The History of Biological Theories

In 1878 the Prussian Minister of Education said in the Landstag, during a debate on a new Education Act, 'Do not think that this law would allow notorious Darwinists to be appointed as science teachers in our secondary schools' (Mittleren Unterrichtsanstalten). Virchow not only did not oppose but he actually voted for the reprimand- ing of one Herman Miiller, a secondary school teacher. Miiller was a well-known botanist and believer in evolu- tion, who had tried to introduce the theory into his school teaching. 1

In these circumstances Darwinism could not flourish; Haeckel retained his opinions, showing how deep was his conviction. A few workers attempted to defend the evolu- tionary theory against the charge that it led to Socialism, but no one except Haeckel sought to show how wrong was Virchow's endeavour to make a fundamental distinction between ' teaching' and 'research'. We may see the results of this discussion in Cosmos a paper which was in favour of Darwinism. This paper had for its motto the defiant phrase : Impavidi frogrediamur! Yet, a year after the lecture in 1878, it thought it necessary to publish an editorial Towards Peace. In this Darwinism was upheld, but its supporters were told 'to guard the religious sentiments of the people in all their simplicity and purity; for the masses pay little attention to con- structive ideas but rather regard to destructive views, refutations and disavowals'.

1 H. Muller published his defence in the pamphlet, Die Hypotbese in der Scbule und der naturgeschicbdicbe Unterricbt in der Realscbule zu Lippstadt. Ein Wort zur Abwebr und Recbtfertigung, Bonn, 1879. Another case of a 'disciplinary* punishment as the result of Darwinist teaching is given in Cosmos, vol. iv, 1878-9, ALTHOUGH the problem of the genetic relationship ji\of living organisms was in every one's mind, Darwin's answer was unexpected. The old 'Naturphilosophie' was dead, but many people still fully believed in a rational plan in Nature and in God.

Men of science in general saw the ever-growing material- ism but for the most part rejected it in disgust. Both philosophically and scientifically they held themselves superior to Biichner and his friends, with their meticulous dilettantism. They were all awaiting a new light on the question of development, and behold! it came from Darwin; but it came in a manner new to science. He offered neither morphological argument nor physiological experiment nor profound speculation concerning the nature of life, but, in the place of these, an enormous mass of quotations from books of travel. He himself belonged to the hated materialists, and deprived the older thinkers of their dearest belief their belief that Nature is rational. Is it surprising that so much obloquy was heaped on the new theory and its exponents ?

But yet the movement increased, and the older thinkers, seeing the uselessness of opposition, began to retire from the contest. Only one or two of the bolder spirits tried to point out that they had already expressed views similar to those of Darwin but without Darwinian materialism. We will consider some of these : Louis Agassiz (1807-73), a Swiss by birth, was a man of science and a traveller who had marked American sym- pathies. While still living in Europe he resolved to com- pile an exhaustive treatise on the fossil fishes. In America he obtained financial support for his plan, and entered on a period of widespread scientific activity.

He contemplated a very full Natural History of the United States, and wrote an Essay on Classification (1858), which was to serve as an introduction to it. In this he gave expression to his philosophical views. People were expecting something very remarkable. Agassiz was not only a palaeontologist and anatomist, he was also a well- known embryologist and geologist. Further, he had made a name by his study of deep-sea fishes. But the work was disappointing. It was perhaps comparison with Darwin's work that belittled it. In Darwin's book were facts and new views concerning Nature ; in Agassiz' only generaliza- tions, reminiscent of ancient philosophical arguments, and illustrated by well-worn examples.

Agassiz believed that there is purposeful guidance behind the universe, which the development of living organisms can partly reveal. This purpose is the manifestation of that fundamental idea which finds expression in the manifold types of animal organization. In the later editions of his book Darwin challenged Agassiz' views. They served, as it were, to illustrate the antithesis of his own, and, as so often happens in these cases, he looked upon every valid objection to his opponent's ideas as an added proof of his own theory. The essence of Agassiz' teaching was that a species is not only defined by its anatomical, but also by its physiological, geographical, and other characters, and that the species is constant in all these respects. Darwin, following his usual method, did not criticize this assertion, but attacked Agassiz' belief in a Divine Plan, in twenty acts of Creation his idea that each species came into existence as a number of individuals, which appeared simultaneously in various parts of the world. He showed that such words as 'God' and 'Creation' explain nothing. Among other men of science who attacked the teaching of Agassiz was Haeckel. He gave it less consideration than had Darwin, regarding it merely as unscientific theology, and hardly worthy of the earnest attention of a man of science.

cized Darwin's views. He did not object to the assump- tion that present-day forms have arisen from extinct ones, but could not accept a theory in which 'Chance' plays so great a role as in the idea of Natural Selection. He believed in 'an inborn tendency to deviate from the parental type, and that these deviations have an effect after a sufficiently long period 7 . He obtained little support. When Darwin came into prominence Owen's fame was already on the wane, and his faults of personal character mitigated against his obtaining a hearing. Owen and Mivart were among the very few whom Darwin treated with contempt.

St. George Mivart, an English convert to Catholic- ism, published several works opposing Darwinism. He regarded the idea of Natural Selection as a false and brutal conception which owed its success largely to its anti- clerical bias and to its apparent simplicity. He himself believed that an inner spiritual force was the cause of development; and he named his theory Tsychogenesis 3 . 'the strongest possible ground for affirming that in the process of evolution we have evidence of the activity of a Great First Cause, ever and always operating throughout Nature in a manner hidden from the eye of sense, but clearly manifested to the intellectual vision of every unprejudiced mind. This action is that secondary or derivative creation, per temporum moras, distinguished by St. Augustine from that instantaneous primary creation which took place, potentialiUr atque causaliter, in the beginning. Thus a belief in 'evolution', far from leading to a denial of 'creation', distinctly affirms it'. (Mivart, The Cat, p. 527.)

In England considerable attention was paid to Mivart's objections to the Darwinian theory; on the Continent they had no influence. H. G. Bronn, at the end of his translation of Darwin's work, gave a criticism of the idea of Natural Selection based on his own views of morphology. His whole atten- tion was focused on the geometry of the living body. He asked why one plant has lancet-shaped and another oval leaves ; why one species has five stamens, another only four ; why one organism finds this structure useful, another the exact opposite. Bronn pointed out that the struggle for existence does not explain these things. He had searched Darwin's book in vain for any proof that such things are inevitable.

Among the supporters of the earlier views was Albert Kolliker, a very able embryologist and histologist. He pointed out that Darwin describes animals as if the only standard by which we can measure their structure is fitness for the struggle for existence, and, as if therefore, the one is better adapted for the fight, the other less so. This view, he said, is incorrect. 'Every organism is perfectly adapted to the purpose it is to serve, and the reason for this perfection is not to be sought for in the organism.' . . . 'The idea that each organism exists for one definite purpose only, rather than that it embodies a general Thought or Law, gives a very one-sided view of creation. It is true that every organ, every organism, has its purpose, but that immediate purpose is not the only reason for its existence.' (Kolliker, 'Uber die Dar- winsche Schopfungstheorie', Zeitschriftfurwiss. Zoologie, 14. 1864.)

Kolliker did not doubt that there is a genetic connexion between different forms : but according to his view evolu- tion has occurred in jumps. He thought that an organism might suddenly have laid eggs from which a new species arose probably under the influence of external condi- tions ; or that the change might have taken place as does metamorphosis in the insect world, where the egg pro- duces a larva, the larva a sexually mature individual unlike itself; or, finally, that the origin of new species might be analogous to the origin of the different kinds of bee, where one queen can produce workers, drones, and new queens.

Von Baer also took part in the discussion. In his youth (1828) he had objected to Lamarck's views. With remark- able insight he had then pointed out that Lamarckism was identical with Meckel's theory, and that on both views animals were looked upon merely as 'rough drafts' of man. Nearly sixty years had passed since he expressed these views, and both philosophic and scientific thought had undergone many changes since he was the leading biologist. To show that he could use new material to support old truths, he published a work in which he cited various new discoveries which, in his view, upheld his old theories.

Von Baer rejected the idea of selection, nor did he believe that Nature is merely a blind mechanism. He con- trasted this view with his old doctrine of the purposeful- ness of every event. There is no need to ascribe the similarity among animals to a common origin it rather proves the similarity of the animal-creating forces. It is illogical for the new teaching to assert that the idea of species is an artificial one, and yet to describe species; there are no grounds for relating men to monkeys.

Baer believed in evolution, but was convinced that the Creative Force had been far mightier in the first epochs of the living world than in our time. He thought this force had continually diminished, and perhaps was already exhausted. He believed further that the higher forms of life might have arisen by spontaneous generation, and he held firmly to the view, which he shared with Kolliker, that species arise by leaps. Baer's criticism of the Darwinian theory had no effect. Darwinians ascribed his want of understanding to senility, and little attention was paid to his writings, even by the opponents of Darwin. His friend Teichmuller, the Dorpat philosopher, agreed with him, but this advocate aroused even less attention.

