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In certain instances this obvious consideration is strikingly illustrated. Thus the salamander, an Amphibian of the newt family, brings forth its young in adult condition without gills.228 But previously to birth they have gills relatively large. The experiment having been tried of bringing some of them forth by artificial means before their time, and placing them in water, the first thing they did was to cast off these big gills, which were speedily replaced by new ones of much smaller size, and evidently better suited for the work required, as they lasted as long as a fortnight.
Here, in the first place, it is quite impossible to suppose that the large gills would continue to appear unless they were of advantage during the period of gestation. It is equally evident that it is not from a previous aquatic condition that they are inherited, for in such a condition they are useless. Finally, as Mr. Mivart observes, the new gills, suitable for unwonted conditions, were developed "not in a struggle for existence against rivals, but directly and spontaneously from the innate nature of the animal."
This view of the matter commended itself on mature consideration to so ardent an evolutionist as Carl Vogt, with whom we may couple M. de Quatrefages, who cites his words with approval as follows:229
It has been laid down as a fundamental law of biogenesis that ontogeny (the development of the individual) and phylogeny (that of the race) must exactly correspond… This law which I long held as well founded is absolutely and radically false. Attentive study of embryology shows us, in fact, that embryos have their own conditions suitable to themselves, very different from those of adults.
"In a word," M. de Quatrefages continues, "the learned Genevan professor rightly considers that, 'The ontogenesis of all organic beings without exception, is the normal result of all the various influences which operate upon such beings.'"
But it must, moreover, be noted that the story which embryology can be made to tell is by no means so plain as we might easily be led to suppose.
Thus, although snakes are held to be descended from lizards, and some of them have rudimentary legs even in the adult stage, others have no trace of limbs even in the egg, while they have vestiges of gills, and thus would seem to be visibly linked to ancient water-dwelling ancestors, and not to far more recent land-dwellers. Again;230 Amphibians (frogs, newts and the like) agree in some respects, as to the development of the germ, with mammals, differing in the same respects from reptiles and birds. But reptiles and birds are supposed to be a more recent development than Amphibia, and therefore should intervene between them and mammals on the genealogical tree. Moreover the eggs of one group of Amphibians are found to exhibit some remarkable resemblances to those of reptiles and birds, from which it would thus appear to have derived them, although on other grounds it is declared to be of an older stock than theirs. Most frogs, toads, and newts come out of the egg as tadpoles, furnished with gills and so breathing in water. This should signify that these creatures are descended from fish or fishlike ancestors. But one frog (Rana opisthodon) is never a tadpole even in the egg, from which he gets out by means of a special opener on his snout which he has somehow acquired. On the other hand certain newts231 breed as tadpoles instead of in their mature form, which looks like an attempt to climb down the tree instead of up.
It will be remembered that the latter phrase was that used by Professor Milnes Marshall. Yet even he expressed himself strongly concerning the exaggerations of Professor Haeckel on this subject. In his review of Haeckel's Anthropogenie,232 after observing that many descriptions of human embryology have been based on observations of dogs, pigs, rabbits, or even chickens and dogfish, he thus continued regarding the book before him:
A student who relied on Professor Haeckel's description, would obtain an entirely erroneous idea of the development of the human embryo… It is a matter for great regret that a book of 900 pages, bearing such a title, should be allowed to appear, in which the account of the actual development of the human embryo is so inadequate or even erroneous.
Far more fundamental, however, is a remark of Mr. Mivart's, that if, as Darwinians say, the development of the individual is an epitome of that of the species, the latter must like the former be due to the action of definite innate laws unconsciously carrying out definite preordained ends and purposes. For although cells or embryos may be indistinguishable from one another, and may appear to us identical in constitution, their differences are absolute. Each is determined to be one sort of animal and no other, and can live at all only on condition of developing towards the prescribed form. – Therefore, whatever evidence the embryonic forms may be supposed to afford in support of Evolution, they have nothing in common with the haphazard process of Natural Selection.
