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Lecture 1: Consciousness, Self-consciousness and the Brain—Mind Problem
Résumé
This lecture is partly in overlapping relationship with the last lectures of my first Gifford series. The usage of the word self-consciousness in contrast to consciousness is considered along with the problem of the development of self-consciousness out of animal consciousness.
The experienced unity of self-consciousness is discussed in relation to the two cerebral hemispheres and in particular to the very recent results obtained by Sperry and his associates using the most subtle and sensitive methods for detection of self-conscious responses of the right hemispheres of commissurotomized patients. This ‘isolated’ hemisphere seems to have a limited self-consciousness in its recognition of faces and objects with appropriate emotional reactions. The various interpretations of these extraordinary results are fully discussed.
The second part of the lecture is devoted to a formulation of the several hypotheses relating to the brain—mind problem and to a critical discussion of the so-called materialist theories of the mind. Two reasons are given for rejecting the claim that these materialist theories are in accord with natural law as it now is. In addition it is claimed that all materialist theories are reducible to determinism which entails a negation of rational discussion. This theme is further developed in Lecture 10. There is formulation and discussion of the alternative hypothesis of dualist-interactionism that was developed in the Lecture 10 of the last series. Finally there is a critical evaluation of the diverse hypotheses formulated by neuroscientists in relation to the brain—mind problem.
1.1 Introduction
Last year in my Gifford Lectures (now published as The Human Mystery, Eccles. 1979a) I traced the line of contingency from the Big Bang to our existence here and now. From that wonderful series of happenings in all their mysterious sequences, I derived much of relevance to the over-riding theme of Natural Theology. The last three lectures dealt in some detail with the structure of the human brain, with conscious perception, with cognitive memory and finally with the brain—mind problem. This series of lectures is planned to continue logically from the first series by considering the wide range of manifestations of consciousness and their relation to the activities in the neuronal machinery of the brain. Hence it is advisable to overlap a little with the last series of lectures in order to establish a continuity of theme between the two series.
Following the procedure adopted by Popper and Eccles (1977) it is proposed to use the term self-conscious mind for the highest mental experiences. It implies knowing that one knows, which is of course initially a subjective or introspective criterion. However by linguistic communication it can be authenticated that other human beings share in this experience of self-knowing. One has only to listen to ordinary conversation, which is largely devoted to recounting the conscious experiences of the speakers. At a lower level there can be consciousness or awareness as indicated by intelligent learned behaviour and by emotional reactions. We can speak of an animal as conscious when it is capable of assessing the complexities of its present situation in the light of past experience and so is able to arrive at an appropriate course of action that is more than a stereotyped instinctive response. In this way it can exhibit an original behaviour pattern which can be learnt, and also which includes a wealth of emotional reactions. Reference should be made to the excellent accounts by Wilson (1975), Thorpe (1974), and Griffin (1976).
You may well ask: when does self-consciousness develop out of such a consciousness? A test for self can be identification in a mirror. Gallup (1977) has found that a chimpanzee can learn with difficulty to recognize itself in a mirror as shown by its use of the mirror image to remove a coloured mark on its face. Monkeys never learn in this way and there are no reported examples with other mammals. So it would seem that anthropoid apes have some primitive knowledge of self, but, as discussed in the last Gifford Lectures (Eccles, 1979a, Chap. 6), a fully developed recognition of self can only be demonstrated in the archeological records of ceremonial burial by Neanderthal man some 80,000 years ago. It can be anticipated that further discoveries will place this critical time much earlier, particularly in view of the evidence from anthropoid apes.
But the above question has also to be asked for the developing human being. The investigations of Amsterdam (1972) lead him to give 18 months for the transition from the conscious baby to the self-conscious child.
Awareness is commonly used as a clinical term to signify that a patient is able to respond to verbal commands and to visual and cutaneous stimuli. One can also use the term self-awareness instead of self-consciousness, but I prefer self-consciousness because it relates directly to the self-conscious mind. However it must not be concluded that the use of this substantive term implies the recognition of mind as a substance in the Cartesian manner. Rather we can refer to mind as an entity. It comprises subjective experiences of all kinds and thus is identical with World 2 as defined by Popper (cf. Fig. 7-1).
