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A Critical Glance Into Darwin Post by :hlpunltd Category :Essays Author :John Burroughs Date :April 2011 Read :1686

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A Critical Glance Into Darwin

I


It is never safe to question Darwin's facts, but it is always safe to question any man's theories. It is with Darwin's theories that I am mainly concerned here. He has already been shorn of his selection doctrines as completely as Samson was shorn of his locks, but there are other phases of his life and teachings that invite discussion.

The study of Darwin's works begets such an affection for the man, for the elements of character displayed on every page, that one is slow in convincing one's self that anything is wrong with his theories. There is danger that one's critical judgment will be blinded by one's partiality for the man.

For the band of brilliant men who surrounded him and championed his doctrines--Spencer, Huxley, Lyall, Hooker, and others--one feels nothing more personal than admiration; unless the eloquent and chivalrous Huxley--the knight in shining armor of the Darwinian theory--inspires a warmer feeling. Darwin himself almost disarms one by his amazing candor and his utter self-abnegation. The question always paramount in his mind is, what is the truth about this matter? What fact have you got for me, he seems to say, that will upset my conclusion? If you have one, that is just what I am looking for.

Could we have been permitted to gaze upon the earth in the middle geologic period, in Jurassic or Triassic times, we should have seen it teeming with huge, uncouth, gigantic forms of animal life, in the sea, on the land, and in the air, and with many lesser forms, but with no sign of man anywhere; ransack the earth from pole to pole and there was no sign or suggestion, so far as we could have seen, of a human being.

Come down the stream of time several millions of years--to our own geologic age--and we find the earth swarming with the human species like an ant-hill with ants, and with a vast number of forms not found in the Mesozoic era; and the men are doing to a large part of the earth what the ants do to a square rod of its surface. Where did they come from? We cannot, in our day, believe that a hand reached down from heaven, or up from below, and placed them there. There is no alternative but to believe that in some way they arose out of the antecedent animal life of the globe; in other words that man is the result of the process of evolution, and that all other existing forms of life, vegetable and animal, are a product of the same movement.

To explain how this came about, what factors and forces entered into the transformation, is the task that Darwin set himself. It was a mighty task, and whether or not his solution of the problem stands the test of time, we must yet bow in reverence before one of the greatest of natural philosophers; for even to have conceived this problem thus clearly, and to have placed it in intelligible form before men's minds, is a great achievement.

Darwin was as far from being as sure of the truth of Darwinism as many of his disciples were, and still are. He said in 1860, in a letter to one of his American correspondents, "I have never for a moment doubted that, though I cannot see my errors, much of my book ("The Origin of Species") will be proved erroneous." Again he said, in 1862, "I look at it as absolutely certain that very much in the 'Origin' will be proved rubbish; but I expect and hope that the framework will stand."

Its framework is the theory of Evolution, which is very sure to stand. In its inception his theory is half-miracle and half-fact. He assumes that in the beginning (as if there ever was or could be a "beginning," in that sense) God created a few forms, animal and vegetable, and then left it to the gods of Evolution, the chief of which is Natural Selection, to do the rest. While Darwin would not admit any predetermining factors in Evolution, or that any innate tendency to progressive development existed, he said he could not look upon the world of living things as the result of chance. Yet in fortuitous, or chance, variation he saw one of the chief factors of Evolution.

The world of Chance into which Darwinism delivers us--what can the thoughtful mind make of it?

That life with all its myriad forms is the result of chance is, according to Professor Osborn, a biological dogma. He everywhere uses the word "chance" as opposed to law, or to the sequence of cause and effect. This, it seems to me, is a misuse of the term. Is law, in this sense, ever suspended or annulled? If one chances to fall off his horse or his house, is it not gravity that pulls him down? Are not the laws of energy everywhere operative in all movements of matter in the material world? Chance is not opposed to law, but to design. Anything that befalls us that was not designed is a matter of chance. The fortuitous enters largely into all human life. If I carelessly toss a stone across the road, it is a matter of chance just where it will fall, but its course is not lawless. Does not gravity act upon it? does not the resistance of the air act upon it? does not the muscular force of my arm act upon it? and does not this complex of physical forces determine the precise spot where the stone shall fall? If, in its fall, it were to hit a bird or a mouse or a flower, that would be a matter of chance, so far as my will was concerned. Is not a meteoric stone falling out of space acted upon by similar forces, which determine where it shall strike the earth? In this case, we must substitute for the energy of my arm the cosmic energy that gives the primal impetus to all heavenly bodies. If the falling aerolite were to hit a person or a house, we should say it was a matter of chance, because it was not planned or designed. But when the shells of the long-range guns hit their invisible target or the bombs from the airplanes hit their marks, chance plays a part, because all the factors that enter into the problem are not and cannot be on the instant accurately measured. The collision of two heavenly bodies in the depth of space, which does happen, is, from our point of view, a matter of chance, although governed by inexorable law.

