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Darwiniana

T >> Thomas Henry Huxley >> Darwiniana




I have seen enough of savages to be able to declare that nothing can be
more admirable than this description of what a savage has to learn. But it
is incomplete. Add to all this the knowledge which a savage is obliged to
gain of the properties of plants, of the characters and habits of animals,
and of the minute indications by which their course is discoverable:
consider that even an Australian can make excellent baskets and nets, and
neatly fitted and beautifully balanced spears; that he learns to use these
so as to be able to transfix a quartern loaf at sixty yards; and that very
often, as in the case of the American Indians, the language of a savage
exhibits complexities which a well-trained European finds it difficult to
master: consider that every time a savage tracks his game he employs a
minuteness of observation, and an accuracy of inductive and deductive
reasoning which, applied to other matters, would assure some reputation to
a man of science, and I think we need ask no further why he possesses such
a fair supply of brains. In complexity and difficulty, I should say that
the intellectual labour of a "good hunter or warrior" considerably exceeds
that of an ordinary Englishman. The Civil Service Examiners are held in
great terror by young Englishmen; but even their ferocity never tempted
them to require a candidate to possess such a knowledge of a parish as Mr.
Wallace justly points out savages may possess of an area a hundred miles or
more in diameter.

But suppose, for the sake of argument, that a savage has more brains than
seems proportioned to his wants, all that can be said is that the objection
to natural selection, if it be one, applies quite as strongly to the lower
animals. The brain of a porpoise is quite wonderful for its mass, and for
the development of the cerebral convolutions. And yet since we have ceased
to credit the story of Arion, it is hard to believe that porpoises are much
troubled with intellect: and still more difficult is it to imagine that
their big brains are only a preparation for the advent of some accomplished
cetacean of the future. Surely, again, a wolf must have too much brains, or
else how is it that a dog with only the same quantity and form of brain is
able to develop such singular intelligence? The wolf stands to the dog in
the same relation as the savage to the man; and, therefore, if Mr.
Wallace's doctrine holds good, a higher power must have superintended the
breeding up of wolves from some inferior stock, in order to prepare them to
become dogs.

Mr. Wallace further maintains that the origin of some of man's mental
faculties by the preservation of useful variations is not possible. Such,
for example, are "the capacity to form ideal conceptions of space and time,
of eternity and infinity; the capacity for intense artistic feelings of
pleasure in form, colour, and composition; and for those abstract notions
of form and number which render geometry and arithmetic possible." "How,"
he asks, "were all or any of these faculties first developed, when they
could have been of no possible use to man in his early stages of
barbarism?"

Surely the answer is not far to seek. The lowest savages are as devoid of
any such conceptions as the brutes themselves. What sort of conceptions of
space and time, of form and number, can be possessed by a savage who has
not got so far as to be able to count beyond five or six, who does not know
how to draw a triangle or a circle, and has not the remotest notion of
separating the particular quality we call form, from the other qualities of
bodies? None of these capacities are exhibited by men, unless they form
part of a tolerably advanced society. And, in such a society, there are
abundant conditions by which a selective influence is exerted in favour of
those persons who exhibit an approximation towards the possession of these
capacities.

The savage who can amuse his fellows by telling a good story over the
nightly fire, is held by them in esteem and rewarded, in one way or
another, for so doing--in other words, it is an advantage to him to possess
this power. He who can carve a paddle, or the figure-head of a canoe
better, similarly profits beyond his duller neighbour. He who counts a
little better than others, gets most yams when barter is going on, and
forms the shrewdest estimate of the numbers of an opposing tribe. The
experience of daily life shows that the conditions of our present social
existence exercise the most extraordinarily powerful selective influence in
favour of novelists, artists, and strong intellects of all kinds; and it
seems unquestionable that all forms of social existence must have had the
same tendency, if we consider the indisputable facts that even animals
possess the power of distinguishing form and number, and that they are
capable of deriving pleasure from particular forms and sounds. If we admit,
as Mr. Wallace does, that the lowest savages are not raised "many grades
above the elephant and the ape;" and if we further admit, as I contend must
be admitted, that the conditions of social life tend, powerfully, to give
an advantage to those individuals who vary in the direction of intellectual
or æsthetic excellence, what is there to interfere with the belief that
these higher faculties, like the rest, owe their development to natural
selection?

