The Pamphlet Collection of Sir Robert Stout: Volume 31
Evidences of Evolution.—I
Evidences of Evolution.—I.
The Untenable Hypotheses.
The Problem of the World's Origin—Three Hypotheses to Account for it—the Hypothesis of its Eternal Existence, the Miltonic Hypothesis; and the Hypothesis of Evolution—Testimonial Evidence Impossible; Circumstantial Evidence of the Highest Value—Geological Proof that the First and Second Hypotheses are Untenable.
To say that a crowded audience greeted Professor Thomas H. Huxley at Chickering Hall on the night of September 18, is to do injustice to the fact. The entrance was thronged at an early hour, and the only consolation of the people who were jammed together in front of the ticket office was that it was a highly respectable crush. Large numbers had evidently deferred the purchase of tickets until the last moment. The trouble was not ended when, after undergoing the last extremity of squeezing, the ticket office was reached and the purchase made. It was quite as difficult to get out from the crowd below as it was to get into it. Not a few agile gentlemen took the alternative of climbing up the sides of the stairs to join the happier throng that they had been long envying—the people that had bought their tickets in advance and had nothing to do but to ascend to the hall.page 6
Within, every seat seemed to be taken before the lecture began, the few vacancies were filled during the first ten minutes afterward, and "wall-flowers" were packed standing behind the seats. The hall was full of familiar faces; of men eminent in the learned professions; of New York's best society. Punctual to the very minute Professor Huxley Came forward upon the platform, and was of course treated with abundant applause. He laid a copy of Milton's Paradise Lost upon the reading desk; nothing else, neither manuscript nor notes. He leaned forward slightly over the desk and began speaking in measured words and with a low tone of voice. Except sometimes to grasp the desk with both hands and lean over it more intently, he did not vary his position or make use of gestures during the lecture.
At first, Professor Huxley was not distinctly heard by the entire audience, but after the noise made by people entering had subsided, there was less difficulty in this respect. He was listened to with the closest attention throughout, and the perfect silence of the audience, except at rare intervals when applause was called forth, gave striking evidence of the interest that was taken, notwithstanding the closeness of the argument and the absence of popular features in the discourse.
Ladies and Gentlemen—We live in and form a part of a system of things of immense diversity and perplexity which we call Nature, and it is a matter of the deepest interest to all of us that we should form just conceptions of the constitution of that system and of its past history. With relation to this Universe, man is in extent little more than a mathematical point, in duration but a fleeting shadow. He is arced shaken in the winds of force; but, as Pascal long ago remarked, although a reed, he is a thinking reed, and, in virtue of that wonderful capacity of thought, he has a power of framing to himself a symbolic conception of the Universe, which, although doubtless highly imperfect, and although wholly inadequate as a picture of that great Whole, yet is sufficient to serve him as a guide-book in his practical affairs. It has taken long, indeed, and accumulations of often fruitless labour, to enable man to look steadly at the glaring phantasmagoria of Nature, to notice her fluctuations, and what is regular among her apparent irregularities; and it is only comparatively lately, within the last few centuries, that t here has emerged the conception of a pervading order and a definite force of things, which we term the course of Nature.
But out of this contemplation of Nature, and out of man's thoughts concerning her, there has in these later times arisen that conception of the constancy of Nature to which I have referred, and that at length has become the guiding conception of modern thought. It has ceased to be almost conceivable to any person who has paid attention to modern thought, that chance should have any place in the Universe, or that events should follow anything but the not twat order of cause and effect. We have come to look upon the present as the child of the past and as the parent of the future; and as we have excluded chance from any share or part in the order of things, so in the present order of Nature men have come to neglect, even as a possibility, the notion of any interference with that order; and whatever may be men's speculative notions upon these points, it is quite certain t hat every intelligent person guides his life and risks his fortune upon the belief that the order of Nature is constant, and the relation of cause to effect unchanged.
The Question a Historical One.
In fact, there is no belief which we entertain which has so complete a logical basin as that to which I have just referred. It underlies tacitly every process of reasoning; it is the foundation of every act of the will. It is based upon the broadest induction, and h is verified by the most constant, regular, and universal of inductive processes. We must recollect that any human belief, however broad its basis, however defensible it may seem, is, after all, only a probable belief, and that our broadest generalizations are simply the highest degrees of probability. Though we page 7 are quite clear about the constancy of Nature at the present time, and in the present order of things, it by no means follows necessarily that we are justified in expanding this generalization into the past, and in denying absolutely that there may have been a time when evidence did not follow a first order, when the relations of cause and effect were not fixed and definite, and when external agencies did not intervene in the general course of Nature. Cautious men will admit that such a change in the order of Nature may have been possible, just as every candid thinker will admit that there may be a world in which two and two do not make four, and in which two straight lines do not in close a space. In fact this question with which I have to deal in the three lectures I shall have the honour of delivering before you, this question as to the past order of Nature, is essentially a historical question, and it is one that must be dealt with in the same way as any historical problem.
I will, if you please, in the first place, state to you what are the views which have been entertained respecting the order of Nature in the past, and then I will consider what evidence is in our possession bearing upon the question, and by what light of criticism that evidence is to be interpreted. So far as I know, there are only three views—three hypotheses—which ever have been entertained, or which well can be entertained, respecting the past history of Nature.
Hypothesis Respecting the Order of Nature.
Upon the first of these the assumption is that the order of Nature which now obtains has always obtained; in other words, that the present course of Nature, the present order of things, has existed from all eternity. The second hypothesis is that the present state of things, the present order of Nature, has had only a limited duration, and that at some period in the past the state of things which we now know—substantially, though not of course in all its details the state of things which we now know—arose and came into existence without any precedent similar condition from which it could have proceeded. The third hypothesis also assumes that the present order of Nature has had but a limited duration, but it supposes that the present order of things proceeded by a natural process from an antecedent order, and that from another antecedent order, and so on; and that on this hypothesis the attempt to fix any limit at which we could assign the commencement of this series of changes is given up. I am very anxious that you shall realize what these three hypotheses actually mean; that is to say, what they involve, if you can imagine a spectator to have been present during the period to which they refer. On the first hypothesis, however far back in time you place that spectator, he would have seen a world, essentially similar, though not perhaps in all its details, to that which now exists. The animals which existed would be the ancestors of those which now exist, and like them; the plants in like manner would be such as we have now, and like them; and the supposition is that at however distant a period of time you place your observer, he would still find mountains, lands, and waters, with animal and vegetable products flourishing upon them and sporting in them just as he finds now. That view has been held. It was a favourite fancy of antiquity, and has survived along down towards the present day, and it is worthy of remark that it is a hypothesis which is not inconsistent with what geologists are familiar with as the doctrine of Uniformitarianism. That doctrine was held by Hutton, and in his earlier days by Lyell. For Hutton was struck by the demonstration of astronomers that the perturbations of the planetary bodies, however great they may be, yet sooner or later righted themselves, and that the solar system contained within itself a self-adjusting power by which these aberrations were cured and it brought back to an equilibrium
Hutton imagined that something of the same kind may go on in the earth, although no one recognised more clearly than he the fact that the dry land is being constantly washed down by rain and rivers and deposited in the sea, and that thus in a certain length of time, greater or shorter, the inequalities of the earth's surface must be levelled and its high lands brought down to the sea. Then, taking in account the internal forces of Nature, by which upheavals become seated and give page 8 rise to new land, these operations may naturally compensate each other, and thus substantially for any assignable time the general features of the earth might remain what they are. And inasmuch as there is no limit under these circumstances to the successive development of the animals and plants, it is clear that the logical development of this idea might lead to the conception of the eternity of the world. Not that I mean to say that either Hutton or Lyell held this conception—assuredly not; they would have been the first to repudiate it. But by the arguments they used it might have been possible to justify this hypothesis.
The Theory of Creation in Paradise Lost.
