How Life became Possible on the Earth
How Life became Possible on the Earth
The Earth Without Life
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FOR some decades past we have been faced with a critical difficulty at the most critical and important point in the history of the earth. In the first place, it has been definitely established that in the earlier period of its history there was no life whatever—as the word is usually understood—upon the earth, as is abundantly shown elsewhere in this work. None of the conditions that make life possible, as we know it, were satisfied. As a recent French writer has said, life is an aquatic phenomenon, absolutely incapable of existence except in the presence of liquid water; and there was an age of vast duration in the history of the earth when all its water must have been in the gaseous state. Other reasons of equal cogency may be at present ignored. The broad fact is that, however widely students of this matter may differ on other points, there is absolute agreement upon the cardinal and initial fact that whereas there is life upon the earth now, there was a time when there was none.
A Gap in the Philosophy of Evolution
Now, in the ever memorable year 1859, Charles Darwin published a volume, the main thesis of which is now universally accepted, wherein the following is the last sentence: “There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.” “The Origin of Species” may be said, in a word, to establish the doctrine of the evolution of living organisms upon the earth “by laws acting around us”—to use Darwin’s own phrase. But Darwin’s work begins with and assumes the existence of life as an established planetary fact. There obviously remains a tremendous gap in the evolutionary philosophy as it stands in our statement of it thus far; and the first fact which we have to note is that the existence and recognition of this supposed gap, so far from being a matter of common recognition from the earliest times, so far from being an observation made by the critics of the doctrine of evolution, is, on the contrary, a special doctrine peculiar to scientific study and of quite recent origin, being indeed established—as was supposed—within the memory of many now living.
If we turn to the first chapter of Genesis, we shall see no suggestion or recognition of the supposed difficulty involved in the beginning of life upon the earth. In this immortal piece of ancient poetry it is stated that after the creation of the heaven and the earth, which were at first “without form and void,” God said, “Let the earth bring forth grass ... and it was so”; and later God said, “Let the waters bring forth abundantly the moving creature that hath life ... let the earth bring forth the living creature after his kind.” Here we have suggested to us the natural origin of living creatures in earth and sea under the will and direction of the Creator as conceived by the poet.
First Ideas on the Origin of LifeThe Coming of Darwin
Partly to the influence of Genesis, partly to the apparent facts of observation, and partly to the views which would naturally be held by poets and thinkers, we may attribute the belief which has been held by man, simple and philosophic alike, since first men began to think, until, we may say, the third quarter of the nineteenth century—the belief that the lowest of living things arose by a natural genesis or so-called spontaneous generation in suitable materials already provided on the land or in the sea. It was not suggested or believed that very large and conspicuous living creatures were thus bred, though it is true that the ancients thought even crocodiles to be generated by the action of the sun upon the slime of the Nile. The living creatures supposed to arise naturally in the womb of earth—the all-mother—were mostly small creatures, like insects and worms. The ordinary belief of the uninstructed to-day—a belief which they share with the greatest thinkers of antiquity and the Renaissance—is that the cheese-mite, for instance, is evolved from the substance of the cheese. Now, it is of particular moment to observe the vast contrast between the significance of this belief prior to the publication of “The Origin of Species” and its significance to-day. Before we accepted the doctrine of organic evolution, the supposed spontaneous origin of the cheese-mite in cheese, or of the maggot in putrid meat, was of no very great moment; a maggot or a cheese-mite is an extremely insignificant object. So far as the great problems of the universe are concerned, a cheese-mite, as we say, is neither “here nor there,” and its spontaneous generation was not regarded as a fact of any great moment.
But then there arose Darwin, who, in establishing the doctrine of organic evolution already supported by his own grandfather, by Lamarck, and Goethe, and Herbert Spencer, gave an entirely new importance to the question. He demonstrated how we could conceive the evolution of all organisms, including man, from a “few simple forms,” under the continuous influence of natural law; and thus such forms ceased to be insignificant, and the manner of their genesis came to be a vital problem in more senses than one. Such organisms—the mite, the maggot, and even the mould—could no longer be regarded as insignificant, for they were revealed as not unlike the ancestors of man himself.