Finally, with respect to the development of the moral sense out of the
simple feelings of pleasure and pain, liking and disliking, with which the
lower animals are provided, I can find nothing in Mr. Wallace's reasonings
which has not already been met by Mr. Mill, Mr. Spencer, or Mr. Darwin.

I do not propose to follow the Quarterly Reviewer and Mr. Mivart through
the long string of objections in matters of detail which they bring against
Mr. Darwin's views. Every one who has considered the matter carefully will
be able to ferret out as many more "difficulties"; but he will also, I
believe, fail as completely as they appear to me to have done, in bringing
forward any fact which is really contradictory of Mr. Darwin's views.
Occasionally, too, their objections and criticisms are based upon errors of
their own. As, for example, when Mr. Mivart and the Quarterly Reviewer
insist upon the resemblances between the eyes of _Cephalopoda_ and
_Vertebrata_, quite forgetting that there are striking and altogether
fundamental differences between them; or when the Quarterly Reviewer
corrects Mr. Darwin for saying that the gibbons, "without having been
taught, can walk or run upright with tolerable quickness, though they move
awkwardly, and much less securely than man." The Quarterly Reviewer says,
"This is a little misleading, inasmuch as it is not stated that this
upright progression is effected by placing the enormously long arms behind
the head, or holding them out backwards as a balance in progression."

Now, before carping at a small statement like this, the Quarterly Reviewer
should have made sure that he was quite right. But he happens to be quite
wrong. I suspect he got his notion of the manner in which a gibbon walks
from a citation in "Man's Place in Nature." But at that time I had not seen
a gibbon walk. Since then I have, and I can testify that nothing can be
more precise than Mr. Darwin's statement. The gibbon I saw walked without
either putting his arms behind his head or holding them out backwards. All
he did was to touch the ground with the outstretched fingers of his long
arms now and then, just as one sees a man who carries a stick, but does not
need one, touch the ground with it as he walks along.

Again, a large number of the objections brought forward by Mr. Mivart and
the Quarterly Reviewer apply to evolution in general, quite as much as to
the particular form of that doctrine advocated by Mr. Darwin; or, to their
notions of Mr. Darwin's views and not to what they really are. An excellent
example of this class of difficulties is to be found in Mr. Mivart's
chapter on "Independent Similarities of Structure." Mr. Mivart says that
these cannot be explained by an "absolute and pure Darwinian," but "that an
innate power and evolutionary law, aided by the corrective action of
natural selection, should have furnished like needs with like aids, is not
at all improbable" (p. 82).

I do not exactly know what Mr. Mivart means by an "absolute and pure
Darwinian;" indeed Mr. Mivart makes that creature hold so many singular
opinions that I doubt if I can ever have seen one alive. But I find nothing
in his statement of the view which he imagines to be originated by himself,
which is really inconsistent with what I understand to be Mr. Darwin's
views.

I apprehend that the foundation of the theory of natural selection is the
fact that living bodies tend incessantly to vary. This variation is neither
indefinite, nor fortuitous, nor does it take place in all directions, in
the strict sense of these words.

Accurately speaking, it is not indefinite, nor does it take place in all
directions, because it is limited by the general characters of the type to
which the organism exhibiting the variation belongs. A whale does not tend
to vary in the direction of producing feathers, nor a bird in the direction
of developing whalebone. In popular language there is no harm in saying
that the waves which break upon the sea-shore are indefinite, fortuitous,
and break in all directions. In scientific language, on the contrary, such
a statement would be a gross error, inasmuch as every particle of foam is
the result of perfectly definite forces, operating according to no less
definite laws. In like manner, every variation of a living form, however
minute, however apparently accidental, is inconceivable except as the
expression of the operation of molecular forces or "powers" resident within
the organism. And, as these forces certainly operate according to definite
laws, their general result is, doubtless, in accordance with some general
law which subsumes them all. And there appears to be no objection to call
this an "evolutionary law." But nobody is the wiser for doing so, or has
thereby contributed, in the least degree, to the advance of the doctrine of
evolution, the great need of which is a theory of variation.

