Chapter 12
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 zoölogic 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 formulæ, 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.
V
WHAT MAKES A POEM?
Pope said that a middling poet was no poet at all. Middling things in art or in any field of human endeavor do not arouse our enthusiasm, and it is enthusiasm that fans the fires of life. There are all degrees of excellence, but in poetry one is always looking for the best. Pope himself holds a place in English literature which he could not hold had he been only a middling poet. He is not a poet of the highest order certainly, but a poet of the third or fourth order--the poet of the reason, the understanding, but not of the creative imagination. It is wit and not soul that keeps Pope alive.
Nearly every age and land has plenty of middling poets. Probably there were never more of them in the land than there are to-day. Scores of volumes of middling verse are issued from the press every week. The magazines all have middling verse; only at rare intervals do they have something more. The May "Atlantic," for instance, had a poem by a (to me) comparatively new writer, Olive Tilford Dargan, that one would hardly stigmatize as middling poetry. Let the reader judge for himself. It is called "Spring in the Study." I quote only the second part:
"What is this sudden gayety that shakes the grayest boughs? A voice is calling fieldward--'T is time to start the ploughs! To set the furrows rolling, while all the old crows nod; And deep as life, the kernel, to cut the golden sod. The pen--let nations have it;--we'll plough a while for God.
"When half the things that must be done are greater than our art, And half the things that must be done are smaller than our heart, And poorest gifts are dear to burn on altars unrevealed, Like music comes the summons, the challenge from the weald! 'They tread immortal measures who make a mellow field!'
"The planet's rather pleasant, alluring in its way; But let the ploughs be idle and none of us can stay. Here's where there is no doubting, no ghosts uncertain stalk, A-traveling with the plough beam, beneath the sailing hawk, Cutting the furrow deep and true where Destiny will walk."
Lafcadio Hearn spoke with deep truth when he said that "the measure of a poet is the largeness of thought which he can bring to any subject, however trifling." Certainly Mrs. Dargan brings this largeness of thought to her subject. Has the significance of the plough ever before been so brought out? She makes one feel that there should be a plough among the constellations. What are the chairs and harps and dippers in comparison?
The poetry of mere talent is always middling poetry--"poems distilled from other poems," as Whitman says. The work of a genius is of a different order. Most current verse is merely sweetened prose put up in verse form. It serves its purpose; the mass of readers like it. Nearly all educated persons can turn it off with little effort. I have done my share of it myself--rhymed natural history, but not poetry. "Waiting" is my nearest approach to a true poem.