Evolution a Continuous Process
The question of the beginning of life upon the earth had only to be satisfactorily answered for the establishment of the belief in a continuous process of evolution by natural law, even from the very beginning of the earth itself “without form and void,” until the production of the highest living organisms which it displays in our own time. And all ages, even by the mouths of their great thinkers and closest observers, had agreed in giving an apparently satisfactory answer to this question. It might well have been thought that Darwin was quite entitled to ignore altogether, as he did, the question of the origin of life. Everyone knew, so to say, that simple living organisms were every day evolved in organic refuse and elsewhere. Darwin himself, if we may judge from a casual remark in a letter, regarded the question apparently as purely speculative, and of small real moment. It is all rubbish, he says, thinking about the origin of life; we might as well argue about the origin of matter. We must beware of illegitimately attributing opinions to the immortal dead, but this remark, though a casual one, does seem to suggest that Darwin regarded these two questions as on all-fours, if not, indeed, as different forms of the same question, and that, if he had actually formulated his views, they would have taken the shape of the doctrine which asserts that life is implicit and potential in matter; in other words, that when suitable conditions arose—such, for instance, as the presence of liquid water—matter would display the properties of life.
An Abyss that could not be Bridged
Now, the remarkable fact—one of the most striking in the history of science—is that the time-honoured belief in spontaneous generation should have been attacked, and attacked with apparent success, just at the very time when it would otherwise have begun to assume real philosophic importance. For ages it had been accepted, taken as a matter of course, and not regarded as having any particular bearing upon the supreme questions. Then there came the time when this belief would have been an all-important link, without which the chain of evolution could not be completed, a link without which we were left to contemplate a perfect chain of inorganic evolution—the history of the earth before life—and a perfect chain of organic evolution—the history of life upon the earth, with an abyss between the two that could not be bridged, for how came life where there was no life? A series of experiments were made, experiments in which, strikingly enough, some of the greatest evolutionists of the day took a leading part, and these seemed to upset, just when it was most wanted by themselves for the establishment of their new doctrine, the belief which had gone without question for so many ages.
Is Life only Self-movement?
Now, some may be inclined to wonder how it should be that certain pioneers of the new doctrine of evolution, such as Tyndall and Huxley, should devote themselves with such persistence andlabour and force to the overthrow of a doctrine which was so necessary for the complete establishment of their own case—so much so, that when they had overthrown it, they found themselves, as regards their own doctrine of evolution, placed in a difficulty from which they did not live to emerge. It is my own belief that this question can be answered, and the answer is of strict relevance to our present inquiry. I believe that Huxley and Tyndall were largely impelled by the desire to oppose a doctrine of the nature of life which was current in their time and is usually called “vitalism.” We shall not begin to understand the question of the beginning of life upon the earth, as that question may be legitimately stated to-day, unless we fully realise in what terms the doctrine of spontaneous generation was accepted in the past, and an understanding of this will teach us that the present-day revival of this doctrine presents it in a form very different from that which it so long held. Our discussion must be somewhat philosophic in character, but the question at issue is a highly philosophic one, and the reason why we have made so little progress in answering it hitherto is that men of science have too frequently discussed it without paying any serious attention to the profound philosophic questions which really underlie it. We have permitted ourselves to talk freely about life and matter, whilst claiming the right to take for granted the absolute validity of our conceptions of life and our conceptions of matter.
It was universally held by those, philosophic and simple, who also held throughout so many centuries the belief in spontaneous generation, that there is an overwhelming contrast between living and lifeless matter, and it was their belief in this overwhelming contrast that led them to give to the doctrine of spontaneous generation, as they held it, a form which cannot possibly be defended. The great character of life was conceived to be self-movement, this self-movement being displayed in the matter which composed the living organisms. But it was universally held that matter, as it was seen otherwise than in living organisms, was obviously and notoriously inert, gross, brute, and dead.
The Influence of Plato
The great influence of Plato taught men to despise matter in this fashion, and there was the everyday experience that a stone lies where it is placed until something from outside moves it, being, therefore, inert, whilst a living creature such as a bird moves freely at its own will. The more strongly men held the natural matter of which the earth is composed to be inert, the more necessary was it to suppose that when life was displayed in it the difference consisted in the taking possession of this dull clay by a vital force—a mystic and wonderful principle of quickening—which endowed even gross, inert matter with activity and power. From the time of Plato until the last few years of the nineteenth century thinkers vied with one another in insisting upon the impotence and grossness and inertness of matter, and each fresh insistence upon this doctrine rendered more necessary a corresponding doctrine of vital force or vitalism, which should explain the amazing transformation undergone by, let us say, the gross and inert matter composing food, when that food was converted by the “living principle” into the tissue of a living creature, and then displayed self-movement.
Philosophy of Dead MatterThe Great Work of Pasteur
This doctrine of vitalism, which held sway for so long, was naturally invoked to explain the origin of life upon the earth, when the advance of astronomy and geology demonstrated a natural evolution for the earth and proved that there must have been a time when no life was possible upon it. The prevalent conception of matter came in at this point and denied altogether any such monstrous doctrine as that the wonderful thing called life could spontaneously arise in the despicable thing called matter. The material of the earth, whether solid, liquid or gaseous, consisted of eternal, unchangeable, and indestructible atoms. These were moved as forces from outside moved them. They had no energy or power of their own. Men simply thought of them as of incredibly minute grains of sand of various shapes and sizes, and it was as impossible to conceive of life being spontaneously generated in a chance heap of inert atoms as to conceive that a heap of grains of sand should organise themselves into a little organism. As for spontaneous generation occurring on the earth to-day, the development of mitesfrom cheese and so forth, that was a very different matter, men must have thought—in so far as they thought at all—since cheese and flesh and so forth were themselves products of life. It is well worth noting that the common doctrine of spontaneous generation was always held in reference to organic materials, such as the slime of the Nile—not the dry sand of the desert. The reader may be inclined to say that men’s beliefs on this subject in the past generation make very confused reading, and indeed, that is true. But the fact is that their beliefs were most confused. The work of Darwin had staggered everybody, and straightforward, systematic, unprejudiced thinking was very nearly impossible in the welter of controversy. Nevertheless, something apparently definite was done. The doctrine of the beginning of life upon the earth was left almost undiscussed, and the accepted notion of the nature of matter—a notion which to us who know radium seems puerile—was left unchallenged in all its falsity. But the work of the great French chemist Pasteur led to a close examination of the belief that humble forms of life are daily produced from lifeless organic materials, and the conclusion was reached that no such spontaneous generation occurs.
Every Living Thing from a Living Thing
This conclusion is of great importance in the history of modern thought, and it was proclaimed with much rejoicing and vigour as a great achievement of science, whilst some of its chief advocates seemed at times to forget the extreme awkwardness of the inferences which had to be made from it. The doctrine may be stated in Latin in the form of the familiar dogma, “Omne vivum ex vivo,” every living thing from a living thing. Just as the existence of a man is quite sufficient to prove to us the prior existence of living human parents, just as we feel sure that every beast of the field has had living parents and that every oak has sprung from an acorn developed in a previous oak, so, according to the doctrine of “Omne vivum ex vivo,” we must believe that every living creature, whether human, animal, or vegetable, whether as big as the mammoth or as small as the smallest microbe not one-twenty-thousandth part of an inch in diameter, has sprung from living parents. Nature, according to this doctrine, was divided—as Nature, being a mighty whole, can never be divided—into two absolute categories, the living and the lifeless, or living matter and dead matter. Dead matter was notoriously dead and impotent, and life could not conceivably arise in it, though it could be used by life for purposes of food. On the other hand, living matter rejoiced in the possession of all those great attributes which lifeless matter lacked, and, in accordance with the contrast between the two kinds of matter, the living could never be produced from the lifeless but only from the living: for every creature, microbe or mammoth or man, we must trace back in imagination a series of living ancestors, differing perhaps in various characters, but always living. This series must be traced back and back and back until——?
Life Evolved from the Lifeless
And there the difficulty arose. For the uninhabitableness of the primitive earth was a fact of which men of science were as certain as if from some habitable planet they had been able to gaze upon it. Notwithstanding the dogma of “Omne vivum ex vivo,” it was impossible to assert that every living creature has anendlessseries of ancestors. How, then, did life begin?
What we may call the doctrine of the older orthodoxy—the doctrine of special creation, of supernatural interposition for the introduction of a new entity into the scheme of things—offered one alternative. To accept it, however, would be to abandon the whole modern conception of natural law and of a universe which was not created once on a day, and has not been tinkered with subsequently, but from everlasting to everlasting is the continuous expression to us of the Infinite and Eternal Power which to some eyes it veils and to others it reveals. Unless we are to abandon our philosophy, this alternative cannot be accepted, and it is now accepted by no philosophic thinker.
MASTER THINKERS WHO HAVE CONTRIBUTED TO OUR KNOWLEDGE OF LIFEPhotos by Gerschel, Maull & Fox, E. Walker, London Stereoscopic, Barraud, and MillsLARGER IMAGE
MASTER THINKERS WHO HAVE CONTRIBUTED TO OUR KNOWLEDGE OF LIFE
Photos by Gerschel, Maull & Fox, E. Walker, London Stereoscopic, Barraud, and Mills
LARGER IMAGE
Thus, whether “Omne vivum ex vivo” be true or false to-day, we are compelled to accept the only other alternative, which is that it has not always been true, or, in other words, that life was spontaneously evolved from the lifeless (so-called) at some remote age in the past. Just at the present time philosophic biology is out of fashion. Minds of the great cast which endeavour to see things in their eternalaspect have been lacking to the science of life since the days when Huxley and Spencer were in the plenitude of their powers. Anyone who cares to compare the principal reviews of the last decade with those same reviews from the year of, say, 1875 to 1890, can readily see this fact for himself. In the absence of that deliberate thought and discussion without which clear ideas on any subject are impossible, what may be called the official opinion of biology at the present time is thus most remarkable and contradictory. On the one hand, it is strenuously asserted as a matter of dogma that at the present day no life is produced or producible upon the earth except by the process of reproduction of previously existing life; and on the other hand it is asserted—when the direct question is put, though otherwise the subject is simply ignored—that life must somehow or other have been naturally evolved in the past, presumably once and for all. I have called this opinion contradictory, and it is indeed far more contradictory and unsatisfactory than it may at present appear. The obvious question that the critic asks is, “If then, why not now?”
“If then, why not now?”Is Life Now Arising from the Lifeless?
The answer alleged is that, of course, the experiments of Pasteur and Tyndall, to which some reference must afterwards be made here, merely demonstrated the impossibility of the spontaneous generation of life in our own day or under any conditions similar to those of our own day; but doubtless the first few simple forms of living matter arose by natural processes at some distant epoch “when the conditions were very different from those that obtain to-day.” Now it happens to be true that every difference between past and present conditions which physics and geology and chemistry can assert tends to the probability that if spontaneous generation is impossible now, it must have been a hundredfold more impossible a hundred million years ago. Yet for some three decades the great majority of biologists have been content to believe that spontaneous generation is impossible now, even though land and sea and sky are packed with organic matter under the very conditions which obviously favour life—as the all but omnipresence of life abundant to-day demonstrates—but that spontaneous generation was possible in the past when, by the hypothesis, there was no organic matter present at all, and when life had to arise in the union and architecture of such simple substances as inorganic carbonates! Such biologists are like those who know that the human organism can be developed from the microscopic germ in a few years, but find it incredible that man can have been developed from lowly organisms in æons of æons. Nor has any living biologist even attempted to make an adequate answer to the question, why what is impossible now should have been possible a hundred million years ago. On the contrary, so soon as the matter is looked at philosophically, we see that all the probabilities, all the analogies, all the great generalisations of science, are in favour of the belief that life must be arising from the lifeless now, as in the past, whenever certain conditions, such as the assemblage of carbon, oxygen, nitrogen and hydrogen in the presence of liquid water, are satisfied.
