Famous Reviews, Selected and Edited with Introductory Notes Part 20

2. That many of these variations tend to an improvement upon the parent stock.

3. That, by a continued selection of these improved specimens as the progenitors of future stock, its powers may be unlimitedly increased.

4. And, lastly, that there is in nature a power continually and universally working out this selection, and so fixing and augmenting these improvements.

Mr. Darwin's whole theory rests upon the truth of these propositions and crumbles utterly away if only one of them fail him. These, therefore, we must closely scrutinise. We will begin with the last in our series, both because we think it the newest and the most ingenious part of Mr.

Darwin's whole argument, and also because, whilst we absolutely deny the mode in which he seeks to apply the existence of the power to help him in his argument, yet we think that he throws great and very interesting light upon the fact that such self-acting power does actively and continuously work in all creation around us.

Mr. Darwin finds then the disseminating and improving power, which he needs to account for the development of new forms in nature, in the principle of "Natural Selection," which is evolved in the strife for room to live and flourish which is evermore maintained between themselves by all living things. One of the most interesting parts of Mr. Darwin's volume is that in which he establishes this law of natural selection; we say establishes, because--repeating that we differ from him totally in the limits which he would a.s.sign to its action--we have no doubt of the existence or of the importance of the law itself.

We come then to these conclusions. All the facts presented to us in the natural world tend to show that none of the variations produced in the fixed forms of animal life, when seen in its most plastic condition under domestication, give any promise of a true trans.m.u.tation of species; first, from the difficulty of acc.u.mulating and fixing variations within the same species; secondly, from the fact that these variations, though most serviceable for man, have no tendency to improve the individual beyond the standard of his own specific type, and so to afford matter, even if they were infinitely produced, for the supposed power of natural selection on which to work; whilst all variations from the mixture of species are barred by the inexorable law of hybrid sterility. Further, the embalmed records of 3,000 years show that there has been no beginning of trans.m.u.tation in the species of our most familiar domesticated animals; and beyond this, that in the countless tribes of animal life around us, down to its lowest and most variable species, no one has ever discovered a single instance of such trans.m.u.tation being now in prospect; no new organ has ever been known to be developed--no new natural instinct to be formed--whilst, finally, in the vast museum of departed animal life which the strata of the earth imbed for our examination, whilst they contain far too complete a representation of the past to be set aside as a mere imperfect record, yet afford no one instance of any such change as having ever been in progress, or give us anywhere the missing links of the a.s.sumed chain, or the remains which would enable now existing variations, by gradual approximations, to shade off into unity. On what then is the new theory based? We say it with unfeigned regret, in dealing with such a man as Mr. Darwin, on the merest hypothesis, supported by the most unbounded a.s.sumptions. These are strong words, but we will give a few instances to prove their truth:--

All physiologists admit that the swim-bladder is h.o.m.ologous or "ideally similar" in position and structure with the lungs of the higher vertebrate animals; hence there _seems to me to be no great difficulty in believing_ that natural selection has actually converted a swim-bladder into a lung, or organ used exclusively for respiration.--p. 191.

_I can indeed hardly doubt_ that all vertebrate animals having true lungs have descended by ordinary generation from the ancient prototype, of which we know nothing, furnished with a floating apparatus or swim-bladder--p. 191.

We must be cautious

In concluding that the most different habits of all _could not_ graduate into each other; that a bat, for instance, _could not_ have been formed by natural selection from an animal which at first could only glide through the air.--p. 204.

Again:--

_I see no difficulty in supposing_ that such links formerly existed, and that each had been formed by the same steps as in the case of the less perfectly gliding squirrels, and that each grade of structure was useful to its possessor. Nor _can I see any insuperable difficulty in further believing_ it possible that the membrane-connected fingers and forearm of the galeopithecus might be greatly lengthened by natural selection, and this, as far as the organs of flight are concerned, would convert it into a bat.--p. 181.

For instance, a swim-bladder has _apparently_ been converted into an air-breathing lung.--p. 181.

And again:--

The electric organs of fishes offer another case of special difficulty: It is impossible to conceive by what steps these wondrous organs have been produced; but, as Owen and others have remarked, their intimate structure closely resembles that of common muscle; and as it has lately been shown that rays have an organ closely a.n.a.logous to the electric apparatus, and yet do not, as Matteucci a.s.serts, discharge any electricity, we must own that we are far too ignorant to argue that _no transition of any kind is possible._--pp. 192-3.

