An Introduction to Comparative Psychology
Chapter 18: The Evolution of Consciousness
C. Lloyd Morgan
WE have, so far, taken for granted the existence of consciousness, and the fact that there are subjective phenomena which we, as comparative psychologists, may study. We have also proceeded throughout on the assumption that subjective phenomena admit of a natural interpretation, as the result of a process or processes of development or evolution, in just the same sense as objective phenomena admit of such interpretation. The question now arises: If consciousness exists, and if consciousness, as we know it, has been evolved, from what has it been evolved? It must be freely and frankly admitted that any suggestion which the comparative psychologist has to make, in attempting to answer such a question, must be speculative. But we must not be afraid of speculation so long as it is on scientific lines, and so long as the basis of speculation is honestly and fearlessly laid bare, and not slurred over and beclouded by ambiguous phraseology. Speculation is but the play of the imagination along the fringe which borders our knowledge; and imagination is the mother of insight.
It has before been pointed out that one of the cardinal steps in making our psychology comparative, and in linking, this branch of science with those branches which deal with the objective aspects of our knowledge, is the correlation of psychical phenomena with physiological phenomena. It would be as idle as it would be disingenuous to pretend that this correlation had as yet been carried far. From the nature of the case, the difficulties of investigation are enor-
(328) -mous. And much of the experimentation in physiological psychology -valuable as it undoubtedly is-deals with questions which are mainly physiological, and hardly touch psychology at all. But such work as has been done tends to strengthen and not to weaken the validity of the assumption ; and, further, suggests that in and through this correlation we may seek a yet wider correlation of that which objectively we know as energy, and that which subjectively we know as consciousness.
Let us, however, put the matter in more concrete form. The dog that, as I write, looks up in my face with eyes so full of affection and of intelligence, suggests a double problem. How has that organic frame, with the bright brown eye and the warm active brain, been evolved, and from what ? How has that keen intelligence and the consciousness it implies been evolved, and from what? We may look at the matter first and chiefly from the point of view of the development of the individual (ontogenesis).
In the common course of generation the dog is developed from a minute egg-cell, one hundredth of an inch or less in diameter, with which a yet more minute sperm has entered into fertile union. Supplied with shelter, warmth, and nutriment, by that maternal self-sacrifice which is a deeply significant fact of organic nature, this little speck of living stuff passes, by a process strictly continuous, though profoundly modified by the catastrophe of birth, into the dog, with its, wealth of intelligence and affection. It is surely impossible, without extravagance, to speak of the fertilized ovum as conscious. Where, then, in the continuous process -of development does consciousness come in ? How, and whence? We are not now-a-days to be put off with the ambiguous assertion that consciousness and intelligence are Cc potentially" present in the germ. We ask: What is actually present therein as the basis of this potentiality? And if we are told that consciousness dawns at, or shortly after, the
(329) catastrophe of birth, then again we ask: Whence comes this dawning consciousness, and by what means does it become associated with the puppy's brain ?
Having thus opened up these several questions, all of like implication, let us now endeavour to set forth the answer which seems most closely in accordance with scientific analogies. And to this end let us consider the living dog. His frame is pulsating with life and restless activity, and somehow associated with the transformations of energy in that brain of his there are states of consciousness. Were his skin, and the walls of his skull, as transparent as glass ; did the molecular vibrations of his brain lie open to our curious scrutiny ; could we trace in detail all the varied and orderly transformations of energy of which that brain is the theatre, -- the accompanying consciousness would still be beyond our reach. We might follow the changes of energy ; he alone would feel the states of consciousness. Now suppose that the dog dies. His body lies before us stiff with the rigor mortis. If we had weighed it previous to death, and if we were to weigh it again after death, the scales would give us no information of the departure of anything material. All signs of consciousness, however, are gone, And could we see through skin and skull into the brain, which during life was the theatre of so complex and orderly a sequence of transformations of energy, we should find that it was still and motionless. We are therefore justified in saying that, omitting minor qualifications, the orderly transformations of energy in the brain and the concomitant consciousness cease together at death. Closely associated during life, varying together in health and sickness, ceasing together at death, what is the nature of their connection?
Let us regard the matter from the objective aspect first, from the side to which the occurrences present themselves as transformations of energy. The state of consciousness being ex hypothesi accompanied by certain molecular vibra-
(329) -tions in the brain or some part thereof, we have to note that from the physical point of view these molecular vibrations constitute an exceedingly complex and orderly mode of energy. It is upon this energy that we must fix our attention, the material structure of the brain being what we 'may call the vehicle of its manifestation. We are too apt to regard the structure as the essential thing on which to concentrate our mental gaze, partly, no doubt, because, through the invaluable labour of microscopists, we know so much that is definite about this structure. But a more penetrating insight enables us to see that the structure is merely the necessary basis of what is the really important thing-the manifestation of energy. The material structure of a steam-engine is of importance. But why ? Because it is the vehicle for the performance of work. That is the really essential part of the business. In like manner nerve-structure is of importance. But why ? Because it is the vehicle for the complex and orderly manifestation of energy. The essential importance of looking at the ,ping machine, at the performance of work, at the energy of the matter in motion, not merely the material structure that is moved,the essential importance, I say, of fixing our attention on this, being fairly grasped, we may now proceed to inquire from what the complex and orderly vibrations of the dog's brain have been evolved. In the fertilized ovum from which the dog was developed (and the same is true of the amoeboid ancestor from which, hypothetically, the race of dogs -has been evolved), there is certainly nothing approaching the orderly complexity of these molecular vibrations. But there are simpler organic modes of motion from which these complex molecular vibrations have arisen by a continuous process of development. It is from these simpler modes of energy in the simpler organic substance of the ovum that the more complex modes of energy which characterize the workings of the dog's brain have been evolved. In the
(331) development of the ovum into the embryo, and thence into the puppy and the dog, we may trace step by step all the stages of the evolution of those material structures which are the vehicles of these special manifestations of organic energy. We may watch the further and further differentiations of the nervous tissue, and the fashioning of the brain and its parts. It is true that we cannot indicate the exact moment when, in the increasing complexity of the tissues, the simpler forms of organic energy pass into the higher form of brain energy accompanied by consciousness. But that is just because it is a continuous development, an evolution. That the passage from the one into the other does actually take place we are bound, by all tile canons of logical reasoning, to admit It is only during life, however, that brain activity occurs, or is possible. A great number of modes of organic energy proceed side by side in the pulsating tissues of the living dog, their orderly continuance being what we term life. And only in and through their orderly continuance is the maintenance of the structure of the tissues rendered possible. The organic structure is like a spinning-top. Only so long as it spins and manifests its proper energy is its stability maintained. All around it are forces which tend to make it totter to its fall. But so long as it spins freely it can resist all minor attempts to upset its stability. And when the dog dies, what happens then ? The specialized molecular vibrations of the brain, in common with other forms of organic energy, cease. The top no longer spins, and the structure totters to its fall. Decomposition sets in. The orderly organic changes which characterize life, give Place to the destructive changes which characterize decay But according to the law of the conservation of energy, although there is decomposition of the tissues of which the body was composed there is no destruction or annihilation' of energy. The particular modes of energy through which the body was instinct with life pass away ; but only to give
(332) rise to their equivalents in other modes of energy. just as the puddle in the road disappears, but only to give origin to an equivalent mass of invisible water vapour ; just as the candle disappears, but only to give rise to its equivalent mass in the products of combustion,-- so throughout life and death the energy which throbs in the tissues neither appears nor disappears except at the expense of, or to the gain of, other modes of energy. Life is like a vortex in a rapid stream ;-on surrounding energy it is dependent for its continued existence ; into surrounding energy it melts away. And this is true not only of individual life, but of life in its entirety.
Turning now from the objective aspect to the subjective aspect, we pass from neural processes to states of consciousness. The states of consciousness in the dog's mind are the subjective aspect of what, from the objective aspect, are the molecular vibrations of his brain tissues. And as in considering the matter objectively, so now, in regarding the mental aspect, we must ask from what the complex and orderly states of consciousness of the dog's mind have been evolved. In the fertilized ovum from which the dog is developed (and the same is true of the amoeboid ancestor from which, hypothetically, the race of dogs has been evolved), nothing so complex as a state of consciousness is to be found. From what then have the states of consciousness been evolved ? Do we not seem forced by parity of reasoning to answer: --Frorn something more simple than consciousness, but of the same order of existence, which answers subjectively to the simpler organic energy of the fertilized ovum ? Such, at any rate, is the hypothesis which appears to me the most logically consistent. It requires, however, no little effort of thought to conceive the existence of those elementary states from which consciousness may have had it-, origin. We may be aided in doing so, perhaps, if we fix our attention on the close association of brain-energy and
(333) states of consciousness, regarding them as distinguishable, but not separable. Now, the nervous energy of the brain is extraordinarily complex; and yet we believe-that it arises by a process of continuous development from the much less complex energy of the fertilized ovum. In the ovum there is no brain-energy; there is only the far simpler germinal energy from which it is evolved. So, too, the consciousness in the dog's. mind is wonderfully complex; but if it has arisen by a process of development, it must have been evolved from something of like nature, only indefinitely simpler. May we not fairly suppose, therefore, that in the fertilized ovum, though there is no consciousness, there are the germinal states from which consciousness may be evolved? Or, to put the matter tersely, may we not say: As the complex molecular vibrations of the brain are to, the simpler molecular vibrations of the ovum, so are the complex states of consciousness associated with the former to the simpler states of infra-consciousness, if we may so call them, associated with the latter. It is the association of consciousness and infra - consciousness with energy - its objective manifestation-that is the distinguishing feature ofthe view which I am endeavouring to set forth. Concomitant with the evolution of higher modes of organic energy from those lowly modes which alone obtain in the ovum or the amoeba, is the evolution of consciousness from lowly modes of infra-consciousness.
