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A Critical Glance Into Darwin
by
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.