Pioneers of Evolution from Thales to Huxley Part 9

"I think that I must have read the Vestiges (see p. 119) before I left England in 1846, but if I did the book made very little impression upon me, and I was not brought into serious contact with the 'species'

question until after 1850. At that time I had long done with the Pentateuchal cosmogony which had been impressed upon my childish understanding as Divine truth with all the authority of parents and instructors, and from which it had cost me many a struggle to get free.

But my mind was unbia.s.sed in respect of any doctrine which presented itself if it professed to be based on purely philosophical and scientific reasoning.... I had not then and I have not now the smallest _a priori_ objection to raise to the account of the creation of animals and plants given in Paradise Lost, in which Milton so vividly embodies the natural sense of Genesis. Far be it from me to say that it is untrue because it is impossible. I confine myself to what must be regarded as a modest and reasonable request for some particle of evidence that the existing species of animals and plants did originate in that way as a condition of my belief in a statement which appears to me to be highly improbable....

"And by way of being perfectly fair, I had exactly the same answer to give to the evolutionists of 1851-58. Within the ranks of the biologists of that time I met with n.o.body, except Dr. Grant, of University College, who had a word to say for Evolution, and his advocacy was not calculated to advance the cause. Outside these ranks the only person known to me whose knowledge and capacity compelled respect, and who was at the same time a thoroughgoing evolutionist, was Mr. Herbert Spencer, whose acquaintance I made, I think, in 1852, and then entered into the bonds of a friends.h.i.+p which I am happy to think has known no interruption.

Many and prolonged were the battles we fought on this topic. But even my friend's rare dialectic skill and copiousness of apt ill.u.s.tration could not drive me from my agnostic position. I took my stand upon two grounds: firstly, that up to that time the evidence in favour of trans.m.u.tation was wholly insufficient; and secondly, that no suggestion respecting the causes of the trans.m.u.tation a.s.sumed which had been made was in any way adequate to explain the phenomena. Looking back at the state of knowledge at that time, I really do not see that any other conclusion was justifiable.

"As I have already said, I imagine that most of those of my contemporaries who thought seriously about the matter were very much in my own state of mind--inclined to say to both Mosaists and Evolutionists 'A plague on both your houses!' and disposed to turn aside from an interminable and apparently fruitless discussion to labour in the fertile fields of ascertainable fact. And I may therefore further suppose that the publication of the Darwin and Wallace papers in 1858, and still more that of the Origin in 1859, had the effect upon them of the flash of light, which to a man who has lost himself in a dark night suddenly reveals a road which, whether it takes him straight home or not, certainly goes his way. That which we were looking for and could not find was a hypothesis respecting the origin of known organic forms which a.s.sumed the operation of no causes but such as could be proved to be actually at work. We wanted, not to pin our faith to that or any other speculation, but to get hold of clear and definite conceptions which could be brought face to face with facts, and have their validity tested. The Origin provided us with the working hypothesis we sought.

Moreover, it did the immense service of freeing us for ever from the dilemma--refuse to accept the creation hypothesis, and what have you to propose that can be accepted by any cautious reasoner? In 1857 I had no answer ready, and I do not think that any one else had. A year later we reproached ourselves with dulness for being perplexed by such an inquiry. My reflection, when I first made myself master of the central idea of the Origin was 'How extremely stupid not to have thought of that!' I suppose that Columbus's companions said much the same when he made the egg stand on end. The facts of variability, of the struggle for existence, of adaptation to conditions, were notorious enough, but none of us had suspected that the road to the heart of the species problem lay through them, until Darwin and Wallace dispelled the darkness, and the beacon-fire of the Origin guided the benighted."

But the disciple soon outstripped the master. As was said of Luther in relation to Erasmus, Huxley hatched the egg that Darwin laid. For in the Origin of Species the theory was not pushed to its obvious conclusion: Darwin only hinted that it "would throw much light on the origin of man and his history." His silence, as he candidly tells us in the Introduction to the Descent of Man, was due to a desire "not to add to the prejudices against his views." No such hesitancy kept Huxley silent.

