[_First published in_ The Nineteenth Century_, for February,_ 1888.]
While I do not concur in sundry of the statements and conclusions
contained in the article entitled "A Great Confession," contributed by
the Duke of Argyll to the last number of this Review, yet I am obliged
to him for having raised afresh the question discussed in it. Though the
injunction "Rest and be thankful," is one for which in many spheres much
may be said--especially in the political, where undue restlessness is
proving very mischievous; yet rest and be thankful is an injunction out
of place in science. Unhappily, while politicians have not duly regarded
it, it appears to have been taken to heart too much by naturalists; in
so far, at least, as concerns the question of the origin of species.
The new biological orthodoxy behaves just as the old biological
orthodoxy did. In the days before Darwin, those who occupied themselves
with the phenomena of life, passed by with unobservant eyes the
multitudinous facts which point to an evolutionary origin for plants and
animals; and they turned deaf ears to those who insisted on the
significance of these facts. Now that they have come to believe in this
evolutionary origin, and have at the same time accepted the hypothesis
that natural selection has been the sole cause of the evolution, they
are similarly unobservant of the multitudinous facts which cannot
rationally be ascribed to that cause; and turn deaf ears to those who
would draw their attention to them. The attitude is the same; it is only
the creed which has changed.
But, as above implied, though the protest of the Duke of Argyll against
this attitude is quite justifiable, it seems to me that many of his
statements cannot be sustained. Some of these concern me personally, and
others are of impersonal concern. I propose to deal with them in the
order in which they occur.
* * * * *
On page 144 the Duke of Argyll quotes me as omitting "for the present
any consideration of a factor which may be distinguished as primordial;"
and he represents me as implying by this "that Darwin's ultimate
conception of some primordial 'breathing of the breath of life' is a
conception which can be omitted only 'for the present.'" Even had there
been no other obvious interpretation, it would have been a somewhat rash
assumption that this was my meaning when referring to an omitted factor;
and it is surprising that this assumption should have been made after
reading the second of the two articles criticised, in which this factor
omitted from the first is dealt with: this omitted third factor being
the direct physico-chemical action of the medium on the organism. Such a
thought as that which the Duke of Argyll ascribes to me, is so
incongruous with the beliefs I have in many places expressed that the
ascription of it never occurred to me as possible.
Lower down on the same page are some other sentences having personal
implications, which I must dispose of before going into the general
question. The Duke says "it is more than doubtful whether any value
attaches to the new factor with which he [I] desires to supplement it
[natural selection]"; and he thinks it "unaccountable" that I "should
make so great a fuss about so small a matter as the effect of use and
disuse of particular organs as a separate and a newly-recognised
factor in the development of varieties." I do not suppose that the Duke
of Argyll intended to cast upon me the disagreeable imputation, that I
claim as new that which all who are even slightly acquainted with the
facts know to be anything rather than new. But his words certainly do
this. How he should have thus written in spite of the extensive
knowledge of the matter which he evidently has, and how he should have
thus written in presence of the evidence contained in the articles he
criticizes, I cannot understand. Naturalists, and multitudes besides
naturalists, know that the hypothesis which I am represented as putting
forward as new, is much older than the hypothesis of natural
selection--goes back at least as far as Dr. Erasmus Darwin. My purpose
was to bring into the foreground again a factor which has, I think, been
of late years improperly ignored; to show that Mr. Darwin recognized
this factor in an increasing degree as he grew older (by showing which I
should have thought I sufficiently excluded the supposition that I
brought it forward as new); to give further evidence that this factor is
in operation; to show there are numerous phenomena which cannot be
interpreted without it; and to argue that if proved operative in any
case, it may be inferred that it is operative on all structures having
active functions.
Strangely enough, this passage, in which I am represented as implying
novelty in a doctrine which I have merely sought to emphasize and
extend, is immediately succeeded by a passage in which the Duke of
Argyll himself represents the doctrine as being familiar and well
established:--
"That organs thus enfeebled [i.e. by persistent disuse] are
transmitted by inheritance to offspring in a like condition of
functional and structural decline, is a correlated physiological
doctrine not generally disputed. The converse case--of increased
strength and development arising out of the habitual and healthy
use of special organs, and of the transmission of these to
offspring--is a case illustrated by many examples in the breeding
of domestic animals. I do not know to what else we can attribute
the long slender legs and bodies of greyhounds so manifestly
adapted to speed of foot, or the delicate powers of smell in
pointers and setters, or a dozen cases of modified structure
effected by artificial selection."