For the moment, however, I propose to postpone this question of the truth of “Omne vivum ex vivo” at the present day, for I desire to throw into the forefront of my argument two quite recent developments of science, unreckoned with because non-existent in the controversy of the ’seventies, and in my judgment not yet duly appraised to-day. In the present and future discussion of the manner and causation of that supreme event in the earth’s history, the beginning of life upon it, we must reckon with two new orders of inquiry relating to facts unthinkably contrasted in physical magnitude yet equally relevant to our subject. The first series of facts with which I will deal areastronomic, and the secondatomic.
The Evidence from Other WorldsVegetable Life on Mars
In discussing the origin of life upon the earth, we of the twentieth century must recognise such facts as may be obtainable in regard to life upon other orbs than ours. Now, in the first place, there is at least one illustrious contemporary astronomer, Professor Pickering, the chief living student of the moon, in whose opinion there are many evidences upon our satellite of the action of vegetation, either past or present. This, of course, is not the place for a discussion of that evidence; it is, however, the place to record the most highly qualified opinion at presentobtainable, and to remind ourselves of the certainty that when the moon was first borne—or born—from the earth, life cannot possibly have been evolved, since the conditions of temperature alone, to name one factor, were such as life could not sustain, no liquid water being extant. There is some reason to suppose, then, that, whatever the present case may be, life was at one time spontaneously evolved upon the moon.
The second piece of astronomical evidence relevant to our inquiry is afforded by the planet Mars. This, of course, is a much controverted question, which cannot receive any discussion here. It suffices to note that Professor Lowell, who is admittedly the greatest living authority on Mars, has observed and photographed, not merely to his own satisfaction, but to that of an ever increasing number of astronomers, signs of vegetation upon Mars. I will say nothing here as to the existence of intelligent beings there. That fascinating and momentous question, upon which there will doubtless be difference of opinion for some time to come, does not now concern us. It is of quite sufficient significance for our present purpose if the existence of merely vegetable life, and no more, upon the planet Mars can be demonstrated, and there are now very few astronomers indeed who question this demonstration, however chary they may be of going any further. I submit that the question of the beginning of life upon the earth should not be considered without reference to the evidence which suggests the spontaneous origin of life upon the moon, and to the practically positive demonstration of the present existence, with seasonal alternations, as on our own earth, of vegetable life in the watered areas of Mars.
The Earth’s Crumbling “Foundations”
These considerations were entirely unknown to the great controversialists of a generation ago; but there is another order of facts, entirely unimagined by them, which are now demonstrable and admitted. For them, or for most of them, the ancient conception of matter which we trace to Plato was substantially true; nay, more. The recent work of the physicists and chemists had endowed that ancient conception of matter as gross and inert and dead with a new concreteness and vividness. One of the greatest physicists of the age, James Clerk-Maxwell, in his famous address to the British Association, spoke of atoms as the “foundation stones of the visible universe, which have existed since the creation unbroken and unworn.” The accepted conception of an atom was that of a passive thing; it had its own inherent shape and properties, which were impressed upon it at its creation. It had “the stamp of the manufactured article,” as Sir John Herschell said, and throughout its endless history it responded to and behaved under the influence of external forces in due accordance with its shape and size. But it was unchangeable, inert and brute, the sport of its surroundings, like the mote in the sun-beam.
Immeasurable Ocean of Energy
But to-day we stand amazed at such conceptions. We have learnt that within the atoms of matter there is a fund of energy so incalculably vast that the sum total of all the energies previously recognised, and now to be styled extra-atomic, is as nothing compared with it. This is a change indeed, that all the energies hitherto known to us should be merely the overflow trickling from the immeasurable ocean of the intra-atomic energy, the very existence of which has been formally and repeatedly denied by practically all thinkers from Plato down to our own time. Matter is not gross and inert, brute and dead. The atom, the so-called unchangeable foundation stone, is, on the contrary, itself an organism, the theatre of Titanic forces about which we at present know practically nothing except that they certainly exist, and are powerful beyond all our previous conceptions. The atom is no atom, but a microcosm; it is no more the unit of inorganic matter than the cell is really the unit of living matter.
Now it is surely evident on consideration, though the significance of the change has been ignored, that the whole discussion of the spontaneous origin or evolution of life in matter takes an entirely new shape when our old and widely erroneous conception of matter is abandoned, and a true one is substituted. Life is a marvellous and characteristic demonstration of energy. When the origin of this energy in matter was formerly discussed, we were told that the constituent parts of matter contain noenergy at all, but now we know that a quite overwhelming proportion of the sum total of universal energy is to be found there, and nowhere else. This is one of the most revolutionary advances in the whole history of thought, and its full significance has yet to be recognised.
There must also be added an essential to any future discussion of this question, the extraordinary achievement of synthetic chemistry, of which Professor Berthelot was the grand master. As long ago as 1828 it was shown that there was at least one exception to the doctrine of the vitalists, that chemical compounds characteristic of living matter cannot be built up except by the living organism. To-day chemistry has succeeded in building up alcohols, starches, sugars, and even the forerunners of the proteids themselves, from the inorganic elements in the laboratory, under the action of non-vital forces. This fact could not be reckoned with a generation ago.
Can Chemistry Build Up Life?
We are now entitled to state very briefly the sequence of events which may reasonably be imagined as culminating in the origin of life upon the earthfor the first time. Whatever we may hold as to the present, we have to recognise that the origin of life for the first time constituted a fact utterly different in certain essentials from any origin of life that may be expected to be occurring to-day. The capital fact is that in the beginning there was no organic matter to serve as food material. If ever there was a case in which it is the first step that costs, it is here. Nothing can be easier than to imagine the spontaneous origin of life in organic matter to-day, favoured with sun and water and air. The case is far different when a primary origin in inorganic matter has to be conceived. But of some things we are certain. We are certain, for instance, that so long as the earth’s surface temperature was above that of boiling water, no life was possible. It was not until the gaseous water in the atmosphere became liquefied by the lowering of the earth’s temperature that the production of life became possible. The first seas were seas of boiling water, or rather water infinitesimally below the boiling point, and we may reasonably suppose, with Buffon, that the Polar seas, being the first to cool, must have provided the first “nest” for life upon the earth. I assume, of course, that this essay will be read in conjunction with that of Professor Sollas upon the formation of the earth [page 79], and that of Dr. Wallace upon the exquisite adaptation between life and the earth to-day [page 91].
The Study of Ferments
But how were those complex organic bodies formed, especially those vastly complex proteids with which all life whatsoever, as we know it, is invariably associated? Apart from the laboratories of the synthetic chemists of to-day, these compounds are always the products of pre-existing life, and yet without them there could be no pre-existing life.
Mystery of the CellIs the Cell a Product of Evolution?
It is my belief that this most difficult question, which quite baffles us, will seem simple and straightforward in another generation, when science has devoted itself on a large scale to a study now in its very infancy—I mean the study of those curious bodies which chemists call ferments. The properties of ferments are shared both by the familiar ferments, such as trypsin and pepsin, and also by certain inorganic substances, such as the metal platinum. Now, though pepsin is a product of living cells, platinum is certainly not. Altogether apart from the living world there are substances which have powers of fermentation; and ferments do not act exclusively, as is erroneously supposed, in breaking down complex compounds, but also build them up from their constituents. The powers of a ferment, moreover, are, so far as we know, inexhaustible. All life whatever is exercised by ferments, and it is true that life, chemically considered, is “a series of fermentations.” Now, there is quite recent evidence already which seems to show that certain ferments, acting in suitable material, have the power of reproducing themselves—that is to say, of converting that material into their like. These facts are highly suggestive, and it is difficult to refrain from suggesting that the gap between living and lifeless matter, which seemed so absolute to our ancestors, and which even to us, who have a new conception of matter, seems wide enough, may yet be bridged by the ferments. We are far too apt, I think, to assume that when we can see no intermediate stage there were no intermediate stages, and thus to make difficulties for ourselves. We declare that life began as a single cell, which was the starting-point of organic evolution.I myself believe rather that the cell constitutes the acme of a vast epoch of evolution, which may yet be reproduced in brief in the laboratory. Denying or declining to think of this, the biologist who knows the amazing complexity and intricacy of the architecture of the cell may well decline to believe that such a thing could spring with a single jump from inorganic matter. We preach and go on preaching that Nature does nothing by jumps, and in the same breath we declare that life began as a simple cell. In another hundred years we may begin to realise that a cell in its own measure and on its own scale is an organism, as complex and mature a product of evolution as a society, or, for the matter of that, as the atom of modern chemistry!
But the reader will legitimately declare that so long as the spontaneous generation of life to-day in the most favourable circumstances is a proved impossibility, he cannot be expected to accept the doctrine of its spontaneous origin in the past. There are signs, however, that the biologists are now beginning to listen to Dr. Charlton Bastian, the sole survivor from the great controversy of the ’seventies, whose book, “The Evolution of Life,” was published only a few months ago. Against Pasteur and Tyndall and Huxley, Dr. Bastian maintained that their experiments, asserted to be conclusive, were not conclusive—the facts observed were certainly facts, but the deductions were unwarrantable. The experiments only proved the impossibility under the experimental conditions. The difference is the difference between proving what you set out to prove, and begging the whole question. First establish conditions under which spontaneous generation is impossible, then demonstrate its non-occurrence under those conditions, and thence infer that it is impossible under any conditions.
The Creed of the Future
The student is right in declining to believe in the spontaneous beginning of life upon the earth so long as the possibility of spontaneous generation to-day is denied, but there are not a few who think that the most conservative attitude that can be adopted is one of suspended judgment.
The present philosophic tendency is undoubtedly in the direction of a return to the ancient conception that matter is not without its own degree of life, and that the distinction between the organic and the inorganic is a distinction of degree and not radical. Nature does not admit of being sorted into any of our puny categories. As the facts accumulate they point more and more definitely towards the opinion that hylozoism, or the doctrine of potential life in all matter, will be part of the scientific creed of the future.
Controversies as to the origin of life, judged in the light of this great conception, seem to become trivial if not puerile. Knowing, as we now do, that Plato’s conception of matter was as false as it possibly could be, and having had revealed to us by radio-activity the omnipresence within the very atoms of matter, of forces incessant and stupendous, we find the doctrine of vitalism, however stated, to be wholly meaningless; we find that the gap between the living and the lifeless is by no means abysmal or impassable.
How Long Has Life Existed?
And the definition of life as self-movement seems to become almost comical, for on that definition surely the whole physical universe, the only perpetual motion machine we know of, is itself alive. A discussion of this question can at the utmost only be suggestive. Very few positive assertions have been made, nor can their number be added to, in reference to a question which is bound to be asked: How long has life existed on the earth? The study of radium and its presence in the earth’s crust alone suffices to abolish altogether the old estimates, and new ones cannot yet be substituted. Only it is certain that the past history of planetary life may be far longer than any previous estimate has indicated. It now seems that the earth is not only not self-cooling, but actually self-heating, and if on the older assumption Lord Kelvin could talk of a hundred million years since, so to speak, water first became wet, and life, as we know it, possible, who shall say of how long periods we may speculate now? Meanwhile, the glass-eyed stare vacantly around them and declare that the progress of science means the destruction of the spirit of wonder and reverence. To them we reply in the words of the Earth Spirit in Goethe’s “Faust”:
“At the whirring loom of Time unawed,I weave the living garment of God.”
“At the whirring loom of Time unawed,I weave the living garment of God.”
“At the whirring loom of Time unawed,I weave the living garment of God.”
“At the whirring loom of Time unawed,
I weave the living garment of God.”
C. W. SALEEBY