
Heredity:--
"Certain observations on the embryology of the lower animals are
held to afford direct proof of this theory of heredity, but they are
too technical to be made clear to ordinary readers. A logical
result of the theory is the impossibility of the transmission of
acquired characters, since the molecular structure of the germ-plasm
is already determined within the embryo; and Weismann holds that
there are no facts which really prove that acquired characters can
be inherited, although their inheritance has, by most writers, been
considered so probable as hardly to stand in need of direct proof.
"We have already seen in the earlier part of this chapter that many
instances of change, imputed to the inheritance of acquired
variations, are really cases of selection."
And the rest of the remarks tend to convey the impression that Mr.
Wallace adopts Professor Weismann's view, but, curiously enough,
though I have gone through Mr. Wallace's book with a special view to
this particular point, I have not been able to find him definitely
committing himself either to the assertion that acquired
modifications never are inherited, or that they sometimes are so.
It is abundantly laid down that Mr. Darwin laid too much stress on
use and disuse, and a residuary impression is left that Mr. Wallace
is endorsing Professor Weismann's view, but I have found it
impossible to collect anything that enables me to define his
position confidently in this respect.
This is natural enough, for Mr. Wallace has entitled his book
Darwinism, and a work denying that use and disuse produced any
effect could not conceivably be called Darwinism. Mr. Herbert
Spencer has recently collected many passages from The Origin of
Species and from Animals and Plants under Domestication," {263}
which show how largely, after all, use and disuse entered into Mr.
Darwin's system, and we know that in his later years he attached
still more importance to them. It was out of the question,
therefore, that Mr. Wallace should categorically deny that their
effects were inheritable. On the other hand, the temptation to
adopt Professor Weismann's view must have been overwhelming to one
who had been already inclined to minimize the effects of use and
disuse. On the whole, one does not see what Mr. Wallace could do,
other than what he has done--unless, of course, he changed his
title, or had been no longer Mr. Wallace.
Besides, thanks to the works of Mr. Spencer, Professor Mivart,
Professor Semper, and very many others, there has for some time been
a growing perception that the Darwinism of Charles Darwin was
doomed. Use and disuse must either do even more than is officially
recognized in Mr. Darwin's later concessions, or they must do a
great deal less. If they can do as much as Mr. Darwin himself said
they did, why should they not do more? Why stop where Mr. Darwin
did? And again, where in the name of all that is reasonable did he
really stop? He drew no line, and on what principle can we say that
so much is possible as effect of use and disuse, but so much more
impossible? If, as Mr. Darwin contended, disuse can so far reduce
an organ as to render it rudimentary, and in many cases get rid of
it altogether, why cannot use create as much as disuse can destroy,
provided it has anything, no matter how low in structure, to begin
with? Let us know where we stand. If it is admitted that use and
disuse can do a good deal, what does a good deal mean? And what is
the proportion between the shares attributable to use and disuse and
to natural selection respectively? If we cannot be told with
absolute precision, let us at any rate have something more definite
than the statement that natural selection is "the most important
means of modification."
Mr. Darwin gave us no help in this respect; and worse than this, he
contradicted himself so flatly as to show that he had very little
definite idea upon the subject at all. Thus in respect to the
winglessness of the Madeira beetles he wrote:--
"In some cases we might easily put down to disuse modifications of
structure, which are wholly or mainly due to natural selection. Mr.
Wollaston has discovered the remarkable fact that 200 beetles, out
of the 550 species (but more are now known) inhabiting Madeira, are
so far deficient in wings that they cannot fly; and that of the 29
endemic genera no less than 23 have all their species in this
condition! Several facts--namely, that beetles in many parts of the
world are frequently blown out to sea and perish; that the beetles
in Madeira, as observed by Mr. Wollaston, lie much concealed until
the wind lulls and the sun shines; that the proportion of wingless
beetles is larger on the exposed Desertas than in Madeira itself;
and especially the extraordinary fact, so strongly insisted on by
Mr. Wollaston, that certain large groups of beetles, elsewhere
excessively numerous, which absolutely require the use of their
wings are here almost entirely absent;--these several considerations
make me believe that the wingless condition of so many Madeira
beetles is mainly due to the action of natural selection, _combined
probably with disuse_ [italics mine]. For during many successive
generations each individual beetle which flew least, either from its
wings having been ever so little less perfectly developed or from
indolent habit, will have had the best chance of surviving, from not
being blown out to sea; and, on the other hand, those beetles which
most readily took to flight would oftenest have been blown to sea,
and thus destroyed." {265}
We should like to know, first, somewhere about how much disuse was
able to do after all, and moreover why, if it can do anything at
all, it should not be able to do all. Mr. Darwin says: "Any change
in structure and function which can be effected by small stages is
within the power of natural selection." "And why not," we ask,
"within the power of use and disuse?" Moreover, on a later page we
find Mr. Darwin saying:--
"_It appears probable that disuse has been the main agent in
rendering organs rudimentary_ [italics mine]. It would at first
lead by slow steps to the more and more complete reduction of a
part, until at last it has become rudimentary--as in the case of the
eyes of animals inhabiting dark caverns, and of the wings of birds
inhabiting oceanic islands, which have seldom been forced by beasts
of prey to take flight, and have ultimately lost the power of
flying. Again, an organ, useful under certain conditions, might
become injurious under others, as _with the wings of beetles living
on small and exposed islands_; and in this case natural selection
will have aided in reducing the organ, until it was rendered
harmless and rudimentary [italics mine]." {266}
So that just as an undefined amount of use and disuse was introduced
on the earlier page to supplement the effects of natural selection
in respect of the wings of beetles on small and exposed islands, we
have here an undefined amount of natural selection introduced to
supplement the effects of use and disuse in respect of the identical
phenomena. In the one passage we find that natural selection has
been the main agent in reducing the wings, though use and disuse
have had an appreciable share in the result; in the other, it is use
and disuse that have been the main agents, though an appreciable
share in the result must be ascribed to natural selection.