In none of the assertions contained in this passage can I agree. Had the
inheritance of "functional and structural decline" been "not generally
disputed," half my argument would have been needless; and had the
inheritance of "increased strength and development" caused by use been
recognized, as "illustrated by many examples," the other half of my
argument would have been needless. But both are disputed; and, if not
positively denied, are held to be unproved. Greyhounds and pointers do
not yield valid evidence, because their peculiarities are more due to
artificial selection than to any other cause. It may, indeed, be doubted
whether greyhounds use their legs more than other dogs. Dogs of all
kinds are daily in the habit of running about and chasing one another at
the top of their speed--other dogs more frequently than greyhounds,
which are not much given to play. The occasions on which greyhounds
exercise their legs in chasing hares, occupy but inconsiderable spaces
in their lives, and can play but small parts in developing their legs.
And then, how about their long heads and sharp noses? Are these
developed by running? The structure of the greyhound is explicable as a
result mainly of selection of variations occasionally arising from
unknown causes; but it is inexplicable otherwise. Still more obviously
invalid is the evidence said to be furnished by pointers and setters.
How can these be said to exercise their organs of smell more than other
dogs? Do not all dogs occupy themselves in sniffing about here and there
all day long: tracing animals of their own kind and of other kinds?
Instead of admitting that the olfactory sense is more exercised in
pointers and setters than in other dogs, it might, contrariwise, be
contended that it is exercised less; seeing that during the greater
parts of their lives they are shut up in kennels where the varieties of
odours, on which to practise their noses, is but small. Clearly if
breeders of sporting dogs have from early days habitually bred from
those puppies of each litter which had the keenest noses (and it is
undeniable that the puppies of each litter are made different from one
another, as are the children in each human family, by unknown
combinations of causes), then the existence of such remarkable powers in
pointers and setters may be accounted for; while it is otherwise
unaccountable. These instances, and many others such, I should have
gladly used in support of my argument, had they been available; but
unfortunately they are not.
On the next page of the Duke of Argyll's article (page 145), occurs a
passage which I must quote at length before I can deal effectually with
its various statements. It runs as follows:--
"But if natural selection is a mere phrase, vague enough and wide
enough to cover any number of the physical causes concerned in
ordinary generation, then the whole of Mr. Spencer's laborious
argument in favour of his 'other factor' becomes an argument worse
than superfluous. It is wholly fallacious in assuming that this
'factor' and 'natural selection' are at all exclusive of, or even
separate from, each other. The factor thus assumed to be new is
simply one of the subordinate cases of heredity. But heredity is
the central idea of natural selection. Therefore natural selection
includes and covers all the causes which can possibly operate
through inheritance. There is thus no difficulty whatever in
referring it to the same one factor whose solitary dominion Mr.
Spencer has plucked up courage to dispute. He will never succeed in
shaking its dictatorship by such a small rebellion. His little
contention is like some bit of Bumbledom setting up for Home
Rule--some parochial vestry claiming independence of a universal
empire. It pretends to set up for itself in some fragment of an
idea. But here is not even a fragment to boast of or to stand up
for. His new factor in organic evolution has neither independence
nor novelty. Mr. Spencer is able to quote himself as having
mentioned it in his _Principles of Biology_ published some twenty
years ago; and by a careful ransacking of Darwin he shows that the
idea was familiar to and admitted by him at least in his last
edition of the _Origin of Species_.... Darwin was a man so much
wiser than all his followers," &c.
Had there not been the Duke of Argyll's signature to the article, I
could scarcely have believed that this passage was written by him.
Remembering that on reading his article in the preceding number of this
Review, I was struck by the extent of knowledge, clearness of
discrimination, and power of exposition, displayed in it, I can scarcely
understand how there has come from the same pen a passage in which none
of these traits are exhibited. Even one wholly unacquainted with the
subject may see in the last two sentences of the above extract, how
strangely its propositions are strung together. While in the first of
them I am represented as bringing forward a "new factor," I am in the
second represented as saying that I mentioned it twenty years ago! In
the same breath I am described as claiming it as new and asserting it as
old! So, again, the uninstructed reader, on comparing the first words of
the extract with the last, will be surprised on seeing in a scientific
article statements so manifestly wanting in precision. If "natural
selection is a mere phrase," how can Mr. Darwin, who thought it
explained the origin of species, be regarded as wise? Surely it must be
more than a mere phrase if it is the key to so many otherwise
inexplicable facts. These examples of incongruous thoughts I give to
prepare the way; and will now go on to examine the chief propositions
which the quoted passage contains.
The Duke of Argyll says that "heredity is the central idea of natural
selection." Now it would, I think, be concluded that those who possess
the central idea of a thing have some consciousness of the thing. Yet
men have possessed the idea of heredity for any number of generations
and have been quite unconscious of natural selection. Clearly the
statement is misleading. It might just as truly be said that the
occurrence of structural variations in organisms is the central idea of
natural selection. And it might just as truly be said that the action of
external agencies in killing some individuals and fostering others is
the central idea of natural selection. No such assertions are correct.
The process has three factors--heredity, variation, and external
action--any one of which being absent, the process ceases. The
conception contains three corresponding ideas, and if any one be struck
out, the conception cannot be framed. No one of them is the central
idea, but they are co-essential ideas.
From the erroneous belief that "heredity is the central idea of natural
selection" the Duke of Argyll draws the conclusion, consequently
erroneous, that "natural selection includes and covers all the causes
which can possibly operate through inheritance." Had he considered the
cases which, in the _Principles of Biology_, I have cited to illustrate
the inheritance of functionally-produced modifications, he would have
seen that his inference is far from correct. I have instanced the
decrease of the jaw among civilized men as a change of structure which
cannot have been produced by the inheritance of spontaneous, or
fortuitous, variations. That changes of structure arising from such
variations may be maintained and increased in successive generations, it
is needful that the individuals in whom they occur shall derive from
them advantages in the struggle for existence--advantages, too,
sufficiently great to aid their survival and multiplication in
considerable degrees. But a decrease of jaw reducing its weight by even
an ounce (which would be a large variation), cannot, by either smaller
weight carried or smaller nutrition required, have appreciably
advantaged any person in the battle of life. Even supposing such
diminution of jaw to be beneficial (and in the resulting decay of teeth
it entails great evils), the benefit can hardly have been such as to
increase the relative multiplication of families in which it occurred
generation after generation. Unless it has done this, however, decreased
size of the jaw cannot have been produced by the natural selection of
favourable variations. How can it then have been produced? Only by
decreased function--by the habitual use of soft food, joined, probably,
with disuse of the teeth as tools. And now mark that this cause operates
on all members of a society which falls into civilized habits.
Generation after generation this decreased function changes its
component families simultaneously. Natural selection does not cover the
case at all--has nothing to do with it. And the like happens in
multitudinous other cases. Every species spreading into a new habitat,
coming in contact with new food, exposed to a different temperature, to
a drier or moister air, to a more irregular surface, to a new soil, &c.,
&c., has its members one and all subject to various changed actions,
which influence its muscular, vascular, respiratory, digestive,
and other systems of organs. If there is inheritance of
functionally-produced modifications, then all its members will transmit
the structural alterations wrought in them, and the species will change
as a whole without the supplanting of some stocks by others. Doubtless
in respect of certain changes natural selection will co-operate. If the
species, being a predacious one, is brought, by migration, into the
presence of prey of greater speed than before; then, while all its
members will have their limbs strengthened by extra action, those in
whom this muscular adaptation is greatest will have their multiplication
furthered; and inheritance of the functionally-increased structures will
be aided, in successive generations, by survival of the fittest. But it
cannot be so with the multitudinous minor changes entailed by the
modified life. The majority of these must be of such relative
unimportance that one of them cannot give to the individual in which it
becomes most marked, advantages which predominate over kindred
advantages gained by other individuals from other changes more
favourably wrought in them. In respect to these, the inherited effects
of use and disuse must accumulate independently of natural selection.
To make clear the relations of these two factors to one another and to
heredity, let us take a case in which the operations of all three may be
severally identified and distinguished.
Here is one of those persons, occasionally met with, who has an
additional finger on each hand, and who, we will suppose, is a
blacksmith. He is neither aided nor much hindered by these additional
fingers; but, by constant use, he has greatly developed the muscles of
his right arm. To avoid a perturbing factor, we will assume that his
wife, too, exercises her arms in an unusual degree: keeps a mangle, and
has all the custom of the neighbourhood. Such being the circumstances,
let us ask what are the established facts, and what are the beliefs and
disbeliefs of biologists.
The first fact is that this six-fingered blacksmith will be likely to
transmit his peculiarity to some of his children; and some of these,
again, to theirs. It is proved that, even in the absence of a like
peculiarity in the other parent, this strange variation of structure
(which we must ascribe to some fortuitous combination of causes) is
often inherited for more than one generation. Now the causes which
produce this persistent six-fingeredness are unquestionably causes which
"operate through inheritance." The Duke of Argyll says that "natural
selection includes and covers all the causes which can possibly operate
through inheritance." How does it cover the causes which operate here?
Natural selection never comes into play at all. There is no fostering of
this peculiarity, since it does not help in the struggle for existence;
and there is no reason to suppose it is such a hindrance in the struggle
that those who have it disappear in consequence. It simply gets
cancelled in the course of generations by the adverse influences of
other stocks.
While biologists admit, or rather assert, that the peculiarity in the
blacksmith's arm which was born with him is transmissible, they deny, or
rather do not admit, that the other peculiarities of his arm, induced by
daily labour--its large muscles and strengthened bones--are
transmissible. They say that there is no proof. The Duke of Argyll
thinks that the inheritance of organs enfeebled by disuse is "not
generally disputed;" and he thinks there is clear proof that the
converse change--increase of size consequent on use--is also inherited.
