Part 6 (1/2)

In spite of the fascination of these theories, however, Lyell was not carried away by them, and it was not for some years that he estimated them at their true value. Meanwhile the new geology made its appearance with the publication of the three volumes of his own _Principles of Geology_, between 1829 and 1833. The significance of the book for biological speculation--for theories of the origin of species--lay in its thesis that the present condition of the earth is the product of geological processes incalculably long. Hitherto the ”catastrophic theory” had been dominant--the notion that a series of immense catastrophic events (like the Deluge) had been responsible for the present condition of the earth's surface. For this Lyell subst.i.tuted his ”Evolutionary Theory,” according to which the almost invisibly slow geological processes which we may now see operating around us, are typical of the behaviour of the crust of this planet for incalculable periods of time; for even the slowest changes, if sufficient time is allowed them, are capable of producing the most stupendous results.

Lyell may be said to have extended the age of the earth _ad infinitum_.

Just as Galileo removed all barriers of s.p.a.ce, Lyell removed those of time. Their joint achievement was to present to humanity a universe infinite both in s.p.a.ce and time--a staggering conception.

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 embarra.s.sment: 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 acc.u.mulate 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 amus.e.m.e.nt 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 acc.u.mulation 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 subst.i.tuted 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.

THE POSITION REACHED.--And with the full publication of Darwin's theories a point was reached when a more or less consistently materialistic position seemed possible. The foundations of such a position had been strengthened by the scientific atomism of Dalton, and the results of German research in the field of _organic_ chemistry seemed to open up possibilities of expressing even life in terms of matter. And, finally, the evolutionary hypothesis had reduced some of the most obscure biological problems to manageable proportions. The prospects for a purely naturalistic philosophy were phenomenally bright.

CHAPTER IX

MATERIALISM AND AGNOSTICISM

FROM SCIENCE TO PHILOSOPHY.--The record of certain important scientific discoveries has occupied us in two recent chapters, and it is now time to examine the philosophic results that were drawn from them. It is true that the generalisations drawn from the results of scientific research were sometimes hasty, and not always sanctioned by the gifted minds to whom these results were due; yet they were a.s.sured a popular reception, and exercised an immense influence. It is not always the most accurate thinkers whose ideas gain the widest currency.

DISCREDIT OF ROMANTICISM.--The Idealistic movement in philosophy which we have seen flouris.h.i.+ng in Germany at the beginning of the nineteenth century, had begun, after the lapse of a generation, to decline.[39] The causes of decline, as often happens, were in part, at least, other than intellectual. Hegelianism had become a.s.sociated with political reaction, and ”a philosophy has lost its charm when it enters the service of absolutism.” And a rising spirit of enterprise in commerce and industry also contributed to a change of att.i.tude, for as material interests develop, men have less leisure for speculation, and often lose their taste for ideals. Probably there should also be taken into account the sentimentality that had attached itself to Romanticism and with which men were sated. This revolt has its most pointed expression in the prose writings of the poet Heine, who attacks with satiric bitterness ”the new troubadours, so morbid and somnambulistic, so high-flown and aristocratic, and altogether so unnatural.”

METAPHYSICS REJECTED.--The reaction against the philosophy of Romanticism took the form of a complete revolt against speculative philosophy. But instead of going back to Kant, and taking up a vigorously critical att.i.tude, it took refuge in the prejudices of ”common sense.” The new movement must be a.s.sociated in the first place with a French thinker, Auguste Comte (1798-1857), who made the attempt to subst.i.tute scientific and _positive_ knowledge for the vague speculations which had hitherto pa.s.sed for philosophy. He was, in fact, the founder of that system of ideas known as Positivism, which (as we shall see) gained great vogue later, especially in England. Comte's doctrine was that, all spheres of Nature now being brought under the sway of positive science, the time had arrived for men, when constructing their conceptions of life and the world, to reject all but such ideas as positive science can accept. The age of theology and speculation was past; the new age of positive science, where both imagination and argumentation should be subordinate to observation, was at hand. Comte, as is well known, became the founder of what he hoped might develop into a new Catholicism--the ”Religion of Humanity,” and an atmosphere of moral idealism permeates his thought.

GERMAN EXTREMISTS.--In Germany, the home of Romanticism, the revolt took a radical shape in the hands of writers like Ludwig Feuerbach (1804-72) and Buchner. ”I unconditionally repudiate absolute, self-sufficing speculation--speculation which draws its material from within,” says the former, in the Introduction to his _Essence of Christianity_[40] (1841) and a.s.serts that he ”places philosophy in the negation of philosophy.”

Buchner, a far less acute thinker than Feuerbach, adopts a similar att.i.tude, protests against pedantry, and appeals (the appeal is always dangerous) to common sense:

”Expositions which are not intelligible to an educated man are scarcely worth the ink they are printed with. Whatever is clearly conceived can be clearly expressed.”

It is not surprising that the book _Force and Matter_ (1855)--in the preface to which these sentiments are expressed--went through sixteen editions in thirty years and was translated into most European languages. It is an extreme expression of the most thorough-going materialism, and the circ.u.mstance that its conclusions were acceptable neither to cautious scientists nor to critical philosophers, did not compromise its authority with the general public. As was only natural, for materialism is a creed for which the evidence is all on the surface, and to which the objections, being less obvious, escape notice. And Buchner's pleas for intelligibility and clearness, though in some sense justified by the inconceivable pedantry of much German metaphysics, was, in point of fact, only a form of cant; for ”there are difficulties lying in the subject-matter itself which cannot be banished from the sphere of philosophy.” Appeals to popular prejudices are not a more legitimate form of philosophic, than of scientific controversy; serious thinkers do not thus stoop to the expedients of the politician.

EFFECTS OF DARWIN'S THEORY.--It would be a serious mistake, then, to imagine that materialistic naturalism had to wait for the publication of the _Origin of Species_ (1859) before it could become a formidable theory. And yet the appearance of Darwin's book had important effects, and among these is to be reckoned a certain weakening of the old ”Argument from Design,” according to which the complexity and delicacy evident everywhere in the world of nature, could not be attributed to chance, but pointed to the existence and activity of a divine Designer.

Paley, during the eighteenth century, had elaborated the argument with a wealth of detailed instances of ”contrivance”: