The History of Biological Theories

Darwin explained the origin of species by the same principle of usefulness. Everything that we know of an organism is or has been useful to it, and this usefulness is the cause of all the phenomena of life. There are just a few attributes which are not obviously useful to the organism, as, when a mechanic makes a machine out of iron, the machine will be black because the iron is black. But * With these important exceptions, we may conclude that the structure of every living creature either now is, or was formerly, of some direct or indirect use to its possessor' (Origin of Species, p. 150).

Darwin made ceaseless efforts to demonstrate the use- fulness of the most diverse structures. The whole question of the relation of organism to environment is very com- plicated. We have already seen that there is scarcely one instance where it is possible to foretell what attribute will favour an animal in the struggle for existence ; nevertheless Darwin attacked the problem boldly. He tried to show how the giraffe throve as its neck lengthened, how the whale profited when it developed the first trace of whale-bone or baleen, the flat-fish when it learned to swim on its side. Utilitarianism is the leading thought in the teaching of

both Darwin and Mill. Those features which are useful to the organism will be retained the harmful ones will disappear; those neither useful nor harmful may persist or may vanish. The earlier philosophers stood awe-in- spired before their ideas of Life, of Purpose, of Unity of Plan, of the Soul, of Beauty, of Endeavour. Darwin re- placed all this by his idea of Natural Selection. In other sciences we see the same tendency to simplifica- tion. A variety of phenomena are replaced by one uni- versal principle. Light, heat, electricity, are wave-motions the properties of matter depend on the nature of elements and molecules, the movement of the planets depends on gravity. But in these cases the principles express the actual nature of the phenomena themselves. We cannot say that there was first a wave-motion, and then light ; or first gravitation, and then planetary motion ; or that there was once salt which was not produced by the combination of sodium and chlorine. But that is how relationships are formulated in the Darwinian biology.

We cannot assert that 'Natural Selection' or 'Useful- ness' explains the intrinsic nature of the eye it is rather the historical cause of its development. The eye was not always as it is to-day a better one appeared one day 'by chance'; this proved more useful, and so was retained. The Darwinists treated every problem in the same manner. To the questions Why is the kangaroo found in Australia and not in Europe F Why has man two eyes and not three ? Why does the lark sing ? Why is the sky blue ? Why does a dog wag his tail ? we get the stereotyped answer : Things were not always thus : but there came a day when the lark began to sing; some hen-bird liked the song and became his mate; she bore him children who could sing too and so on.

Once upon a time the dog could not wag his tail ; one day a crafty animal noticed that if he wagged it, he could empty his rectum more easily; thus tail- wagging became connected with a feeling of pleasure ; the discovery be- came a habit ; it was inherited by his descendants. Now, you see why the dog wags his tail when he is pleased ! l You ask Why is the sky blue ? Once, it looked by no means blue, but a steely grey. Man's eye learned to dis- tinguish a blue colour inheritance and so on!

THOSE who hold that new ideas originate in the thought currents of an epoch, will find confirmation of this in the fact that Darwin and Wallace lit upon the same theory. Although in upbringing and intellectual disposition the two men were very different, they both came to believe in the transformation of species, they discovered the doctrine of Natural Selection simultane- ously, and formulated it under the influence of Malthus. Alfred Russell Wallace (1823) was for a time a teacher, then a railway engineer, finally a naturalist and traveller. His mentality was distinctly peculiar. He believed in phrenology, his interest in it being a lasting one. In his youth he was an ardent spiritualist. He accepted the miracles of Lourdes. He was strongly influenced by socialist theories. He maintained that the State should not support scientific research, just as it should not support factories for the production of carpet patterns ; both only served private ends, and could be safely left to the care of those interested in them. It should, however, encourage the popularization of science.

The reading of the Vestiges turned Wallace's attention to the study of the origin of species. Shortly after the appearance of this book in 1 847, he and his friend Bates went to the region of the Amazon, to collect 'facts for the solution of the question of the origin of species'. Bates remained in America, and later came to the support of Darwin with his theory of Mimicry. Wallace, however, returned to England, bringing with him his collection of specimens, but the ship in which he was returning was burnt at sea, and all his belongings were destroyed. He remained in England for two years, then set off once more this time to the Malay Archipelago and in 1855 he sent home from Borneo his first communi- cation on the origin of species. Stimulated by reading the

work of Malthus, he sent a second communication in 1858, in which he gave, as did Darwin, 'Natural Selection' (although he did not actually use this term) as the explana- tion of the origin of species. Much has been made of this very striking coincidence, but there is little really extraordinary about it. Wallace had for long been studying the origin of existing animals. In a work he published in 1855 he suggested, for the first time, reasons why the animals of consecutive geological periods are nearly related. He had then no idea of causes underlying the transformation of species, nor does he seem even to have considered that such causes may exist. The one fact which he sought to prove was that each species when it arises is 'coincident', both in time and place, with a nearly related pre-existing one. He gives reasons in support of this assertion founded on the facts of geo- graphical distribution, of geological sequence, and on the existence of a natural system.

On becoming aware that there may have been a trans- formation of species, Wallace began to seek its cause. He read the work of Malthus, and it was an obvious step to apply his theory relating to human progress to progress in Nature. Having adopted the method of Malthus, Wallace could not avoid reaching the ideas of a struggle for existence and of a natural selection, as these are merely the logical consequences of the premises. In its concrete development, Wallace's theory differs from Darwin's in certain important respects. Darwin was a more abstract thinker than Wallace. He emphasized the struggle for existence, variation, heredity, natural selection in short, the theoretical side of his teaching. Wallace, on the other hand, attached importance to his examination of the facts of geographical and geological distribution ; he compared the faunas of different districts, and en- deavoured to show how the animal types occurring in consecutive periods of the world's history were inter- related. He studied the colours and habits of animals more for their own sake than to prove the theory of evolution.

He disagreed with Darwin in several minor points; he thought that one factor Natural Selection was sufficient to account for evolution; he refused to accept the doctrine of the inheritance of acquired characters; he also considered that the various races of domestic animals must be looked upon as monstrosities and not analogous to wild races. Wallace sent his paper on the origin of species to Darwin, asking him to arrange for its publication. It reached Darwin just as he was preparing his own work and caused him considerable embarrassment, for he saw himself robbed of the fruits of his own labour. Finally Wallace's manuscript and certain old letters and manu- scripts of Darwin's which treated of the origin of species were published simultaneously.

Later, Wallace criticized Darwin's idea of sexual selection. He thought that the struggle for existence was enough to explain the beauty of animal form and colour, (T. Wallace : Tropical Nature and other Essays, London, 1878.) He also threw doubt on those theories that sought to explain the origin of man, pointing out the paucity of our knowledge of prehistoric man. He empha- sized the fact that the existence of tertiary man is assumed, but nothing known about him. He combated the assump- tion that the ancestors of modern man were always less highly developed than he, and pointed out that the inhabitants of many islands, as well as the natives of Central America and the Egyptians, were more highly civilized in prehistoric times than to-day.

Wallace favoured the belief that man is not related to the animal on his spiritual side, but that his soul was breathed into him from a supernatural world. Only thus could he account for mathematical talent, for musical genius, the capacity for martyrdom, true friendship for, in short, all the highest human qualities and capacities. Many bodily structures, such as the form of the foot, the hand, the upright walk, the naked skin, cannot be ex- plained by any theory of natural selection.

In Wallace's view God, the Creator, has intervened three times in the history of life. Once, when He created living matter ; a second time when, living matter having reached a higher level, He breathed into it consciousness ; a third time, when He gave a soul to man (Wallace, Darwinism, 1889). Wallace was convinced, as a spiritualist, that space is full of spirits. One, he thought, may have entered a monkey and so brought about his transformation into a man !

Darwin devoted his whole life to the study of the origin of species and natural selection, and after the year 1859 a ^ his published work dealt more or less directly with these topics. Wallace, on the other hand, dissipated his energy. The result of this and of certain peculiarities in his views was that Wallace's influence on the development of bio- logical theory was never comparable with Darwin's. I. Darwinism in England. ARWIN became known as a scientist particularly

"as a geologist by his Voyage of a Naturalist on the Beagle. From 1837 onwards his friends knew that he was endeavouring to formulate a theory of the natural history of Creation. The way for publication was prepared by the appearance of the Vestiges. When Wallace produced his paper on a similar theme in 1858, and Darwin pub- lished the short account of his own work, the general interest greatly increased. It is true that Darwin had suggested that he was working at the problem of species in the second edition of his Naturalist's Voyage, but the very significant change in his point of view had remained unnoticed.