The position of Michaelis, who was among the oppo- nents of the theory, was a quite peculiar one. Originally a Catholic priest, he rejected the doctrine of Papal Infalli- bility, and founded with Dollinger the sect of 'Old Catholics'. In addition to his theological polemics he published a series of treatises on Natural Philosophy, in which he rejected Darwin's principles, and pleaded for the Platonic view of Nature. These works impress the modern reader curiously. He seems to know few scientific

facts, and his writing is often obscure. Few had enough patience to read his works to the end. But Michaelis was very much in earnest in his opposition to Haeckel. He opposed the fundamental idea of the newer thinkers that all complex objects must be explained by reference to simpler ones. He thought we must begin with the know- ledge of man, in order to understand the rest of Nature. For Nature is only the expression (not even the develop- ment) of one idea, which reveals itself everywhere in the solar system, in the mineral, plant, and animal worlds. We should not search for evolutionary trees, but for ideal types. Michaelis regarded as such central forms or types the moss among plants and the mollusc among animals.

According to him the differences between the two are determined by the difference in their direction of growth; the plant's axis is vertical it grows with one end pointing towards the earth's centre, the other towards the centre of the solar system. It is therefore more nearly related to this than is the animal which has its axis horizontal. In man the original form of the plant is repeated in a fully developed animal body. Michaelis often speaks of a 'struggle for existence', but he uses this expression in an idealistic manner. In the flower, for example, he conceives the original plant nature (a bud which would tend to elon- gate) to be struggling for its existence with a sexual nature which is tending to overthrow the original plant form.

With such ideas which were merely late offshoots of a philosophy already relegated to oblivion Michaelis did not influence the Darwinians. They could not understand him and made no effort to do so. He is never quoted in scientific writings. In France Darwin was ably criticized, not only by Flourens and d'Archiac, but also by de Quatrefages. The latter writer pointed out how Darwin always speaks of the possibility rather than of the necessity for his conclusions, and how often we could arrive with equal probability at exactly opposite views. Further, he pointed out that Darwin makes too much of the incompleteness of the

geological record. Our knowledge of extinct animals is enough to show that in the history of life on our earth there has never been the chaos demanded by the theory. He also rejected Darwin's idea of species, his references to chance, &c. Quatrefages' criticism is valuable even to-day, and yet it seems to have been much neglected by later evolutionists. The above criticisms were all directed against special aspects of Darwin's teaching. An attempt to discuss and to refute the whole theory was made by the German botanist Albert Wigand, who issued a three-volume work dealing with it. 1 This remains, even to-day, the most complete on the subject, and although issued over fifty years ago contains practically all that can be said against Darwinism.

Wigand explains that Darwinism is much more than a theory ; it is a frame of mind which dominates thought, a resuscitated 'Naturphilosophie', in which the terms 'Polarity', 'Totality', 'Subject', 'Object' are replaced by such as 'Struggle for Existence', 'Inheritance', 'Selection', and so on. Darwinism is as far removed from science as is a fairy- tale from history. It has no programme, no method, no logic. He asserts that the mode of origin of new forms is quite beyond human understanding, for in no circum- stances can differences between phenomena be explained by a general principle. Neither the law of gravity, nor any such general law can enable us to understand the differences between the planets, the minerals, the elements, between light, warmth and electricity ; nor can the differ- ences between animals be explained. Such differences can only be experienced they cannot be divined. Wigand shows further how Darwin disguised the difficulties of his theory by the amassing of facts; he points out the defects in Darwin's conceptions of species, of heredity, of fitness and so on.

1 Wigand, Der Darwinimus und die Naturforscbung New tons und Cuviers, Braunschweig, 1874-5. All these are valid objections and are recognized to-day. Yet even Wigand's criticism was faulty. It is almost entirely directed against Darwin's logic, but the Darwin- ians were not interested in discussions of method or of philosophy. Wigand, too, though a good critic of the faults of his opponents, was quite unable to formulate any ideas of his own. He opposed Darwin's teaching of expediency, and then, to justify the idea of purpose, he postulated a God who is a simple immaterial Being standing outside Nature, and determining its purpose.

In opposition to Darwin's idea of descent with modifica- tion, he formulated his own theory of descent . l He assumed that there were in the beginning primitive cells, which contained the essence of both the plant and the animal. From these arose plant and animal cells ; the plant cells were subdivided into those of Thallophytes and Cormo- phytes ; these again produced cells of narrower range, till finally the original cells of the narrowest groups of the species were formed. From these plants then developed. Wigand himself apparently came later to consider this theory as of minor importance.