In the spirit of Plato's Laws, he followed the argument whithersoever it led. In 1860 he delivered a course of lectures to working-men On the Relations of Man to the Lower Animals, and in 1862, a couple of lectures on the same subject at the Edinburgh Philosophical Inst.i.tution.

The important and significant feature of these discourses was the demonstration that no cerebral barrier divides man from apes; that the attempt to draw a psychical distinction between him and the lower animals is futile; and that "even the highest faculties of feeling and of intellect begin to germinate in lower forms of life." The lectures were published in 1863 in a volume ent.i.tled Evidence as to Man's Place in Nature; and it was with pride warranted by the results of subsequent researches that Huxley, in a letter to the writer, thus refers to the book when arranging for its reissue among the Collected Essays--

I was looking through Man's Place in Nature the other day. I do not think there is a word I need delete, nor anything I need add, except in confirmation and extension of the doctrine there laid down. That is great good fortune for a book thirty years old, and one that a very shrewd friend of mine implored me not to publish, as it would certainly ruin all my prospects.

The spa.r.s.e annotations to the whole series of reprinted matter show that the like permanence attends all his writings. And yet, true workman, with ideal ever lying ahead, as he was, he remarked to the writer that never did a book come hot from the press, but he wished that he could suppress it and rewrite it.

But before dealing with the momentous issues raised in Man's Place in Nature, we must return to 1860. For that was the "Sturm und Drang"

period. Then, at Oxford, "home of lost causes," as Matthew Arnold apostrophizes her in the Preface to his Essays in Criticism, was fought, on Sat.u.r.day, 30th of June, a memorable duel between biologist and bishop; perhaps in its issues, more memorable than the historic discussion on the traditional doctrine of special creation between Cuvier and Geoffroy Saint-Hilaire in the French Academy in 1830.

Both Huxley and Wilberforce were doughty champions. The scene of combat, the Museum Library, was crammed to suffocation. Fainting women were carried out. There had been "words" between Owen and Huxley on the previous Thursday. Owen contended that there were certain fundamental differences between the brains of man and apes. Huxley met this with "direct and unqualified contradiction," and pledged himself to "justify that unusual procedure elsewhere." No wonder that the atmosphere was electric. The bishop was up to time. Declamation usurped the vacant place of argument in his speech, and the declamation became acrid. He finished his harangue by asking Huxley whether he was related by his grandfather's or grandmother's side to an ape. "The Lord hath delivered him into my hands," whispered Huxley to a friend at his side, as he rose to reply. After setting his opponent an example in demonstrating his case by evidence which, although refuting Owen, evoked no admission of error from him then or ever after, Huxley referred to the personal remark of Wilberforce. And this is what he said--

I a.s.serted, and I repeat, that a man has no reason to be ashamed of having an ape for his grandfather. If there were an ancestor whom I should feel shame in recalling, it would be a _man_, a man of restless and versatile intellect, who, not content with an equivocal success in his own sphere of activity, plunges into scientific questions with which he has no real acquaintance, only to obscure them by an aimless rhetoric, and distract the attention of his hearers from the real point at issue by eloquent digressions, and skilled appeals to religious prejudice.

Perhaps the best comment on a piece of what is now ancient history is to quote the admissions made by Lord Salisbury--a rigid High Churchman--in his presidential address to the British a.s.sociation in this same city of Oxford in 1894--

Few now are found to doubt that animals separated by differences far exceeding those that distinguish what we know as species have yet descended from common ancestors.... Darwin has, as a matter of fact, disposed of the doctrine of the immutability of species.