Now all this was to be altered. Huxley, Hooker, and Lyell all friends of Darwin prepared the public mind to receive his book, and so it came about that the first edition of the Origin of Species was sold out on the day of publication (1859). A second edition appeared a month later, a third at the end of a year, and many after this. Darwin's theory was thus spared the neglect so often the fate of new theories. This interest did not mean, however, that all men agreed with it. There were many who opposed it, their objections being aroused by the materialistic tendency of the work, by its teaching about natural selection, and by the view there expressed on the origin of Man, rather than by Darwin's ideas on the blood relationship of animals. In The Times, the Saturday Review, Atkenceum, Edinburgh Review, London Review, and many other journals, articles on Darwin's work appeared side by side with controversies on Home Rule and accounts of events in India. Meetings were arranged at which writers, statesmen, and bishops

brought their debating talents to bear on the subject of the origin of Man. Travellers sent particulars from distant lands which seemed to them to confirm or disprove the theory. The question was discussed until a new problem arose to occupy men's minds. Darwin himself took no part in this newspaper agitation but was interested in the spread of his theory ; and the eagerness of his friends to establish the truth of the theory drew from him the following request to Huxley:

'If you write to von Baer, for heaven's sake tell him that we should think one nod of approbation on our side of the greatest value ; and, if he does write anything, beg him to send us a copy, for I would try and get it translated and published in the Athenaum and in Silliman to touch up Agassiz* (Life and Letters of Charles Darwin, ii, p. 330). In his letters there constantly occur such expressions as 'this or that man agrees entirely partly with certain reservations', just such expressions as are used by speakers electioneering. Darwin fully understood the demands of publicity, and did not place obstacles in the path of those friends who were defending the theory.

In his work the Creator is pictured as having twice actively intervened in the affairs of our planet. He cites a Church dignitary who agrees with this view. The applica- tion of his theory to man is suggested in an extremely 'correct' way: * Although in the Origin of Species the derivation of any particular species is never discussed, yet I thought it best, in order that no honourable man should accuse me of concealing my views, to add that, by the work, light would be thrown on the origin of man and his history. It would have been useless and injurious to the success of the book to have paraded, without giving any evidence, my conviction with respect to his origin' (Life and Letters, i, p. 94).

Nevertheless, the book aroused tremendous opposition. The High Church party took offence. A Bishop wrote a strong criticism of Darwin, and Richard Owen and the Duke of Argyll joined the Church party in their opposition. The Roman Catholic zoologist, Mivart, also criticized the doctrine of Natural Selection very adversely. But Charles Lyell, who was a friend of some of the higher clergy, gradually prepared the way for a more friendly reception. The anatomist Richard Owen (1809-92) a supporter of the old idealistic school rejected the theory, calling the doctrine of Natural Selection 'ancient scholasticism' not a very suitable comparison. (In the Edinburgh Review, 1860.) There was, however, little to be feared from Owen. He had long passed the zenith of his fame, and he was not a clear writer.

George Campbell, Duke of Argyll (1823-1900) was a much more dangerous opponent. A striking stylist and orator, a statesman who was successively Postmaster- General, and Secretary of State for India, he found time, from his duties to Church and State, to study geology and ornithology. A member of the older rationalistic school, he endeavoured to collect evidence of the 'catastrophic' theory from his geological observations in Scotland. Basing his objections on the structure of birds, he re- jected Darwin's teaching on the grounds of its materialism and lack of logic. He opposed to it his belief in the ordered plan of Nature. The history of organisms must naturally conform to the fundamental laws of such a reasoned plan.

The Duke analysed Darwin's work on the pollination of orchids. He shows that Darwin, in spite of his ob j ection to teleological explanations, is here looking solely for a purpose in Nature; that he sees in every structure a definite purpose, and explains each feature as the one best fitted for its particular end. He ably takes up this idea of Darwin's. He, too, believes that there is a plan behind every organism (such as Darwin assumed in his teaching concerning homologous parts), and this plan is modified according to reasonable laws and for definite ends. The very same laws hold sway, the Duke would have us believe, in the realm of Nature and in the actions of Man. Neither

Man nor Nature is at the mercy of unreasoning chance both are subject to definite and rational laws. In addition to Owen and the Duke of Argyll many other writers opposed Darwin's theories ; among his chief supporters were Huxley, Mill, Buckle, Lyell, and Hooker. Professor Huxley (1825-95), a philosopher, a clear and able writer, a clever debater and a distinguished biologist, was the most successful of those who sought to win acceptance for the theory. He was a man of very inde- pendent mind and of great experience. He began his scientific career by working at anatomy and histology, then he turned to palaeontology, and finally came forth as a philosopher. He was considerably influenced by von Baer and by Carlyle. Huxley's scientific achievement, as is so often the case with men who have strong critical faculties, was mainly negative. No well-known biological theory bears his name, but his attacks on older theories are note- worthy. In his anatomical work he rejected the old verte- brate view of the skull, and replaced it by a modern embryological one. In palaeontology he opposed the preva- lent ideas of the number of extinct types. In philosophy he rejected Comte, and was critical of any belief in God. He repudiated the doctrine of the equality of men, nor did he share the general enthusiasm for the emancipation of women.

