§ 1 Of the Fact of the Evolution of Behaviour There Is No Doubt. § 2 Difficulty of Understanding the Process. § 3 Provisional Sketch of the Evolution of Behaviour. § 4 The Efficiency of Mind in Everyday Life. § 5 The Evolutionary Efficiency of Mind.
§ 1 Of the Fact of the Evolution of Behaviour There Is No Doubt.
IN a typical human life, thinking and feeling and willing bulk largely, and we naturally inquire into the historical setting of these capacities. We cannot make the mental states of animals the object of direct observation; on the other hand, we cannot believe that mental states began with Man. So we seek for indirect evidence that animals share them. Can we discern stages in mental evolution? And this raises another question: In human evolution the practical importance of mind is certain; has it also counted in the evolution of organisms?
It should be possible to discuss these questions in a scientific way without going into the metaphysical question whether the stuff out of which the world is built can be thought of as independent of mind, and without discussing the difficult question of the relation of mind to body, if it be rightly called a relation. It goes without saying that we cannot derive mind from anything else of a different kind; if we seem to do so we are deceiving ourselves with verbal jugglery. It may also be said at the outset that if the genetic view we adopt here results in suggesting that animal behaviour is easy to understand or is a commonplace affair, then it is being wrongly stated. Whatever view we take as to the nature of mind and its relation to bodily activity, it is a fact that as we follow the main line of animal evolution, behaviour becomes more masterly, more plastic, more like our own. As regards behaviour the slipper-animalcule is surpassed by the earthworm, the worm by the blackbird, and the bird by the cat. There is increasing freedom, subtlety, and resourcefulness of behaviour. Many will admit this at once, who will not take the further step of supposing that the progressive evolution of behaviour is associated with a clarifying and strengthening of what, by analogy with ourselves, we may call the stream of inner lifethe flow of feeling, will, and thought. We suppose that there is a rill of inner life growing in volume until it becomes a stream, because as we pass from lower to higher animals there is more and more behaviour that we cannot fully describe in purely physiological terms. But before we think tentatively of the stages in the evolution of behaviour, we must give heed to some preliminary considerations.
§ 2. Difficulty of Understanding the Process.
First, we must try to avoid any facile reading of the man into the beast. In ourselves we know that some stimulus often sets agoing a vigorous internal activity of thought-processes, involving an experimenting with imagery and playing with centrally aroused sensations. This goes on in our brain and it brings fatigue. It may be associated with movements in larynx and tongue, with speaking to ourselves, and with changes in eyes and brow and heart; but there is not at the time anything to show for it in our explicit behaviour, and our neighbour offers us a penny for our thoughts. Yet our future actionin the case of a genius, the history of the worldmay be modified by this hour of hard thinking. Is there that sort of inner life of the mind-body in animals? We must not expect too much. Not only is our nervous system a much more differentiated and integrated nervous system than that of even the highest animals, but we have language and we have developed the possibilities it affords of inter-subjective communion. A few animals have a limited vocabulary, but no animals have more than the primordia of language, so we must not suppose that the mental furnishings of animals are like our own. Some experts have warned naturalists that the search for reasoning, imagery, and the like among animals must forever remain futile. On the other hand, we should remember that in our own case there is much in mind besides those inferences which we are accustomed to regard as distinctive of intelligence. There is a continuous flow of mingled sensations, perceptions, ideas, feelings, desires, and volitions,a stream sometimes clear and peaceful, sometimes muddy and turbulent. It is probable that among the lower animals, the flow does not show much in the way of perceptions and ideas, still less in the way of experiments with these. We know that in our own individual development the earlier stages are largely pre-intellectual, mainly emotional. It is extremely improbable that the starfish laboriously disarming the sea-urchin has made any inference on the subject, for its nervous system has no ganglia; but it is difficult to make sense of the operation without crediting the creature with conation, with conation, with something of the nature of endeavour, not necessarily with full antecedent awareness, but with a determination of action in relation to the result that will accrue.
Another great difficulty lies in the fact that at stage after stage, as we have seen, there is a tendency to organisation or automatisation of capacities for behaviour, and if we attend too exclusively to these we are apt to get the impression that the naturalist's suggestion of mind is a mere courtesy to the psychologist. But it is necessary to look into the less conspicuous deviations from routine which sometimes show the hand of mind on the reins, and to inquire into the stages of initiative and testing which may have preceded the automatisation.
Perhaps the biggest difficulty of all is to think of germinal variations supplying the appropriate materials for the evolution of complicated instinctive behaviour or for capacities of perceptual inference. Nowhere does the problem of the origin as distinguished from the survival of fit variations appear so baffling as here.
§ 3. Provisional Sketch of the Evolution of Behaviour.
What, then, shall we say of the Evolution of Behaviour?
(a) A starting-point may be found in the tentative movements of simple creatures, swimming about in the pond, called hither and thither by slight differences in temperature, oxygenation, and the like, or, if there is no particular stimulus, moving in straight lines, or curves, or spiralsexpending their energy, expressing themselves in modes of locomotion which are often characteristic, yet every now and then striking the note of tentative endeavour. There is an occasional new departure, some experiment, a hint of the bent bow. As Professor Jennings Has graphically described, the amba hunts another amba, captures it, loses it, recaptures it, loses it. Much importance must be attached to simple searchings and probings. As the late Mr. Darbishire put it: If Necessity was the mother of Invention, Curiosity was almost certainly its father.
(b) At an early stage there must have been established a number of particular answers to stimuli, which in the case of Unicellulars may be called organic reactions, keeping the word reflexes for creatures with a nervous system. A good illustration is the answer-back so familiar in the case of the slipper-animalcule, Paramecium. To every hurtful stimulation it gives the same answer:it reverses its cilia, it retreats, it twists a little on its axis, it feels its way, and goes full steam aheadoften in this way avoiding the obnoxious stimulus. The capacity of exhibiting this uniform reaction is organised or enregistered in the creature; and these ingrained capacities increase in number.
(c) The next step is the trial and error or perseverance procedure. One reaction is tried after another, till, it may be, one of the movements relieves the creature from stimulation. The Stentor reacts in four different ways to the microscopic dust which the experimenter showers on it; three answers are ineffective, the fourth saves the situation. There is a persisting state of the organism which varies the answers, there is probably a simple expression of conation or endeavour.
(d) The main line is continued in such behaviour as is illustrated by multicellular ganglionless animals like star-fishes. There is persistent co-ordination of acts towards a definite result. There is sensori-motor experimentation. Our picture here is that of the brainless starfish persistently disarming the brainless sea-urchin, wrenching off the pedicellariæ from area after area. This is purposive behaviour, but the purposiveness has not reached a perceptual level. Consciousness is at work, and its precise function in sensori-motor action is to grasp the unique combination of stimuli, each of which having its special reaction modified by the concomitant reactions, there follows a response appropriate to the unique situation as a whole (Hobhouse, Mind in Evolution, 1915, p. 62).
(e) With the establishment of a nervous system there was opened up the possibility of a new kind of hereditary automatisation or organisation,that of reflex actions and tropisms. The former are usually movements of parts of the animal, the latter movements of the whole creature. A reflex action is the predetermined result of the activation of an inborn structural arrangement of receptor, conductor, and effector, which gives a uniform response to a given stimulus. It may be very perfect from the first, or it may improve by practice, or it may result from individual habituation: but typically it is an outcome of pre-established hereditary organisation, definite linkages of sensory neurons, associative neurons, motor neurons, and muscular elements. In effect reflex actions seem purposive, but in process they are organisational. If there was originally an operative purposiveness, it has receded into pre-formed structure.
Our pictures are of the sea-anemone closing its tentacles on a victim, of the nestling opening its mouth at the touch of food in its mother's beak, of the starfish surrendering an arm in the spasms of capture, of the young mammal sucking whatever is put into its mouth. Antecedent to reflexes there is more or less random flow of activity which is now and then definitised in experiment and endeavour. Reflexes imply the establishment of definite channels for the flow.
Tropisms are more or less obligatory movements of the whole organism, or of a large part of it, which automatically make towards securing physiological equilibrium in reference to particular stimuli. Thus an organism moves towards or away from light and heat, electric currents and diffusing chemical reagents, water currents, and the earth and so on. It must not be said that heliotropic animals desire the light or dislike the darkness; the tropisms are more or less forced movements which work automatically like a gyroscope.
Our evolutionary theory is that reflexes and tropisms are economical automatisations, enregistrations, or organisations of capacities which are continually being called into action in the ordinary life of the creature. They require neither thought nor endeavour; they are ingrained and almost as much part of the constitution as, say, breathing movements. Their survival value is (1) that they admit of the rapid automatic execution of life-preservative or species-preservative movements (an automatism for which in unusual conditions there may be a heavy tax to pay); and (2) that they leave the organism more free to use, if it can, the second string of purposive endeavour.
(f) The main line continues in a kind of behaviour which shows evidence of learning, of utilising previous experience to compass an end which is not necessarily immediate. The note of inference is beginning to be sounded. There is experimentation and correlation at a higher level than that of the starfish. It is the dawn of intelligence, and may be illustrated by cases like the following. A young octopus trying to capture a hermit-crab is stung by the sea-anemone which is the crustacean's partner. It avoids further encounters. Old octopuses, however, learn to extract the hermit-crab without touching the sea-anemone. Prof. Lloyd Morgan calls, this profiting by experience through the exercise of intelligence. Dahl relates that when a spider is given a fly that has been steeped in turpentine, it will not for a time dart at another fly of that species. This is like simple learning.
(g) The improvement of the brain opened up a new possibility in the way of hereditary organisationthat of instinctive behaviour. In virtue of inborn nervous predispositions the animal seems to be from the first aware of the significance of certain stimuli and configurations, and obeys an impulsion to a definite routine which is singularly effective, though more or less independent of practice. Pure instinctive behaviour is well illustrated by ants, bees, and wasps; but there and elsewhere it may be mingled with experimental, including intelligent, behaviour. Of instinctive behaviour very perfect in its first performance many pictures rise in the mind:the chick neatly removing the top of the imprisoning egg-shell, the month-old kitten exhibiting without imitation almost a complete repertoire of movements used by the adult cat in catching and killing mice, the young guinea-pig nibbling at a carrot at the end of the first day after birth. In illustration of instinctive activities that improve or change under various influences we may recall the pecking of chicks and the singing of some birds. Of the serial succession of steps in instinctive behaviour there is no better illustration than the way in which the Yucca moth on its first flight visits and pollinates the Yucca flowers and lays eggs in the ovary.
(h) The next level is that of intelligent behaviour, which is characteristic of the higher reaches of the big-brained line of evolution. It implies trial and error experimentation on subtler lines and more definite profiting by experience. Psychologists interpret it as implying perceptualinference, some working with ideas. It is reflective and inferential, as contrasted with instinctive and intuitive.
When the Greek eagle lets a tortoise fall from a height on the rocks below so that its strong carapace is broken, when beavers cut a canal right through an island in a big rivera task not practically justified till completed,when a collie dog at the bidding of a few sounds and signs accomplishes a really difficult thing in the way of sheep-driving, it is probable that we have to do with intelligent behaviour.
We have seen that, at various lower levels of behaviour, the perfecting rôle of practice is recognisable, and this is the case also at the level of intelligence. We are familiar with the individual habituation of exercises which originally required attentive selection and detailed control. Certain structural changes in the nervous system come about as the result of frequent performance, and what was at first laboured becomes very automaticor so facilitated up to a certain point that the mind is free to attend to finishing touches. It is not known, that the results of individual habituation can be entailed in a representative way on the offspring.
(i) The climax is the rational conduct occasionally exhibited by Man. We cannot describe such conduct without using general terms; it involves experimenting with ideas, conceptual as distinguished from perceptual inference; it is controlled with reference to an ideal or conceived purpose. Man has his reflexes and a little instinctive behaviour; most of his activity is either intelligent, or was originally intelligent, but has become habitual; the point is that, if occasion arise, Man may instantaneously pass from a lower level to that of rational conduct.