We must now take a further step, -- one, however, in which all evolutionists will not be prepared to follow us, For those, however, who believe that the organic has risen on this earth by process of natural development from the inorganic, the hypothesis must be more sweeping in ]is range. We must say that all modes of energy of whatever kind, whether organic or inorganic, have their conscious or infra-conscious aspect. Startling as this may sound, there is, I believe, no other logical conclusion possible for the
(334) evolutionist pur sang. For where are we to draw the line ? The states of consciousness of the higher animals have been evolved from lower forms of infra-consciousness in the amoeba-like or yet more simple protoplasmic germs in the dawn of life. But if those low forms of organic infra-consciousness were themselves evolved, from what could they arise, if they were not developed from yet more lowly forms of infra-consciousness, similar in kind, but inferior in degree, associated with inorganic modes of energy? In any case it is here submitted that this doctrine, that infra-consciousness is associated with all forms of energy, is necessarily implied in the phrase mental evolution for all thoroughgoing evolutionists who have grasped the distinction between consciousness and energy. And if this be admitted there is disclosed, by implication, an answer behind and beyond that ordinarily given to a question which has again and again been asked-the question : Is there a conservation of consciousness analogous to the conservation of energy ? The negative answer generally given to this question results from the fact that the question itself has always been put in a form which does not admit of a satisfactory solution. There is not a conservation of consciousness any more than there is a conservation of nerve-energy or a conservation of electrical energy. There is no conservation of nerve-energy, because this is only one mode of energy which may be transformed into other modes. Not until we have generalized energy so as to include all its modes can we speak ,of conservation in reference to it. So, too, not until we have generalized that universal form of existence, of which consciousness is only the highest and most developed mode, so as to include all modes, can we speak of conservation in reference to it. But so generalized, I submit that there is a conservation of that form of existence which includes both consciousness and infra-consciousness, co-ordinate and co-extensive with the conservation of energy. just as the
(335) dominant nerve-changes in the dog's brain are like a special vortex in the onward-flowing stream of the world's energy, so are the states of consciousness in his mind like a special vortex in the onward-flowing stream of that mode of existence which, whether it have risen to the level of consciousness or not, is still of the conscious and infra-conscious order. For the believer in scientific monism there is but one vortex, objectively presented as energy, subjectively felt in consciousness. For the dualist there are two vortices, -- (1) an objective vortex, and (2) a subjective vortex, each associated with the other. In either case the vortex is dependent for its continual existence on surrounding stores of that out of which it has arisen; and in either case the modern tendencies of scientific thought suggest conservation, which is but the antithesis of creation ex nihilo.
A few words in conclusion, to present the matter from a somewhat different point of view. Consciousness exists : of that there is no doubt. How did it come to exist? There seem three possible answers to this question :-(I.) It was specially created in man, or in some lower organism from which man has been evolved ; (2.) It has been directly evolved from energy; (3.) It has been evolved, as I have suggested, from infra-consciousness.
Now, the first answer-- that of special creation-is, in my opinion, a logically tenable one, and one with which I have sincere sympathy. I do not hold it myself, because it does not seem to me either the highest or the most probable view of the matter; but if others hold it on these grounds, so let it be. With the second answer I am in distinct and direct antagonism. I do not think it has a single genuine fact of observation or a single rational inference from observation in its favour. Its supporters may be left to make out a case for it if they can. The third answer is that which I have endeavoured to set forth. If, then, these three answers exhaust the logical possibilities of the case,
(336) and if the second is inadmissible, through default of evidence in its favour, we are left in presence of the first and third. Either special creation, or evolution from infra-consciousness ; there is no other alternative.
Accepting as I do the alternative of evolution, I nevertheless see in this evolution the continuous manifestation of a synthetic synthesis, which finds its expression in the primary laws of nature and of mind, and with which I. shall deal further in the next chapter. Herein I seem to find the essence of the whole process, that which makes it comprehensible and rational. Regarding man physically and psychically as the crowning product of this evolution, I nevertheless conceive him to be the self-conscious outcome of an activity, selective and synthetic, which is neither energy nor consciousness; which has not been evolved, but through the action of which evolution has been rendered possible ; which is neither subject nor object, but underlies and is common to both.