The second hypothesis is that to which I have referred as the hypothesis which supposes that this order of things had at some no very remote time a sudden origin making it such as it now is. That is the doctrine which you will find stated most fully and clearly in the immortal poem of John Milton, the English Divina Commedia, "Paradise Lost." I believe it is alone through the influence of that remarkable work, combined with daily teachings to which we have all listened in our childhood, that this hypothesis owes its general wide diffusion as one of the current beliefs of English-speaking people. If you turn to the VIIth book of "Paradise Lost," you will find there stated the theory, the hypothesis to which I refer, which is this: That this visible Universe of ours made its appearance at no great distance of time from the present day, and that the parts of which it is composed made their appearance in a certain definite order in the space of six natural days, in such a manner that in the first of these days light appeared; in the second, the firmament or sky separated the water above from the water beneath it; on the third day the waters drew away from the dry land, and from it the vast vegetable life which now exists made its appearance; that the fourth day was devoted to the apparition of the sun, the stars, the moon, and the planets; that on the fifth day aquatic animals originated within the waters; and then on the sixth day the earth gave rise to our four-footed terrestrial creatures and to all varieties of terrestrial animals except birds, which had appeared on the preceding day; and finally, man appeared upon the earth, and the work of fashioning the Universe was finished. John Milton, as I have said, leaves no doubt whatever as to how, in his judgment, these marvellous processes occurred. I doubt not that his immortal poem is familiar to all of you, but I should like to recall one passage to your minds, in order that I may be justified in what I shall have to say. Regarding the perfectly concrete, definite conception which Milton had of what he thought had been the mode of origin of the animal world, he says:—
The sixth, and of creation last, arose
With evening harps and matin; when God said,
"Let the Earth bring forth soul living in her kind,
Cattle and creeping things, and beast of the earth,
Each in their kind." The earth obey'd, and straight
Opening her fertile womb, teem'd at a birth
Innumerous living creatures, perfect forms,
Undid and full-grown; out of the ground up rose
As from his lair, the wild beast, where he wons
In forest wild, in thicket, brake, or den;
Among the trees in pairs they rose, and walk'd;
The cattle in the fields and meadows green;
Those rare and solitary, these in flocks
Pasturing at once, and in broad herds upsprung.
The grassy clods now calved; now half appears
The tawny lion, pawing to get free
His hinder parts, then springs, as broke from bonds,
And rampant shakes his blinded mane; the ounce,
The libber!, and the tiger, as the mole
Rising, the crumbled earth above them threw
In hillocks; the swift stag from under ground
Bore up his branching head; scarce from his mould
Behemoth, biggest born of earth, upheav'd
His vastness; fleeced the flocks and bleating rose
As plants; ambiguous between sea and land,
The river-horse and scaly crocodile
At once canto forth whatever creeps the ground
Insect or worm.
There is no doubt as to the meaning of that hypothesis, or as to what a man of Milton's genius expected would have been actually visible to one who could know and witness the process, the origination of living things as he describes it.
The Evolution Hypothesis.
And then comes the third hypothesis, which is the hypothesis of Evolution, and that supposes that at any given period in the past we should meet with a state of things more or less similar to the present, but less similar in proportion as we go back in time; that the physical form of the earth could be traced back in this way to a condition in which its parts were separated, as little more than & nebulous cloud making part of a whole in which we find the sun and the other planetary bodies also resolved; and that if we traced back the animal world and the vegetable world, we should find preceding what now exist animals and plants not identical with them, but like them, only increasing their differences as we go back in time, and at the same time becoming simpler and simpler, until finally we should arrive at that gelatinous mass which, so far as our present knowledge goes, is the common foundation of all life. The tendency of science is to justify the speculation that that also could be traced further back, perhaps to the general nebulous origin of matter.
The hypothesis of Evolution supposes that in all this vast progression there would be no breach of continuity, no point at which we could say "this is a natural process," and "this is not a natural process," but that the whole might be strictly compared to that wonderful series of changes which may be seen going on every day under our eye, in virtue of which there arises out of that semi-fluid, homogeneous substance which we call an egg, the complicated organisation of one of the higher animals. That, in a few words, is what is meant by the hypothesis of Evolution.
I have already suggested that in dealing with these three hypotheses, endeavouring to form a judgment as to which of them is the more worthy of belief, or whether none is worthy of belief, our condition of mind should be that suspension of judgment which is so difficult to all but trained minds—I have suggested that in dealing with these questions we should be indifferent to all a priori considerations. The question is a question of fact, historical fact. The Universe has come into existence somehow or other, and the question is whether it came into existence in one fashion, or whether it came into existence in another; and as the essential preliminary to this consideration, permit me to say two or three words as to the nature of' historical evidence, and the kinds of historical evidence. The evidence as to the occurrence of any fact in past time is of one or two kinds, which for convenience sake, I will speak of on the one hand as testimonial evidence, and on the other as circumstantial evidence. By testimonial evidence, I mean human testimony; and by circumstantial evidence, I mean evidence which is not human testimony. Let me illustrate by a familiar figure what I mean by these two kinds of evidence, and what is to be said respecting their value.
Human and Circumstantial Testimony Compared.
Suppose that a man tells you that he saw a person strike another and kill him; that is testimonial evidence of the fact of murder. But it is possible to have circumstantial evidence of the fact of murder. That is to say, you may find a man dying with a wound upon his head having exactly the form and character of the wound which is made by an axe, and with due precaution you may conclude with the utmost certainty that the man has been murdered—is dying in consequence of the violence inflicted by that implement. We are very much in the habit of considering circumstantial evidence as of less value than testimonial evidence, and it may be in many eases where the circumstances are not perfectly clear and perfectly intelligible that it is a dangerous and uncertain kind of evidence; but it must not be forgotten that in many cases it is quite as good as testimonial evidence, and that in many eases it is a great deal better than testimonial evidence. For example, take the case to which I referred just now. The circumstantial evidence is better and more convincing than the testimonial evidence, foe it is impossible under the circumstances that I have mentioned to suppose that page 10 the man had met his death from any cause but the violent blow of the axe. The circumstantial evidence in favour of a murder having been committed, in that case is as complete and as convincing as evidence can be. It is evidence which is open multitudinous doubts. He may have been actuated by malice. It has constantly happened that even an accurate man has declared a thing has happened in some particular way, when a careful analysis of the circumstantial evidence has shown that it did not happen in that way, but in some other way.
Now we must turn to our three hypotheses. Let me first direct your attention to what is to be said about the hypothesis of the eternity of this state of thins in which we now are. What will first strike you is that that is a hypothesis which, whether true or false, is not capable of verification by evidence; for in order to secure testimony to an eternity of duration you must have a eternity of witnesses or an infinity of circumstances, and neither of these are attainable, It is utterly impossible that such evidence should be carried beyond a certain point of time, and all that could be said at most would be that there was nothing to contradict the hypothesis. But when you look, not to the testimonial evidence—which might not be good for much in this case—but to the circumstantial evidence, then you find that this hypothesis is absolutely incompatible with that circumstantial evidence, and the latter is of so plain and so simple a character that it is impossible in any way to escape from the conclusions which it forces upon us.
The Order of Nature.page 11 page 12
You are, in fact, all aware that the crust of the earth, the superficial part of the earth, is not of a homogeneous character, but that it is made up of a number of beds of strata, the titles of the principal groups of which are placed upon that diagram—beds of sand, beds of stone, beds of clay, of slate, of granite, and various other materials.
On further examination it is found that these beds of solid material are of exactly the same nature as those which are at present being formed under known conditions of the surface of the earth: that that chalk, for example, which forms a great part of the cretaceous formation in some parts of the world, that that chalk is identical in its physical and chemical characters, or practically so, with a substance which is now being formed at the bottom of the Atlantic Ocean, and covers an enormous area; that other bodies of rock are comparable with the sands which are being formed upon sea-shores, packed together, and so on. Thus it comes to be certain that each of these bodies of rock, of which a total of not less than 70,000 feet is known, that all these have been deposited and formed by natural agencies, either out of the waste and washing of the dry land, or else as the product of plants and animals. Now, these rocks or strata are full of the remains of animals and plants. Countless thousands of species of animals and plants as perfectly recognizable as those which you meet with in herbaria of the present day, as the shells and remains which you pick up upon the beach—countless thousands of species of these creatures have been imbedded in the sand or mud or limestone, just as they arc being imbedded now. They furnish us with a record which cannot be subject to any misinterpretation, looking at it broadly, as to the kinds of things that have lived upon the surface of the earth during the time that is registered by this great thickness of stratified rock. The most superficial study of these remains shows us that the animals and plants which live at the present time have had only a temporary duration; that you will find them and such as they are for the most part only in that upper most strata here called post-tertiary. As you go back in time they become scantier, their places are taken by other forms more diversified, and in the Jurassic and triassic you find yet others, different from the cretaceous or tertiary, and from those of the present day, and so on as you go further and further back. Why, then, the circumstantial evidence absolutely negatives the conception of the eternity of the present condition of things. We Cat say with certainty that such has not been the course of Nature. We can say with certainty that the present condition of things has been for a comparatively short period, and that so far as animal and vegetable nature are concerned, that that has been preceded by a different condition of things. We can pursue this fact until we come to the lowest of stratified rocks, in which we lose the indications of life totally. The hypothesis of the eternity of the present condition of things may therefore be put out of court altogether.