Few, also, are now found to doubt not only that doctrine, but also the doctrine that all life-forms have a common origin; plants and animals being alike built-up of matter which is identical in character. This doctrine, to-day a commonplace of biology, was, thirty years ago, rank heresy, since it seemed to reduce the soul of man to the level of his biliary duct. Hence the Oxford storm was but a capful of wind compared with that which raged round Huxley's lecture on The Physical Basis of Life delivered, thus aggravating the offence, on a "Sabbath" evening in Edinburgh in 1868. People had settled down, with more or less vague understanding of the matter, into quiescent acceptance of Darwinism. And now their somnolence was rudely shaken by this Southron troubler of Israel, with his production of a bottle of solution of smelling salts, and a pinch or two of other ingredients, which represented the elementary substances entering into the composition of every living thing from a jelly-speck to man. Well might the removal of the stopper to that bottle take their breath away! Microscopists, philosophers "so-called," and clerics alike raised the cry of "gross materialism,"

never pausing to read Huxley's antic.i.p.atory answer to the baseless charge, an answer repeated again and again in his writings, as in the essay of Descartes' Discourse touching the method of using one's reason rightly, and in his Hume. In season and out of season he never wearies in insisting that there is nothing in the doctrine inconsistent with the purest idealism. "All the phenomena of Nature are, in their ultimate a.n.a.lysis, known to us only as facts of consciousness." The cyclone thus raised travelled westward on the heels of Tyndall, when in 1874 he a.s.serted the fundamental ident.i.ty of the organic and inorganic; das.h.i.+ng, as his Celtic blood stirred him, the statements with a touch of poetry in the famous phrase that "the genius of Newton was potential in the fires of the sun."

The ancient belief in "spontaneous generation," which Redi's experiments upset, was the subject of Huxley's Presidential Address to the British a.s.sociation in 1870. But while he showed how subsequent investigation confirmed the doctrine of Abiogenesis, or the non-production of living from dead matter, he made this statement in support of Tyndall's creed as to the fundamental unity of the vital and the non-vital.

"Looking back through the prodigious vista of the past, I find no record of the commencement of life, and therefore I am devoid of any means of forming a definite conclusion as to the conditions of its appearance.

Belief, in the scientific sense of the word, is a serious matter, and needs strong foundations. To say, therefore, in the admitted absence of evidence, that I have any belief as to the mode in which the existing forms of life have originated, would be using words in a wrong sense.

But expectation is permissible where belief is not; and if it were given to me to look beyond the abyss of geologically recorded time to the still more remote period when the earth was pa.s.sing through physical and chemical conditions which it can no more see again than a man can recall his infancy, I should expect to be a witness of the evolution of living protoplasm from non-living matter. I should expect to see it appear under forms of great simplicity, endowed, like existing fungi, with the power of determining the formation of new protoplasm from such matters as ammonium carbonates, oxalates, and tartrates, alkaline and earthy phosphates, and water, without the aid of light. That is the expectation to which a.n.a.logical reasoning leads me; but I beg you once more to recollect that I have no right to call my opinion anything but an act of philosophical faith."

Huxley was the Apostle Paul of the Darwinian movement, and one main result of his active propagandism was to so effectively prepare the way for the reception of the profounder issues involved in the theory of the origin of species, that the publication of Darwin's Descent of Man in 1871 created mild excitement. And the weight of his support is the greater because he never omitted to lay stress on the obscurity which still hides the causes of variation which, it must be kept in mind, natural selection cannot bring about, and on which it can only act. He insists on the non-implication of the larger theory with its subordinate parts, or with the fate of them. The "doctrine of Evolution is a generalisation of certain facts which may be observed by any one who will take the necessary trouble." The facts are those which biologists cla.s.s under the heads of Embryology and Palaeontology, to the conclusions from which "all future philosophical and theological speculations will have to accommodate themselves."

That is the direction of the revolution to which the publication of Man's Place in Nature gave impetus; and it is in the all-round application of the theory of man's descent that Huxley stands foremost, both as leader and lawgiver. Mr. Spencer has never shrunk from controversy, but he has not forsaken the study for the arena, and hence his influence, great and abiding as it is, has been less direct and personal than that of his comrade, "ever a fighter," who, in Browning's words, "marched breast forward." Man's Place in Nature was the first of a series of deliverances upon the most serious questions that can occupy the mind; and its successors, the brilliant monograph on Hume, published in 1879, and the Romanes Lecture on Evolution and Ethics, delivered at Oxford, 18th of May, 1893, are but expansions of the thesis laid down in that wonderful little volume; wonderful in the prevision which fills it, and in the justification which it has received from all subsequent research, notably in psychology.

If the propositions therein maintained are unshaken, then there is no possible reconciliation between Evolution and Theology, and all the smooth sayings in attempted harmonies between the two, of which Professor Drummond's Ascent of Man is a type, and in speeches at Church Congresses of which that delivered by Archdeacon Wilson (see p. 161) is a type, do but hypnotize the "light half-believers of our casual creeds." To some there are "signs of the times" which point to approaching acquiescence in the sentiment of Ovid, paralleled by a famous pa.s.sage in Gibbon, that "the existence of the G.o.ds is a matter of public policy, and we must believe it accordingly." It looks like the prelude to surrender of what is the cardinal dogma of Christianity when we read in the Archdeacon's address that "the theory of Evolution is indeed fatal to certain _quasi_-mythological doctrines of the Atonement which once prevailed, but it is in harmony with its spirit." For those doctrines, as the Venerable apologist may learn from the evidence in Frazer's Golden Bough (chap. iii, _pa.s.sim_), are wholly mythological, because barbaric. But, in truth, there is not a dogma of Christendom, not a foundation on which the dogma rests, that Evolution does not traverse. The Church of England adopts "as thoroughly to be received and believed," the three ancient creeds, known as the Apostles', the Athanasian, and the Nicene. There is not a sentence in any one of these which finds confirmation; and only a sentence or two that find neither confirmation nor contradiction, in Evolution.

The question, on which reams of paper have been wasted, lies in a nutsh.e.l.l. The statements in the Creeds profess to have warrant in the direct words of the Bible; or in inferences drawn from those words, as defined by the Councils of the Church. The decisions of these Councils represent the opinion of the majority of fallible men composing those a.s.semblies, and no number of fallible parts can make an infallible whole. As Selden quaintly puts it (Table Talk, x.x.x, Councils), "they talk (but blasphemously enough) that the Holy Ghost is president of their General Councils, when the truth is the odd man is still the Holy Ghost." With this same "odd man" rested the decision as to what books should be included or excluded from the collection on which the Church bases its authority and formulates its creeds. So, in the last result, both sets of questions are settled by a human tribunal employing a circular argument. But, dismissing this for the moment, let us see to what issues the controversy is narrowed, to quote Huxley's words (written in 1871), by "the spontaneous retreat of the enemy from nine-tenths of the territory which he occupied ten years ago."

The battle has no longer to be fought over the question of the fundamental ident.i.ty of the physical structure of man and of the anthropoid apes. The most enlightened Protestant divines accept this as proven; and not a few Catholic divines are adopting an att.i.tude toward it which is only the prelude to surrender. Matters must have moved apace in the Church which Huxley, backed by history, describes as "that vigorous and consistent enemy of the highest intellectual, moral, and social life of mankind," to permit the Roman Catholic Professor of Physics in the University of Notre Dame, America, to parley as follows:

"Granting that future researches in palaeontology, anthropology, and biology, shall demonstrate beyond doubt that man is genetically related to the inferior animals, and we have seen how far scientists are from such a demonstration (?), there will not be, even in such an improbable event, the slightest ground for imagining that then, at last, the conclusions of science are hopelessly at variance with the declarations of the sacred text, or the authorised teachings of the Church of Christ.

All that would logically follow from the demonstration of the animal origin of man, would be a modification of the traditional view regarding the origin of the body of our first ancestor. We should be obliged to revise the interpretation that has usually been given to the words of Scripture which refer to the formation of Adam's body, and read these words in the sense which Evolution demands, a sense which, as we have seen, may be attributed to the words of the inspired record, without either distorting the meaning of terms, or in any way doing violence to the text" (Evolution and Dogma. By the Reverend J. A. Zahm, Ph. D., C.S.C., pp. 364, 365).

Upon this suggested revision of writings which are claimed as forming part of a divine revelation, one of the highest authorities, Francisco Suarez, thus refers, in his Tractatus de Opere s.e.x Dierum, to the elastic interpretation given in his time to the "days" in the first chapter of Genesis. "It is not probable that G.o.d, in inspiring Moses to write a history of the Creation, which was to be believed by ordinary people, would have made him use language the true meaning of which it was hard to discover, and still harder to believe." Three centuries have pa.s.sed since these wise words were penned, and the reproof which they convey is as much needed now as then.

In near connection with the question of man's origin is that of his antiquity. The existence of his remains, rare as they are everywhere, in deposits older than the Pleistocene or Quaternary Epoch is not proven.

This applies to the remarkable fragments found by Dr. Dubois in Java, the character of which, in the judgment of several palaeontologists, indicates the nearest approach between man and ape hitherto discovered.

But the evidence of the physical relation of these two being conclusive, the exact place of man in the earth's time-record is rendered of subordinate importance.

The theologians have come to their last ditch in contesting that the mental differences between man and the lower animals are fundamental, being differences of kind, and therefore that no gradual process from the mental faculties of the one to those of the other has taken place.

This struggle against the application of the theory of Evolution to man's intellectual and spiritual nature will be long and stubborn. It is a matter of life and death to the theologian to show that he has in revelation, and in the world-wide belief of mankind in spiritual existences without, and in a spirit or soul within, evidence of the supernatural. The evolutionist has no such corresponding deep concern.

When the argument against him is adduced from the Bible, he can only challenge the ground on which that book is cited as divine authority, or as an authority at all. Granting, for the sake of argument, that a revelation has been made, the writings purporting to contain it must comply with the twofold condition attaching to it, namely, that it makes known matters which the human mind could not, unaided, have found out; and that it embodies those matters in language as to the meaning of which there can be no doubt whatever. If there be any sacred books which comply with these conditions, they have yet to be discovered.

When the argument against the evolutionist is drawn from human testimony, he does not dispute the existence of the belief in a soul and in all the accompanying apparatus of the supernatural; but he calls in the anthropologist to explain how these arose in the barbaric mind.

Meanwhile, let us summarize the evidence which points to the psychical unity between man and the lower life-forms. As stated on p. 187, Mr.

Herbert Spencer traces the gradual evolution of consciousness from "the blurred, indeterminate feeling which responds to a single nerve pulsation or shock." There is no trace of a nervous system in the simplest organisms, but this counts for little, because there are also no traces of a mouth, or a stomach, or limbs. In these seemingly structureless creatures every part does everything. The amoeba eats and drinks, digests and excretes, manifests "irritability," that is, responds to the various stimuli of its surroundings, and multiplies, without possessing special organs for these various functions. Division of labour arises at a slightly higher stage, when rudimentary organs appear; the development of function and organ going on simultaneously.

Speaking broadly, the functions of living things are threefold: they feed; they reproduce; they respond to their "environment," and it is this last-named function--communication with surroundings--which is the special work of the nervous system. It was an old Greek maxim that "a man may once say a thing as he would have said it: he cannot say it twice." This is the warrant for transferring a few sentences on the origin of the nerves from my Story of Creation. They are but a meagre abstract of Mr. Spencer's long, but luminous exposition of the subject.

"As every part of an organism is made up of cells, and as the functions govern the form of the cells, the origin of nerves must be due to a modification in cell shape and arrangement, whereby certain tracts or fibres of communication between the body and its surroundings are established.

"But what excited that modification? The all-surrounding medium, without which no life had been, which determined its limits, and _touches_ it at every point with its throbs and vibrations. In the beginnings of a primitive layer or skin manifested by creatures a stage above the lowest, unlikenesses would arise, and certain parts, by reason of their finer structure, would be the more readily stimulated by, and the more quickly responsive to, the ceaseless action of the surroundings, the result being that an extra sensitiveness along the lines of least resistance would be set up in those more delicate parts. These, developing, like all things else, by use, would become more and more the selected paths of the impulses, leading, as the molecular waves thrilled them, to structural changes or modification into nerve-cells, and nerve-fibres, of increasing complexity as we ascend the scale of life.

The entire nervous system, with its connections; the brain and all the subtle mechanism with which it controls the body; the organs of the senses alike begin as sacs formed by infoldings of the primitive outer skin."

Biologists are agreed that a certain stage in the organization of the nervous system--the germs of which, we saw, are visible in the quivering of an amoeba, and probably in plants as well as animals--must be reached before consciousness is manifest. Obscurity still hangs round the stage at which mere irritability pa.s.ses into sensibility, but so long as the continuity of development is clear, the gradations are of lesser importance. And, for the present purpose, there is no need to descend far in the life-scale; if the psychical connection between man and the mammals immediately beneath him is proven, the connection of the mammals with the lowest invertebrate may be a.s.sumed as also established.

Speaking only of vertebrates, the brain being, whether in fish or man, the organ of mental phenomena, how far does its structure support or destroy the theory of mental continuity? In Man's Place in Nature, and its invaluable supplement, the second part of the monograph on Hume, this subject is expounded by Huxley with his usual clearness. In the older book he traces the gradual modification of brain in the series of backboned animals. He points out that the brain of a fish is very small compared with the spinal cord into which it is continued, that in reptiles the ma.s.s of brain, relatively to the spinal cord, is larger, and still larger in birds, until among the lowest mammals, as the opossums and kangaroos, the brain is so increased in proportion as to be extremely different from that of fish, bird, or reptile. Between these marsupials and the highest or placental mammals, there occurs "the greatest leap anywhere made by Nature in her brain work." Then follows this important statement in favour of continuity.

"As if to demonstrate, by a striking example, the impossibility of erecting any cerebral barrier between man and the apes, Nature has provided us, in the latter animals, with an almost complete series of gradations from brains little higher than that of a Rodent to brains little lower than that of Man." After giving technical descriptions in proof of this, and laying special stress on the presence of the structure known as the "hippocampus minor" in the brain of man as well as of the ape--in the denial of which Owen cut such a sorry figure, Huxley adds:

"So far as cerebral structure goes, therefore, it is clear that Man differs less from the Chimpanzee or the Orang than these do even from the Monkeys, and that the difference between the brains of the Chimpanzee and of Man is almost insignificant when compared with that between the Chimpanzee brain and that of a Lemur.... Thus, whatever system of organs be studied, the comparison of their modifications in the ape series leads to one and the same result,--that the structural differences which separate Man from the Gorilla and the Chimpanzee are not so great as those which separate the Gorilla from the lower apes.

But in enunciating this important truth I must guard myself against a form of misunderstanding which is very prevalent ... that the structural differences between man and even the highest apes are small and insignificant. Let me then distinctly a.s.sert, on the contrary, that they are great and significant; that every bone of a Gorilla bears marks by which it might be distinguished from the corresponding bone of a Man; and that, in the present creation, at any rate, no intermediate link bridges over the gap between _h.o.m.o_ and _Troglodytes_. It would be no less wrong than absurd to deny the existence of this chasm; but it is at least equally wrong and absurd to exaggerate its magnitude, and, resting on the admitted fact of its existence, to refuse to inquire whether it is wide or narrow. Remember, if you will, that there is no existing link between Man and the Gorilla, but do not forget that there is a no less sharp line of demarcation, a no less complete absence of any traditional form, between the Gorilla and the Orang, or the Orang and the Gibbon."

