The History of Biological Theories

Cope rejects Lamarck's view that the soul is derived from non-living forces, and that it only becomes a factor in evolution in the higher forms of life. A vital force, he asserts, is the cause of all evolution. It determines why physical and mental forces act, now on this part of the body, and then on the other : 'If then, we grant the propositions, first, that effort and use modify structure ; and, second, that effort and use are determined by mind in direct ratio to its development, we are led to the con- clusion that evolution is an outgrowth of mind, and that mind is the parent of the forms of living nature.

'If structure is the effect of the control over matter exercised by mind, it is evident that evolution of mind must be directly followed by the corresponding development of organs. , . . But the animal mind being generally occupied with simple functions, its expressions in structure are usually nothing more than the pro- gressive creation of improved instruments for obtaining food, resisting climate, escaping enemies, and reproducing their kind' (E. D. Cope, The Origin of the Fittest, 1887).

Cope calls this force the 'growth force', and considers its laws of action. It reminds us of Nageli's 'principle of perfection', ^his growth force does not influence all parts of the body simultaneously; in some parts evolution goes on quickly, in others slowly. In man, the develop- ment of the head was rapid, while that of the arms and the hips was retarded. Compared with his other teeth, the canines of man show retarded evolutionrj Cope held peculiar views about the evolution of species. Darwin believed the difference between genera and species

to be merely quantitative, individuals of the same species having more characteristics in common than have the different species which form the genus. Cope's views were similar to those of Agassiz. He taught that each organism possesses some characters which denote its species, others denoting the genus, still others marking the order. Hence the same species can be repeated in different genera; evolution may bring about a change in the characteristics of the species, the characters of the genus remaining constant ; or, conversely, the genus characters may change, while those denoting the species remain unaltered. Con- sequently it is very probable that 'the same specific form has existed through a succession of genera and perhaps in different epochs of geologic time'.

Birds that screech and birds that sing, Diptera and Hymenoptera, furnish us with examples. Many species of screeching birds he supposed to have changed the character of their call and to have become singing birds, while retaining all the other characteristics of their original species. He believed that Diptera gave rise to Hymenoptera in a similar manner. Cope calls such series of organisms as the screeching and singing birds, Diptera and Hymeno- ptera, placental and non-placental mammals, homologous series, and corresponding species in the two series hetero- logous species.

One objection brought against Cope's views on classi- fication is that no transitional forms between separate groups are known to palaeontology. His theories have, however, never been subjected to any very critical exami- nation by zoologists. Influenced by the theories of de Vries, many recent investigators have come to agree with his ideas* Osborn, Hyatt, Scott, Waagen, Neumayer, and Steinmann, among palaeontologists, Packard the zoologist, and Geddes the botanist, have expressed views similar to those of Cope.

Rather less closely related to the views of Cope are those of Ettingshausen and Krasan, the Austrian palaeonto- logists (1888 onwards). Studying extinct oaks and beeches^ they came to the conclusion that all the specific characters of modern oaks or beeches were to be found in the ancestral forms, but that these were originally undiffer- entiated and combined in every possible way. The an- cestral form, for example, bore many types of leaf, each such type now characterizing a definite species. 'Each tree seems at that time to have possessed an unlimited capacity for producing new kinds of leaf. Heredity hardly existed ; the same type of tree might produce the same form of leaf in very different parts of the world, but this would not necessarily be the result of any very close phylogenetic relationship' (C. von Ettingshausen, Unter- suchungen uber Ontogenese, 1890). 'The story of the evolu- tion of the various kinds of oak is not a story of the pro- duction of new forms which did not exist previously ; it is rather that all the various possibilities which originally existed have been realized in the course of time. Thus from one very varying species, a whole series of varieties has been evolved. These lack the freshness and power of adaptation of the original ancestral form.'

These authors consider that the unit elements of structure, i. e. the morphological characteristics of species, are immutable; the infinite variety of species is due to varying combinations of these elements. They agree with Cope in believing that these elements represent something unchanging and having an independent existence. They also agree with him in the view that morphological similari- ties do not necessarily represent relation by descent. They believe, as he did, that some characteristics of a plant evolve, while others remain constant ; that the transition from Cryptogam to Phanerogam, for example (e. g. from Lepidodendron to Araucaria), occurred in this manner. The plant retained the vegetative habit of its ancestor, but completely altered its method of reproduction.

C. Brunner von Wattenswyl, an Austrian entomologist (1873), believed that evolution results from the action of mind. In man there is a desire for perfection which enables him to rise above the utilitarianism of everyday life. So, in nature, the leading principle is an urge towards an ever higher goal ; this may be at one time the structural perfecting, at another the beautifying of the body. Like Cope, he taught that one genus of animals may be trans- formed into another suddenly by saltation, while the specific characters remain unaltered. Brunner believed that the species is merely the genus 'raised to a higher power', as he calls it.

Eimer, the zoologist, first became known by his criticism of Weismann. He had been publishing work on develop- ment since 1874. He began with a study of the wall lizard (Lacerta muralis) which is very variable both in coloura- tion and in marking. This work received little attention. At that time research was chiefly of the genealogical tree type inspired by Haeckel. Microscopic work was emphasized and observations on colouration were dis- missed as Very inexact'.

In 1888 Eimer published a treatise on the origin of species, constituting the second part of a work on the colours of butterflies. Later he applied his theory to other animals. In his work on lizards he suggested that all lizards tend to pass through the same series of phylogenetic stages in regard to marking and colouration, but that the develop- ment of each individual is arrested at a different point in the series. The wall lizards, for example, were originally black with longitudinal stripes. More recent lizards be- came spotted and lighter in colour. These changes were due, he thought, to the action of some internal cause. The most highly developed animals are very brightly coloured and transversely striped. We can still find ex- amples of each of these stages in evolution. Black lizards have survived on bare rocks, where, looking like shadows, they have escaped the eyes of their enemies. In under- growth brighter colours are developed, for here only those survive who have reached this stage in development. Hence natural selection is purely negative in its effect,

getting rid of inappropriate forms, but not producing new ones. According to Eimer, these changes of colour first make their appearance on the hinder parts of the body, and they spread from thence forwards. He asserts, further, that they first appear in the male, later in the female. Eimer found similar phenomena in butterflies. The original colouration of the butterfly consisted, according to him, of eleven longitudinal stripes on a light-coloured wing. (Our modern butterfly, Papilio podalirius y which has a yellow wing with ten longitudinal striations, is assumed to be very near to the ancestral form.) From this form later types developed. The more recent they are the shorter their stripes, until these become merely spots such as occur in the swallow-tail butterfly, Papilio macbaon. These spots then spread transversely, giving rise to forms like Papilio xuthus. Finally, they spread over the whole wing, producing a uniform black colouration.

Eimer, like Nageli, thought that natural selection was of secondary importance. The principal cause of evolution is that the organism outgrows the limits of individuality. This phyletic growth would be favoured by climate, nutri- ment, and so on, but it is the result of something in the original constitution, and it tends to the production of new forms ; hence it is the immediate cause of variation. Eimer therefore concluded that variation can only proceed in one direction not in many, as Darwin had suggested; for this reason he called his theory Orthogenesis.

Eimer undoubtedly arrived independently at his theory of orthogenesis. It is extraordinary that, although Eimer constantly refers to Lamarck and Cope and applauds their theories, nevertheless he does not realize that their views include his idea of orthogenesis. It was foolish of him to contrast his views with those of Nageli ; he had no grounds for doing this, for the two views are very closely related. He also strongly emphasized the differences between his ideas and the theories of Weismann; he objected in particular to Weismann's denial of the inheritance of acquired characters. He had no reason to do this, for the

matter was not only not vital for his theory, but it was actually in agreement with it. Before the time of Eimer, Taylor had pointed out that the markings in plants and animals are due to lines determined by the internal structure of the body. We do not find that Butler's name is often mentioned in the literature of Darwinism. He was eccentric and was guilty of a personal attack on Darwin. His name was never mentioned by the Darwinists in their discussions. They seem to have banned it in honour of their master.

In his book Life and Habit (1878), which is full of original psychological observations, Butler points out that we may look upon phylogenetic development as a continual process of becoming accustomed to new activities. He gives many examples of actions which, having been constantly re- peated, become automatic. The more we are practiced in any art, the less conscious are we of the manner of its performance, and, indeed, consciousness disturbs that per- formance. A pianist, playing some well-known piece from memory, will suddenly stop if he attempts consciously to control his fingering.