The present series of lectures on ‘The Human Psyche’ is necessarily based on the full range of experiences that relate to the conscious self, though concepts of subconsciousness are also explored. There is still the tendency for materialist philosophers to denigrate the term ‘mind’ to ‘minding’ and to reject the substantive use of mind, as was done by Ryle (1949) in his influential book The Concept of Mind. It appeared at that time that the word mind had been finally exorcised, it being sufficient to characterize our experiences of human beings in descriptive terms of their actions and of their verbal behaviour. However Ryle was soon answered in a remarkable book by Beloff (1962) - The Existence of Mind.
Though the disciples of Ryle still actively promulgate reductionism in the various materialist theories of the mind (Smart, 1963; Armstrong, 1968; Blakemore, 1977), there has been from the time of Beloff's book a remarkable reaction in a literature that ranges from a sober re-evaluation of the mind-brain relationships studied in various clinical conditions, for example in the writings of Penfield (1975), Sperry (1976; 1977), Zangwill (1976) and their associates to a veritable flowering of poetic imagery by Jaynes (1976), who begins his extraordinary book On the origin of consciousness in the breakdown of the bicameral mind by a pæan of praise:
O, what a world of unseen visions and heard silences, this insubstantial country of the mind! What ineffable essences, these touchless rememberings and unshowable reveries! And the privacy of it all! A secret theater of speechless monologue and prevenient counsel, an invisible mansion of all moods, musings, and mysteries, an infinite resort of disappointments and discoveries. A whole kingdom where each of us reigns reclusively alone, questioning what we will, commanding what we can. A hidden hermitage where we may study out the troubled book of what we have done and yet may do. An introcosm that is more myself than anything I can find in a mirror. This consciousness that is myself of selves, that is everything, and yet nothing at all - what is it?
And where did it come from?
And why?
We can contrast this rhapsody with the testing procedures of experimental neuropsychology with its coloured patches or gratings, its pure tones and clicks, its taps and vibrations. These are techniques of analytic experiments and must not be regarded as revealing the initial stages, sensa, of the perceptual process, as if for example we sense a picture as a consequence of putting together small colour patches, as in a mosaic. On the contrary perceptions arise in consciousness as fully formed pictures or as sounds of speech or music, being replete with meaning (Gibson, 1966; Thorpe, 1974). It is not of course denied that there are subconscious processes on the way to the conscious perception of pictures or sounds or felt objects of infinite variety, as we shall discuss in Lecture 3.
The brain—mind problem has now come into an exciting era where conference after conference brings together philosophers, psychologists, psychiatrists, neurologists, neurobiologists and experts in machine intelligence. They declaim, they argue, they dispute and may even on rare occasions agree! Moreover there has been a rich variety of books as well as the numerous published texts of conferences. The book The Self and Its Brain by Popper and me (1977) would seem to have achieved the doubtful distinction of being at the centre of a philosophical storm, as witness the spate of critical reviews aimed at it. It is all to the good that there is this revival of interest in the greatest problem confronting us - our nature and our destiny. Perhaps it is good that such emotions are aroused by irreconcilable confrontations. But it is to be regretted that sometimes beliefs are held with dogmatic fervour, and that there may be a lack of humility in the uncritical zeal with which dogmatic beliefs are expounded. Before embarking on a consideration of brain—mind theories in all their diversity and even strangeness, I will consider a most important issue on which there are fascinating experimental investigations, namely our experience of mental unity or singleness.
1.2 Unity of Consciousness and Commissurotomy
It is a universal experience that subjectively there is a mental unity that is recognized as a continuity from one's earliest memories. It is the basis of the concept of the self. Weiss (1969) expresses this well, speaking of
The unity which is my greatest experience: that even though I know I am constantly changing - all molecules are changing, everything in me is being turned over substantially - there is nevertheless my identity, my consciousness of being essentially the same that I was 20 years ago. However much I may have changed, the continuity of my identity has remained undisrupted.
Nevertheless we have two cerebral hemispheres and there has been an amazing range of discussion with respect to their functions and the degree to which they may exercise separate functions. Historically this disputation can be traced back to the identification of the speech centres in the left cerebral hemisphere (Fig. 1-1) by Broca and Wernicke as a result of locating the lesions that caused aphasias. There has subsequently been an enormous literature on the effects of clinical lesions on cerebral function, not only of the linguistic functions, but also for example of the apraxia from lesions of the right parietal lobe. Unfortunately clinical lesions are usually not well circumscribed and so do not give clear localization for the disordered function. A remarkable advance was made by Gordon Holmes who systematically investigated injuries by missiles in the First World War in order to define the topographic localization of the visual field in the occipital lobe (cf. Popper and Eccles, 1977, Fig. E2-5).
