Religion and Science from Galileo to Bergson

by J. C. Hardwick

Results of Lyell's Theory.—Though Lyell's boldness disturbed a good many of his contemporaries, those biologists who were engaged upon seeking the origin of species were thankful to one who had removed the chief obstacle to the solution of their difficulties. They were now relieved of one embarrassment: Lyell gave them the power to draw on the Bank of Time to any extent; bankruptcy was no longer possible.[37]

Indeed, Lyell seems himself to have been convinced of the evolutionary origin of species (though the mode of its operation still remained a mystery for him no less than for the biologists themselves). In fact, it became quite evident that the idea of "continuity" which the Principles of Geology had established in the inorganic world, must be equally applicable to the organic world.

Darwin.—The theory of a common descent of species had occurred, as early as 1837, to an enthusiastic student of Lyell's writings, who was also a personal friend. Charles Darwin had collected much geological, botanical, and zoological matter on his voyage with the Beagle round the world, and continued for twenty years to accumulate an immense volume of data to substantiate a theory which had first suddenly suggested itself to him in 1838 as the result of reading for amusement Malthus' Essay on the Principle of Population.

This celebrated book, first published in 1798, had attempted to describe the forces which ensure the multiplication, or check the increase of population. The proposition laid down by Malthus was that population tends to vary with the means of subsistence. He had studied his problem from a social or political point of view, but the same principle was seen by Darwin to apply to all living creatures. Two forces are seen everywhere in conflict: (a) the luxuriant powers of reproduction possessed by and exercised by each species; (b) the difficulties and obstacles by which the species tend to be eliminated. The contest between the powers of reproduction and those of elimination—this "over-production" and "crowding-out"—is what was afterwards termed the "struggle for existence."

"Natural Selection."—Darwin's momentous theory was that this struggle, proceeding for untold ages, had resulted in the continual formation of new species. Granted that the numerous offspring of any individual member of a species tend to vary, those variations survive which happen to be best fitted to cope with the environment. These in their turn leave offspring, the variations and the selections are repeated, and so on ad infinitum; and the result is that entirely new species are formed by a long process of insignificant changes. This, briefly put, is the celebrated theory of "Natural Selection."

The habit of scientific caution was characteristic of Darwin, who at first would not write down "even the briefest sketch" of his hypothesis, but devoted nearly twenty years to the accumulation of evidential data. His friends continually warned him that he would be forestalled, and this actually occurred, as is well known, in 1858, when the book which was to give the new theory to the world was already half written. The naturalist, Alfred Russell Wallace, on a collecting expedition in the East Indies, "in a flash of insight" while sick with fever, found the same solution of the mystery that had puzzled biologists so long. Wallace's letter to Darwin, containing the abstract of his theory, came "like a bolt from the blue."

The behaviour of the two men was worthy of the highest traditions of scientific research. The matter was put into the hands of Lyell, and Wallace's paper, together with certain extracts from Darwin's unpublished notes, were read before the Linnean Society, and the preparation of Darwin's book was hurried on. In November, 1859, The Origin of Species was published.

Results of Darwin's Theory.—The importance (for the general trend of thought) of this joint achievement of Darwin and Wallace was considerable, and could not but be regarded as an extension of the mechanical theory. The origin of species might still to some extent remain mysterious (for "natural selection" was soon realised to be only one of many factors at work in evolution), yet the area of mystery was patently reduced, and the "inexplicable" driven further back. A formula had been provided, which seemed to be as valid, and likely to prove as permanent and fruitful in biological research as Newton's law of gravity had been in the realm of physics.

In point of fact, Darwin had only substituted new problems of "variation" and "heredity" for the old one of the diversity of species; but an impression was created by the new discoveries that a purely mechanical explanation of the origin of life and even of mind was within reach.

The Descent of Man.—With regard to "mind," the impression was re-inforced by Darwin's next book—the Descent of Man, where the gap between man and the animals was finally bridged. The work was merely an extension of the principles previously applied by him, and as a theory it had been present to Darwin's mind as far back as 1837. As soon as he had become "convinced that species were mutable productions," he could not "avoid the belief that man must come under the same law."[38] Indeed the Descent was nothing more than a corollary to the Origin of Species. The earlier work contains the whole of Darwinism.