Sometimes Mr. Darwin seems for a moment to recoil himself from this extravagant liberty of speculation, as when he says, concerning the eye,--

To suppose that the eye, with its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree.--p. 186.

But he soon returns to his new wantonness of conjecture, and, without the shadow of a fact, contents himself with saying that--

he _suspects_ that any sensitive nerve may be rendered sensitive to light, and likewise to those coa.r.s.er vibrations of the air which produce sound.--p-187.

And in the following pa.s.sage he carries this extravagance to the highest pitch, requiring a licence for advancing as true any theory which cannot be demonstrated to be actually impossible:--

If it could be demonstrated that any complex organ existed, _which could not possibly_ have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find no such case.--p. 189.

Another of these a.s.sumptions is not a little remarkable. It suits his argument to deduce all our known varieties of pigeons from the rock-pigeon (the Columba livia), and this parentage is traced out, though not, we think, to demonstration, yet with great ingenuity and patience. But another branch of the argument would be greatly strengthened by establis.h.i.+ng the descent of our various breeds of dogs with their perfect power of fertile inter-breeding from different natural species. And accordingly, though every fact as to the canine race is parallel to the facts which have been used before to establish the common parentage of the pigeons in Columba livia, all these are thrown over in a moment, and Mr. Darwin, first a.s.suming, without the shadow of proof, that our domestic breeds are descended from different species, proceeds calmly to argue from this, as though it were a demonstrated certainty.

It _seems to me unlikely_ in the case of the dog-genus, which is distributed in a wild state throughout the world, that since man first appeared one species alone should have been domesticated.--p. 18.

In some cases _I do not doubt_ that the intercrossing of species aboriginally distinct has played an important part in the origin of our domestic productions.--p. 43.

What new words are these for a loyal disciple of the true Baconian philosophy?--"I can conceive"--"It is not incredible"--"I do not doubt"

--"It is conceivable."

For myself, _I venture confidently_ to look back thousands on thousands of generations, and I see an animal striped like a zebra, but perhaps otherwise very differently constructed, the common parent of our domestic horse, whether or not it be descended from one or more wild stocks of the a.s.s, hemionous, quagga, or zebra.--p. 167.

In the name of all true philosophy we protest against such a mode of dealing with nature, as utterly dishonourable to all natural science, as reducing it from its present lofty level of being one of the n.o.blest trainers of man's intellect and instructors of his mind, to being a mere idle play of the fancy, without the basis of fact or the discipline of observation. In the "Arabian Nights" we are not offended as at an impossibility when Amina sprinkles her husband with water and transforms him into a dog, but we cannot open the august doors of the venerable temple of scientific truth to the genii and magicians of romance. We plead guilty to Mr. Darwin's imputation that

the chief cause of our natural unwillingness to admit that one species has given birth to other and distinct species is that we are always slow in admitting any great change of which we do not see the intermediate steps.--p. 481.

In this tardiness to admit great changes suggested by the imagination, but the steps of which we cannot see, is the true spirit of philosophy.

a.n.a.lysis, says Professor Sedgwick, consists in making experiments and observations, and in drawing general conclusions from them by induction, and admitting of no objections against the conclusions but such as are taken from experiments or other certain truths; for _hypotheses are not to be regarded in experimental philosophy._[1]

[1] "A Discourse on the Studies of the University," by A. Sedgwick, p.

102.

The other solvent which Mr. Darwin most freely and, we think, unphilosophically employs to get rid of difficulties, is his use of time. This he shortens or prolongs at will by the mere wave of his magician's rod. Thus the duration of whole epochs, during which certain forms of animal life prevailed, is gathered up into a point, whilst an unlimited expanse of years, "impressing his mind with a sense of eternity," is suddenly interposed between that and the next series, though geology proclaims the transition to have been one of gentle and, it may be, swift accomplishment. All this too is made the more startling because it is used to meet the objections drawn from facts. "We see none of your works," says the observer of nature; "we see no beginnings of the portentous change; we see plainly beings of another order in creation, but we find amongst them no tendencies to these altered organisms." "True," says the great magician, with a calmness no difficulty derived from the obstinacy of facts can disturb; "true, but remember the effect of time. Throw in a few hundreds of millions of years more or less, and why should not all these changes be possible, and, if possible, why may I not a.s.sume them to be real?"

Together with this large licence of a.s.sumption we notice in this book several instances of receiving as facts whatever seems to bear out the theory upon the slightest evidence, and rejecting summarily others, merely because they are fatal to it. We grieve to charge upon Mr. Darwin this freedom in handling facts, but truth extorts it from us. That the loose statements and unfounded speculations of this book should come from the author of the monograms on Cirripedes, and the writer, in the natural history of the Voyage of the "Beagle," of the paper on the Coral Reefs, is indeed a sad warning how far the love of a theory may seduce even a first-rate naturalist from the very articles of his creed.

This treatment of facts is followed up by another favourite line of argument, namely, that by this hypothesis difficulties otherwise inextricable are solved. Such pa.s.sages abound. Take a few, selected almost at random, to ill.u.s.trate what we mean:--

How inexplicable are these facts on the ordinary view of creation!--p.

436.

Such facts as the presence of peculiar species of bats and the absence of other mammals on oceanic islands are utterly inexplicable on the theory of independent acts of creation.--pp. 477-8.

It must be admitted that these facts receive no explanation on the theory of creation.--p. 478.

The inhabitants of the Cape de Verde Islands are related to those of Africa, like those of the Galapagos to America. I believe this grand fact can receive no sort of explanation on the ordinary view of independent creation.--pp. 398-9.

Now what can be more simply reconcilable with that theory than Mr.

Darwin's own account of the mode in which the migration of animal life from one distant region to another is continually accomplished?

Take another of these suggestions:--

It is inexplicable, on the theory of creation, why a part developed in a very unusual manner in any one species of a genus, and therefore, as we may naturally infer, of great importance to the species, should be eminently liable to variation.--p. 474.

Why "inexplicable"? Such a liability to variation might most naturally be expected in the part "unusually developed," because such unusual development is of the nature of a monstrosity, and monsters are always tending to relapse into likeness to the normal type. Yet this argument is one on which he mainly relies to establish his theory, for he sums all up in this triumphant inference:--

I cannot believe that a false theory would explain, as it seems to me that the theory of natural selection does explain, the several large cla.s.ses of facts above specified.--p. 480.

Now, as to all this, we deny, first, that many of these difficulties are "inexplicable on any other supposition." Of the greatest of them (128, 194) we shall have to speak before we conclude. We will here touch only on one of those which are continually reappearing in Mr. Darwin's pages, in order to ill.u.s.trate his mode of dealing with them. He finds, then, one of these "inexplicable difficulties" in the fact, that the young of the blackbird, instead of resembling the adult in the colour of its plumage, is like the young of many other birds spotted, and triumphantly declaring that--

No one will suppose that the stripes on the whelp of a lion, or the spots on the young blackbird, are of any use to these animals, or are related to the conditions to which they are exposed.--pp. 439-40--

he draws from them one of his strongest arguments for this alleged community of descent. Yet what is more certain to every observant field-naturalist than that this alleged uselessness of colouring is one of the greatest protections to the young bird, imperfect in its flight, perching on every spray, sitting unwarily on every bush through which the rays of suns.h.i.+ne dapple every bough to the colour of its own plumage, and so give it a facility of escape which it would utterly want if it bore the marked and prominent colours, the beauty of which the adult bird needs to recommend him to his mate, and can safely bear with his increased habits of vigilance and power of wing?

But, secondly, as to many of these difficulties, the alleged solving of which is one great proof of the truth of Mr. Darwin's theory, we are compelled to join issue with him on another ground, and deny that he gives us any solution at all. Thus, for instance, Mr. Darwin builds a most ingenious argument on the tendency of the young of the horse, a.s.s, zebra, and quagga, to bear on their shoulders and on their legs certain barred stripes. Up these bars (bars sinister, as we think, as to any true descent of existing animals from their fancied prototype) he mounts through his "thousands and thousands of generations," to the existence of his "common parent, otherwise perhaps very differently constructed, but striped like a zebra."--(p. 67.) "How inexplicable," he exclaims, "on the theory of creation, is the occasional appearance of stripes on the shoulder and legs of several species of the horse genus and in their hybrids!"--(p. 473.) He tells us that to suppose that each species was created with a tendency "like this, is to make the works of G.o.d a mere mockery and deception"; and he satisfies himself that all difficulty is gone when he refers the stripes to his hypothetical thousands on thousands of years removed progenitor. But how is his difficulty really affected? for why is the striping of one species a less real difficulty than the striping of many?