Most important information on the functions of the various lobes (Fig. 1-1) of both hemispheres has been derived from studies by Milner and others of patients in whom circumscribed lesions were made for therapeutic reasons (cf. Chap. E6, Popper and Eccles, 1977). However by far the most important evidence relating to the unity of consciousness comes from the studies by Sperry and his associates on commissurotomized patients. In the operation there was section of the corpus callosum, the great tract of nerve fibres, about 200 million, that links the two cerebral hemispheres (Figs. 1-2, 1-3, 1-4). It must be recognized that the connections of the hemispheres to lower brain regions remain intact. It must further be recognized that the two hemispheres have been intimately linked in all the cerebral activities of the subject prior to the operation, and that each hemisphere will carry the memories of these many years of conjoint performances.
 It is fortunate that severing this immense linkage by the 200 million fibres of the corpus callosum gives so little apparent disability to the patient, so much so that nothing significant was recognized until Sperry carried out his very discriminative investigations. The general performances of the body in standing, walking, diving and swimming and in sleeping and waking are still normally linked because the cross-linkages at lower levels of the brain are not affected by the commissurotomy (cf. Fig. 1-4). In Chap. E5 of Popper and Eccles (1977) there is fairly comprehensive account of all the discriminative testing of hemispheral performance after the commissurotomy.
    In summary, (Fig. 1-5) we can say that the left (speaking) hemisphere has a linguistic ability not greatly impaired. It also carries a good memory of the past linked with a good intellectual performance and with an emotional life not greatly disturbed. However it is deficient in all spatial and constructional tasks. By contrast the right hemisphere has a very limited linguistic ability. It has access to a considerable auditory vocabulary, being able to recognize commands and to relate words presented by hearing or vision to pictorial representations. It was also surprising that the right hemisphere responded to verbs as effectively as to action names. Despite all this display of language comprehension, the right hemisphere is extremely deficient in expression in speech or in writing, which is effectively zero. However, in contrast to the left hemisphere, it is very effective in all spatial and constructive tasks and it is also proficient in global recognition tasks.
Gordon et al. (1971) found that the unity of conscious experience was conserved after section of the anterior and middle thirds of the corpus callosum. It was concluded that the linkages of the parietal and occipital cortices in the posterior third are vitally concerned in conscious unity. However the commissural linkage between the frontal lobes must not be excluded because this linkage could be conserved by a transcallosal pathway that operates via the immense association connections to the parietal and temporal lobes and their intact callosal connections.
When more sophisticated investigations were developed, allowing up to 2 h of continued testing, it became clear that the right hemisphere was displaying evidence of conscious responses at a level superior to those exhibited by any non-human primates. It will be appreciated that there is no indubitable test for consciousness, but it is generally accepted that the higher animals, birds and mammals, display conscious behaviour when they act intelligently and emotionally and are able to learn appropriate reactions. On those criteria the consciousness of the right hemisphere is indubitable, as is diagrammed in Fig. 1-2. The perplexing question is whether the right hemisphere is self-conscious, meaning by that, that it knows and is conscious of its selfhood. As stated by Sperry et al. (1979):
Self-consciousness appears to be almost strictly a human attribute, according to present evidence drawn mainly from mirror self-recognition tests. It seems not to be found in animals below the primates, and only to a limited extent in the great apes. In human childhood self-consciousness makes its appearance relatively late in development, appearing first at around 18 months of age. Thus ontogenetically as well as phylogenetically self-consciousness can be rated as a relatively advanced stage of conscious awareness.
Sperry et al. (1979) report investigations on two commissurotomy patients which were designed to test for aspects of self-consciousness and general social awareness in the right hemisphere. In these tests a wide variety of pictures of persons as well as of familiar objects and scenes were presented in assembled arrays to the left visual field of the patient and hence exclusively to the right hemisphere (cf. Fig. 1-3). The subject could always identify the familiar photograph in the ensemble of pictures, but there were difficulties in specifying what it was and the investigators had to adopt a rather informative prompting system before the right hemisphere identification could be expressed in language, presumably by the left hemisphere. Their dramatic conclusions of approximate equality of the two hemispheres in identification may be criticized as being derived from a rather optimistic over-interpretation of the subject's responses, as illustrated in the experimental protocols. Nevertheless there is remarkable evidence in favour of a limited self-consciousness of the right hemisphere. I quote the most convincing account of the last part of a testing session in which the subject LB had been expressing his approval or disapproval of various photographs of persons by thumbs up or thumbs down signalling by his left hand.
Towards the end of this testing session, LB was presented with a choice array containing 4 portrait photos of adult males, 3 strangers and one of himself in the lower left position. When asked if he recognized any of these LB pointed promptly to the photo of himself. Asked for a thumb sign evaluation, he gave a decisive ‘thumbs-down’ response but unlike other ‘thumbs-down’ signals, this one was accompanied by a wide, sheepish and (to all appearances) a self-conscious grin. When we then asked if he knew who it was, LB after only a short hesitation guessed correctly ‘myself’. Interpretation: LB recognized himself readily with the right hemisphere. The tongue-in-cheek ‘thumbs-down’ response to his own photo accompanied by a broad grin indicates not only self-recognition in the minor hemisphere but also a subtle sense of humor and self-conscious perspective befitting the total situation. The emotional effect was transferred centrally and also peripherally and was sufficiently distinctive, combined with other cues, that the left hemisphere soon guessed the correct identification.
It can hardly be doubted that the right hemisphere has at least a limited self-consciousness.
In summary Sperry et al. (1979) state:
The ability of the commissurotomy subjects with visual input lateralized to the left half field to recognize, select and identify from among neutral items in a choice array pictures of themselves, their family, relatives, acquaintances, pets, belongings and also political, historical and religious figures and personalities from the entertainment world, all at a level quite comparable to that of the left hemisphere of the same subject is taken to indicate the presence in the right hemisphere of a well developed sense of self and social awareness. The kinds of emotional reactions that were generated and the selectivity of responses to follow-up questions of the examiners and to vocal cues from the subjects’ own comments showed that true identifications were made in the right hemisphere… It was possible to exclude significant assistance from the vocal hemisphere in the initial identification process in most instances because the content of the vocal comments indicated that the speaking hemisphere had remained unaware of what the mute hemisphere had recognized and was reacting to.
The overall level of the right hemisphere's ability to identify test items and also the quality of the accompanying emotional and evaluative responses were of the same order approximately as those obtained from the right visual field and left hemisphere. Occasional discrepancies between left field and right field renonses were the exception rather than the rule, and did not exceed the intrahemispheric range of variation from one test session to another and in general can hardly be considered indicative of valid left-right differences. Taken together, the present data strongly reinforce the assumption that human subjectivity is basically much the same in the two hemispheres.
Actually the emotional reactions generated by picture stimulation of the right hemisphere would be dependent on the connectivities to the limbic system in particular (cf. Lecture 5), which are unaffected by commissurotomy and so are able to spread to the left hemisphere to give a consciously experienced emotion (cf. Fig. 1-4).
These tests for the existence of mind and of self-conscious mind are at a relatively simple pictorial and emotional level. We can still doubt if the right hemisphere has a full self-conscious existence. For example, does it plan and worry about the future, does it make decisions and judgements based on some value system? These are essential qualifications for personhood as ordinarily understood (Strawson, 1959; Popper and Eccles, 1977, Sects. 31 and 33). Let us now consider the bearing of these findings on the unity of the consciously experiencing self.
As pointed out by DeWitt (1975), very important problems are raised by the commissurotomy investigations of Sperry and associates and a wide range of interpretations has been offered.
(1) Puccetti (1973) is the most extreme in that he regards the commissurotomy patients as having two minds with radically different properties, and each of these is a distinct person. In fact he goes so far as to propose that this dual personality obtains before the commissurotomy. I quote his actual statements:
Either commissurotomy results in two minds or it does not; if it does, it also yields two persons.