When we look back over the vaguely discerned succession of modes of behaviour, we detect what may be called the tactics of the evolutionary advance. At level after level, there has been an organisation or automatisation or enregistration of behaviour so that an organism can do things effectively without having to think about it. The answer comes pat, and there is an economy of time and life. In reflex actions, tropisms, and instinctive behaviour we see the activation of capacities which have become part of the hereditary constitution. The great result has been that the organism, freed from having to attend to and control these organised activities, has been able to push on to finer issues. As individuals we are aware of this result being attained by habituation, but there is little warrant for supposing that the successive organisations we have referred to have arisen by the entailment of the results of often repeated performance. We say this because we do not know how it could be arranged, because we have no evidence of the transmission of intelligent-habitual capacities, because some of the most striking pieces of instinctive behaviour occur only once in a lifetime, and for other reasons.
How, then, could the successive organisations be accomplished? The probable answer is that they are all due to germinal variations in the direction of a complexified nervous system. New departures which have been called, from the psychical side, inborn inspirations prompted changes in behaviour, and these were tested and sifted in the individual lifetime. For a time the germinal variation might be in the direction of differentiating and integrating the brain; for a time there might be a specialisation in the seat of some particular activity; and again there might be variation leading to short-circuits.
We are still at the stage of metaphor in regard to the factors in the evolution of behaviour; but metaphor is less dangerous than false simplicity. Our metaphorical picture is thisthe germ-cell just beginning to develop is an implicit organism of great complexity, an individuality in the one-cell phase of its being, a mind-body or body-mind telescoped down. It varies, it makes experiments in internal re-arrangement, in self-expression. It is a blind artist, its sketches are submitted to the criticism of the fully-formed organism, the seeing artist, who will put them in the proper light and bring out what there is in them of value.
If the Amba has in its small way a mind, an aspect of itself corresponding to our mind, and if the Amba uses it when it goes a-hunting,two not unreasonable hypotheses,then it may be that the germ-cell has also its analogue of minda not unreasonable hypothesis, since it develops into a creature with a mind. And this leads us to the hypothesis that the more momentous variations may be inexplicable if we keep only one aspect of the germ-cell in view. And if so, could there be a more relevant opportunity for the mental side showing itself than in variations which lead to new departures in behaviour?
In any case, the hypothesis that hereditary organisation of capacities of behaviour comes about by the entailment of the results of individual practice, experimenting, and learning cannot be readily maintained. On the other hand, while it is difficult to think clearly of the origin of great improvements in behaviour by germinal variation, and of the relative automatisation of them arising in the same way, there is no special difficulty in understanding their persistence on this theory. For variations that arise from within have often great staying power in inheritance.
The Germinal Origin of Improvements in Instinctive Behaviour. We must linger over the difficulty, which many-biologists feel acutely, of trying to account for improvements in instinctive behaviour by variations in the germ-cell.
When an organ, such as the proboscis of an elephant, has shown in successive ages a gradual increase and differentiation, as the skulls of fossil Proboscidea seem to indicate, the non-Lamarckian evolutionist supposes that this is due to the selection of variants in the direction of elongation, these variants being the expressions of appropriate changes in germinal organisation. The change in germinal organisation, say a strengthening of certain primary constituents, operates during the active process of proboscis-development, or of proboscis-growth, for it need not begin to exert its influence until long after the foundations have been. laid. Thus a long-billed bird need not show much or anything in the way of a long bill until after it is hatched. The general idea is that an improvement of structure comes about as the expression of a germinal variation which asserts itself during the activity of development or growth. It is not necessary to think of it as asserting itself only once, for the highly differentiated structure, such as a snail's horn or a newt's lens, may be regrown if it be lost. The germinal variation includes a residual capacity (localised at the base of the horn or in the tissue near the lens) for reproducing or regenerating what has been lost. The general idea, we repeat, is that a cumulative germinal variation, implying a perfecting of some part of the germinal organisation, expresses itself in the course of generations in a cumulative improvement of a certain routine of developmental or growth activity.
If this be admitted as conceivable, then it is not a great step to pass to the improvement of instinctive activities as the result of progressive germinal variations and, of course, the personal testing of these. For the line between development and the expression of instinctive capacity is hard to draw. Both are actualisations of the implicit, the ingrained, the enregistered. Both are expressions of organic memory. As M. Joussain says (1912, p. 156), Instinct is a prolongation of the organising work: the effort by which the chick breaks its shell, frees itself the débris, and begins to walk, is a continuation of the development by which its organs have been built up in the egg. He proceeds to say, though the speculation is not necessary for our point: If the final stroke of the beak is conscious and voluntary, the work immediately antecedent must likewise be so, and thus backwards. It is, then, by its own effort that the egg is developed into a bird. But this will sound absurd to those who are satisfied with the simplicist formulæ of the mechanical school.
Organic Memory. In his interesting Esquisse d'une Philosophie de la Nature (1912), M. Joussain makes much of the conception of organic memory. The transition from mechanism (tropism?) to instinct and from instinct to intelligence, as likewise from automatism to spontaneity and from spontaneity to freedom, is correlated with the extension of memory. In the animal, the complexity and differentiation of the organism are correlated with the extension of specific memory The relative independence of the organism in respect to its environment increases with its complexity and differentiation, and consequently with the specific memory. The higher the animal's degree of organisation, the more it is capable of altering its reactions in answer to stimuli from without, the more reserve of energy it has and freedom in using it. The independence of the creature is thus greater in proportion to the extent'of its remembrance, and in this sense one may say that memory enfranchises it from the dominion of matter.
It seems to us, however, that there is need for discrimination here between the little-brain type, with its climax in ants and bees, and the big-brain type, with its climax in dog and horse. The enregistration of capacities of effective routine reaches a high degree of perfection in ants and bees, and we may call it racial memory if we please. But while it makes for mastery of the usual, it does not bring any gift of freedomnot even of educability. It is an enregistration of capacities of concatenated reflexes, but certainly not of reflection. It is a memory that kills originality. We agree therefore with those who distinguish the enregistering of instinctive capacity from the enregistering of intelligent capacity, the power of discerning relations, of controlled not reflex behaviour. It is comparable in a way to the experience of many students who remember little of what they have learned, read, or even solved, but who have as their reward a capacity of rapid judgment.
§ 4. The Efficiency of Mind in Everyday Life.