The forms of inanimate objects--rocks, hills, rivers, lakes--are matters of chance, since they serve no purpose: any other form would be as fit; but the forms of living things are always purposeful. Is it possible to believe that the human body, with all its complicated mechanism, its many wonderful organs of secretion and excretion and assimilation, is any more matter of chance than a watch or a phonograph is? Though what agent to substitute for the word "chance," I confess I do not know. The short cut to an omnipotent Creator sitting apart from the thing created will not satisfy the naturalist. And to make energy itself creative, as Professor Osborn does, is only to substitute one god for another. I can no more think of the course of organic evolution as being accidental in the Darwinian sense, than I can think of the evolution of the printing-press or the aeroplane as being accidental, although chance has played its part. Can we think of the first little horse of which we have any record, the eohippus of three or four millions of years ago, as evolving by accidental variations into the horse of our time, without presupposing an equine impulse to development? As well might we trust our ships to the winds and waves with the expectation that they will reach their several ports.

Are we to believe that we live in an entirely mechanical and fortuitous world--a world which has no interior, which is only a maze of acting, reacting, and interacting of blind physical forces? According to the chance theory, the struggle of a living body to exist does not differ from the vicissitudes of, say, water seeking an equilibrium, or heat a uniform temperature.

Chance has played an important part in human history, and in all life-history--often, no doubt, the main part--since history began. It was by chance that Columbus discovered America; he simply blundered upon it. He had set out on his voyage with something quite different in view. But his ship, and the crew, and the voyage itself, were not matters of chance but of purpose.

According to the selectionists' theory, chance gave the bird its wings, the fish its fins, the porcupine its quills, the skunk its fetid secretion, the cuttlefish its ink, the swordfish its sword, the electric eel its powerful battery; it gave the giraffe its long neck, the camel its hump, the horse its hoof, the ruminants their horns and double stomach, and so on. According to Weismann, it gave us our eyes, our ears, our hands with the fingers and opposing thumb, it gave us all the complicated and wonderful organs of our bodies, and all their circulation, respiration, digestion, assimilation, secretion, excretion, reproduction. All we are, or can be, the selectionist credits to Natural Selection.

Try to think of that wonderful organ, the eye, with all its marvelous powers and adaptations, as the result of what we call chance or Natural Selection. Well may Darwin have said that the eye made him shudder when he tried to account for it by Natural Selection. Why, its adaptations in one respect alone, minor though they be, are enough to stagger any number of selectionists. I refer to the rows of peculiar glands that secrete an oily substance, differing in chemical composition from any other secretion, a secretion which keeps the eyelids from sticking together in sleep. "Behavior as lawless as snowflakes," says Whitman--a phrase which probably stuck to him from Rousseau; but are snowflakes and raindrops lawless? To us creatures of purpose, they are so because the order of their falling is haphazard. They obey their own laws. Again we see chance working inside of law.

When the sower scatters the seed-grains from his hand, he does not and cannot determine the point of soil upon which any of them shall fall, but there is design in his being there and in sowing the seed. Astronomy is an exact science, biology is not. The celestial events always happen on time. The astronomers can tell us to the fraction of a second when the eclipses of the sun and moon and the transit of the inferior planets across the sun's disk will take place. They know and have measured all the forces that bring them about. Now, if we knew with the same mathematical precision all the elements that enter into the complex of forces which shapes our lives, could we forecast the future with the same accuracy with which the astronomers forecast the movements of the orbs? or are there incommensurable factors in life?

 

II

How are we to reconcile the obvious hit-and-miss method of Nature with the reign of law, or with a world of design? Consider the seeds of a plant or a tree, as sown by the wind. It is a matter of chance where they alight; it is hit or miss with them always. Yet the seeds, say, of the cat-tail flag always find the wet or the marshy places. If they had a topographical map of the country and a hundred eyes they could not succeed better. Of course, there are vastly more failures than successes with them, but one success in ten thousand trials is enough. They go to all points of the compass with the wind, and sooner or later hit the mark. Chance decides where the seed shall fall, but it was not chance that gave wings to this and other seeds. The hooks and wings and springs and parachutes that wind-sown seeds possess are not matters of chance: they all show design. So here is design working in a hit-and-miss world.

There are chance details in any general plan. The general forms which a maple or an oak or an elm takes in the forest or in the field are fixed, but many of the details are quite accidental. All the individual trees of a species have a general resemblance, but one differs from another in the number and exact distribution of the branches, and in many other ways. We cannot solve the fundamental problems of biology by addition and subtraction. He who sees nothing transcendent and mysterious in the universe does not see deeply; he lacks that vision without which the people perish. All organic and structural changes are adaptive from the first; they do not need natural selection to whip them into shape. All it can do is to serve as a weeding-out process.

Acquired characters are not inherited, but those organic changes which are the result of the indwelling impulse of development are inherited. So dominant and fundamental are the results of this impulse that cross-breeding does not wipe them out.

 


III

While I cannot believe that we live in a world of chance, any more than Darwin could, yet I feel that I am as free from any teleological taint as he was. The world-old notion of a creator and director, sitting apart from the universe and shaping and controlling all its affairs, a magnified king or emperor, finds no lodgment in my mind. Kings and despots have had their day, both in heaven and on earth. The universe is a democracy. The Whole directs the Whole. Every particle plays its own part, and yet the universe is a unit as much as is the human body, with all its myriad of individual cells, and all its many separate organs functioning in harmony. And the mind I see in nature is just as obvious as the mind I see in myself, and subject to the same imperfections and limitations.

In following Lamarck I am not disturbed by the bogey of teleology, or the ghost of mysticism. I am persuaded that there is something immanent in the universe, pervading every atom and molecule in it, that knows what it wants--a Cosmic Mind or Intelligence that we must take account of if we would make any headway in trying to understand the world in which we find ourselves.

When we deny God it is always in behalf of some other god. We are compelled to recognize something not ourselves from which we proceed, and in which we live and move and have our being, call it energy, or will, or Jehovah, or Ancient of Days. We cannot deny it because we are a part of it. As well might the fountain deny the sea or the cloud. Each of us is a fraction of the universal Eternal Intelligence. Is it unscientific to believe that our own minds have their counterpart or their origin in the nature of which we form a part? Is our own intelligence all there is of mind-manifestation in the universe? Where did we get this divine gift? Did we take all there was of it? Certainly we did not ourselves invent it. It would require considerable wit to do that. Mind is immanent in nature, but in man alone it becomes self-conscious. Wherever there is adaptation of means to an end, there is mind.

Yet we use the terms "guidance," "predetermination," and so on, at the risk of being misunderstood. All such terms are charged with the meaning that our daily lives impart to them and, when applied to the processes of the Cosmos, are only half-truths. From our experience with objects and forces in this world, the earth ought to rest upon something, and that object upon something, and the moon ought to fall upon the earth, and the earth fall into the sun, and, in fact, the whole sidereal system ought to collapse. But it does not, and will not. As nearly as we can put it into words, the whole visible universe floats in a boundless and fathomless sea of energy; and that is all we know about it.

If chance brought us here and endowed us with our bodies and our minds, and keeps us here, and adapts us to the world in which we live, is not Chance a good enough god for any of us? Or if Natural Selection did it, or orthogenesis or epigenesis, or any other genesis, have we not in any of these found a god equal to the occasion? Darwin goes wrong, if I may be allowed to say so, when he describes or characterizes the activities of Nature in terms of our own activities. Man's selection affords no clue to Nature's selection, and the best to man is not the best to Nature. For instance, she is concerned with color and form only so far as they have survival value. We are concerned more with intrinsic values.

"Man," says Darwin, "selects only for his own good; Nature only for the good of the being which she tends." But Nature's good is of another order than man's: it is the good of all. Nature aims at a general good, man at a particular good to himself. Man waters his garden; Nature sends the rain broadcast upon the just and the unjust, upon the sea as upon the land. Man directs and controls his planting and his harvesting along specific lines: he selects his seed and prepares his soil; Nature has no system in this respect: she trusts her seeds to the winds and the waters, and to beasts and birds, and her harvest rarely fails.

Nature's methods, we say, are blind, haphazard; the wind blows where it listeth, and the seeds fall where the winds and waters carry them; the frosts blight this section and spare that; the rains flood the country in the West and the drought burns up the vegetation in the East. And yet we survive and prosper. Nature averages up well. We see nothing like purpose or will in her total scheme of things, yet inside her hit-and-miss methods, her storms and tornadoes and earthquakes and distempers, we see a fundamental benefaction. If it is not good-will, it amounts to the same thing. Our fathers saw special providences, but we see only unchangeable laws. To compare Nature's selection with man's selection is like arguing from man's art to Nature's art. Nature has no art, no architecture, no music. Her temples, as the poets tell us, are the woods, her harps the branches of the trees, her minstrels the birds and insects, her gardens the fields and waysides--all safe comparisons for purposes of literature, but not for purposes of science.

Man alone selects, or works by a definite method. Might we not as well say that Nature ploughs and plants and trims and harvests? We pick out our favorites among plants and animals, those that best suit our purpose. We go straight to our object, with as little delay and waste as possible. Not so Nature. Her course is always a round-about one. Our petty economies are no concern of hers. Our choice selection of rich milkers, prolific poultry, or heavy-fleeced sheep is with her quickly sacrificed for the qualities of strength and cunning and speed, as these alone have survival value. Man wants specific results at once. Nature works slowly to general results. Her army is drilled only in battle. Her tools grow sharper in the using. The strength of her species is the strength of the obstacles they overcome.

What is called Darwinism is entirely an anthropomorphic view of Nature--Nature humanized and doing as man does. What is called Natural Selection is man's selection read into animate nature. We see in nature what we have to call intelligence--the adaptation of means to ends. We see purpose in all living things, but not in the same sense in non-living things. The purpose is not in the light, but in the eye; in the ear, but not in the sound; in the lungs, and not in the air; in the stomach, and not in the food; in the various organs of the body, and not in the forces that surround and act upon it. We cannot say that the purpose of the clouds is to bring rain, or of the sun to give light and warmth, in the sense that we can say it is the purpose of the eyelid to protect the eye, of the teeth to masticate the food, or of the varnish upon the leaves to protect the leaves.

The world was not made for us, but we are here because the world was made as it is. We are the secondary fact and not the primary. Nature is non-human, non-moral, non-religious, non-scientific, though it is from her that we get our ideas of all these things. All parts and organs of living bodies have, or have had, a purpose. Nature is blind, but she knows what she wants and she gets it. She is blind, I say, because she is all eyes, and sees through the buds of her trees and the rootlets of her plants as well as by the optic nerves in her animals. And, though I believe that the accumulation of variations is the key to new species, yet this accumulation is not based upon outward utility but upon an innate tendency to development--the push of life, or creative evolution, as Bergson names it; not primarily because the variations are advantages, but because the formation of a new species is such a slow process, stretches over such a period of geologic time, that the slight variations from generation to generation could have no survival value. The primary factor is the inherent tendency to development. The origin of species is on a scale of time of enormous magnitude. What takes place among our domestic animals of a summer day is by no means a safe guide as to what befell their ancestors in the abysses of geologic time. It is true that Nature may be read in the little as well as in the big,--_Natura in minimis existat_,--in the gnat as well as in the elephant; but she cannot be read in our yearly calendars as she can in the calendars of the geologic strata. Species go out and species come in; the book of natural revelation opens and closes at chance places, and rarely do we get a continuous record--in no other case more clearly than in that of the horse.

The horse was a horse, from the first five-toed animal in Eocene times, millions of years ago, through all the intermediate forms of four-toed and three-toed, down to the one-toed superb creature of our own day. Amid all the hazards and delays of that vast stretch of time, one may say, the horse-impulse never faltered. The survival value of the slight gains in size and strength from millennium to millennium could have played no part. It was the indwelling necessity toward development that determined the issue. This assertion does not deliver us into the hands of teleology, but is based upon the idea that ontogeny and phylogeny are under the same law of growth. In the little eohippus was potentially the horse we know, as surely as the oak is potential in the acorn, or the bird potential in the egg, whatever element of mystery may enter into the problem.

In fields where speed wins, the fleetest are the fittest. In fields where strength wins, the strongest are the fittest. In fields where sense-acuteness wins, the keenest of eye, ears, and nose are the fittest.

When we come to the race of man, the fittest to survive, from our moral and intellectual point of view, is not always the best. The lower orders of humanity are usually better fitted to survive than the higher orders--they are much more prolific and adaptive. The tares are better fitted to survive than the wheat. Every man's hand is against the weeds, and every man's hand gives a lift to the corn and the wheat, but the weeds do not fail. There is nothing like original sin to keep a man or a plant going. Emerson's gardener was probably better fitted to survive than Emerson; Newton's butler than Newton himself.

Most naturalists will side with Darwin in rejecting the idea of Asa Gray, that the stream of variation has been guided by a higher power, unless they think of the will of this power as inherent in every molecule of matter; but guidance in the usual theological sense is not to be thought of; the principle of guidance cannot be separated from the thing guided. It recalls a parable of Charles Kingsley's which he related to Huxley. A heathen khan in Tartary was visited by a pair of proselytizing moollahs. The first moollah said, "O Khan, worship my god. He is so wise that he made all things!" Moollah Number Two said, "O Khan, worship my god. He is so wise that he makes all things make themselves!" Number Two won the day.

 


IV

How often it turns out that a man's minor works outlive his major! This is true in both literature and science, but more often in the former than in the latter. Darwin furnishes a case in the field of science. He evidently looked upon his "Origin of Species" as his great contribution to biological science; but it is highly probable that his "Voyage of the Beagle" will outlast all his other books. The "Voyage" is of perennial interest and finds new readers in each generation. I find myself re-reading it every eight or ten years. I have lately read it for the fourth time. It is not an argument or a polemic; it is a personal narrative of a disinterested yet keen observer, and is always fresh and satisfying. For the first time we see a comparatively unknown country like South America through the eyes of a born and trained naturalist. It is the one book of his that makes a wide appeal and touches life and nature the most closely.

We may say that Darwin was a Darwinian from the first,--a naturalist and a philosopher combined,--and was predisposed to look at animate nature in the way his works have since made us familiar with.

In his trip on the Beagle he saw from the start with the eyes of a born evolutionist. In South America he saw the fossil remains of the Toxodon, and observed, "How wonderful are the different orders, at the present time so well separated, blended together in the different points of the structure of the Toxodon!" All forms of life attracted him. He looked into the brine-pans of Lymington and found that water with one quarter of a pound of salt to the pint was inhabited, and he was led to say: "Well may we affirm that every part of the world is habitable! Whether lakes of brine or those subterranean ones hidden beneath volcanic mountains,--warm mineral springs,--the wide expanse and depth of the ocean,--the upper regions of the atmosphere, and even the surface of perpetual snow,--all support organic beings."

He studies the parasitical habit of the cuckoo and hits on an explanation of it. He speculates why the partridges and deer in South America are so tame.

His "Voyage of the Beagle" alone would insure him lasting fame. It is a classic among scientific books of travel. Here is a traveler of a new kind: a natural-history voyager, a man bent on seeing and taking note of everything going on in nature about him, in the non-human, as well as in the human world. The minuteness of his observation and the significance of its subject-matter are a lesson to all observers. Darwin's interests are so varied and genuine. One sees in this volume the seed-bed of much of his subsequent work. He was quite a young man (twenty-four) when he made this voyage; he was ill more than half the time; he was as yet only an observer and appreciator of Nature, quite free from any theories about her ways and methods. He says that this was by far the most important event of his life and determined his whole career. His theory of descent was already latent in his mind, as is evinced by an observation he made about the relationship in South America between the extinct and the living forms. "This relationship," he said, "will, I do not doubt, hereafter throw more light on the appearance of organic beings on our earth, and their disappearance from it, than any other class of facts."

He looked into the muddy waters of the sea off the coast of Chile, and found a curious new form of minute life--microscopic animals that exploded as they swam through the water. In South America he saw an intimate relationship between the extinct species of ant-eaters, armadillos, tapirs, peccaries, guanacos, opossums, and so on, and the living species of these animals; and he adds that the wonderful relationship in the same continent between the dead and the living would doubtless hereafter throw more light on the appearance of organic beings on our earth, and their disappearance from it, than any other class of facts.

His observation of the evidences of the rise and fall of thousands of feet of the earth along the Cordilleras leads him to make this rather startling statement: "Daily it is forced home on the mind of the geologist that nothing, not even the wind that blows, is so unstable as the level of the crust of the earth."

There is now and then a twinkle of humor in Darwin's eyes, as when he says that in the high altitude of the Andes the inhabitants recommend onions for the "puna," or shortness of breath, but that he found nothing so good as fossil shells.

Water boils at such a low temperature in the high Andes that potatoes will not cook if boiled all night. Darwin heard his guides discussing the cause. "They had come to the simple conclusion that 'the cursed pot' (which was a new one) did not choose to boil potatoes."

In all Darwin's record we see that the book of nature, which ordinary travelers barely glance at, he opened and carefully perused.

 


V

Natural Selection turns out to be of only secondary importance. It is not creative, but only confirmative. It is a weeding-out process; it is Nature's way of improving the stock. Its tendency is to make species more and more hardy and virile. The weak and insufficiently endowed among all forms tend to drop out. Life to all creatures is more or less a struggle, a struggle with the environment, with the inorganic forces,--storm, heat, cold, sterile land, and engulfing floods,--and it is a struggle with competing forms for food and shelter and a place in the sun. The strongest, the most amply endowed with what we call vitality or power to live, win. Species have come to be what they are through this process. Immunity from disease comes through this fight for life; and adaptability--through trial and struggle species adapt themselves, as do our own bodies, to new and severe conditions. The naturally weak fall by the wayside as in an army on a forced march.

Every creature becomes the stronger by the opposition it overcomes. Natural Selection gives speed, where speed is the condition of safety, strength where strength is the condition, keenness and quickness of sense-perception where these are demanded. Natural Selection works upon these attributes and tends to perfect them. Any group of men or beasts or birds brought under any unusual strain from cold, hunger, labor, effort, will undergo a weeding-out process. Populate the land with more animal life than it can support, or with more vegetable forms than it can sustain, and a weeding-out process will begin. A fuller measure of vitality, or a certain hardiness and toughness, will enable some species to hold on longer than others, and, maybe, keep up the fight till the struggle lessens and victory is won.

The flame of life is easily blown out in certain forms, and is very tenacious in others. How unequally the power to resist cold, for instance, seems to be distributed among plants and trees, and probably among animals! One spring an unseasonable cold snap in May (mercury 28) killed or withered about one per cent of the leaves on the lilacs, and one tenth of one per cent of the leaves of our crab-apple tree. In the woods around Slabsides I observed that nearly half the plants of Solomon's-seal (_Polygonatum_) and false Solomon's-seal (_Smilacina_) were withered. The vital power, the power to live, seems stronger in some plants than in others of the same kind. I suppose this law holds throughout animate nature. When a strain of any kind comes, these weaker ones drop out. In reading the stories of Arctic explorers, I see this process going on among their dog-teams: some have greater power of endurance than others. A few are constantly dropping out or falling by the wayside. With an army on a forced march the same thing happens. In the struggle for existence the weak go to the wall. Of course the struggle among animals is at least a toughening process. It seems as if the old Indian legend, that the strength of the foe overcome passes into the victor, were true. But how a new species could arrive as the result of such struggle is past finding out. Variation with all forms of life is more or less constant, but it is around a given mean. Only those acquired characters are transmitted that arise from the needs of the organism.

A vast number of changes in plants and animals are superficial and in no way vital. It is hard to find two leaves of the same tree that will exactly coincide in all their details; but a difference that was in some way a decided advantage would tend to be inherited and passed along. It is said that the rabbits in Australia have developed a longer and stronger nail on the first toe of each front foot, which aids them in climbing over the wire fences. The aye-aye has a specially adapted finger for extracting insects from their hiding-places. Undoubtedly such things are inherited. The snowshoes of the partridge and rabbit are inherited. The needs of the organism influence structure. The spines in the quills in the tails of woodpeckers, and in the brown creeper, are other cases in point. The nuthatch has no spines on its tail, because it can move in all directions, as well with head down as with head up. I have read of a serpent somewhere that feeds upon eggs. As the serpent has no lips or distendable cheeks, and as its mechanism of deglutition acts very slowly, an egg crushed in the mouth would be mostly spilled. So the eggs are swallowed whole; but in the throat they come in contact with sharp tooth-like spines, which are not teeth, but downward projections from the backbone, and which serve to break the shells of the eggs. Radical or vital variations are rare, and we do not witness them any more than we witness the birth of a new species. And that is all there is to Natural Selection. It is a name for a process of elimination which is constantly going on in animate nature all about us. It is in no sense creative, it originates nothing, but clinches and toughens existing forms.

The mutation theory of De Vries is a much more convincing theory of the origin of species than is Darwin's Natural Selection. If things would only mutate a little oftener! But they seem very reluctant to do so. There does seem to have been some mutation among plants,--De Vries has discovered several such,--but in animal life where are the mutants? When or where has a new species originated in this way? Surely not during the historic period.

Fluctuations are in all directions around a center--the mean is always returned to; but mutations, or the progressive steps in evolution, are divergent lines away from the center. Fluctuations are superficial and of little significance; but mutations, if they occur, involve deep-seated, fundamental factors, factors more or less responsive to the environment, but not called into being by it. Of the four factors in the Darwinian formula,--variation, heredity, the struggle, and natural selection,--variation is the most negligible; it furnishes an insufficient handle for selection to take hold of. Something more radical must lead the way to new species.

As applied to species, the fittest to survive is a misleading term. All are fit to survive from the fact that they do survive. In a world where, as a rule, the race is to the swift and the battle to the strong, the slow and the frail also survive because they do not come in competition with the swift and the strong. Nature mothers all, and assigns to each its sphere.

The Darwinians are hostile to Lamarck with his inner developing and perfecting principle, and, by the same token, to Aristotle, who is the father of the theory. They regard organic evolution as a purely mechanical process.

Variation can work only upon a variable tendency--an inherent impulse to development. A rock, a hill, a stream, may change, but it is not variable in the biological sense: it can never become anything but a rock, a hill, a stream; but a flower, an egg, a seed, a plant, a baby, can. What I mean to say is that there must be the primordial tendency to development which Natural Selection is powerless to beget, and which it can only speed up or augment. It cannot give the wing to the seed, or the spring, or the hook; or the feather to the bird; or the scale to the fish; but it can perfect all these things. The fittest of its kind does stand the best chance to survive.

 


VI

After we have Darwin shorn of his selection theories, what has he left? His significance is not lessened. He is still the most impressive figure in modern biological science. His attitude of mind, the problems he tackled, his methods of work, the nature and scope of his inquiries, together with his candor, and his simplicity and devotion to truth, are a precious heritage to all mankind.

Darwin's work is monumental because he belongs to the class of monumental men. The doctrine of evolution as applied to animate nature reached its complete evolution in his mind. He stated the theory in broader and fuller terms than had any man before him; he made it cover the whole stupendous course of evolution. He showed man once for all an integral part of the zooelogic system. He elevated natural history, or biology, to the ranks of the great sciences, a worthy member of the triumvirate--astronomy, geology, biology. He taught us how to cross-question the very gods of life in their council chambers; he showed us what significance attaches to the simplest facts of natural history.

Darwin impresses by his personality not less than by his logic and his vast storehouse of observations. He was a great man before he was a great natural-history philosopher. His patient and painstaking observation is a lesson to all nature students. The minutest facts engaged him. He studies the difference between the stamens of the same plant. He counted nine thousand seeds, one by one, from artificially fertilized pods. Plants from two pollens, he says, grow at different rates. Any difference in the position of the pistil, or in the size and color of the stamens, in individuals of the same species grown together, was of keen interest to him.

The best thing about Darwinism is Darwin--his candor, his patience, his simplicity, his devotion to truth, and his power of observation. This is about what Professor T. H. Morgan meant when he said: "It is the spirit of Darwinism, not its formulae, that we proclaim as our best heritage." He gave us a new point of view of the drama of creation; he gave us ideas that are applicable to the whole domain of human activities. It is true, he was not a pioneer in this field: he did not blaze the first trail through this wilderness of biological facts and records; rather was he like a master-engineer who surveys and establishes the great highway. All the world now travels along the course he established and perfected. He made the long road of evolution easy, and he placed upon permanent foundations the doctrine of the animal origin of man. He taught the world to think in terms of evolution, and he pointed the way to a rational explanation of the diversity of living forms.


(The end)
John Burroughs's essay: A Critical Glance Into Darwin

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