But biologists dispute both of these alleged kinds of inheritance. If
proof is wanted, it will be found in the proceedings at the last meeting
of the British Association, in a paper entitled "Are Acquired Characters
Hereditary?" by Professor Ray Lankester, and in the discussion raised by
that paper. Had this form of inheritance been, as the Duke of Argyll
says, "not generally disputed," I should not have written the first of
the two articles he criticizes.
But supposing it proved, as it may hereafter be, that such a
functionally-produced change of structure as the blacksmith's arm shows
us, is transmissible, the persistent inheritance is again of a kind with
which natural selection has nothing to do. If the greatly strengthened
arm enabled the blacksmith and his descendants, having like strengthened
arms, to carry on the battle of life in a much more successful way than
it was carried on by other men, survival of the fittest would ensure the
maintenance and increase of this trait in successive generations. But
the skill of the carpenter enables him to earn quite as much as his
stronger neighbour. By the various arts he has been taught, the plumber
gets as large a weekly wage. The small shopkeeper by his foresight in
buying and prudence in selling, the village-schoolmaster by his
knowledge, the farm-bailiff by his diligence and care, succeed in the
struggle for existence equally well. The advantage of a strong arm does
not predominate over the advantages which other men gain by their innate
or acquired powers of other kinds; and therefore natural selection
cannot operate so as to increase the trait. Before it can be increased,
it is neutralized by the unions of those who have it with those who have
other traits. To whatever extent, therefore, inheritance of this
functionally-produced modification operates, it operates independently
of natural selection.
One other point has to be noted--the relative importance of this factor.
If additional developments of muscles and bones may be transmitted--if,
as Mr. Darwin held, there are various other structural modifications
caused by use and disuse which imply inheritance of this kind--if
acquired characters are hereditary, as the Duke of Argyll believes; then
the area over which this factor of organic evolution operates is
enormous. Not every muscle only, but every nerve and nerve-centre, every
blood-vessel, every viscus, and nearly every bone, may be increased or
decreased by its influence. Excepting parts which have passive
functions, such as dermal appendages and the bones which form the skull,
the implication is that nearly every organ in the body may be modified
in successive generations by the augmented or diminished activity
required of it; and, save in the few cases where the change caused is
one which conduces to survival in a pre-eminent degree, it will be thus
modified independently of natural selection. Though this factor can
operate but little in the vegetal world, and can play but a subordinate
part in the lowest animal world; yet, seeing that all the active organs
of all animals are subject to its influence, it has an immense sphere.
The Duke of Argyll compares the claim made for this factor to "some bit
of Bumbledom setting up for Home Rule--some parochial vestry claiming
independence of a universal empire." But, far from this, the claim made
for it is to an empire, less indeed than that of natural selection, and
over a small part of which natural selection exercises concurrent power;
but of which the independent part has an area that is immense.
It seems to me, then, that the Duke of Argyll is mistaken in four of the
propositions contained in the passages I have quoted. The inheritance of
acquired characters _is_ disputed by biologists, though he thinks it is
not. It is not true that "heredity is the central idea of natural
selection." The statement that natural selection includes and covers all
the causes which can possibly operate through inheritance, is quite
erroneous. And if the inheritance of acquired characters is a factor at
all, the dominion it rules over is not insignificant but vast.
* * * * *
Here I must break off, after dealing with a page and a half of the Duke
of Argyll's article. A state of health which has prevented me from
publishing anything since "The Factors of Organic Evolution," now nearly
two years ago, prevents me from carrying the matter further. Could I
have pursued the argument it would, I believe, have been practicable to
show that various other positions taken up by the Duke of Argyll do not
admit of effectual defence. But whether or not this is probable, the
reader must be left to judge for himself. On one further point only will
I say a word; and this chiefly because, if I pass it by, a mistaken
impression of a serious kind may be diffused. The Duke of Argyll
represents me as "giving up" the "famous phrase" "survival of the
fittest," and wishing "to abandon it." He does this because I have
pointed out that its words have connotations against which we must be on
our guard, if we would avoid certain distortions of thought. With equal
propriety he might say that an astronomer abandons the statement that
the planets move in elliptic orbits, because he warns his readers that
in the heavens there exist no such things as orbits, but that the
planets sweep on through a pathless void, in directions perpetually
changed by gravitation.
I regret that I should have had thus to dissent so entirely from various
of the statements made, and conclusions drawn, by the Duke of Argyll,
because, as I have already implied, I think he has done good service by
raising afresh the question he has dealt with. Though the advantages
which he hopes may result from the discussion are widely unlike the
advantages which I hope may result from it, yet we agree in the belief
that advantages may be looked for.