We now come to what I would call Milton's Hypothesis—the hypothesis that the present condition of things has endured for a comparatively moderate time, and at the commencement of that time came into existence within the course of six days. I doubt not that it may have excited some surprise in your mind that I should have spoken of this as Milton's hypothesis, rather than that I should choose the terms which are much more familiar to you, such as "the doctrine of creation," or "the Biblical doctrine," or "the doctrine of Moses," all of which terms as applied to the hypothesis to which I have just referred, are certainly much more familiar to you than the title of the Miltonic hypothesis. But I have had, what I cannot but think are very weighty reasons for taking the course which I have pursued. For example, I have discarded the title of the hypothesis of creation, because my present business is not with the question as to how Nature has originated, as to the causes which have lead to her origination, but as to the manner and order of her origination. Our present inquiry is not why the objects which constitute Nature came into existence, but when they came into existence, aud in what order. This is a strictly historical page 13 question, a question its completely historical as that about the date at which the Angles and the Jutes invaded England. But the other question about creation is a philosophical question, and one which cannot be solved or approached or touched by the historical method. What we want to know is whether there is evidence in the facts, F o far as they are known, that things arose in the way described by Milton, or not; and when that question is settled, it will be time enough to inquire as to why they arose.
In the second place, I have not spoken of it as the Biblical hypothesis. It is quite true that persons as diverse in their general views as Milton the Protestant, and the Jesuit Father Suarez, agree in giving the 1st chapter of Genesis the interpretation as adopted by Milton. It is quite true that that interpretation, unless I mistake, is that which has been instilled into every one of us in our childhood; but I do not for one moment venture to say that it could properly be called the Biblical doctrine. In the first place, it is not my business to say what the Hebrew text contains, and what it does not; and in the second place, were I to say that this was the Biblical hypothesis, I should be met by the authority of many eminent scholars, to say nothing of men of science, who in recent times have absolutely denied that this doctrine is to be found in Genesis at all. If we are to listen to them, we must believe that what seem so clearly defined as days of creation—as if very great pains had been taken that there should be no mistake—that these are not days at all, but periods that we may make just as long as convenience requires. We are also to understand that it is consistent with that phraseology to believe that plants and animals may have been evolved by natural processes, lasting for millions of years, out of similar rudiments. A person who is not a Hebrew scholar can only stand by and admire the marvellous flexibility of a language which admits of such diverse interpretations. (Applause and laughter.)
Professor Huxley not an Authority on the Bible.
Assuredly in the face of such contradictory authority upon matters upon which one is competent to form no judgment, he will abstain from giving any opinion, as I do; and in the third place, I have carefully abstained from speaking of this as a Mosaic doctrine, became we are now assured upon the authority of the highest critics, and even of dignitaries in the church, that there is no evidence whatever that Moses ever wrote this chapter, or knew anything about it. I don't say—I give no opinion—it would be an impertinence on my part to volunteer an opinion upon such subject. But that being the state of opinion among the scholars and clergy, it is well for us the laity, who stand outside, to avoid entangling ourselves in such a vexed question. So, as there is a doubt, and as happily Milton leaves us no conceivable ambiguity as to what he means, I will continue to speak of it as the Miltonian hypothesis. (Applause.)
Now then we have to test that hypothesis. For my part I have no prejudice one way or the other. If there is evidence in favour of this view, I have no sort of theoretical difficulties in the way of accepting it, but there must be evidence. We men of science get an awkward habit—no I won't call it that, for it is a valuable habit—of reasoning, so that we believe nothing unless there is evidence for it, and we have a way of looking upon belief which is not based upon evidence not only as illogical, but as immoral. We will, if you phase, test this view in the light of facts, for by what. I have said you will understand that I don't propose to discuss the question of what testimonial evidence is to be adduced in favour of this view. If those, whose business it is to judge, are not united as to the authenticity of the document or the fact as to who it is bears witness, the discussion of testimonial evidence is superfluous. But one regards this less because the circumstantial evidence, if carefully considered, brings him to the conclusion that the theory is inadequate altogether, and cannot be adduced. And the considerations upon which I base that conclusion are of the simplest possible character. Whatever the liability of interpretation of Milton's views, it is quite impossible to deny that the kernel of the whole matter is a page 14 statement as to a certain order or succession of living forms. It is stated that plants, for example, made their appearance upon the third day, and not before. And you will understand that by plants was meant the plants which now live—the trees and shrubs which we now have. It is one of two things—either the existing plants have been the result of a different origination of which we have no record for supposition, or else they have arisen by that dreaded process of evolution from the original stock. And in the second place, it is clear that there was no animal life before the fourth day, and then on the fourth day marine animals and birds appeared. And, it is further clear, that terrestrial life made its appearance upon the sixth day and not before. Hence it follows that in this record, if in this large mass of circumstantial evidence as to what really has happened in the past history of the Globe—of in that we find down to a certain point indications of the existence of terrestrial animals, it is perfectly certain that all that has taken place since that time must be referred to the sixth day. In this great carboniferous formation, from whence America has derived so vast a proportion of her actual and potential wealth, in that formation and in the beds of coal which are formed from the vegetation of that period, we find abundant evidence of the existence of terrestrial animals. They have been described not only by European naturalists, but by your own naturalists. There are to be found in the coal of your own coalfields numerous insects allied to our own cockroaches. There are to be found there scorpions of large size, and so similar to existing scorpions that it requires the practical eye of the naturalist to distinguish them—and even spiders. Inasmuch as these things can be proved to have had full life in the carboniferous epoch, it is perfectly clear that if the Miltonic account is correct, those huge rocks extending from the middle of the palteozoic formations must belong to the day or period, which is termed by Milton the sixth day of the creation. But further, it is expressly stated that aquatic animals took their origin upon the fifth, and did not exist before, hence all formations in which aquatic animals can be proved to exist and therefore lived at the time these formations were deposited, all those must have been deposited during the time since the period which Milton speaks of as the fifth day. But there is absolutely no fossiliferous rock in which you do not find the remains of marine animals. The lowest forms of life in the silurian are marine animals, and if the view which is entertained by Principal Dawson and Dr. Carpenter of the eozoon be correct, if it is true that animal remains exist at a period as far antecedent to the deposit in the coal as the coal is from us, at the very bottom, in a series of stratified rock, in what are called the Laurentian strata, it follows plainly enough from this that the whole series of stratified rocks, if they are to be brought into harmony with Milton at all, must be referred to the sixth day, and we cannot hope to find the slightest trace of the work of the other days in our stratified formations. When one comes to consider this, one sees how absolutely futile are the attempts that have been made to run a parallel between the stratified rocks as we know them, mid the account which Milton gives of it. The whole series of stratified rocks must be referred to the two last periods. It is of course futile to look in carboniferous rocks in the miocene for animals, which according to the hypothesis, were of the sixth day. Not only is there this objection to any attempt to run a parallel between the Miltonic account and the actual facts, but there is further difficulty. In the Miltonic account, the order in which animals should have made their appearance in the stratified rock would be this:—Fishes, including the great whale, and birds; after that, all varieties of terrestrial animals. Nothing could be further from the facts as we find them. As a matter of fact, we know of not the slightest evidence of the existence of birds before what are there indicated (pointing to the chart), as the jurassic, and perhaps the triassic formations.
Other Failures of the Miltonic Theory.
If there were any parallel between the Miltonic account and the circumstantial evidence, we ought to have abundant evidence in the devonian, the silurian, and the carboniferous rocks. I need not tell you that this is not the ease, and that not a trace of birds makes its appearance until the far later period which I have mentioned.page 15
And again, if it be true that all varieties of fishes and the great whales and the like, made their appearance on the fifth day, then we ought to find the remains of these things in the older rocks—in those which preceded the carboniferous epoch. Fishes, it is true, we find, and numerous ones; but the great whales are absent, and the fishes are not such as now live. Not one solitary species of fish now in existence is to be found there, and hence you are introduced again to the difficulty, to the dilemma, that either the creatures which were created then, which came into existence the sixth day, were not those which are found at present, or are not the direct and immediate predecessors of those which now exist; but in that ease you must either have had a fresh species of which nothing has been said, or else the whole story must be given up as absolutely devoid of any circumstantial evidence.