But even this last statement is misleading. How can commissurotomy create two minds or persons if there was just one before? Which mind, the left brain-based one or the right brain-based one is brand new? And how are we to make a choice here? Both brains, as we have seen, were conscious and functioning in their rather specialised ways before the operation. It is just that they then functioned more synchronously - because of the commissural connections … If that is so, if we cerebrally intact twin-brained human beings are really compounds of two persons, which is me? Am I the person whose conscious unity is rooted in left brain information-processing and right hand motor control; or am I the person whose consciousness is based in right brain activity and subordinate left hand control?
(2) Sperry (1976), Bogen (1969) and Gazzaniga (1971) also propose that there are two self-conscious minds, i.e., the commissurotomy has split the mind into two, even the self-conscious mind, but normally there is only one person. (Bogen, 1969) states:
One of the most obvious and fundamental features of the cerebrum is that it is double. Various kinds of evidence, especially from hemispherectomy, have made it clear that one hemisphere is sufficient to sustain a personality or mind. We may then conclude that the individual with two intact hemispheres has the capacity for two distinct minds, - each of us has two minds in one person.
(3) The view of MacKay (1978) and Eccles (1979a) is that in commissurotomy a conscious mind has been split off in association with the right hemisphere, the left hemisphere remaining with a relatively intact self-conscious mind and the associated personhood.
DeWitt (1975) makes the point that the presence of language marks the difference between the existence of self-consciousness and the complete absence of any awareness of self. I would agree in general, but I worry about what is meant by language because the right hemisphere certainly has a fair performance in understanding language though it is at zero level in expression (Zaidel, 1976). I think that, in the light of Sperry et al.'s (1979) recent investigations, there is some self-consciousness in the right hemisphere, but it is of a limited kind and would not qualify the right hemisphere to have personhood on the criteria mentioned above. Thus the commissurotomy has split a fragment off from the self-conscious mind, but the person remains apparently unscathed with mental unity intact in its now exclusive left hemisphere association. However, it would be agreed that emotional reactions stemming from the right hemisphere can involve the left hemisphere via the partly unsplit limbic system (Fig. 1-4). So the person remains emotionally attached also to the right hemisphere.
I would agree with DeWitt's (1975) interpretation of the situation after commissurotomy:
Both minor and major hemispheres are conscious in that they both, no doubt, have the basic phenomenal awareness of perceptions, sensations, etc. And they both have minds … in that they exhibit elaborated, organised systems of response hierarchies, i.e., intentional behaviour. But in addition I would conjecture that only the major hemisphere has a self; only the language utilising brain is capable of the abstract cognising necessary in order to be aware of itself as a unique being. In a word, only the major hemisphere is aware of itself as a self.
This corresponds to the situation in real life, where the associates of the patient find no difficulty after the operation in regarding it as the self or person that it was before the operation. The patients themselves would of course concur, but they do have a problem arising from the splitting of the conscious mind. There is the difficulty in controlling the movements emanating from the activity of the right hemisphere with its associated mind. These movements are completely beyond the control of the conscious self or person that is exercised through the left hemisphere. For example they refer to their uncontrollable left hand as their ‘rogue hand’.
It would seem that this interpretation of DeWitt conforms with all the observational data on the commissurotomy subjects, but avoids the extreme philosophical difficulties inherent in the hypothesis of Puccetti that even normally there is a duality of personhood - ‘two persons in one brain’ as he provocatively expresses it.
Nagel (1971) has presented a critical study of the findings on commissurotomized patients in an attempt to arrive at a solution of the numbers of minds and numbers of persons! He finds it difficult to conceive what it may be like to be a commissurotomy patient. He favours the hypothesis that they have two minds, but finds this in conflict with the behavioural integration displayed by the patients. So he finishes with a destructive critique of the whole concept of the person and retreats to some behavioural control system within the brain and between the hemispheres that somehow unites all the complexities of the individual person. But he regards the unity of the person as an illusion!