Besides, who has seen the uncles and aunts going away with the
uniformity that is necessary for Mr. Darwin's contention? We know
that birds and insects do often get blown out to sea and perish, but
in order to establish Mr. Darwin's position we want the evidence of
those who watched the reduction of the wings during the many
generations in the course of which it was being effected, and who
can testify that all, or the overwhelming majority, of the beetles
born with fairly well-developed wings got blown out to sea, while
those alone survived whose wings were congenitally degenerate. Who
saw them go, or can point to analogous cases so conclusive as to
compel assent from any equitable thinker?
Darwinians of the stamp of Mr. Thiselton Dyer, Professor Ray
Lankester, or Mr. Romanes, insist on their pound of flesh in the
matter of irrefragable demonstration. They complain of us for not
bringing forward someone who has been able to detect the movement of
the hour-hand of a watch during a second of time, and when we fail
to do so, declare triumphantly that we have no evidence that there
is any connection between the beating of a second and the movement
of the hour-hand. When we say that rain comes from the condensation
of moisture in the atmosphere, they demand of us a rain-drop from
moisture not yet condensed. If they stickle for proof and cavil on
the ninth part of a hair, as they do when we bring forward what we
deem excellent instances of the transmission of an acquired
characteristic, why may not we, too, demand at any rate some
evidence that the unmodified beetles actually did always, or nearly
always, get blown out to sea, during the reduction above referred
to, and that it is to this fact, and not to the masterly inactivity
of their fathers and mothers, that the Madeira beetles owe their
winglessness? If we begin stickling for proof in this way, our
opponents would not be long in letting us know that absolute proof
is unattainable on any subject, that reasonable presumption is our
highest certainty, and that crying out for too much evidence is as
bad as accepting too little. Truth is like a photographic
sensitized plate, which is equally ruined by over and by under
exposure, and the just exposure for which can never be absolutely
determined.
Surely if disuse can be credited with the vast powers involved in
Mr. Darwin's statement that it has probably "been the main agent in
rendering organs rudimentary," no limits are assignable to the
accumulated effects of habit, provided the effects of habit, or use
and disuse, are supposed, as Mr. Darwin supposed them, to be
inheritable at all. Darwinians have at length woke up to the
dilemma in which they are placed by the manner in which Mr. Darwin
tried to sit on the two stools of use and disuse, and natural
selection of accidental variations, at the same time. The knell of
Charles-Darwinism is rung in Mr. Wallace's present book, and in the
general perception on the part of biologists that we must either
assign to use and disuse such a predominant share in modification as
to make it the feature most proper to be insisted on, or deny that
the modifications, whether of mind or body, acquired during a single
lifetime, are ever transmitted at all. If they can be inherited at
all, they can be accumulated. If they can be accumulated at all,
they can be so, for anything that appears to the contrary, to the
extent of the specific and generic differences with which we are
surrounded. The only thing to do is to pluck them out root and
branch: they are as a cancer which, if the smallest fibre be left
unexcised, will grow again, and kill any system on to which it is
allowed to fasten. Mr. Wallace, therefore, may well be excused if
he casts longing eyes towards Weismannism.
And what was Mr. Darwin's system? Who can make head or tail of the
inextricable muddle in which he left it? The Origin of Species in
its latest shape is the reduction of hedging to an absurdity. How
did Mr. Darwin himself leave it in the last chapter of the last
edition of the Origin of Species? He wrote:--
"I have now recapitulated the facts and considerations which have
thoroughly convinced me that species have been modified during a
long course of descent. 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. It appears that I
formerly underrated the frequency and value of these latter forms of
variation, as leading to permanent modifications of structure
independently of natural selection."
The "numerous, successive, slight, favourable variations" above
referred to are intended to be fortuitous, accidental, spontaneous.
It is the essence of Mr. Darwin's theory that this should be so.
Mr. Darwin's solemn statement, therefore, of his theory, after he
had done his best or his worst with it, is, when stripped of
surplusage, as follows:--
"The modification of species has been mainly effected by
accumulation of spontaneous variations; it has been aided in an
important manner by accumulation of variations due to use and
disuse, and in an unimportant manner by spontaneous variations; I do
not even now think that spontaneous variations have been very
important, but I used once to think them less important than I do
now."
It is a discouraging symptom of the age that such a system should
have been so long belauded, and it is a sign of returning
intelligence that even he who has been more especially the alter ego
of Mr. Darwin should have felt constrained to close the chapter of
Charles-Darwinism as a living theory, and relegate it to the
important but not very creditable place in history which it must
henceforth occupy. It is astonishing, however, that Mr. Wallace
should have quoted the extract from the Origin of Species just
given, as he has done on p. 412 of his Darwinism, without betraying
any sign that he has caught its driftlessness--for drift, other than
a desire to hedge, it assuredly has not got. The battle now turns
on the question whether modifications of either structure or
instinct due to use or disuse are ever inherited, or whether they
are not. Can the effects of habit be transmitted to progeny at all?
We know that more usually they are not transmitted to any
perceptible extent, but we believe also that occasionally, and
indeed not infrequently, they are inherited and even intensified.
What are our grounds for this opinion? It will be my object to put
these forward in the following number of the Universal Review.