An introduction to comparative psychology

Preface

MY central object in this work is to discuss the relation of the psychology of man to that of llic higher animals, since such a discussion forms in my opinion the best introduction to Com- • parative Psychology. A secondary object, subordinate indeed, yet forming an integral part of my plan, is to consider the place of consciousness in nature, the relation of psychical evolution to physical and biological evolution, and the light which comparative psychology throws on certain philosophical problems. It was my original intention to compare my own results with those which have been reached by previous observers and thinkers in this field of investigation and inquiry. But I found that, in the first place, this would largely increase the bulk of the book ; that, in the second place, it would introduce a controversial tone, which I was desirous of avoiding ; and that it would in other ways interfere with what appeared the most convenient mode of developing my subject. I therefore abandoned my original intention, and adopted a more direct method of exposition and discussion. It is, however, all the more incumbent on me to acknowledge my indebtedness to my predecessors and contemporaries. Those whose acquaintance with the subject is most wide and extensive, will best be able to judge how far what I have written is a

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im-rr it-statement of what has already been written, and h.iw l.ir, if at all, I teve done something towards advancing the boundaries of our knowledge or rendering the knowledge that we possess clearer and more exact. Others will perhaps do well to regard me as a secretary who has, I trust, with due diligence thrown into convenient form the data with which he has been supplied.

It is right that I should particularly call attention to my indebtedness to the works of Mr Herbert Spencer, whose description of relations as " the momentary feelings accompanying transitions" in consciousness contains the germinal idea from which my own treatment of the perception of relations has developed ; of Professor William James, whose conception of a wave of consciousness I have adopted ; of Professor Romanes,* to whom I owe much, and in many ways ; and of Professor Mivart, in whose writings I find many things with which I am in cordial agreement, and not a little from which I must dissent.

In the body of the work there will be found a description of certain experiments and observations on newly-hatched chicks and ducklings, some of which have already been published in the Fortnightly Review for August 1893, and in Natural Science for March 1894. Similar observations have been made by previous observers, and the results obtained by Douglas Spalding and Professor Eimer are often quoted. In my own work on "Animal Life and Intelligence" I cited some of these results.- Shortly

* The death of Professor Romanes, since this too brief acknowledgment of all that I owe to him was written and printed, has entailed a loss to Science which is irreparable, and a loss to his personal friends which lies too deep for words.

PREFACE.

after the publication of that book, I received from my friend, Mr T. Mann Jones, a letter informing me that experiments and observations of his own gave different results, and had led him to regard with critical suspicion much that was written about the " philosopher's chick." He especially adduced the instinctive knowledge of the cry of a hawk, as such, said to be shown by young turkeys in the absence of individual experience, as in his opinion an unwarrantable assumption. I therefore determined to carry out a series of observations for myself, especially as I wished to study association in young birds. The results of these observations are, on the whole, confirmatory of those to which Mr Mann Jones's investigation (which I trust he may be induced to publish) had led him. With regard, therefore, to the observations and experiments in this matter described in this book, I would ask the reader to bear in mind, that they are repetitions of similar observations made by many previous observers; that the results to which they lead differ in some respects from those obtained by Spalding and by Professor Eimer ; and that they are, in their general tendency, confirmatory of the views which Mr Mann Jones has communicated to me, and of the general conclusions on instinct in young birds advocated by Dr A. R. Wallace, Mr W. H. Hudson, and others.

I have laid much stress on the paramount importance of systematic and sustained observation as the only safe basis for conclusions concerning the intelligence of animals. The observations, hereafter- described, of the way in which dogs deal with the difficulty of bringing a stick through vertical railings, affords a case in point. But with regard to this case,

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!iould here state that I have received communicatwo correspondents — Miss M. E. Garnons Williams and "Ouida" — describing observations which show that dogs sometimes meet the difficulty without preliminary bungling. I do not think that such occasional observations invalidate the conclusions reached by systematic investigation. I would, however, urge ill those who have the good fortune to witness the performance of some conspicuously intelligent action in any animal, not to rest content with merely recording it, but to make it the basis of further observation directed to the end of ascertaining its true nature. The records of casual observation are not without their interest ; but the results of detailed investigation arc, for comparative psychology, of far greater value.

I would strongly urge upon my readers the advisability of testing, by careful introspection, all my statements concerning the mental processes of man. Only thus can a valid basis either of appreciation or of criticism be obtained. It must not be forgotten that introspective psychology is an essential preliminary to comparative psychology, and that, if it is to produce results of scientific value, it must be based upon exact and oft-repeated observation. Such observation, however, requires special training, not less than objective observation in physics or in biology. It would be an inestimable boon to comparative psycho-

\ , if all those who venture to discuss the problems with which this science deals would submit to some preparatory discipline in the methods and. results of introspective observation.

I have endeavoured throughout to be self-consistent in my use of technical terms. But it will be noticed

PREFACE. Xlll

that some terms, such as " perception " and " conception," " percept " and " concept," are employed in senses somewhat different from those which are commonly accepted ; and indeed different from those which I had myself been led to adopt in a previous book. On this matter I would court criticism. In another work, now in the press, entitled " Psychology for Teachers," I have further endeavoured to give clear expression to my views in this matter ; and I beg to refer those who are interested in the matter to that work. «

I have received friendly help and criticism from many correspondents, to whom I hereby tender my best thanks. Among these I would especially mention Mr T. Mann Jones, some of whose observations on animals are quoted in the Appendix of Mr Herbert Spencer's volume on "Justice." Mr Jones has been good enough to supply me with much information which is the outcome of his wide experience of domestic animals, and also to give me permission to make use of the information he thus, placed at my disposal. One of my chief grounds for not availing myself of this privilege, is my hoparthat Mr Jones may himself be induced to publish a work on animal intelligence, in which these observations would find a fitting place. But I am anxious here to acknowledge how helpful my correspondence with him has been to me in my own work. Another correspondent who has favoured me with helpful criticism is Mr H. B. Medlicott. If the following pages show that I am not able fully to accept the view which he put forward in his pamphlet on " The Evolution of Mind in Man," I can assure him that I am not the less grateful for the xiv PREFACE.

elucidation of that view with which he has favoured me in private correspondence. I have also to thank my friends Mr Norman Wyld and Mr Sidney H. Reynolds, my brother Dr Llewellyn Morgan, and s A she, for the trouble they have taken in reading much of my work in MS. or in proof, and for the valuable assistance they have rendered me.

In conclusion, I desire to express my indebtedness to the Editors and Publishers of the Fortnightly Review, the Monist, the New World, and Natural Science, for their courteous permission to introduce parts of articles which have appeared in their pages.

After nine years of further observation and reflection, there are some parts of this work which I should like to recast. Among other things, I should come into line with the leading psychologists of recent times in the use of the word " perception." But I am loth to make more changes than are absolutely necessary. Hence, apart from some few additions and corrections, I have restricted the alterations to a restatement of the latter part of the chapter on " Conceptual Thought," and a complete revision of the chapter in wjiich the question, "Do Animals Reason?" is discussed. I have there, as far as space allowed, drawn attention to the results of a large number of recent observations.

C. LLOYD MORGAN.

BRISTOL, September 1903.

COMPARATIVE PSYCHOLOGY.

AN INTRODUCTION

TO

PROLEGOMENA.

IN a treatise on human psychology, it may be possible and advisable to proceed on purely empirical lines and to keep in the background the philosophy of the subject. But in a consideration of comparative psychology, which introduces the conception of evolution, and| of the relation of mind to the organism, such a procedure seems to be neither possible nor advisable. It will conduce to clearness and prevent misconception, therefore, if I here prefix to"rny work an introductory section, containing, in the form of prolegomena, a succinct account of the monistic views which I accept.* Nearly every philosopher contends now-a-days that he is a monist. But there are monists and monists. I must therefore endeavour to state clearly the form of monism which I accept.

First of all, I accept a monistic theory of knowledge. The dualist starts with the conception of a subject introduced

* Those for whom philosophy has no special interest will do well to pass over these prolegomena and proceed at once to Chapter I. Those on the other hand for whom the philosophical interest is central should re-read this section after the perusal of the body of the hook.

A r INTRODUCTION TO COMPARATIVE PSYCHOLOGY.