When Mr. Mivart tells us that his "aim has been to support the doctrine
that these species have been evolved by ordinary _natural laws_ (for
the most part unknown), aided by the _subordinate_ action of 'natural
selection'" (pp. 332-3), he seems to be of opinion that his enterprise has
the merit of novelty. All I can say is that I have never had the slightest
notion that Mr. Darwin's aim is in any way different from this. If I affirm
that "species have been evolved by variation [Footnote: Including under
this head hereditary transmission.] (a natural process, the laws of which
are for the most part unknown), aided by the subordinate action of natural
selection," it seems to me that I enunciate a proposition which constitutes
the very pith and marrow of the first edition of the "Origin of Species."
And what the evolutionist stands in need of just now, is not an iteration
of the fundamental principle of Darwinism, but some light upon the
questions, What are the limits of variation? and, If a variety has arisen,
can that variety be perpetuated, or even intensified, when selective
conditions are indifferent, or perhaps unfavourable to its existence? I
cannot find that Mr. Darwin has ever been very dogmatic in answering these
questions. Formerly, he seems to have inclined to reply to them in the
negative, while now his inclination is the other way. Leaving aside those
broad questions of theology, philosophy, and ethics, by the discussion of
which neither the Quarterly Reviewer nor Mr. Mivart can be said to have
damaged Darwinism--whatever else they have injured--this is what their
criticisms come to. They confound a struggle for some rifle-pits with an
assault on the fortress.

In some respects, finally, I can only characterise the Quarterly Reviewer's
treatment of Mr. Darwin as alike unjust and unbecoming. Language of this
strength requires justification, and on that ground I add the remarks which
follow.

The Quarterly Reviewer opens his essay by a careful enumeration of all
those points upon which, during the course of thirteen years of incessant
labour, Mr. Darwin has modified his opinions. It has often and justly been
remarked, that what strikes a candid student of Mr. Darwin's works is not
so much his industry, his knowledge, or even the surprising fertility of
his inventive genius; but that unswerving truthfulness and honesty which
never permit him to hide a weak place, or gloss over a difficulty, but lead
him, on all occasions, to point out the weak places in his own armour, and
even sometimes, it appears to me, to make admissions against himself which
are quite unnecessary. A critic who desires to attack Mr. Darwin has only
to read his works with a desire to observe, not their merits, but their
defects, and he will find, ready to hand, more adverse suggestions than are
likely ever to have suggested themselves to his own sharpness, without Mr.
Darwin's self-denying aid.

Now this quality of scientific candour is not so common that it needs to be
discouraged; and it appears to me to deserve other treatment than that
adopted by the Quarterly Reviewer, who deals with Mr. Darwin as an Old
Bailey barrister deals with a man against whom he wishes to obtain a
conviction, _per fas aut nefas_, and opens his case by endeavouring to
create a prejudice against the prisoner in the minds of the jury. In his
eagerness to carry out this laudable design, the Quarterly Reviewer cannot
even state the history of the doctrine of natural selection without an
oblique and entirely unjustifiable attempt to depreciate Mr. Darwin. "To
Mr. Darwin," says he, "and (through Mr. Wallace's reticence) to Mr. Darwin
alone, is due the credit of having first brought it prominently forward and
demonstrated its truth." No one can less desire than I do, to throw a doubt
upon Mr. Wallace's originality, or to question his claim to the honour of
being one of the originators of the doctrine of natural selection; but the
statement that Mr. Darwin has the sole credit of originating the doctrine
because of Mr. Wallace's reticence is simply ridiculous. The proof of this
is, in the first place, afforded by Mr. Wallace himself, whose noble
freedom from petty jealousy in this matter smaller folk would do well to
imitate, and who writes thus:--"I have felt all my life, and I still feel,
the most sincere satisfaction that Mr. Darwin had been at work long before
me and that it was not left for me to attempt to write the 'Origin of
Species.' I have long since measured my own strength, and know well that it
would be quite unequal to that task." So that if there was any reticence at
all in the matter, it was Mr. Darwin's reticence during the long twenty
years of study which intervened between the conception and the publication
of his theory, which gave Mr. Wallace the chance of being an independent
discoverer of the importance of natural selection. And, finally, if it be
recollected that Mr. Darwin's and Mr. Wallace's essays were published
simultaneously in the "Journal of the Linnæan Society" for 1858, it follows
that the Reviewer, while obliquely depreciating Mr. Darwin's deserts, has
in reality awarded to him a priority which, in legal strictness, does not
exist.