There is no use going farther without facing the position of those who maintain that all this discussion is an unnecessary complication of the problem, who believe that to speak of an inner life besides metabolism is only a façon de parler, who regard mind at the best as a useless epiphenomenon.
The first respiratory movements of the newborn offspring are commanded by delicately adjusted inborn structural arrangements in the medulla oblongata; these are set into activity by external stimuli or by slight changes in the alkalinity (Hydrogen-ion concentration) of the blood; and these again are due to a slight asphyxia resulting from the withdrawal of the maternal circulation.
So when it comes to sucking, swallowing, digesting, and the like, appropriate stimuli pull the trigger of pre-formed adjustment, and one reflex process evokes another, and so the creature gets on.
We have an inherited set of triggers called ceptors, contact-ceptors, chemical-ceptors, thermal-ceptors, and so on; and these are connected with wires, nerves, or conductors, which pass on the stimulus to the areas of muscular activity. There may be threshold-resistances to be overcome so that undue impetuosity of response is avoided; there are arrangements for the summation of stimuli, for laying down paths so that action-patterns are formed; and all has a phylogenetic reference, that is to say, neuro-muscular pre-arrangements work well to-day because all has been wrought out through the ages in reference to frequently recurrent problems. It is hardly possible to exaggerate the nicety of adaptivenessthe brain is the storage battery, the muscles the seat of motor activity, the liver makes fuel and helps to remove ashes, the thyroid gland effects speed control, the adrenal body has to do with counteracting the accumulation of acid waste-products, and so on through the inter-dependent series of organs which make up the kinetic system of the body. What need is there for mind? Is it more than a name for versatility of nervous response?
In an admirable exposition of Man as an Adaptive Mechanism, Professor Crile shows how much the human body is good for without any help from the human mind. It is strange, however, that one of his notable advances in surgery is associated with the recognition of the importance of fear or anticipation before operations, and we cannot agree that fear or anticipation is adequately accounted for in terms of physiology. Another strange thing is that Professor Crile includes among the functions of his adaptive mechanism the fabrication of thought. One might say that it was not a good thought that Professor Crile's mechanism fabricated when it conceived of the organism as a mechanism; but his position is theoretically impossiblea contradiction in terms.
The apsychic formulation seems unsound practically as well as theoretically. On the theory that mind does not count, we may make much of a horse or a dog, but certainly not most. There is a great deal of sound sense, we think, in the quaint words of one of the old breeders, Gervase Markham (1C21): You shall beginne to handle and instruct your dogge at four months old; make him most loving and familiar with you, taking a delight in your company, also mix with this familiarity a kindly awe and obedience which you shall procure rather by tenderness than by terrefying him, which only maketh him sly. It is wrong ever to hurry your young dogge, give him time to fix himself and much liberty of movement, handle him firmly hut tenderly. (Quoted by Dr. N. C. MacNamara in his Instinct and Intelligence,1915, p. 183.)
There are two fallacies in the doctrine of the uselessness of mind. In the first place, it ignores the fact that the process of organisation (otherwise called automatisation and still more unfortunately mechanisation) has the effect of increasing efficiency at a higher level. It enables the creature to meet novel circumstances, to experiment, to make a purposeful use of its own experience, which is what we call intelligence. Just as in our own life we practise labour-saving, time-saving, worry-saving methodical devices, so as to have our mind more free for its own adventures, so the consummate registration that the organism exhibits is a device for the emancipation of mind.
The second fallacy is the assumption that what now takes place reflexly, tropistically, or instinctively never required mental control. Without accepting the theory that reflexes have been organised by habituation, we may recall such experiences as learning to ride a bicycle, which show how extraordinarily automatic movements may become which originally required all our attention and a good deal of strong will. In cases like playing the violin the original efforts often require a good deal of intelligence, for those learn best who see clearly the relation of means to end.
Of reflexes, Professor Sherrington writes (p. 388): Perfected during the course of ages, they have during that course attained a stability, a certainty, and an ease of performance beside which the stability and facility of the most ingrained habit acquired during an individual life is presumably small. But theirs is of itself a machine-like fatality To these ancient invariable reflexes, consciousness, in the ordinary meaning of the term, is not adjunct. The subject as an active agent does not direct them and cannot introspect them.
But he goes on to show that, in higher animals especially, reflexes are under some control. We know this in connection with coughing, eye-closing, and smiling. Some people can slow down their heart and suppress the pharyngeal reflex of swallowing. Certain it is, he continues (p. 390), that if we study the process by which in ourselves this, control over reflex action is acquired by an individual, psychical factors loom large, and more is known of them than of the purely physiological modus operandi involved in the attainment of the control.
My mind to me a kingdom is, and to many men the inner life of contemplation, imagination, æsthetic emotion, hard thinking, and the like, is the real life. In everyday human life we see evidence of the efficiency of mind when a man copes with novel difficulties, when he anticipates a rarely occurring risk, when of set purpose he correlates his acts and those of others towards a distant end, when affective states (such as joy) exert a demonstrable influence on the functions of the body. We should not spend time in making such obvious remarks, were it not for the activity of the hard-headed mechanists, who write, for instance, thus: So until the opposite can be proved we must accept the proposition that also human intelligence comprises no psychical factor, and that it has arisen phylogenetically through continual transformation and refinement of physico-chemical nerve-processes.
It is interesting to notice the growing tendency to recognise both physiological and psychological factors in the chain of causation of mental and nervous disorders. Thus Dr. Bernard Hart writes (1918, p. 16): We have, indeed, reached the paradoxical conclusion that, while in many mental disorders mental factors play only a minor part amongst the causes which have produced them, in nervous disorders these mental factors are of fundamental significance. The conviction that in the so-called nervous disorders the predominant part is played by mental causes has been steadily growing during the forty years which have elapsed since the work of Charcot, and has been greatly strengthened by the experience given to us by the war.
§ 5. The Evolutionary Efficiency of Mind.
What is true of the everyday human life is true also in history that mind has counted for much, notably in traditional folk-ways and ideals, and in the external registration of ideas in literature and art. The question is whether mind has practically counted in Animal Evolution.
To this question two extreme answers have been given. According to the thoroughgoing mechanistic school what is called mind has not been in any degree avera causa in evolution. Thus one of them, Le Dantec, writes that consciousness is certainly not an acting partner in the firm of life, it is at most a sleeping partner.
According to the thoroughgoing vitalist school, mind is the essential driving force in all evolutionary change. Thus Samuel Butler maintained that it was necessary to have a psychological theory of heredity and a psychological theory of the origin of organic novelties, besides recognising at every turn that the organism is a genuine purposeful agent, striving, endeavouring, trying to make the best of things. Dr. W. MacDougall may be cited as a modern animist who thinks, for instance, that the truest description of even individual development is one which recognises the efficiency of an anima animans.
Can we steer between the Scylla of Montaigne's generous anthropomorphism and the Charybdis of Descartes's simplicist automatism? We cannot accept the view that mind is the essential driving force in all evolutionary change, since this depreciates what, we may call the physiological driving force inherent in organisms, simply as unified protoplasmic reaction-systems. We quote again what Spinoza said: No one has yet learned from experience what the body, regarded merely as body, is able to do in accordance with its own natural laws, or what it cannot do. On the other hand, we cannot accept the apsychic view, because it gives a false simplicity to the facts, and because it implies a gap between man and animals which our experience of higher animals and lower men leads us to regard as incredible.
Our theoretical position is that certain pieces of behaviour can be approximately formulated in terms of the organisation and metabolism of the animal as treated of in sound physiology of a non-mechanistic type, but that there are other pieces of behaviour which cannot be approximately formulated without postulating factors like desire, conation, imagery, feeling, correlating, putting two and two together, interpreting perception in light of memory, awareness of the relation of means to end, and, in the most advanced stage, deliberately thinking or experimenting with ideas. We are not supposing that these expressions of mentality are independent of metabolism; we say merely that the concept Organism has to be enriched by that of Body-mind or Mind-body.
Our problem, then, is to indicate the lines along which we may look for indirect evidence that Mind, in the sense defined, has counted in Organic Evolution, in life's innumerable venturings. The great Russian embryologist von Baer said that the history of Nature is nothing but the history of the ever-advancing victory of spirit over matter. Was von Baer right or do animals, for instance, play the game all unawares and unbeknown to themselves?
We may refer, to begin with, to the way in which some creatures select their environment. If organisms were agents in producing those novelties which we call variations and mutations, as a bird is an agent in building a nest or a spider in weaving a web, we might say that they were artists of their own fortunes. But the variations and mutations are due to the organism in the germ-cell phase of its being, and, whatever be our surmise, we have no data for speaking of the mentality involved. What we do know, however, is that the full-grown organism sometimes plays these novelties as cards in its game; it puts them to the test of use; it experiments with them; it tries what locks these new keys will fit. It seems to the open-air naturalist indisputable that the organism is an experimental agent.
Prof. James Ward laid emphasis many years ago on what he called subjective or hedonic selection on the part of animals. Without denying the importance of natural selection, he directed attention, to organismal selection. Environment selects organisms, in a metaphorical sense; organisms select environments, in a less metaphorical sense. Creatures seek out corners that please them most, that suit them best; and this selective agency on the creature's part has been one of the conditions of that advance from lower to higher forms which has puzzled so many.
Thuseven if there were no natural selection of variations fortuitously occurring, and even if there were no struggle for subsistence, stillthe will to live, the spontaneous restriction of each individual to so much of the common environment as evokes reaction by its hedonic effects (with the increasing adaptation and adjustment that will thus ensue), and, finally, the pursuit of betterment to which satiety urges and novelty prompts,these conditions, really implying no more than the most rudimentary facts of mind, will account for definite variations to an apparently unlimited extent (Naturalism and Agnosticism, I, 1899, p. 229).
There is little knowledge as yet in regard to variations which arise in response to environmental stimuli, and as to modifications which result from changed environmental influence we do not know that they are transmissible, so that the importance of subjective selection may not be so direct as Professor Ward supposes. But its importance may be great if the organism picks out corners in which it can use its individual peculiarities most effectively, where it can give them a chance, where it can test them, where it can gain elbow-room for having more. Needless to say in attributing importance to the animal's selection of environment, we must walk warily. Professor Ward says that in subjective selection there is nothing metaphorical, but we have to make sure in each case that there is really selection, in which the organism feels and wills and knows. In a green environment a spider-crab masks itself with green Algæ, but it will do this without guidance from its brain. If when covered with borrowed livery of green it be transferred to an aquarium half green, half red, it always goes to the green half. If its livery be red seaweed, put on in a red environment, it will go to the red half. But we must not say very much about the choice being consciously related to the disguise, for a crab that has lived for a while in a green environment is always positively susceptible to green, and will always go to the green side even with no disguise on.
It is probable that personal agency has operated in cases among big-brained animals where there has been a drastic change of habit and habitat. Thus Alfred Russel Wallace referred with reasonable admiration to the water-ouzels or dippers. These well-known birds are relatives of wrens, with very short wings and tail, and very dense plumage. They frequent, exclusively, mountain streams in the northern hemisphere; they fly under water; they walk along the bed of the torrent; they are continually immersed without getting wet. Doubtless the habit was gradually perfected, but it is difficult to escape the view that the dippers showed more than physiological endeavour in utilising their variations in reference to the extraordinary change of life which they illustrate. To some extent they probably selected the. vacant place in Nature which they have won. For here we have a bird, which, in its whole structure, shows a close affinity to the smaller typical perching birds, but which has departed from all its allies in its habits and mode of life, and has secured for itself a place in nature where it has few competitors and few enemies(Darwinism, 1889, p. 117).
There is another promiseful line of inquiry,to study among animals with complex brains any unusual devices which are not part of the ordinary routine of the creatures' life nor absolutely necessary for the survival of the race. It is desirable to exclude, in the first instance, all devices which fall into these two categories, lest we be misled by extraordinary instinctive capacities, which, at any rate, are not so clever as they look. The cases we are thinking of may be illustrated by the way rooks and gulls lift exposed cockles and mussels in their bills and allow them to fall from a height on the hard shingle so that the shells are broken and the flesh made available. It is very unlikely that the device was thought out; but it is probable that the birds intelligently took advantage of a hint which a chance fall afforded.
A third line of evidence may perhaps be found in persistent endeavour towards a distant goal. There is a kind of vital inertia that admits of physiological explanation. A plant goes on growing up to a certain limit, and this may be for a time accelerative, as in the case of a green leaf, which utilises more and more matter and energy the larger it grows. The almost ceaseless movements of relatively simple creatures, like jellyfishes, or of more complex creatures like water-mites, or of still more complex forms like fishes, may illustrate this organic inertia. Perhaps not very much higher is the way in which a burrowing beetle-larva will cat on and on with little or no interruption under the bark of the tree, until its constitution begins to change and it becomes a pupa just below the surface. The degree of conation (if any) that may be reasonably assumed in such cases, must remain at present a matter of opinion. But organic momentum or perseverance proves inadequate when there is persistent, yet interrupted, co-ordination of activities towards a distant result. The following interesting case is quoted by Professor Hobhouse (Mind in Evolution, 2nd Ed., 1915, p. 80).
A sandhopper is feeding amongst seaweed and a crab approaches behind a clump of weed; which he uses as cover. There was a distance of about eight inches between the two animals, which the crab had to cross without alarming his victim. Presently he left his cover, and, crouching down, crept towards the sandhopper. When he had got about half-way, the sandhopper stopped eating, and turned towards the crab, which immediately disappeared in the sand. Presently the sand rose nearer the sandhopper, the crab reappeared, took a stealthy step or two towards the victim, and then sprang upon him. There are here a succession of acts of diverse characterwatching, stealthy creeping, hiding, and pouncing, all brought into operation as the case required. Here is a series of sensori-motor acts adjusted from moment to moment, not to a series of simple sense stimuli, but to the changing phases of a complex situation. Is not this beyond physiologically explicable inertia or momentum?
Those who believe that the only realities are objective physical things and processes (the monistic panhylists) are of course aware of the behaviour of the higher animals, but they regard this as purely objective, leaving consciousness out. Against this view many objections may be urged; Mr. W. P. Montague states four (1912, p. 271). (1) We can be conscious of our behaviour. But if behaviour is itself consciousness, there seems nothing left in terms of which we can define the consciousness of behaviour. (2) Behaviour is always a movement or chain of movements in space either of the organism as a whole or of something in the organism, such as neural current. But the square root of minus one of which we are conscious is not a bodily movement, nor is our consciousness of the life of Julius Cæsar. (3) All that is visible or profitably observable as behaviour relates to movements, with which it is physiologically impossible for consciousness to be identified or even directly correlated. For physiology teaches us that consciousness depends upon, or is immediately and directly bound up with neural currents which are always intra-organic, if not intracortical. (4) Finally, consciousness does at each moment of a train of conscious behaviour have for its contents past incidents of the behaviour that are no longer and future incidents that are not yet. In short, it seems impossible either to get rid of consciousness,a strange psychophobia, or to define it in terms of any objective process.
What is implied in saying that the mind counts in behaviour? What distinguishes an abc-process, in which mind operates, from an ab-process, such as a simple reflex action, which may be called purely physiological? The clearest answer that we know to this question has been given by Prof. C. Lloyd Morgan (1915, p. 10). The c-factor is not mere awareness. It is always pre-awareness. It is always awareness which, by however little, forestalls the coming event; always in a measure anticipatory; always representative of that the like of which may follow in sensory presentation. It is always this at its very lowest level; and at its highest level it is this developed into definite and distinct prevision of ends, thus rising to the fully teleological status. Furthermore its presence or absence, as criterion of mind, is not only a speculative problem but one of inference based on evidence afforded by observation. When an organism profits by experience, as we say,when for example a chick avoids nauseous caterpillars after (and only after) seizing their like in its bill,we may infer pre-awareness of what is, or may be, just coming in further presentation. This is our c-factor in an early phase of development; and even at this early stage the study of behaviour may afford evidence from which its presence or absence may be inferred.
What, then, does such pre-awareness imply? It implies (1) the prior occurrence of direct awareness of like nature; (2) the retention of some change of structure associated with such direct awareness; (3) the revival of awareness in representative fashion; and (4) the time-precedence of this revival to the occurrence of like awareness in sensory presentation. If, for example, a chick has pre-awareness of the taste-meaning of the lady-bird it sees, there must have been prior awareness of live insects as nauseous; the effects of that prior awareness must be structurally retained; the meaning must be functionally revived; and this must preventboth in the older and in the more modern sense of this wordthe recurrence of the nauseous taste in sensory presentation. It is this prevention which renders pre-awareness effective in the guidance of behaviour.
Now, if this view, so clearly expressed by one of the founders of comparative psychology, be correct, we get two flashes of light on the problem of the evolution of mind. While no suggestion can be offered as to the first emergence of the psychical factorsay the pre-awareness of meaning within a sphere of interestwe may find a pre-condition of it in the physiological capacity of registration and retention which has been recognised as one of the characteristics of organisms. And secondly, in the minute structure of the brain (notably the cerebral cortex) of higher animals there is what may be called an appropriate anatomical basis. That is to say, there is a loop-line'system, in which inhibiting or controlling cells intervene between the receptive or sensory centres receiving sense-impressions and the effector or motor centres commanding action. As Prof. Lloyd Morgan tersely puts it, We are now in a position to characterise our abc-process as that of loop-lines whereon pre-awareness, prospective meaning, or prevision of ends, intervenes between the sensory presentation and the response (1915, p. 12).
Very suggestive of mentality are some of the variations in play-instincts as exhibited by kittens, puppies, kids, lambs, and the like. Mr. Hamerton describes the diversity of games exhibited by his young goats, one succeeding another when a new suggestion was made. A psychological element is surely hinted at in cases which seem to the observer like sham-hunts or sham-fights, but it is not the old-established forms of play that seem to us most significant, for they are instinctive. We see more interest in novelties. Thus Dr. Levick gives a graphic description of a pastime among Adélie penguins in the Far South. They would board an ice-floe until it could hold no more, and get carried by the tide to the lower end of the rookery, where every bird would suddenly jump off and swim back against the stream to catch a fresh floe and get another ride down.
A digger-wasp coming to its burrow with a paralysed spider has been seen to place its booty in the fork of a plant away from the ants. Another has been seen to grip a small stone and use it to beat down the earth over its burrow. Forel's ants brought from Alegeria, where they have open, doors to their nests, began to close them with pellets when they were bothered by visitors of other species. Very suggestive also of awareness are some of the normal changes in instinctive behaviour. Thus some woodpeckers bring their young first seeds, then partly opened cones, then complete cones.
The scientific mind is almost morbidly afraid of being too generous; but common sense recoils from making the world magical. Thus it is well known that instinctive behaviour often changes greatly with the state and situation of the organism, and it is usual to give physiological explanations of the change. We often doubt if these physiological explanations are adequate until we supplement them with Prof. Lloyd Morgan's view that instinct is organic behaviour suffused with awareness. Speaking of the Noddy Tern, Prof. J. B. Watson writes: Before the egg is laid the birds are timid and will fly up at the slightest disturbance. After the egg is laid the birds become exceedingly bold. They will fiercely attack the encroachment of any other bird and will even attack the human intruder. A large number of the birds will actually sit on the nest and allow themselves to be removed bodily from it before offering to fly. The egg is kept constantly covered. They turn it round and round with the beak; they go to the water to wet the breast feathers to keep it moist; they shove one another aside, when the shifts are made, without exposing the egg for any length of time. When we are dealing with a big-brained effective organism like a Tern we cannot help feeling that the description does not lose in scientific accuracy by allowing a modicum of awareness.
Another way in which some degree of intelligence may have evolutionary import is in connection with habit-forming. Many of the higher animals are born, with very imperfect capacities, but they eke this out by the rapid acquisition of habits. Given an imperfect pecking-capacity, the adaptation may become perfect by habituation. Now we do not suppose that all habit-forming implies mental processes, but we maintain that some do, namely those which involve an appreciation of the situation. It is said that batting and bowling are hard intellectual exercises, involving a multitude of rapid judgments. So it may be with some vitally important habits of animals; and survival is with the educable.
Some interesting data bearing on our problem may be obtained from a study of what may be called conventions among social animals. Taking penguins again, a case where independent observers confirm one another, we find that the early incubatory task is very arduous, involving in the Adélie penguin a minimum total abstinence from food of about eighteen days and a maximum of twenty-eight. Later on, the two parents relieve one another at frequent intervals, and they have a good deal of what looks like fun. To get more time without leaving the young birds to be killed by skuas or by hooligan cocks (idle bachelors and wicked widowers) the parents pool their offspring in groups, which are left in charge of a few conscientious philo-progenitive persons (there is great individuality among the members of the penguinery), who ward off the skuas and do their best to keep the chicks from straying. The holidaying parents bring food at intervalswhen their conscience smites themand they remain loyal to their own créches. If a story like this stood alone we would think that the generous interpretation we have hinted at was mistaken, but there are a great many stories of this sort, so many that the apsychic theory of the laboratory-naturalists begins to appear like a superstition.
Living creatures are often treated too generously, for they are extraordinarily limited in many ways. This is peculiarly true when instinctive capacities are strong. With different individuals of the now extinct Passenger Pigeon, Professor Whitman made the simple experiment of removing the eggs a few inches outside the nest. The bird returning sat down n the nest as if nothing had happened; seemed to feel dimly, however, that something was wrong; she missed something, she knew not what, for she showed no interest in the two eggs lying within reach; after a few minutes she flew away. Of course we must not be too hard on her, for even rational social personalities sometimes behave in a quite extraordinarily stupid way when their routine is disturbed.
But our recognition of the limitedness that often marks the animal must not be allowed to become an obsession, and we venture to think that there is a good deal to be said for the common-sense view which credits the big-brained type, where instincts are not dominant and where educability is well-marked, with the analogues of our perceptual inference, our simpler emotions and affective states, and our desires and volitions.
If birds, for instance, have no genuine joyousness, they make at times such an extraordinarily good imitation of it, that a statement of the apsychic theory gives one a disagreeable impressionthat if this be accurate, then we are living in a conjuring show.
'Tis the merry nightingale
That crowds and hurries and precipitates
With thick fast warble his delicious notes,
As he were fearful that an April night
Would be too short for him to utter forth
His love-chant, and disburthen his full soul
Of all his music.
Is this good poetry and bad science? Is the joyousness only in the raptured ear of men, or has the nightingale really a full soul?
The critic says: But if the nightingale, why not also the cricket and other insect-instrumentalists? Perhaps the best answer would be Why not?; but we are inclined rather to point out that the bird has a highly developed brain, not on the same line or level as that of higher mammals, but still a fine big brain, which may be reasonably credited with the possibility of a stream of inner life fuller than is likely to flow in any representative of the little-brain line of evolution.
The critic again intervenes, pointing out that these nerve-storms of excitement are due to the liberation of internal secretions, and that they may be induced by injections and by dieting. That of course is the physiologist's business, to work out the series of metabolic happenings; but our point is that in the cases which are experimentally open to us, namely ourselves, we know that a physical event,such as the receiving of good news,will, we cannot explain how, except on the unity-of-the-organism theory or symbolism, set in motion a series of physico-chemical, and vital processes, complex beyond the ken of the wisest.
There is another line of evidence of a particularly interesting kind, that obtainable from the records of trained animals. A dog may exhibit remarkable ability in doing certain things in response to words. Speaking from where he could not be seen in a room in the Johns Hopkins Laboratory, Mr. Dixie Taylor said to his dog Jasper, Go to the next room and bring me a paper lying on the floor. The dog went and executed the command; it appeared to have an associative memory for about a hundred words. Prof. J. B. Watson, a tough-minded behaviourist, ends his chapter on The Limits of Training in Animals by saying the behaviour laboratories must be prepared to admit that the sympathetic upbringing of animals in the home, where they are thrown into constant contact with human beings, does produce in them a certain complex type of behaviour for which the laboratory concepts, as they now exist, are inadequate to supply explanation.
A terrier was allowed in the dining-room, where it sometimes received a bone from the table. The convention was that the door was at once opened for it when it sought exit with the bone in its mouth. It disdained bread. One evening it heard barking outside. It had, however, on that occasion no bone. It snapped up a piece of bread and made for the door. When it was opened, it dropped the bread and ran out to join its fellows (McCabe, Evolution of Mind, p. 222).
Professor Whitman once said that he had studied pigeons for so many years that he got as far inside their heads as it was possible to go without metempsychosis; and it is probable that a reliable appreciation of the depth of animal life may be got by making a sympathetic study of some suitable animal like dog or horse. For there we meet with something approaching our own personality, which leads us on just as our mother's personality did in most momentous ways long ago. The animals also may become aware in new ways of our personality and send out tendrils of intelligence and emotion which are impossible in ordinary circumstances.
Lastly, may we notice once again the risk of concentrating attention on reflexes, tropisms, instincts, predispositions, habituations. If we have read the story aright it is part of the tactics of evolution to increase organisation or enregistration so that freedom may be more worth while. How inaccurate might be a parsimonious account of the intellectual value of the daily routine of a very methodical worker. Only in flashes does the intelligence or the reason gleam out convincingly. We should look out for such flashes in animal life. We see one when a wounded dog, being dressed, checks a bite and turns it into a caress.
Was Hume ironical when he said, No truth appears to me more evident than that beasts are endowed with thought and reason as well as men. The arguments are in this case so obvious that they never escape the most stupid and ignorant. The fact is that it is peculiarily difficult to find evidences of thinking among animals. We cannot find an objective criterion of intelligence; we have to rely on the treacherous argument from analogy. Yet how are we to establish a contact between our mind and a bird's or to find a common denominator between our behaviour and a hive-bee's? We are faced with the dangers of fanciful anthropomorphism on the one hand and false simplicity on the other. Perhaps we should rest satisfied in the meantime with a general cumulative impression. Certainly we should avoid staking any conclusion on particular cases. We must try to refrain from Lo Here! and Lo There! One of the most beautiful things in the world is the dawning of feeling and thinking in a child; it is like the coming of spring. But how impossible it is to punctuate. Similarly we must hesitate as to the boundary lines in Animal Evolution between behaviour which can be adequately described physiologically and that which requires the use of subjective terms if we are to do it justice. Perhaps it does not matter very much, for the organism as we know it is a unity; never only body, never only mind. Our knowledge is not sufficient yet to allow us to say, except in a few cases, when it is acting more as a body-mind and when more as a mind-body. But what seems important in our interpretation of Animate Nature is the cumulative evidence that in organisms also there is a flow of inner life, though it be but a slender rill as compared with our full stream.
There is something to be said, too, if we believe in continuity of evolution. Enthralled as many weak or oppressed human lives are, there is ample experience of self-determination, and, after all, the most potent force in the world may be a new idea. Now, inclined as we are to emphasise man's apartness, we feel the extreme improbability of the view that in the animal world, with which he is solidary, mind does not count. In plain words, the apsychic view is outrageous.
As we follow the main line, of animal evolution we see behaviour becoming more complicated and masterly, more like our own. There is evidence of a rill of inner life growing into a stream, i.e., there is much that we cannot fully describe in purely physiological terms, there is an increasing difficulty in describing what we see without using psychological terms. This proposition can be discussed apart from any theory of the mind-body relation. It must be noted that it is very difficult for Man to get mentally near the lower animals, whose mental stream is probably in greater part pre-intellectual, more conative than cognitive.
(a) In the evolution of behaviour a starting-point may be found in the restless tentative movements of Unicellular Animalcules, not far removed from internal automatic movements, (b) Gradually there is established a capacity for reacting in a uniform way to frequently recurring stimuli, (c) The next step is the pursuance of a trial and error method, one reaction being given after another, until, it may be, one relieves the stimulation. (d) The main line is represented by such behaviour as an amæba exhibits when on the hunt, and this is continued into the sensori-motor experimentation and co-ordination of acts exhibited by ganglionless animals like starfishes, (e) The establishment of a nervous system opened up the possibility of another kind of automatisation,that of reflex actions and tropisms. (f) The main line is continued in experimental behaviour at a higher level, where there is definite evidence of learning, where the creature utilises its own experience to compass an end which is not necessarily immediate, (g) The improvement of the brain opened up the possibility of another kind of hereditary organisationthat seen in instinctive behaviour. There is a hereditary awareness of the practical significance of certain configurations and an impulsion to an effective routine which is in some measure independent of practice. Instinctive and experimental (sometimes intelligent) behaviour are often mingled, sometimes the one element predominates, sometimes the other, (h) The main line is continued into intelligent behaviour, implying experimentation and perceptual inference. Of this in the individual lifetime there may be habituation. (i) The climax is in Man's rational conduct, implying conceptual inference and rational purposefulness.
The general feature of the whole evolution is that organisation or automatisation is effected at stage after stage, so that the organism is able to push on less embarrassed. The general result seems to be a growing emancipation of mentalitygrowing evidence of a subjective aspect over and above ordinary activities.
According to the extreme mechanistic schools, behaviour is, or will be, thoroughly explicable in physiological terms, i.e., in protoplasmic terms, i.e., in physico-chemical terms. Even Man is but an adaptive mechanism, we are told by a physiological authority, who enumerates, however, among the functions of the mechanism the fabrication of thoughtincluding the concept of adaptive mechanism. But this view is a contradiction in terms theoretically, and a contradiction of common-sense practically. On the apsychic theory, that mind does not count, we may make much of horse and dog, but certainly not the most. In man's everyday life (apart from contemplation, imagination, æsthetic emotion, hard thinking, and the like), there is familiar evidence of the efficiency of mind in coping with novel difficulties, in anticipating a rarely occurring risk, in the purposeful correlation of acts towards a distant end, in the influence of affective states (such as joy) on the functions of the body, and so on. Of similar efficiency among animals there is presumptive evidence.
The further question is whether mind has practically counted in Animate Evolution. Some have answered that mind is not in any degree a vera causa in evolution. Others that mind is the essential driving force in all evolutionary change. But a middle position seems more defensible.
There is a physiological driving force in organisms, and in many cases they are body-minds rather than mind-bodies. But the evolutionary efficiency of mind is seen among animals in the search for suitable environments, in intelligent life-favouring devices, in persistent endeavour towards a distant goal, in training the young, in the conventions of social life, in the impelling influence of emotions, and in many other cases. Cunning has been more of a factor than luck.