And here again Professor Huxley found himself obliged to enter his caveat, and to intimate his opinion that some of his friends were inclined to build too confidently upon this foundation. As his biographer Professor Weldon writes in the Dictionary of National Biography:
Darwin had suggested an interpretation of the facts of embryology which led to the hope that a fuller knowledge of development might reveal the history of all the great groups of animals at least in its main outlines. This hope was of service as a stimulus to research, but the attempt to interpret the phenomena observed led to speculations which were often fanciful and always incapable of verification. Huxley was keenly sensible of the danger attending the use of a hypothetical explanation, leading to conclusions which cannot be experimentally tested, and he carefully avoided it… In the preface to the Manual of the Comparative Anatomy of Invertebrated Animals, he says: "I have abstained from discussing questions of ætiology,233 not because I underestimate their importance, or am insensible to the interest of the great problem of Evolution, but because, to my mind, the growing tendency to mix up ætiological speculations with morphological generalizations will, if unchecked, throw Biology into confusion."
Accordingly, Huxley himself based his faith in Evolution on palæontological evidence, and attempted to decide the precise course it had followed only "in the few cases where the evidence seemed to him sufficiently complete." This line of enquiry we have still to pursue, but meanwhile, it is evident that the phenomena we have been considering, failing to meet the approval of so thorough-going an Evolutionist as he undoubtedly was, cannot be said to furnish convincing scientific evidence in favour of Darwinism.
It will be asked how it comes to pass, if the Darwinian system really lies open to so many objections, that it occupies so large a place in scientific estimation. To this we must reply that, in spite of its great name, its success has throughout been popular rather than truly scientific, and that as time went on it has lost ground among the class of men best qualified to judge. Evolutionists there are in plenty, – but very few genuine Darwinists, and amongst these can by no means be reckoned all who adopt the title, for not a few of them – as Romanes and Weismann – profess doctrines which cannot be reconciled with those of Darwin himself. Meanwhile, an increasing volume of scientific opinion sets definitely against Darwinism as an adequate explanation of the philosophy of life, and falls into the view expressed long ago by Charles Robin234 who, as a freethinker, had no antecedent objections against it, "Darwinism is a fiction, a poetical accumulation of probabilities without proof, and of attractive explanations without demonstration."
It would be tedious to cite testimonies at length, but, in addition to M. de Quatrefages who has made a full and careful study of the whole question, [Charles Darwin et ses précurseurs Français, and Les Emules de Darwin] may be mentioned such continental scholars as Blanchard [La vie des êtres animés], Wigand [Der Darwinismus und die Naturforschung, etc.], Wolff [Beiträge zur Kritik der darwinschen Lehre], Hamann [Entwicklungslehre und Darwinismus], Pauly [Wahres und Falsches an Darwins Lehre], Driesch [Biologisches Zentralblatt, 1896 and 1902], Plate [Bedeutung und Tragweite des Darwinschen Selektionsprincip], Hertwig [Address to Naturalist Congress, Aachen, 1900], Heer [Urwelt der Schweiz], Kölliker [Ueber die darwin'sche Schöpfungstheorie], Eimer [Entstehung der Arten], Von Hartmann [Wahrheit und Irrthum im Darwinismus], Schilde [Antidarwinistisches im Ausland], Du Bois-Reymond [Conference, August 2, 1881, etc.], Virchow [Freiheit der Wissenschaft, etc.], Nägeli [Mechanisch-physiologische Theorie der Abstammungslehre], Schaafhausen [Ueber die anthropologischen Fragen], Fechner [Ideen zur Schöpfungs-und Entwicklungsgeschichte der Organismen], Jakob [Der Mensch, etc.], Diebolder [Darwins Grundprinzip, etc.], Huber [Die Lehre Darwins kritisch betrachtet], Joseph Ranke, and Von Bauer, – all of whom either reject Darwinism altogether, or admit it only with fatal reservations.
Special weight must attach to the adverse verdict of M. Fabre, styled by Darwin himself "that inimitable observer," who declares that he cannot reconcile the theory with the facts he encounters.235
It must be sufficient to quote one or two of our own countrymen, whose utterances will enable us to form an opinion as to the true scientific status of the doctrine.
We may begin with Huxley, the great popular champion of Darwinism, who did more than any other man to spread the new doctrine. Yet, strange to say, he seems never to have really accepted its fundamental tenet himself, always appearing very shy of Natural Selection, and carefully abstaining from committing himself to any responsibility for it. Thus in his treatise on Man's Place in Nature, he thus explains his position in its regard:
Mr. Darwin's hypothesis is not, so far as I am aware, inconsistent with any biological fact; on the contrary, if admitted, the facts of Development, of Comparative Anatomy, of Geographical Distribution, and of Palæontology, become connected together, and exhibit a meaning such as they never possessed before; and I, for one, am firmly convinced, that if not precisely true, that hypothesis is as near an approximation to the truth as, for example, the Copernican hypothesis was to the true theory of the planetary motions. But for all this, our acceptance of the Darwinian hypothesis must be provisional so long as one link in the chain of evidence is wanting; and so long as all the animals and plants certainly produced by selective breeding from a common stock are fertile with one another, the link will be wanting. For, so long, selective breeding will not be proved to be competent to do all that is required of it to produce natural species.
This missing link, like various others, has never been supplied, and in consequence Professor Huxley never abandoned his attitude of reserve. On the contrary, when, in 1880, he delivered an address to celebrate "the Coming of Age of the Origin of Species" he discharged the task without once mentioning Natural Selection, which is to that work as the Prince of Denmark is to Hamlet.
But there is one passage in the said address, which deserves to be specially remembered:
History warns us that it is the customary fate of new truths to begin as heresies and to end as superstitions; and, as matters now stand, it is hardly rash to anticipate that, in another twenty years, the new generation, educated under the influences of the present day, will be in danger of accepting the main doctrines of the Origin of Species, with as little reflection, and it may be with as little justification, as so many of our contemporaries, twenty years ago, rejected them.
In 1886, Professor Romanes pronounced as follows:236
"At present it would be impossible to find any working naturalist who supposes that survival of the fittest is competent to explain all the phenomena of species-formation."
As to the actual position now occupied in Scientific opinion by Mr. Darwin's hypotheses, we may content ourselves with the declaration of Professor S. H. Vines in his Presidential address to the Linnean Society, May 24, 1902.
1. It is established that Natural Selection, though it may have perpetuated species, cannot have originated any.
2. It is still a mystery why Evolution should tend from the lower to the higher, from simple to complex organisms.
3. The facts seem to admit of no other interpretation than that variation is not [as Darwin supposed] indeterminate, but that there is in living matter an inherent determination in favour of variation in the higher direction.
That is to say, Darwin's Origin of Species does not explain the Origin of Species; and as to the laws which govern Evolution we can be sure only that they are not those which he assigned.
In like manner, Sir Oliver Lodge pronounces:237
Take the origin of species by the persistence of favourable variations; how is the appearance of these same favourable variations accounted for? Except by artificial selection not at all. Given their appearance, their development by struggle and inheritance and survival can be explained; but that they arose spontaneously, by random changes without purpose, is an assertion which cannot be made.
We are thus in a position to form our own judgment as to the claim made on behalf of Mr. Darwin, with which we started this chapter – namely, that he has eliminated all mystery from the organic world by the discovery of natural mechanical laws by which all its operations are governed. It is, indeed, difficult to understand how Darwinists themselves can suppose their system to make any such claim, for, as M. Paul Vignon truly observes,238 "La science darwinnienne s'imaginait avoir triomphé du Sphinx, alors qu'elle avait simplement décomposé le problème dans une monnaie d'énigmes moins rébarbatives en apparence." As has been said, it is far more on account of the vast consequences professedly based upon it, as a sure foundation stone, than for its own sake, that it has seemed advisable to devote so much attention to the study of Darwinism, quite apart from which the whole question of organic Evolution still demands consideration.
It seems far more just to conclude with M. Fabre:239
Let us acknowledge that in truth we know nothing about anything, so far as ultimate truths are concerned. Scientifically considered nature is a riddle to which human curiosity can find no answer. Hypothesis follows hypothesis, the ruins of theories are piled one on another, but truth ever escapes us. To learn how to remain in ignorance may well be the final lesson of wisdom.240
XVI
THE FACTS OF EVOLUTION
LEAVING the field of speculation and "ætiology," we have now to enquire, not to what causes organic Evolution may be attributable, but how far it can be shewn to have actually occurred. This can be learnt only from the history of life upon earth as disclosed by the evidence of palæontology, or the geological record, and we are thus brought to the investigation of that evidence, by which alone, as Professor Huxley agrees, can the truth about Evolution be scientifically or satisfactorily established. In his address recently mentioned on occasion of the twenty-first birthday of the Origin of Species, having spoken of various advances of our knowledge, as in comparative anatomy and embryology, which had helped to win acceptance for transformist doctrines, he thus continued:
But all this remains mere secondary evidence. It may remove dissent, but it does not compel assent. Primary and direct evidence in favour of evolution can be furnished only by palæontology. The geological record, so soon as it approaches completeness, must, when properly questioned, yield either an affirmative or a negative answer; if evolution has taken place, there will its mark be left; if it has not taken place, there will be its refutation.
This is common sense. Evolution can claim to be a scientific truth, only so far as clear evidence is forthcoming that Evolution there has been. If the geological record be sufficiently complete to prove or disprove its claims, the question is settled for ever. If, on the other hand, the record be not complete enough for a conclusive verdict, it is, at least, hard to understand the grounds of such a statement as that the doctrine of Evolution has long since passed beyond the stage of discussion among scientific thinkers;241 or that of Professor Marsh, that to doubt Evolution is to doubt Science; or of Professor Huxley himself242– "So far as the animal world is concerned, Evolution is no longer a speculation, but a matter of historical fact."
This historical enquiry is accordingly all-important, and it is one which should be easy to undertake without any prepossessions, for it is hard to see upon what à priori grounds these could rest. That there has been Evolution in one sense of the term is obvious, – that is to say, development of organic types from lower to higher forms, from the sea-weed or fungus to the oak or the rose, from the star-fish or the coral-insect, to the eagle or to man. The question is, not whether there has been such a progressive succession of forms, but whether one form has proceeded from another genetically, being produced in the same manner as individuals of a species now are. That this has been the case, as Professor Huxley tells us in the same address, is the cornerstone of evolutionary teaching. He appears indeed to restrict Evolution within the limits of classes and groups, but such restriction is so contrary to all his principles that the words which seem to imply it can scarcely be taken as having any definite significance. Should the appearance of different classes and groups require to be severally accounted for, we should be landed back in the system of separate creations against which he is never tired of inveighing.
The fundamental doctrine of all forms of the theory of evolution applied to biology [he says] is that the innumerable species, genera, and families of organic beings with which the world is peopled have all descended, each within its own class or group, from common parents, and have all been modified in the course of descent.
And, holding as he does that palæontology furnishes the necessary evidence, he thus continues:
And, in the view of the facts of geology, it follows that all living animals and plants are the lineal descendants of those which lived long before the Silurian epoch.
Here is a plain issue, and one, as has been said, to be discussed without prejudice. That the innumerable forms of organic life should thus have been genetically derived one from another, is no more difficult to conceive than that they should have come into existence at all. Moreover, it appears to our minds almost a first principle that natural law must suffice to account for the phenomena of nature from beginning to end, and that any system is self-condemned which finds anywhere in these phenomena evidence of a non-natural, or supernatural, interposition. Has not such a theologian as Suarez, following St. Augustine, laid it down as an axiom243 that God does not directly interfere with the operations of Nature, when He can effect His purposes through natural causes? Undoubtedly, too, it is difficult for our minds to imagine in what way, except through genetic evolution, the successive production of more and more developed types could be effected.
But, as has before been observed, what seems to us probable is not therefore proved to be true. What we want are facts, and by facts we must be ready to abide. At the same time, it is not very easy to understand the supreme importance which evolutionists generally appear to attach to the descent of all living creatures from some one original, and their abhorrence of the idea that the power, whatever it was, which first produced life, may have operated repeatedly, at different epochs, to repeat the production. It seems to be assumed that this must imply "miracle" and interruption of the continuity of Nature, to admit which is irrational and unscientific. But since life did unquestionably once originate somehow, which Science makes no attempt to deny, why should it be so improper to suppose that it originated more than once, at various times and in various forms, and that, consequently, genetic descent with modification, or "Evolution," is not the explanation of typic development? As Sir J. W. Dawson writes244 concerning the oyster tribe, whereof two species are found in the Coal Measures (one European and the other American), and a continuous succession of species ever since:
All these species may have proceeded from one origin, by descent with modification, or, on the other hand, the same causes which led to their origination in the Carboniferous may have operated again and again.
It must, however, be remembered that, if the theory of genetic descent with accumulation of minute modifications be the true explanation of the production of new forms, it necessarily follows, that could a complete record be forthcoming of the ancestry of any actual species, there would be found in that pedigree no distinction of species or genera, for no sharply marked lines of limitation would be discoverable. It would be like the case of a man who had been photographed every hour of his life from birth to old age; – immense though the difference might be between the two extremes, the gradations of change would at all points pass as imperceptibly into one another as do the phases of the moon. This consideration is both fundamental and obvious, yet it would seem to be almost universally ignored. It appears to be thought that, in order to demonstrate the fact of evolution, all that is needed is to find a form here and there, in some sense intermediate between others, – like the reptilian birds already mentioned. This would imply that the course of Evolution must be like that of an army, making long marches from point to point, and traceable only by the remains of its camp-fires: whereas it should be as that of a glacier continuously creeping on, and leaving its tracks at one point as much as another. What are wanted, therefore, as evidence for Evolution, are not isolated specific forms uniting some characteristics of those which they are supposed to connect, – as Nelson's men-of-war form a stepping-stone between the vessels of the Norsemen and the ironclads of the present day, – but a series sufficient to show, or at least to indicate, that all changes have been gradual and insensible, without the introduction at any point of a new element. To pursue the illustration, such a new element would be gunpowder or steam in the evolution of the battle-ship, for by no mere development could bows or javelins produce a cannon, or sailing ships a steamboat.
Therefore, in proportion as the geological record approaches completeness, its testimony, – if it is to be in favour of Evolution – must tend more and more in this direction, and unless, in some instance at least, clear evidence be discoverable of the melting of one form into another, it cannot possibly be said that we have sufficient proof that such a process ever occurred. Mere graduated resemblance of isolated forms does not necessarily imply such transmutation, as we see for example in the methodical progression of shape, exhibited by various crystals, and even more remarkably in the affinities which we can recognize among what we know as elementary substances.
There is another important point to be borne in mind. According to the teaching of Evolutionists such as Darwin or Haeckel,245 every Species has originated from a single ancestor, – or, as they should rather say, from a single pair.
If this were so, it would necessarily follow that every new form, originating in some particular spot of earth, would very gradually spread thence to other regions, fighting its way along. As Mr. Darwin acknowledges,246 "The development by this means (i.e. Natural Selection) of a group of forms, all of which are descended from some one progenitor, must have been an extremely slow process; and the progenitors must have lived long before their modified descendants."