Huxley had greater critical powers than Darwin or Spencer. He had some of the good qualities of both, while intellectually he was much more versatile. He was better read and had a clear and agreeable style. Nevertheless he left behind much less original work than did either of the others, perhaps because of his addiction to controversy. He fought for Darwin, but he did not accept his funda- mental law that all living things undergo gradual modi- fication. He supported Herbert Spencer, in spite of the fact that he did not believe in the general equality of men, nor did he think, with Spencer, that morality had developed as the result of the struggle for existence.

and vet he was no complete Darwinist, for he never wholly believed in the phylogenetic scheme. He was no dogmatist, still less did he appreciate concrete formulas or the plastic presentation of any of his ideas. The name Agnostic, which he himself invented in 1869, expresses his negative religious views. It fitted the whole trend of his scientific thought. Huxley used all his experience and all his powers of persuasion in the service of Darwin. He wrote favourable reports of his work, made his teaching known to the masses, gave him his support in the newspapers and at assemblies, and skilfully countered the theological attacks. A critic of Darwinism appeared in the person of Bishop Wilberforce, who obtained his scientific facts from Owen. Huxley pointed out some gross errors in the work of Wilberforce and held it up to public derision, so hitting at Owen. At a meeting of the British Association at Oxford he displayed his ability as a debater, silencing his opponent, the Bishop, by an apt retort. It was merely the triumph of clever repartee, but there were 700 present who saw Huxley's superiority of knowledge and of debating force, and these meant more for the success of the theory than any demonstration of deep truth would have done.

Huxley defeated Owen in a similar fashion in an historic controversy. Owen did not express himself very happily as to the difference between the human brain and that of the monkey. Huxley attacked his statement and proved it to be incorrect. In vain did Owen defend himself by demonstrating that Huxley had misinterpreted his words. Huxley had gained the public ear. The interest in the controversy was so great that a popular song was composed about it. 1

1 The song is quoted in Huxley's Life, vol. i, p. 191. We may quote the words of both parties, so that the reader may judge for himself. Owen wrote Their (hemispheres of man) posterior development is so marked (see page following), that anatomists have assigned to that part the character of a third lobe ; it is peculiar to the genus Homo, and equally peculiar is the posterior horn of the important opponents. Men were accustomed to the inductive methods used by him methods borrowed from political economy and made familiar by books on that subject. All that was now necessary was that those interested in such a controversy should make up their minds about the theory. This done, the matter was ended.

In France Darwin's theories were very coldly received. Parisian science still lived on the Cuvier tradition, or was under the influence of Comte's Positivism. These empha- sized exactness of method, clarity of expression, and the importance of experiment. Claude Bernard and Pasteur were the leaders of biological thought. Both were anti- Darwinists. Among Cuvier's followers, Flourens, de Quatrefages, Milne-Edwards, Brogniart, de Beaumont, Barrande, d'Archiac opposed the new theory. Even later Darwin's teaching was never very fully accepted in France. His books were, it is true, translated into French. Martins the zoologist and Soury the philosopher accepted his teaching regarding evolution, although the latter rather preferred the German version of the theory. Such scien- tists as Giard, Perrier, Marey, Bert, and popular writers like Dumont, Ferriere, Rosse, and Duval accepted Darwin- ism, but they never expressed more than a mild scientific interest in his views.

When speaking of France, we must not omit to record the official treatment meted out to him by the French Academy. At the first attempt to elect him as a foreign member, he only received five votes. Later, he was chosen as a botanist, and even at that election the votes of only twenty-six zoologists out of forty were in his favour. lateral ventricle, and the hippocampus minor which characterize the hind lobe of each hemisphere . . .' (Journ. Linn. Soc., vol. ii, s. 19). These words imply that this marked development is a characteristic feature of human anatomy. Huxley, however, pointed out that Owen is incorrect when he maintains that the above- mentioned parts are characteristically human 'the third lobe is neither peculiar to nor characteristic of Man' . . . &c. (Nat. Hist. Rev., 1861, p. 67). See Owen's defence in the Edinburgh Review, v. 240, 1863, p. 558.

Darwinism, born in England, found its spiritual home in Germany. Although Darwin, Huxley, Wallace, Francis Galton, and Herbert Spencer lived in England, the majority of the younger scientists went to Germany, to Haeckel, Weismann, and others, to be taught the new theory. This was because it was never taught in England as a scientific system. German scholars were the first to transform this teaching into a 'school of thought'. It was the Germans who gave it a dogmatic and logical form.