The brains of man and ape being fundamentally the same in structure, it follows that the functions which they perform are fundamentally the same. The large array of facts mustered by a series of careful observers prove how futile is the argument which, in his pride of birth, man advances against psychical continuity. Vain is the search after boundary lines between reflex action and instinct, and between instinct and reason. Barriers there are between man and brute, for articulate speech and the consequent power to transmit experiences has set up these, and they remain impa.s.sable. "The potentialities of language, as the vocal symbol of thought, lay in the faculty of modulating and articulating the voice. The potentialities of writing, as the visual symbol of thought, lay in the hand that could draw, and in the mimetic tendency which we know was gratified by drawing as far back as the days of Quaternary man"

(Huxley's Essays on Controverted Questions, p. 47). But these specially human characteristics are no sufficing warrant for denying that the sensations, emotions, thoughts, and volitions of man vary in kind from those of the lower creation. "The essential resemblances in all points of structure and function, so far as they can be studied, between the nervous system of man and that of the dog, leave no reasonable doubt that the processes which go on in the one are just like those which take place in the other. In the dog, there can be no doubt that the nervous matter which lies between the retina and the muscles undergoes a series of changes, precisely a.n.a.logous to those which, in the man, give rise to sensation, a train of thought, and volition." This pa.s.sage occurs in Huxley's Reply to Mr. Darwin's Critics, which appeared in the Contemporary Review, 1871, and it may be supplemented by a quotation from the chapter on The Mental Phenomena of Animals in his Hume. "It seems hard to a.s.sign any good reason for denying to the higher animals any mental state or process in which the employment of the vocal or visual symbols of which language is composed is not involved; and comparative psychology confirms the position in relation to the rest of the animal world a.s.signed to man by comparative anatomy. As comparative anatomy is easily able to show that, physically, man is but the last term of a long series of forms, which lead, by slow gradations, from the highest mammal to the almost formless speck of living protoplasm, which lies on the shadowy boundary between animal and vegetable life; so, comparative psychology, though but a young science, and far short of her elder sister's growth, points to the same conclusion."

Within recent years the psychologists are doing remarkable work in attacking the problem of the mechanics of mental operations, and already in Europe and America some thirty laboratories have been started for experimental work. The subject is somewhat abstruse for detailed reference here, and it must suffice to say that the psychologist, beginning with observations upon himself, measuring, for example, "the degree of sensibility of his own eye to luminous irritations, or of his own skin to p.r.i.c.king, pa.s.ses on to like inquiry into the numerical relations between the energy of the stimuli of light, sound, and so forth, and the energy of the sensations which they arouse in the nerve-channels." An excellent summary, with references to the newest authorities on the subject, is given by Prince Kropotkin in the Nineteenth Century of August, 1896.

All this, to the superficial onlooker, seems rank materialism. But we cannot think without a brain any more than we can see without eyes, and any inquiry into the operation of the organ of thought must run on the same lines as inquiry into the operations of any other organ of the body. And the inquiry leaves us at the point whence we began in so far as any light is thrown on the connection between the molecular vibrations in nerve-tissue and the mental processes of which they are the indispensable accompaniment. Changes take place in some of the thousands of millions of brain-cells in every thought that we think, and in every emotion that we feel, but the nexus remains an impenetrable mystery. Nevertheless, if we may not say that the brain secretes thought as we say that the liver secretes bile, we may also not say that the mind is detachable from the nervous system, and that it is an ent.i.ty independent of it. Were it this, not only would it stand outside the ordinary conditions of development, but it would also maintain the equilibrium which a dose of narcotics or of alcohol, or which starvation and gorging alike rapidly upset.

In his posthumous essay On the Immortality of the Soul, Hume says: "Matter and spirit are at bottom equally unknown, and we cannot determine what qualities inhere in the one or in the other." That is the conclusion to which the wisest come. And in the ultimate correlation of the physical and psychical lies the hope of arrival at that terminus of unity which was the dream of the ancient Greeks, and to which all inquiry makes approach. How, in these matters, philosophy is at one, is again seen in Huxley's admission that "in respect of the great problems of philosophy, the post-Darwinian generation is, in one sense, exactly where the prae-Darwinian generations were. They remain insoluble. But the present generation has the advantage of being better provided with the means of freeing itself from the tyranny of certain sham solutions."

Science explains, and, in explaining, dissipates the pseudo-mysteries by which man, in his myth-making stage, when conception of the order of the universe was yet unborn, accounted for everything. But she may borrow the Apostle's words, "Behold! I show you a mystery," and give to them a profounder meaning as she confesses that the origin and ultimate destiny of matter and motion; the causes which determine the behaviour of atoms, whether they are arranged in the lovely and varying forms which mark their crystals, or whether they are quivering with the life which is common to the amoeba and the man; the conversion of the inorganic into the organic by the green plant, and the relation between nerve-changes and consciousness; are all impenetrable mysteries.

In his speech on the commemoration of the jubilee of his Professors.h.i.+p in the University of Glasgow last year, Lord Kelvin said, "I know no more of electric and magnetic force, or of the relation between ether, electricity, and ponderable matter, or of chemical affinity than I knew and tried to teach my students of natural philosophy fifty years ago in my first session as professor."

This recognition of limitations will content those who seek not "after a sign". For others, that search will continue to have encouragement not only from the theologian, but from the pseudo-scientific who have travelled some distance with the Pioneers of Evolution, but who refuse to follow them further. In each of these there is present the "theological bias" whose varied forms are skilfully a.n.a.lyzed by Mr.

Spencer in his chapter under that heading in the Study of Sociology.

This explains the att.i.tude of various groups which are severally represented by Mr. St. George Mivart, and the late Dr. W. B. Carpenter; by Professor Sir Geo. G. Stokes, and Mr. Alfred Russel Wallace. The first-named is a Roman Catholic; the second was a Unitarian; the third is an orthodox Churchman, and the fourth, as already seen, is a Spiritualist. In his Genesis of Species, Mr. Mivart contends that "man's body was evolved from pre-existing material (symbolised by the term 'dust of the earth'), and was therefore only derivatively created, i. e., by the operation of secondary laws," but that "his soul, on the other hand, was created in quite a different way ... by the direct action of the Almighty (symbolised by the term breathing)," p. 325. In his Mental Physiology, Dr. Carpenter postulates an Ego or Will which presides over, without sharing in, the causally determined action of the other mental functions and their correlated bodily processes; "an ent.i.ty which does not depend for its existence on any play of physical or vital forces, but which makes these forces subservient to its determinations"

(p. 27). Professor Mivart actually cites St. Augustine and Cardinal Newman as authorities in support of his theory of the special creation of the soul. He might with equal effect subpoena Dr. Joseph Parker or General Booth as authorities. Dr. Carpenter argued as became a good Unitarian. In his Gifford Lectures on Natural Theology, Professor Stokes a.s.serts, drawing "on sources of information which lie beyond man's natural powers," in other words, appealing to the Bible, that G.o.d made man immortal and upright, and endowed him with freedom of the will. As, without the exercise of this, man would have been as a mere automaton, he was exposed to the temptation of the devil, and fell. Thereby he became "subject to death like the lower animals," and by the "natural effect of heredity," transmitted the taint of sin to his offspring. The eternal life thus forfeited was restored by the voluntary sacrifice of Christ, but can be secured only to those who have faith in him. This doctrine, which is no novel one, is known as "conditional immortality."

Professor Stokes attaches "no value to the belief in a future life by metaphysical arguments founded on the supposed nature of the soul itself," and he admits that the purely psychic theory which would discard the body altogether in regard to the process of thought is beset by very great difficulties. So he once more has recourse to "sources of information which lie beyond man's natural powers." Following up certain distinctions between "soul" and "spirit" drawn by the Apostle Paul in his tripart.i.te division of man, Professor Stokes, somewhat in keeping with Dr. Carpenter, a.s.sumes an "Ego, which, on the one hand, is not to be identified with thought, which may exist while thought is in abeyance, and which may, with the future body of which the Christian religion speaks, be the medium of continuity of thought.... What the nature of this body might be we do not know; but we are pretty distinctly informed that it would be something very different from that of our present body, very different in its properties and functions, and yet no less our own than our present body." "Words, words, words," as Hamlet says.