I have grouped before you in a few words, some little time ago, a statement of the sum and substance of Milton's hypothesis. Let me try now to put before you, in a few words, the sum and substance of the circumstantial evidence as to the past history of the earth, which is written without the possibility of mistake, with no chance of error in the stratified rocks. What we find is, that that great series of formations represents a period of time of which our human chronologies hardly afford use unit of measure. I will not pretend to say how we ought to measure this time, in millions or in billions of years. Happily for my purpose and my argument that is wholly unessential. But that the time was enormous, was vast, there is no sort of question.
We find written upon this record, and as resulting from the simplest methods of interpretation, the conviction that all that is now dry land has once been at the bottom of the waters. If I leave out of view certain patches of metamorphosed rocks, certain volcanic products, it is perfectly certain that at a comparatively recent period of the world's history, that epoch which is written. On the chart as the cretaceous epoch—it is perfectly certain that at that time, none of the great physical features which at present mark the surface of the Globe existed. It is certain Unit the Rocky Mountains were not. It is certain t hat the Himalaya Mountains were not. It is certain that the Alps and the Pyrenees had no existence. The evidence of the simplest possible character is simply this:—We find raised up on the crags of these mountains, elevated by the forces of upheaval which have given rise to them, masses of cretaceous rock which formed the bottom of the sea before those mountains existed. It is, therefore, perfectly clear, that the elementary forces which gave rise to those mountains are subsequent to the cretaceous epoch; that the mountains themselves are largely made up of the materials deposited in the sea, which once occupied their place. We meet as we go back in time with constant alternations of sea and land, of estuary and open ocean, and in correspondence with these alterations, we meet with changes in the fauna and flora of the kind I have stated.
But none of these gives us any right to believe, no inspection of these changes gives us the slightest right to believe, that there has been any discontinuity in natural processes. There is no trace of cataclysm, of great sweeping deluge, of sudden destruction of organic life. The appearances which were formerly interpreted in that way have all been shown to be delusive as our knowledge has increased and as the blanks between the different formations have been filled up. It can now be shown that there is no absolute break between formation and formation, that there has been no sudden disappearance of all the forms of life at one time and replacement by another, but that everything has gone on slowly and gradually, that one form has died out and another has taken its place, and that thus by slow degrees one fauna has been replaced by another. So that within the whole of the immense period indicated by these stratified rocks, there is assuredly—leaving Evolution out of the question altogether—not the slightest trace of any break in the uniformity of Nature's operations, not a shadow of indication that events have followed in other than their natural and orderly sequence.page 16
That, I say, is the most natural teaching of the circumstantial evidence contained in the stratified rock. I leave you to consider how far by any ingenuity of interpretation, by any stretching of the meaning of language, this evidence can be brought into the smallest similarity with that view which I have put before yon as the Miltonic doctrine.
There remains the third hypothesis—what I have spoken of as the hypothesis of Evolution; and I propose that in lectures to come we shall consider that as carefully as we have considered the other two hypothesis. I need not tray that it is quite hopeless to look for testimonial evidence of Evolution. The very nature of the case precludes the possibility of such evidence. Our important inquiry is, what foundation circumstantial evidence lends to that hypothesis, or whether it lends any, or whether it controverts it; and I shall deal with the matter entirely as a question of history. I shall not indulge in the discussion of any speculative probabilities. I shall not attempt to show that Nature is unintelligible unless we adopt some such hypothesis—for anything I know about it it is the nature of Nature. She has often been puzzling, and I have no reason to suppose she is bound to fit herself to our notions: hut I shall deal with the matter entirely from the point of view of history, and I shall place before you three kinds of evidence entirely based upon what we know of the forms of animal life which are contained in the series of stratified rock. I shall endeavour to show you that there is one kind of evidence which is neutral, which neither helps Evolution nor is inconsistent with it, I shall then endeavour to show you that there is a second kind of evidence which indicates a strong probability in favour of Evolution but does not prove it; and, lastly, I shall endeavour to show that there is a third kind of evidence which, being as complete as any evidence which we can hope to obtain upon such a subject, and being wholly and entirely in favor of Evolution, may be fairly called demonstrative evidence of its having occurred.
But these matters, ladies and gentlemen, I propose to deal with in the next two lectures.