into the midst of a separately and independently existent objective world. For him the problem of knowledge is how these independent existences, subject and object, can be brought into relation. In the monistic theory of knowledge it is maintained that to start with the conception of subject and object as independent existences is false method, and that the assumed independence and separateness is nowise axiomatic. Starting then from the common ground of naive experience, it contends that, prior to philosophizing, there is neither subject nor object, but just a bit of common practical experience. When a child sees a sweet, or when a dog sees a cat, there is a piece of naive and eminently real experience upon which more or less energetic action may follow. It is only when we seek to explain the experience that we polarize it in our thought into subject and object. But what logical right have we to say that the subject and object, which we can thus distinguish in thought, are separate in existence? No doubt it is a not uncommon, and a not unnatural, fallacy to endow with independent existence the distinguishable products of our abstract and analytic thought. The distinguishable redness and scent of a rflse may thus come to be regarded as not only distinguishable in thought, but also separable in existence. But, until it shall be shown that " distinguishable in thought " and " separate in existence " are interchangeable expressions, or that whatever is distinguishable is also independent, the conclusion is obviously fallacious. And it is this fallacy which the monist regards as the fundamental error of the dualistic theory of knowledge. While dualism, then, starts with what I deem the illegitimate assumption of the independence of subject and object, the monist, starting from the common ground of experience, looks upon subject and object as the distinguishable aspects of that which in experience is one and indivisible. They are distinct from each other, and the distinction is fundamental ; but they are nowise independent and separate in existence. The apparent dualism is a dualism of aspect, not a dualism of existence. It need only be added that this is a theory of knowledge, and of the experience of which knowledge is the outcome. Of that which is not known and not experienced, it neither asserts nor denies anything. But, accepting as it does the reality of experience, it does assert that the aspect which we polarize as objective is just as real, and real in the same sense, as the aspect we polarize as subjective. The reality of object and subject is strictly co-ordinate. And those who hold this view regard as little better than nonsense the assertion that whereas the reality of the subject is unquestionable, the reality of the object is a matter that is open to discussion. Self and cosmos are of co-ordinate reality : they are the polarized aspects of experience as explained through reason.

But a theory of knowledge is not a complete interpretation of nature. There lies on a lonely mountain height a stone. I ascend the mountain, and the stone becomes an object of experience. That we may explain on our monistic theory of knowledge. But how about the stone before I got there, and after I had left the mountain top, when it was not yet or no longer an object of experience ? To this question the theory of knowledge that is modest and knows its business replies : — " I do not know. I deal with experience. I can tell you nothing concerning that which is not yet experienced or no longer experienced. That is a matter of the interpretation of nature."

There are some excellent folk who believe that a philosophy can be built up without assumptions. I am not among their number. Hypotheses, or assumptions, are as necessary in philosophy as they are in science. I assume that nature is wider than actual experience. I assume that the stone on that lonely mountain top exists in some form capable of again appearing as object, and that this continuous existence is quite independent of whether anyone is there to experience it as object or not. I cannot possibly prove this, and do not attempt to do so. I suppose I accept it for this reason, that of the two hypotheses (a) that it continues to exist in some form or other whether it be an object of experience or not, and (l>) that it dodges in and out of existence according as it is experienced or not-experienced, (a) appeals to me as the more rational assumption. Anyhow, if I cannot prove (a), neither can anyone else prove (£). I assume, then, that the world, which forms the objective aspect of experience, continues somehow to exist quite independently of its being sensed or perceived. That there is a nature to interpret is thus an hypothesis or assumption, the sole justification of which is that, though it can never be proved, it accords more satisfactorily with the facts of experience than any other assumption. It does not conflict with, but supplements the monistic theory of knowledge. It fills in the gaps of actual experience with " permanent possibilities " of experience.

I pass now to a second phase of monism. I accept a monistic interpretation of nature. What do I mean by a monistic interpretation ? Well, the essence of this view comes out when we consider the position of man in nature. According to this hypothesis, man, as an organism, is one and indivisible (though variously maimable), no matter how many aspects he may present subjectively or objectively. That the inorganic and organic world have reached their present condition through process of evolution, is now widely accepted. But the dualist contends that mind is a separable existence, sui generis, forming no part of the natural world into which it is temporarily introduced. Here the monist joins issue, and contends that, alike in its biological and its psychological aspect, the organism is the product of evolution ; that mind is not extranatural nor supra-natural, but one of the aspects of natural existence.

Observe the frankly hypothetical nature of this view. The monist assumes that what we call nature is co-extensive with knowable existence. He assumes that far, very far, as we may be at present from anything like a complete or adequate explanation of nature, yet still this nature is explicable, and that by one method, the method of scientific procedure. Herein lies the essence of monism as an interpretation of nature. If in the wide region of the known and the knowable there be any modes of existence which not only are not explicable, but from their very nature never can be explicable, as parts of one self-consistent whole, our monism falls to the ground. We contend that it is this to which science, philosophy, poetry, ay and religion too, has been tending throughout the centuries of human progress.

A monistic interpretation of nature, so long as it holds true to the main principle of being throughout self-consistent, allows any amount of individual freedom in the treatment of details. It is characterized, not by the possession of a common scientific or philosophic creed, but by a common aim. It appears to me, for example, that in the evolution which sweeps through nature, the process is throughout characterized by the following traits: — (i.) It is selective; (2.) it is synthetic; (3.) it tends from chaos to cosmos. And these traits seem to me characteristic alike of inorganic, organic, and mental evolution. Now I dare say there are not half-a-dozen independent monists who will agree with me in singling out these three traits for especial prominence. But what does that matter? My aim is monistic, as is also theirs. And there is plenty of roum for many differences and even divergences of opinion among those who are in search of a self-consistent theory of thought and things.

I now turn to a third aspect of monism, which may be termed analytic monism. This consists in an analysjs^pf the object of knowledge, or in other words, of nature as known and knowable. Now here it is essential quite clearly to l> the fact that all that we know must, in the act of becoming known, be an object of knowledge. The object of knowledge is not merely the object of sense, but includes also the object of thought. All that we know of the subject, all that we attribute to the self, must, in becoming known, be the object of thought. It is only in reflection or introspection, which is also retrospection, that this is possible. You cannot analyse any bit of experience at the moment when it is being experienced, you can only look back upon it in a subsequent moment of reflection. In that subsequent moment it may be polarized into object and subject, and either the objective aspect or the subjective aspect may then be the object of thought. In this way the subjective aspecjt of experience in moment («) may be the object of thoughtexperience in any subsequent moment (g). But never can the subject of experience in any moment be the object of knowledge in the same moment. Hence it follows that without reflection there can be no knowledge of the subjective aspect of experience. And hence it follows also that our knowledge is always dealing with the self of a moment ago. It is an assumption which can never be proved, but one on the validity of which we all place implicit reliance, that the subject is continuous, and that the subject of the present moment is practically identical with the subject of a moment ago, of which we have knowledge through reflective thought.

Let us now take that natural object which we call a man, and let us assume that he is constituted in all essential respects as we are. We analyse him in thought; and we may carry our analysis but a short distance, or as far as ever we can. Analyse him a little way down, and we reach the conception of body and mind. It is clear that the concepts of this analysis are closely connected in origin with the concepts reached by the analysis of experience, and that body and mind are analogous to the object and subject of sense experience. Now the fact to which analytic monism should, as it seems to me, stick close, is that body and mind are the products of analysis. What is practically given is the man ; and this man is one and indivisible, though he maybe polarized in analysis into a bodily aspect and a conscious aspect. It may be said that this is an assumption. Granted. It is part of the fundamental assumption of the monistic interpretation of nature. According to that assumption or hypothesis, the organism in all its aspects is a product of natural evolution. We proceed to study that product. We analyse these aspects. We find that a certain group of them hang together in a special way, and we call them bodily aspects ; and we find that a quite different group of them hang together in their special way, and we call them mental aspects. There is no getting on without an hypothesis of some kind, and this is the one which the monist adopts. The dualist says that the organism in its bodily aspect is a product of evolution, or of some other process of genesis, and that the mind is implanted therein by some extranatural process. That is his assumption. The future must decide which assumption is the more reasonable.

According to the monistic assumption, then; the organism is one and indivisible, but is polarizable in analytic thought into a bodily and a mental or conscious aspect. Body and mind, like object and subject, are distinguishable but not separable. And now we may proceed to carry the analysis deeper. We reach the brain, or some part of it ; and here our analysis discloses, as one aspect, certain forms of nervous change or transformation of energy, and, as the other aspect, certain phases of consciousness. Note clearly that this is merely through carrying further the same process of analysis; and that, of the products of analysis, neither can claim priority or superior validity to the other. They are strictly co-ordinate : each is as real as the other. The true reality

S INTRODUCTION TO COMPARATIVE PSYCHOLOGY.

is the man with which the analysis starts : no valid product of the analysis of that man, through the application of rational thought, can be more real than another.

The question then arises : Given an organism in which analysis gives two aspects, complex energy and complex consciousness, from what have these been evolved by an evolution which is selective,^ synthetic, and cosmic or determinate? From the nature of the case, the bodily aspect is that of which alone we can have objective knowledge. We trace the evolution backwards and find, in our interpretation thereof, simpler and simpler organisms, until the organic passes into the inorganic. We find the energy less and less complex as we look- back through the vista of the past. And what about the other aspect ? Does it not seem reasonable to suppose that, no matter what stage we select, analysis would still disclose the two aspects ? That with the simpler modes of nerve-energy there would go simpler modes of consciousness, and that with infra-neural modes of energy there would be infra-consciousness, or that from which consciousness as we know it has arisen in process of evolution ? This is admittedly speculative. But is it illogical?

Let us return, however, from this speculative excursion, to emphasize again the fact that for monism the organism in practical experience is the starting-point ; that it is one and indivisible, though it has different aspects,, which may be distinguished in analytic thought ; and that these aspects are strictly co-ordinate — neither is before nor after the other.

Opposed to such a view are — (i.) the hypothesis of materialism, according to which the body is the real substance, the mind being one of its properties ; and (2.) the hypothesis of what may be termed psychism, which is, in the words of Charles Kingsley, that " your soul makes your body, just as a snail makes its shell," that mind is the reality and body the mere phenomenal appearance. These views depart from the cardinal principle of monism, which is that practical experience is the fountainhead of reality. They give to one product of the analysis of this experience a validity superior to that of another product of this analysis.

Now analytic monism by itself is insufficient and partial. It is open to the criticism that, while professedly monistic, it postulates a dual aspect, and is therefore merely dualism, in disguise. But this criticism falls to the ground when this a'halytic monism is taken in association with the monistic theory of knowledge and the monistic interpretation of nature and of man. Monism must be judged as a whole, or not at all. Its cardinal tenets are : — That nature is one and indivisible, and is explicable on one method, the method of knowledge; that experience is one and indivisible, though we may distinguish its subjective and objective aspects ; that man is one and indivisible, though our analysis may disclose two strongly contrasted aspects, body and mind. It contends that man in both aspects, biological and psychological, is the product of an evolution that is one and continuous ; and, combining the results of its theory of knowledge with those of its analysis of man, it identifies the mind, as a product of evolution, with the subject, as given in experience.

There is one further result of the analysis of experience upon which I must briefly touch in bringing these prolegomena to a conclusion. Monism regards nature and experience as one and indivisible, and all apparent dualism, as a dualism of aspect, distinguishable in thought, but indissoluble in existence. It contends, as I have endeavoured to show, that the individual mind on the one hand, and the cosmos on the other hand, are alike products of an evolution which is one and continuous. In both the products which we thus distinguish we find a synthesis which is selective and determinate. Empirically, that is as far as we are justified in going. Empirically we must just accept this continuous and progressive synthesis as the ultimate conelusion of science. But it is characteristic of man as a thinker that he is seldom able to stop here. He is constrained to take one further step in his analysis; and it only remains for me to indicate the nature of this final step as od in the light of a monistic philosophy. The selective synthesis of the cosmos, which we call evolution, is regarded as the manifestation, under the conditions of time and space, of an underlying activity which is the ultimate cause thereof. This underlying activity is not a product of i -volution ; it is that in and through which evolution is irndcred possible. In like manner the selective synthesis of my mind, which we term its natural development, is regarded as the manifestation, under the conditions of time .uid space, of an underlying activity, one in existence with and yet distinct in analysis from that of the cosmos at large. This underlying activity, which is the ultimate essence of my individual personality, is not a product of evolution ; it is that in and through which the evolution of my consciousness is rendered possible. Object and subject are thus the correlative modes of manifestation of an underlying activity, one in existence, but none the less fundamentally distinct in aspect.

The questions briefly considered in these Prolegomena have been recently (1903) discussed at length by Prof. C. A. Strong, in a work entitled Why the Mind has a Body. He reaches the conclusion that the reality— the thing in itself — underlying experience and knowledge is consciousness. Those who believe that, amid all the multifarious differentiations of noumenal existence, the most fundamental, for human experience and thought, is that into the diverse aspects of subject and object, mind and not mind— those, I say, who have been led to such a metaphysical interpretation will find it impossible to accept the view that one of these differentiated aspects has preserved all the reality which the other has wholly lost.

THE WAVE OF CONSCIOUSNESS. II

Chapter I. The Wave Of Consciousness

T DO not propose to begin by defining consciousness. Any definition would be found, when analysed, to involve a direct reference to primary experience. I shall therefore assume that my reader has this primary experience; that he is conscious, and that he knows what I mean when I say that he is conscious. And I ask him to verify in his own experience the preliminary statements which I make in this chapter. The first of these is, that we are only directly aware of present states of consciousness. I use the word "present," not in its abstract sense of an ideal boundary between past and future, but as descriptive of a short but not inappreciable period of time. I shall speak of this short period of time as the moment of consciousness. This phrase, as used in this work, is descriptive of the short period which constitutes the now of consciousness. We are only directly aware, I repeat, of that which transpires within the moment of consciousness. This may, however, seem to be contrary to experience. It may be objected that consciousness deals not only with the present but also with the past and with the future ; that this, indeed, is one of its distinctive features. But a little consideration will enable us to see that the past or the future must be made present to consciousness through memory or anticipation. The recollection of this morning's breakfast is a present state of consciousness ; and the expectation of to-morrow's sunrise is also a present state of consciousness. That is to say, in strict phraseology, consciousness does not deal with the past or the future, but with representations of past or future events. And these representations occur in the present moment of consciousness.