Many other workers raised similar objections to Darwin- ism; Leydig, the zoologist, for example, who rejected Darwin's idea of the working of chance, and urged scien- tists to search for the laws governing evolution ; Alexander Braun, the botanist ; Baumgrtner, the zoologist ; Wagner, the physiologist; Huber, the philosopher, and many others. To-day, when we look back upon these old criticisms of Darwin's views and the answers given by his supporters, it soon becomes obvious that here are two opposing worlds of thought speaking different languages. Darwin's aim was to describe Evolution; his opposers affirmed that he did not understand it. Darwin sought for causes ; they for motives. For him evolution supplied a chronicle of the universe, full of the smallest incidents ; they affirmed that

1 He develops this theory in his treatise Die Genealogie der Urzellen als Lotung des Desxendcnzproblfms, Braunschweig, 1872. he had not discovered behind the world's development any great plan. By the word 'Law' he denoted the probability with which a definite conclusion can be deduced from known events ; for them Law denoted that eternal and changeless Law which gives meaning to the manifold variety of nature. It was thus that misunderstandings were caused among both the older and younger schools of thought. The Darwinists were very much surprised when men like von Baer, Kolliker, and Braun rejected the new teaching, although the idea of development was not new to them. Unable to understand this opposition, they suspected that these opponents were denying their earlier and better convictions for fear of the consequences. Lyell himself did not escape this suspicion, for in his work The Geological Evidences of the Antiquity of Man, although he

showed that the earth was probably inhabited by man before the Ice Age, and did not reject the idea that Man may have come from a monkey-like ancestor, yet he always opposed the materialistic tendency given to these ideas by Darwin. It is significant how distasteful to the older generation was that youthful courage which led the younger men to follow their ideas to their logical con- clusion, and to defend them publicly. In his own school Darwin himself was certainly the best controversialist, and in the later editions of his book he tried to answer the scientific objections to his theory which had been brought forward by Agassiz, Bronn, Mivart, Nageli, and others. He frequently misunderstood their objections, however, and answered them only too often with the words We are as yet profoundly ignorant of this'.

Huxley's clever reply to Kolliker missed the point. Kolliker, he said, feels that the theory lays too much stress on purpose; now it is well known that Darwin has banished the idea of purpose from natural science. But this artifice is too simple ; it is quite obvious to the reader that the word 'purpose' has different meanings in the two sentences. Huxley's ideas were not, in fact, as different from Kolliker's as might be thought. Though a loyal friend of Darwin, he by no means blindly accepted all his teaching. In particular, he did not wholly agree with the idea of Natural Selection, but preferred the hypothesis that new species arise from older ones by 'transmuta- tion without transition 5 . He gave a very non-Darwinian analogy from chemistry one combination passing into another, there being no intermediate forms which link the two.

'In an organic compound, having a precise and definite composi- tion, you may effect all sorts of transmutations by substituting an atom of one element for an atom of another element. You may in this way produce a vast series of modifications ; but each modifica- tion is definite in its composition, and there are no transitional or intermediate steps between one definite compound and another. I have a sort of notion that similar laws of definite combination rule over the modifications of organic bodies, and that, in passing from species to species, Natura fecit saltum? (Life and Letters of Thomas Henry Huxley, vol. i, p. 173.)

It is true that these words were written some months before Darwin's book appeared, but when this was pub- lished Huxley, in praising it, pointed out that Darwin had increased his own difficulties by rejecting the idea of a saltus in organic Nature. Kolliker was a friend of Huxley, and there were others who fared worse than he did. The French had little sympathy with the idea of Natural Selection, and so it was simply assumed that their science was decadent. They did not, in fact, produce nearly as much work as did the Germans. We cannot wonder that opponents whose intellectual calibre was not very great received little atten- tion ; but even Wigand's fine work was ignored or treated with contempt. Dodel-Port considered it unworthy of notice. Vogt joked about the thickness of the book. Krause wrote that it would not be read even by Wigand's friends. In his review of the Darwinian literature Seidlitz said that it was 'the most valuable among the anti- Darwinian writings, for it costs four crowns ' !

Zockler's book on the History of the Relation between Science and Religion (1877) contains a full and objective criticism of Darwinism from the theological point of view. If we may judge from the Darwinian literature, it was hardly realized that such a book existed. Is this to be wondered at ? Even in the nineties it was said that Kolliker had seriously damaged his reputation by his criticism of Darwinism. Such is the power of public opinion. Apparently Darwin himself did not feel certain of his victory. Outwardly he had conquered along the whole line. Enemies were silenced or in retreat. Yet the criti- cism had not been without effect. Very striking, in the midst of all this apparent success, are the words he wrote in 1871. Speaking of the objections to his theory he said: