Part 4 (1/2)

Huxley then proceeded to shew that uniforlected this last and y, the atteht the world into its present condition He gave a striking display of the wide knowledge of his reading by going back to the foundation of this branch ofa masterly account of the then little-known treatise of Immanuel Kant, who in 1775 had written _An Attein of the Universe upon Newtonian Principles_ Next he declared that evolution embraced all that was sound in both catastrophis the arbitrary lireat question to which these observations upon the existing schools of geology had led The e, then Sir William Thomson, now Lord Kelvin, and Huxley's immediate successor in the Presidential Chair of the Royal Society, had stated that the English school of geology had assus, Tho state of things on the earth--all geological history showing continuity of life--must be limited within some such period of time as one hundred million years”

This pronouncement had been received with acclaical sciences, as a sign of internal dissensions within the house of science Huxley, then, as all through the latter part of his life, at once constituted hiuments one by one, shewed by a series of reat deal to be said for the other side, and that physicists were as little certain as geologists could be of the exact duration of time that had elapsed since the dawn of life His plea for lobe than physicists illing to allow reical literature But he carried the question much farther The inference which idely drawn by the eneuists had overestie of the cooled earth there was not time for the evolution of animals and plants to have taken place

Huxley pointed out a fact which should be quite obvious, but which even yet is frequently neglected The evidence for the gradual appearance of life in the past history of the earth depends simply on the fact that the successive forth of tith of time which was taken up by the for the evolution of life, made plain by fossil records, to have taken place very slowly is that geologists have stated that the deposition of the strata took place very slowly Whether these strata were deposited slowly or less sloe know that the fory takes her ti in the slow rate of change in living forh a series of deposits which, geology inforical clock is wrong, all the naturalist will have to do is to ly; and I venture to point out that, e are told that the lis have inhabited this planet to one, two, or three hundred ical speculation, the _onus probandi_ rests on the s forward not a shadow of evidence in its support”

Perhaps, although this is now an old controversy, it is worth while to recall that the keenness of Huxley's language was not directed against Sir William Thomson, bethoue out an interesting scientific question upon which their conclusions differed, but between Huxley and those outsiders ere always ready to turn any dubious question in science into an argueneral conclusions of science

The last tiical Society was in 1870, and he occupied his Presidential address by a review of the ”old judgiven in the course of his first address in 1862 The address was entitled ”Palaeontology and Evolution,” and the most important part of it was a coy would not supply definite evidence of the transformation of species

Important discoveries had coher vertebrates, he declared that, however one ht ”sift and criticise them,” they left a clear balance in favour of the doctrine of the evolution of living forms one frouainst a conclusion for which he hoped aluments apparently favourable to what he expected to be true, Huxley made an important distinction, the value of which becooes on In the first flush of enthusiasists allowed their zeal to outrun discretion in the for or extinct creatures, and so soon as they found gradations of structure present, they arranged their specimens in a linear series, from the siement was a representation of the family tree The fact that the line of descent apparently could have followed along the direction they suggested they were inclined to take as evidence that it had so followed Huxley made the most careful distinction bethat he called interht to be placed in linear order,

Every fossil which takes an intermediate place between forms of life already known may be said, so far as it is intermediate, to be evidence in favour of evolution, inasmuch as it shews a possible road by which evolution may have taken place But the mere discovery of such a form does not, in itself, prove that evolution took place by and through it, nor does it constitute eneral The fact that _Anoplotheridae_ are inters and ruminants does not tell us whether the rus fros, rued from some common stock

A familiar instance will make the point at issue plain Everyone knows that in many respects, in the structure of the skeleton, and the curve of the backbone, and in the developorilla and its allies, are intermediate between man and the lower monkeys In the early days of evolution it was assuorilla, etc, were therefore to be regarded as ancestors of man, and they appear as such in y We no that it is exceedingly probable that the gorilla and its allies, although truly inter a possible path of evolution from the brute to man, are not the actual ancestors of man, but cousins, descendants like man from some more or less remote coe is more and more to throw stress on the value of Huxley's distinction, and to minimise confusion between ”intermediate” and truly ancestral types

CHAPTER VI

HUXLEY AND DARWIN

Early Ideas on Evolution--Erasmus Darwin--Lamarck--Herbert Spencer--Difference between Evolution and Natural Selection--Huxley's Preparation for Evolution--The Novelty of Natural Selection--The Advantage of Natural Selection as a Working Hypothesis--Huxley's Unchanged Position with regard to Evolution and Natural Selection froether as ical work in the last chapter, it followed that we anticipated much that falls properly within this chapter The year 1859, the date of publication of _The Origin of Species_, is a momentous date in the history of this century, as it was the year in which there was given to the world a theory that not only revolutionised scientific opinion, but altered the trend of ale, and the part played in it by Huxley, it is necessary to be quite clear as to what Darwin did In the first place, he did not invent evolution The idea that all the varied structures in the world, the divergent forms of rocks and minerals and crystals, the innumerable trees and herbs that cover the face of the earth like a reat and sh the air or people the waters,--that all these had arisen by natural laws from a primitive unformed material was known to the Greeks, was developed by the Romans, and even received the approval of early Christian Fathers, rote long before the idea had been invented that the naive legends of the Old Testain of the world After a long interval, in which scientific thought was stifled by theological dogmatism, the theory of evolution, particularly in its application to ani before Darwin published _The Origin of Species_ Buffon, the great French naturalist, and Erasrandfather of Charles, had expressed in the clearest way the possibility that species had not been created independently, but had arisen from other species Lamarck had worked out a theory of descent in the fullest detail, and regarded it as the foundation of the whole science of biology He taught that the beginning of life consisted only of the simplest and lowest plants and animals; that the more complex animals and plants arose from these, and that even man himself had come from ape-like mammals He held that the course of development of the earth and of all the creatures upon it was a slow and continuous change, uninterrupted by violent revolutions He su propositions[D]:

”1 Life tends by its inherent forces to increase the volu body and of all its parts up to a limit deterive rise to new ans

”3 The developans is in proportion to their employ”

He supported especially the last two propositions by a series of examples as to the effects of use and disuse; and the iraffes had produced their long necks by continually stretching up towards the trees on which they fed, is well known to everyone However, the ingenious speculations of Lae of actual knowledge of anatomy, and lacked experimental proof He entirely failed to convince his contemporaries; and Darwin hiained nothing fros of Lamarck's book There can be little doubt but that several Continental writers, in particular Haeckel, have exaggerated Lamarck's services to the development of the idea of evolution On the other hand, Lyell, although he strongly opposed the ideas of Laressional creation due to the great Agassiz, had prepared the way for Darwin by his advocacy of natural causes and slow changes in opposition to the catastrophic and ued most strenuously in favour of evolution Thus, in an ie quoted by Mr Clodd from the _Leader_ of March 20, 1852, Spencer had written as follows:

”Those who cavalierly reject the theory of evolution, as not adequately supported by facts, seeet that their own theory is not supported by facts at all Like the iven belief, they deorous proof of any adverse belief, but assume that their own needs none Here we find, scattered over the globe, vegetable and ani to Humboldt) some 320,000 species, and of the other, some 2,000,000 species (see Carpenter); and if to these we add the nuetable species that have become extinct, we may safely esti, on the earth, at no less than ten millions Well, which is the most rational theory about these ten millions of species?

Is it most likely that there have been ten millions of special creations; or is it e of circumstances, ten millions of varieties have been produced, as varieties are being produced still? Even could the supporters of the developination of species by the process of modification is conceivable, they would be in a better position than their opponents But they can do much more than this They can shew that the process of es in all organis influences They can shew that in successive generations these changes continue, until ultimately the new conditions become the natural ones They can shew that in cultivated plants, domesticated animals, and in the several races of men, such alterations have taken place They can show that the degrees of difference so produced are often, as in dogs, greater than those on which distinctions of species have been founded They can shew, too, that the changes daily taking place in ourselves--the facility that attends long practice, and the loss of aptitude that begins when practice ceases,--the strengthening of the passions habitually gratified, and the weakening of those habitually curbed,--the develop to the use made of it--are all explicable on this principle And thus they can shew that throughout all organic nature there is at work a n as the cause of these specific differences; an influence which, though slow in its action, does, in ties--an influence which, to all appearance, would produce in the reat varieties of condition which geological records ie”

These and ether fros of the half-century before the publication of the _Origin_, show conclusively that the idea of evolution was far froh the first part of this century dissatisfaction with the doctrine of the fixity of species and of their reat contribution of Daras this: First, by his theory of natural selection, he brought together the known facts of variation, of struggle for existence, and of adaptation to varying conditions, in such a way that they provided men with a rational and known cause, a cause the operation of which could be seen, for the origin of species by in of species, he brought together not only proofs of the actual operation of natural selection, but a body of evidence in favour of the fact of evolution that was, beyond all co than had been adduced by any earlier philosophical or biological writer He convinced naturalists that evolution was by far theworld had come to be what it is, and he do world was not an insoluble probleical study, and the result of the incoation that followed the year 1859 was a continual increase of evidence in favour of the probability of evolution, until now the whole scientific world, and the majority of those who are unscientific, are content to accept evolution as the only reasonable explanation of the living world It is well to re forward the theory of struggle for existence and resulting survival of the fittest, was the actual cause of the present assured position of evolution as a first principle of science, it by no means follows that the survival of the fittest has become similarly a first principle of science At cross roads a traveller ht path from a quite unsatisfactory reason Darwin hi forward his own theory of natural selection, adencies in evolution, and at various ti the course of his life he was inclined to attach, now encies Huxley, as we shall soon come to see, never wavered in his adhesion to the facts of evolution after 1859; but, froarded natural selection as only the most probable cause of the occurrence of evolution Other naturalists, of wholand, and WK Brooks in A importance to the purely Darwinian factor of natural selection; while others again, such as Herbert Spencer in England, and the late Professor Cope and a large Aly the importance of what may be called the Lamarckian factors of evolution,--the inherited effects of increased or dians, the direct influence of the environment, and so forth From the fact that Darwin has persuaded the world of the truth of evolution, evolution is often called Darwinish scientifically inaccurate sense of the term, Huxley was a strict Darwinian, a Darwinian of the Darwinians Froh natural selection had been formulated by several writers before Darwin, and had been siin of Species_ was the foundation of the modern acceptation of evolution, and natural selection was the key-note of the origin of species, natural selection may be called Darwinism with both historical and scientific accuracy; and in this sense of the ter and broad-minded Darwinian, as far from persuaded that his tenet had athe distinctions bethat see froht worthy to be absorbed The present writer has thought it so iuish between these two sides of the word _Darwinism_, that for the sake of clearness he has stated what he believes to be the truth of Huxley's relation to Darwin before beginning detailed exposition of it

In consideration of Huxley's position before 1859, the radual preparation that it was in_ He was like an engineer boring a tunnel through a norant of how near he was to the pleasant valley on the other side; and, above all, ignorant how rapidly he was being hty excavation from the other side To use what is perhaps a more exact simile: he was like a child with half the pieces of a puzzle-ether as far as they would fit, and quite ignorant that presently the reiven hiaps he had necessarily left, and transforible whole Let us consider some of these map pieces The ultimate picture was the conception of the whole world of life, past and present, as a single faradually spreading out first into the two main branches of animals and plants, and then into the endless series of co and extinct aniether the scattered frag to see here and there whole branches, as yet separate at their lower ends, but in theeneral reseression froreatest of these branches that he had pieced together was the group of Medusae and their allies, non as Clenterates He had formed similar branches for the Molluscs and eneral lectures on the whole aniement of the main divisions, or, as he called them, _types_ He had seen in each particular branch the clearest evidence of the laws of grohich had directed its develop of gradual modifications of common typical structures, were identical in the different branches He had taken clear hold of Von Baer's conception that the younger stages of different types were es, and here and there he had es or simplest forms of his different branches, and had shown that, without co it, he was ready for the idea that just as the separate pieces could be arranged to forht cole tree And finally, in his lectures on ”Protoplasm and Cells,” and on the ”Codoms,” he had reached the conclusion that the twoworld were formed of the same stuff, displayed in identical fashi+on the elementary functions of life, and were creatures of the sa this close approach to modern conceptions, he was not an evolutionist When, in public, he expressed deliberate convictions, these convictions were against the general idea of evolution, until very shortly before 1859 In this opposition he was supported partly by the critical scepticisularly unwilling to accept any theories of any kind, but chiefly from the fact that the books of the two chief supporters of evolutionary conceptions impressed him very unfavourably Huxley writes:

”I had studied Laes_ with due care; but neither of theative and critical attitude As for the _Vestiges_, I confess that the book sihly unscientific habit of mind manifested by the writer If it had any influence on ainst evolution; and the only review I ever have qualery is one I wrote on the _Vestiges_ while under that influence With respect to the _Philosophie Zoologique_, it is no reproach to Lamarck to say that the discussion of the species question in that work, whatever ht be said for it in 1809, was e of half a century later In that interval of time, the elucidation of the structure of the lower aniiven rise to wholly new conceptions of their relations; histology and ey had been reconstituted; the facts of distribution, geological and geographical, had been prodigiously ist whose studies had carried hi, in 1850 one-half of Lauments were obsolete, and the other half erroneous or defective, in virtue of o to deal with the various classes of evidence which had been brought to light since his tiradual e of conditions--was, on the face of it, inapplicable to the whole vegetable world I do not think that any iique_ now, and who afterwards takes up Lyell's trenchant and effective criticism (published as far back as 1830) will be disposed to allot to Laical evolution than that which Bacon assigns to hienerally--_buccinator tantum_”

On the other hand, Huxley's friendshi+p with Darwin and with Lyell began to make him less certain about the fixity of species He tells us that during his first intervieith Darhich occurred soon after his return from the _Rattlesnake_, he

”expressed his belief in the sharpness of the lines of deroups and in the absence of transitional fore I was not aware at that ti over the species question; and the huentle answer, that such was not altogether his view, long haunted and puzzled ely in destroying this youthful confidence, and a letter written by Lyell and quoted by Huxley in the chapter he communicated to Darwin's _Life and Letters_, states that in April, 1856, ”when Huxley, Hooker, and Wollaston were at Darwin's last week they (all four of theainst species; further I believe, than they are prepared to go” Another quotation froin of Species_ will make it plain beyond all doubt that he was not a Darwinian before Darwin