Mr. Mivart, whose opinions so often concur with those of the Quarterly
Reviewer, puts the case in a way, which I much regret to be obliged to say,
is, in my judgment, quite as incorrect; though the injustice may be less
glaring. He says that the theory of natural selection is, in general,
exclusively associated with the name of Mr. Darwin, "on account of the
noble self-abnegation of Mr. Wallace." As I have said, no one can honour
Mr. Wallace more than I do, both for what he has done and for what he has
not done, in his relation to Mr. Darwin. And perhaps nothing is more
creditable to him than his frank declaration that he could not have written
such a work as the "Origin of Species." But, by this declaration, the
person most directly interested in the matter repudiates, by anticipation,
Mr. Mivart's suggestion that Mr. Darwin's eminence is more or less due to
Mr. Wallace's modesty.




VI

EVOLUTION IN BIOLOGY

[1878]


In the former half of the eighteenth century, the term "evolution" was
introduced into biological writings, in order to denote the mode in which
some of the most eminent physiologists of that time conceived that the
generations of living things took place; in opposition to the hypothesis
advocated, in the preceding century, by Harvey in that remarkable work
[Footnote: The _Exercitationes de Generatione Animalium_, which Dr.
George Ent extracted from him and published in 1651.] which would give him
a claim to rank among the founders of biological science, even had he not
been the discoverer of the circulation of the blood.

One of Harvey's prime objects is to defend and establish, on the basis of
direct observation, the opinion already held by Aristotle; that, in the
higher animals at any rate, the formation of the new organism by the
process of generation takes place, not suddenly, by simultaneous accretion
of rudiments of all, or of the most important, of the organs of the adult;
nor by sudden metamorphosis of a formative substance into a miniature of
the whole, which subsequently grows; but by _epigenesis_, or
successive differentiation of a relatively homogeneous rudiment into the
parts and structures which are characteristic of the adult.

"Et primò, quidem, quoniam per _epigenesin_ sive partium
superexorientium additamentum pullum fabricari certum est: quænam pars ante
alias omnes exstruatur, et quid de illa ejusque generandi modo observandum
veniat, dispiciemus. Ratum sane est et in ovo manifestè apparet quod
_Aristoteles_ de perfectorum animalium generatione enuntiat: nimirum,
non omnes partes simul fieri, sed ordine aliam post aliam; primùmque
existere particulam genitalem, cujus virtute postea (tanquam ex principio
quodam) reliquæ omnes partes prosiliant. Qualem in plantarum seminibus
(fabis, putà, aut glandibus) gemmam sive apicem protuberantem cernimus,
totius futuræ arboris principium. _Estque hæc particula, velut filius
emancipatus seorsumquc collocatus, et principium per se vivens; unde
postea, membrorum ordo describitur; et quæcunque ad absolvendum animal
pertinent, disponuntur._ [Footnote: _De Generatione Animalium_,
lib. ii. cap. x.] Quoniam enim _nulla pars se ipsam generat; sed postquam
generata est, se ipsam jam auget; ideo eam primùm oriri necesse est, quæ
principium augendi contineat (sive enim planta, sive animal est, æque
omnibus inest quod vim habeat vegetandi, sive nutriendi_), [Footnote:
_De Generatione_, lib. ii. cap. iv.] simulque reliquas omnes partes
suo quamque ordine distinguat et formet; proindeque in eadem primogenita
particula anima primario inest, sensus, motusque, et totius vitæ auctor et
principium." (Exercitatio 51.)

Harvey proceeds to contrast this view with that of the "Medici," or
followers of Hippocrates and Galen, who, "badly philosophising," imagined
that the brain, the heart, and the liver were simultaneously first
generated in the form of vesicles; and, at the same time, while expressing
his agreement with Aristotle in the principle of epigenesis, he maintains
that it is the blood which is the primal generative part, and not, as
Aristotle thought, the heart.

In the latter part of the seventeenth century, the doctrine of epigenesis,
thus advocated by Harvey, was controverted, on the ground of direct
observation, by Malpighi, who affirmed that the body of the chick is to be
seen in the egg, before the _punctum sanguineum_ makes it appearance.
But, from this perfectly correct observation a conclusion which is by no
means warranted was drawn; namely, that the chick, as a whole, really
exists in the egg antecedently to incubation; and that what happens in the
course of the latter process is no addition of new parts, "alias post alias
natas," as Harvey puts it, but a simple expansion, or unfolding, of the
organs which already exist, though they are too small and inconspicuous to
be discovered. The weight of Malpighi's observations therefore fell into
the scale of that doctrine which Harvey terms _metamorphosis_, in
contradistinction to epigenesis.