Butler says that this is what happens in life. We are so accustomed to existence that it does not occur to us to think about it. When we do begin to think, we begin at once to doubt ; and we formulate the phrase cogito, ergo sum to reassure ourselves of that existence. We may assume that many actions now performed quite automatically were once performed deliberately and for a conscious pur- pose. We have, for example, trained ourselves most marvellously to breathe. A newly born child makes a few attempts at breathing, like a man trying to remember some procedure that he has formerly practised ; these attempts only last a few minutes. Swallowing, digesting, seeing, hearing we are able to do all these things unerringly and unconsciously because they have been done by thousands of generations before us.

It is the specifically human activities speech, the main- tenance of the upright position, art, science, which require conscious performance, and are most under our conscious control. Man has only recently raised himself to the level of these attainments, and each man has to practise them anew. Eating, drinking, sobbing, breathing, seeing, hear- ing, are functions which our pre-human ancestors had already acquired, and these are now more subconscious. Least controllable of all are the activities which were already practised by pre-vertebrate ancestors, e.g. the circulation of the blood.

We may regard the development of the embryo as the repetition of well-practised and at first conscious attempts to form flesh, bones, beak, and so on. Even the protozoa, when they form shells or stretch out pseudopodia just where these will help them to obtain food, are performing actions at once conscious and purposeful. They pass on their experience to their descendants; we may imagine, then, that the personality of the ancestral protozoon con- tinues to exist in these descendants and is constantly being enriched by new experiences.

Since the whole of the present organic world has been derived, by an unbroken series, from some original proto- zoon, we may assume that the personality of the ancestral protozoon continues to live in all existing organisms. And not it only, but the personalities of all those later direct forefathers, who lived, amassed experiences, and so brought about the progress of the organic world. All organisms then, from the single cell to Man, had originally a common personality. Later these were separated into various centres of memory, hence into separate person- alities; and these lost all sense of their near relationship.

The life of an individual then, is a repetition of all those things which this individual has done a billion times already. If, however, new and unforeseen circumstances arise, in which he cannot trust to his memory, he must act consciously. The result will be either adaptation to new conditions or annihilation. What annihilation means is best shown by an example. A wheat grain passes into a hen's gizzard, that is, into quite unaccustomed surroundings. At first it thinks that it has been sown, and endeavours to germinate. Soon it becomes aware of the new conditions, becomes confused, and is ground up by the gizzard. The hen has brought the grain into such circumstances that its habits must overcome those of the grain. The grain is digested that is, it loses its own individuality and partakes of that of the hen. It forgets its own past and becomes a part of the hen's past. Hence, when there is a fight to the death between two organisms, this means that the one is forced by the other into circumstances for which its predecessors had not yet prepared it.

It would take us too far afield to give further examples of Butler's ingenious use of analogy; the analogy between memory, and the likeness of children to their ancestors ; between errors of memory and disorders of development ; between the sudden remembrance of an experience long forgotten, and atavism ; between the results of crossing, and the uncertainty of the man who sees in front of him two possible solutions of a problem. Butler considers that all the phenomena of heredity are merely exercises in memory. Variability he also explains psychologically. Organisms strive to fulfil their needs, as man strives for progress and invents and perfects machines to help him to attain his end. Human inventions often begin from some very trivial observation, of which no one can say at first whither it will lead. So organisms progress from small beginnings. They perfect their parts by constant use; they may even acquire new parts as the result of chance influences ; they then work away at these new parts and so they develop them further. Natural selection is only of negative im- portance; it cuts off all unsuccessful attempts at pro- gress.

Butler knew that his views were nearer to those of Lamarck and Erasmus Darwin than to those of Charles Darwin, and wrote a work to prove that Darwin's grand- father, Lamarck, and Buffon, had given a better inter- pretation of evolution than had Darwin. Butler's ideas met with approval from Wallace in England, and from Miiller in Germany, But the psycho- logical bias of his theories did not fit the spirit of the times, and his views were almost completely ignored,

Pauly, of Munich, has formulated (1905) a theory closely similar to that of Butler. He supposes that the organism, in its endeavour to realize its individual purpose, makes some new discovery. This new discovery exerts an influence on the next generation which will, therefore, attain to a greater or lesser degree of perfection, according as the discovery is advantageous or the reverse. The first sea-sponge that produced needles of silica to support its body made a less profitable invention than did the Tuni- cate which discovered the notochord. This notochord, used and perfected by the vertebrates in so many ways, was endowed with greater technical possibilities. The de- cendants of the notochordal creature perfected the organ step by step, until they arrived at that delicate mechanism, the human skeleton. So the first man who rubbed amber on his clothes was leading up to electrical science, though he could have no idea of all the electrical development that would result.

Pauly says that his theory is Lamarckianism, but in this he is mistaken. In his belief in the blind striving of the aspiring organism, he is nearer Darwin than Lamarck, as he is in his very utilitarian ideas about the organic world. Before Butler, Ewald Hering, the physiologist, had pointed out an analogy between the development of body and of soul (1870). Butler looked upon this idea of similarity as a discovery a new fact. Hering regarded it as a pure deduction from Fechner's theory, which affirms that our psychical and our material lives are two parallel aspects of one event.

According to Hering a stimulus causes a reaction in the organism, and leaves behind it some trace in the form of a permanent change in molecular constitution. Conse- quently, when the same stimulus recurs the reaction is somewhat altered. From the moment when it comes into existence an organism is continually exposed to the action of stimuli, and these all leave traces of their action in the inner structure of the organism. Each alters it in some slight degree. Hence we may look on the whole organism as the sum of all the material changes which it has under- gone since the beginning of its existence. It is a principle of psychophysics that the objective side of subjective and conscious memory is a permanent change in the living substance as the result of a constantly repeated stimulation. On this view we may regard memory as the fundamental quality of the organism. All changes in mind and body are the results of this memory.

In the seventies Hering's theory aroused much discus- sion. It made no lasting impression, however, for it con- tained nothing new, but simply used the word 'memory' for the acquisition of new characters, nor did it consider any of the real problems either of mental or of material According to Hering's view, life consists merely of the passive repetition of all that has been learned, all that has been acquired. It teaches that imagination is but the sum of all memories, the organism merely the sum of all acquired characters. It ignores the most characteristic quality of the organism and of the soul that the organism embodies some special idea, and that its mental images assume a special form. This idea, this form, are creations of the organism itself, and are not merely the result of a series of stimuli.

Hering's theory can easily be extended to include an hypothesis about evolution. This step was taken by Semon (1906), who endeavoured to save Darwinism by giving to it a psychological interpretation. He sought material analogies for such psychological conceptions as thought, memory, experience, association, and so on. Following a bad modern fashion he began by giving these entities new names. Mneme which is the title of his work is to represent the sum of all those characteristics acquired by the organism and its ancestors; engramm, a single material change resulting from a stimulus. The words, are, in fact, no aid to the discussion. The work has been favourably received in Darwinian quarters.

Among the earlier biologists, von Reichenau asserted (1881) that evolution among living forms is to be regarded purely psychologically as the effect of the action of will and of choice on the part of the animal ; in his study of secondary sexual characters he suggested that Lamarck and Roux had sought to solve the problem of evolution along these lines. Schopenhauer paid considerable attention to biological problems. His fundamental idea of the metaphysical will is closely related to the problems of instinct and so to those of biology. His works contain a curious mixture of facts, fantasies, and eccentricities. The philosophy of Schopen- hauer is very closely related to Neo-Lamarckianism, in as far as that is a real philosophy and not merely a thought- less reaction against Darwinism. What he has to say about 'will 5 in animals, about Naturphilosophie and science, about sexual life and so on, is still worth reading.

Schopenhauer himself spoke disparagingly of Darwin's theory. He also criticized the mechanistic tendency of Lamarck's views. With remarkable insight into the real inwardness of the problem, he repudiated phylogeny alto- gether, and, in contrast to it, upheld Geoffroy's idea of unity of plan. Edward von Hartmann, who was a pupil of Schopen- hauer, tried to show that there is an intimate connexion between philosophy and science, but he was not able even in this field to avoid the illogicalities characteristic of his