CHAPTER I INTRODUCTION WHAT ORGANIC EVOLUTION IS-DEFINITIONS [The following selections are representative both of the older and of the newer attitudes of thinkers on the subject of organic evolution. The earlier writers were greatly impressed with the sublimity of the idea and found it in full accord with their religious faith. The later writers are less awed by the vastness of the process and hence adopt a more completely materialistic attitude. It is not necessary, however, to discard one's religious beliefs in order to adopt a scientific attitude toward the problems of organic evolution. These points of view are well expressed in the following quotations.-ED.] "The world has been evolved, not created; it has arisen little by little from a small beginning, and has increased through the activity of the elemental forces embodied in itself, and so has rather grown than suddenly come into being at an almighty word. What a sublime idea of the infinite might of the great Architect! the Cause of all causes, the Father of all fathers, the Ens entium! For if we could compare the Infinite it would surely require a greater Infinite to cause the causes of effects than to produce the effects themselves. "All that happens in the world depends on the forces that prevail in it, and results according to law; but where these forces and their substratum, Matter, come from, we know not, and here we have room for faith."-Erasmus Darwin, as interpreted by Weismann. "When I first came to the notion, . . . . of a succession of extinction of species, and creation of new ones, going on perpetually now, and through an indefinite period of the past, and to continue for ages to come, all in accommodation to the changes which must continue in the inanimate and habitable earth, the idea struck me as the grandest which I had ever conceived, so far as regards the attributes of the Presiding Mind."-From a letter of Sir Charles Lyell to Sir John Herschel, 1836. 1 See Joseph Le Conte, Relation of Evolution to Materialism, chap. iii. From R. S. Lull, Organic Evolution (The Macmillan Company. Reprinted by permission). "It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the condition of life, and from use and disuse; a Ratio of Increase so high as to lead to a struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is a 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, while 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."-Charles Darwin, Origin of Species, concluding paragraph. "Speaking broadly we find as a fact that transmutation of species through the geologic ages has been accompanied by increasing divergence of type, by the increased specialization of certain forms, and by the closer and closer adaptation to conditions of life on the part of the forms most highly specialized, the more perfect adaptation and the more elaborate specialization being associated with the greatest variety or variation in the environment. Accepting for this process the name organic evolution, Herbert Spencer has deduced from it the general law, that as life endures generation after generation, its character, as shown in structure and function, undergoes constant differentiation and specialization. In this view, the transmutation of species is not merely an observed process, but a primitive necessity involved in the very organization of life itself."-D. S. Jordan and V. L. Kellogg, Evolution and Animal Life (1908), p. 4. "The Doctrine of Evolution is a body of principles and facts concerning the present condition and past history of the living and lifeless things that make up the universe. It teaches that natural processes have gone on in the earlier ages of the world as they do to-day, and that natural forces have ordered the production of all things about which we know."-Henry Edward Crampton, The Doctrine of Evolution (1911), p. I. "Evolution is the gradual development from the simple unorganized condition of primal matter to the complex structure of the physical universe; and in like manner, from the beginning of organic life on the habitable planet, a gradual unfolding and branching out into all the varied forms of beings which constitute the animal and plant kingdoms. The first is called Inorganic, the last Organic Evolution." -Richard Swann Lull, Organic Evolution (1917), p. 6. THE MODERN ATTITUDE AS TO THE TRUTH OF THE "Among that public which, though educated and intelligent, is not yet professionally scientific, there has been, of late, a widespread belief that naturalists have become very doubtful as to the truth of the theory of evolution and are casting about for some more satisfactory substitute, which shall better explain the infinitely varied and manifold character of the organic world. This belief is an altogether mistaken one, for never before have the students of animals and plants been so nearly unanimous in their acceptance of the theory as they are to-day. It is true that there are still some dissentient voices, as there have been ever since the publication of Darwin's 'Origin of Species,' but the whole trend of scientific opinion is strongly in favor of the evolutionary hypothesis."-William Berryman Scott, The Theory of Evolution, p. 1. "But the biological sciences were still slower [than the physical sciences] to come to their true position as dignified science. Here was the last stronghold of the supernaturalist. Thrust out from the field of 'physical science' it was in the phenomena of life that the last stand was made by those who claim that supernatural agency intervenes in nature in such a way as to modify the natural order of events. When Darwin came to dislodge them from this, their last intrenchment, there was a fight, intense and bitter, but, like all attempts to stay the progress of human knowledge, this final struggle of the supernaturalists was foredoomed to failure. The theory of evolution has taken its place beside the other great conceptions of natural relations, and largely through its establishment biology has become truly a science with a large group of phenomena consistently arranged and properly classified. The discussion which followed the publication of Darwin's 'Origin of Species' lasted for nearly a generation, but it is now practically closed, so far as any attempt to discredit evolution as a true scientific generalization is concerned. Scientists are no longer questioning the fact of evolution; they are busied rather with the attempt to further explore and more perfectly understand the operation of the factors that are at work to produce that development of animals and plants which we call organic evolution."-Maynard M. Metcalf, An Outline of the Theory of Organic Evolution (1911), pp. xxii-xxiii. "Biologists turned aside from general theories of evolution and their deductive application to special problems of descent, in order to take up objective experiments on variation and heredity for their own sake. This was not due to any doubts concerning the reality of evolution or to any lack of interest in its problems. It was a policy of masterly inactivity deliberately adopted; for further discussions concerning the causes of evolution had clearly become futile until a more adequate and critical view of existing genetic phenomena had been attained."-E. B. Wilson (address as president of the American Association for the Advancement of Science, 1914). "The theory of development, as it was revived by Darwin nearly half a century ago, is in its modern form prevailingly unhistorical. True, it has forced beneath its sceptre the methods of investigation of all the sciences which deal with the living world and to-day almost completely controls scientific thought. . . . . And yet science does not sincerely rejoice in its conquests. Only a few incorrigible and uncritically disposed optimists steadfastly proclaim what glorious progress we have made; otherwise, in scientific as in lay circles, there prevails a widespread feeling of uncertainty and doubt. Not as though the correctness of the principle of descent were seriously questioned; rather does the conviction steadily grow that it is indispensable for the comprehension of living nature, indeed selfevident."-Gustav Steinmann (translated by W. B. Scott from Die Abstammungslehre [1908], pp. 1–2). "The many converging lines of evidence point so clearly to the central fact of the origin of forms of life by an evolutionary process that we are compelled to accept this deduction, but as to almost all the essential featurcs, whether of cause or of mode, by which specific diversity has become what we perceive it to be, we have to confess an ignorance nearly total."-William Bateson, Problems of Genetics (1913), p. 248. "The demonstration of evolution as a universal law of living nature is the great intellectual achievement of the nineteenth century. Evolution has outgrown the rank of a theory, for it has won a place in natural law beside Newton's law of gravitation, and in one sense holds a still higher rank, because evolution is the universal master, while gravitation is among its many agents. Nor is the law of evolution any longer to be associated with any single name, not even with that of Darwin, who was its greatest exponent. It is natural that evolution and Darwinism should be closely connected in many minds, but we must keep clear the distinction that evolution is a law, while Darwinism is merely one of the several ways of interpreting the workings of this law. "In contrast to the unity of opinion on the law of evolution is the wide diversity of opinion on the causes of evolution. In fact, the causes of the evolution of life are as mysterious as the law of evolution is certain. Some contend that we already know the chief causes of evolution, others contend that we know little or nothing of them. In this open court of conjecture, of hypothesis, of more or less heated controversy the names of Lamarck, of Darwin, of Weismann figure prominently as leaders of different schools of opinion; while there are others, like myself, who for various reasons belong to no school, and are as agnostic about Lamarckism, as they are about Darwinism or Weismannism, or the more recent form of Darwinism, termed Mutation by De Vries. "In truth, from the period of the earlier stages of Greek thought man has been eager to discover some natural cause of evolution, and to abandon the idea of supernatural intervention in the order of nature. Between the appearance of The Origin of Species, in 1859, and the present time there have been great waves of faith in one explanation and then in another: each of these waves of confidence has ended in disappointment, until finally we have reached a stage of very general scepticism. Thus the long period of evolution, experiment, and reasoning which began with the French natural philosopher, Buffon, one hundred and fifty years ago, ends in 1916 with the general feeling that our search for causes, far from being near completion, has only just begun. |