The views of Malpighi were warmly welcomed, on philosophical grounds, by
Leibnitz, [Footnote: "Cependant, pour revenir aux formes ordinaires ou aux
âmes matérielles, cette durée qu'il leur faut attribuer à la place de celle
qu'on avoit attribuée aux atomes pourroit faire douter si elles ne vont pas
de corps en corps; ce qui seroit la métempsychose, à peu près comme
quelques philosophes ont cru la transmission du mouvement et celle des
espèces. Mais cette imagination est bien éloignée de la nature des choses.
Il n'y a point de tel passage; et c'est ici où les transformations de
Messieurs Swammerdam, Malpighi, et Leewenhoek, qui sont des plus excellens
observateurs de notre tems, sont venues à mon secours, et m'ont fait
admettre plus aisément, que l'animal, et toute autre substance organisée ne
commence point lorsque nous le croyons, et que sa generation apparente
n'est qu'une développement et une espèce d'augmentation. Aussi ai je
remarqué que l'auteur de la _Recherche de la Verité_, M. Regis, M.
Hartsoeker, et d'autres habiles hommes n'ont pas été fort éloignés de ce
sentiment." Leibnitz, _Système Nouveau de la Nature_, 1695. The
doctrine of "Embôitement" is contained in the _Considérations sur le
Principe de Vie_, 1705; the preface to the _Theodicée_, 1710; and
the _Principes de la Nature et de la Grace_ (§ 6), 1718.] who found in
them a support to his hypothesis of monads, and by Malebranche; [Footnote:
"Il est vrai que la pensée la plus raisonnable et la plus conforme à
l'experience sur cette question très difficile de la formation du foetus;
c'est que les enfans sont déja presque tout formés avant même l'action par
laquelle ils sont conçus; et que leurs mères ne font que leur donner
l'accroissement ordinaire dans le temps de la grossesse." _De la
Recherche de la Verité_, livre ii. chap. vii. p. 334, 7th ed., 1721.]
while, in the middle of the eighteenth century, not only speculative
considerations, but a great number of new and interesting observations on
the phenomena of generation, led the ingenious Bonnet, and Haller,
[Footnote: The writer is indebted to Dr. Allen Thomson for reference to the
evidence contained in a note to Haller's edition of Boerhaave's
_Prælectiones Academicæ_, vol. v. pt. ii. p. 497, published in 1744,
that Haller originally advocated epigenesis.] the first physiologist of the
age, to adopt, advocate, and extend them.

Bonnet affirms that, before fecundation, the hen's egg contains an
excessively minute but complete chick; and that fecundation and incubation
simply cause this germ to absorb nutritious matters, which are deposited in
the interstices of the elementary structures of which the miniature chick,
or germ, is made up. The consequence of this intussusceptive growth is the
"development" or "evolution" of the germ into the visible bird. Thus an
organised individual (_tout organisé_) "is a composite body consisting
of the original, or _elementary_, parts and of the matters which have
been associated with them by the aid of nutrition;" so that, if these
matters could be extracted from the individual (_tout_), it would, so
to speak, become concentrated in a point, and would thus be restored to its
primitive condition of a _germ_; "just as by extracting from a bone
the calcareous substance which is the source of its hardness, it is reduced
to its primitive state of gristle or membrane." [Footnote:
_Considérations sur les Corps organisés, chap. x.] "Evolution" and
"development" are, for Bonnet, synonymous terms; and since by "evolution"
he means simply the expansion of that which was invisible into visibility,
he was naturally led to the conclusion, at which Leibnitz had arrived by a
different line of reasoning, that no such thing as generation, in the
proper sense of the word, exists in Nature. The growth of an organic being
is simply a process of enlargement as a particle of dry gelatine may be
swelled up by the intussusception of water; its death is a shrinkage, such
as the swelled jelly might undergo on desiccation. Nothing really new is
produced in the living world, but the germs which develop have existed
since the beginning of things; and nothing really dies, but, when what we
call death takes place, the living thing shrinks back into its germ state.
[Footnote: Bonnet had the courage of his opinions, and in the
_Palingénésie Philosophique_, part vi. chap, iv., he develops a
hypothesis which he terms "évolution naturelle;" and which, making
allowance for his peculiar views of the nature of generation, bears no
small resemblance to what is understood by "evolution" at the present
day:--

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