One recognizes the difficulties raised by the splitting of the mind in commissurotomy and even more so in the existence of a fragment of the self-conscious mind associated with the isolated right hemisphere, but this is no excuse for Nagel's pessimism, as he calls it! We can agree with his statement in footnote 11 that commissurotomy is just one way of dividing the brain. There could be cortical deconnections within one hemisphere, separating the prefrontal lobes, as was bilaterally done in prefrontal leucotomy for example. But, as we shall see in Lecture 2 the liaison of mind with brain must not be treated as a problem of limited regions of action. It will be proposed that the self-conscious mind normally is in liaison with an immense territory of cortical modules that are dispersed through the whole neocortex. Furthermore it has to be recognized that there is an immense ongoing operation of communication between modules by impulses in the association fibres of one hemisphere numbering about two thousand million as well as the 200 million commissural fibres. It is this immense communication system that enables the spatio-temporal patterns of activity in the 4 million modules (cf. Lecture 2) to give in coded form the extremely rich information that is read out by the self-conscious mind and that is the basis of our ineffable experience of mental unity.
1.3 Hypotheses Relating to the Brain—Mind Problem
1.3.1 Introductory Considerations
It is not possible here to give a detailed appraisal of the immense philosophical literature on the brain—mind or body—mind problem. Fortunately this has recently been done in a masterly manner by Popper (Popper and Eccles, 1977, Chaps. P1, P3, P4, and P5). He has critically surveyed the historical development of the problem from the earliest records of Greek thought. I will begin by a simple description and diagram of the principal varieties of this extremely complex and subtle philosophy, concentrating specifically on the formulations that relate to the brain rather than the body, because clinical neurology and the neurosciences make it abundantly clear that the mind has no direct access to the body. All interactions with the body are mediated by the brain, and furthermore only by the higher levels of cerebral activity.
For our present purpose it is of value to clarify the arguments firstly by introducing the three-world philosophy of Popper (cf. Fig. 7-1) and secondly by developing an explanatory diagram (Fig. 1-6) of the principal theories so that the materialist theories of the mind can be contrasted with the dualist-interactionist theory that is here being proposed.
World 1 is the whole material world of the cosmos both inorganic and organic, including all of biology, even human brains, and all man-made objects.
World 2 is the world of conscious experiences, or of the mind, not only of our immediate perceptual experiences, visual, auditory, tactile, pain, hunger, anger, joy, fear etc., but also of our memories, imaginings, thoughts, planned actions, and centrally thereto of our unique self as an experiencing being.
World 3 is the world of human creativity - for example the objective contents of thoughts underlying scientific, artistic and literary expression. Thus World 3 is the world of culture in all of its manifestations, as has been expressed by Popper in Chap. P2 of Popper and Eccles (1977).
1.3.2 Survey of Brain—Mind Hypotheses
The dominant theories of the brain—mind relationship that are today held by neuroscientists are purely materialistic in the sense that the brain is given complete mastery (Pribram, 1971; Rensch, 1971, 1974; Barlow, 1972; Doty, 1975; Wilson, 1976; Blakemore, 1977; Mountcastle, 1978b; Edelman, 1978). The existence of mind or consciousness is not denied, but it is relegated to the passive role of mental experiences accompanying some types of brain action, as in psychoneural identity, but with absolutely no effective action on the brain. The complex neural machinery of the brain functions in its determined materialistic fashion regardless of any consciousness that may accompany it. The ‘common sense’ experiences that we can control our actions to some extent or that we can express our thoughts in language are alleged to be illusory. Actually it is rare for this to be stated so baldly, but despite all the sophisticated cover-up the situation is exactly as stated. An effective causality is denied to the self-conscious mind per se.
In Fig. 1-6 World 1 is divided into World 1P and an infinitesimally small World 1M. In general, materialist theories are those subscribing to the statement that mental events can have no effective action on the brain events in World 1— that World 1 is closed to any conceivable outside influence such as is postulated in dualist-interactionism. This closedness of World 1 is ensured in four different ways in the four varieties of materialism illustrated in Fig. 1-6.
1) Radical materialism: It is asserted that all is World 1P. There is a denial or repudiation of the existence of mental events. They are simply illusory. The brain—mind problem is a non-problem!
2) Panpsychism: It is asserted that all matter has an inside mental or protopsychical state. Since this state is an integral part of matter, it can have no action on it. The closedness of World 1 is safeguarded.
3) Epiphenomenalism: Mental states exist in relation to some material happenings, but causally are completely irrelevant. Again the closedness of World 1 is safeguarded.
4) The identity theory or the central state theory or the psychoneural identity theory: Mental states exist as an inner aspect of some material structures that in present formulations are restricted to brain structures such as nerve cells. This postulated ‘identity’ may appear to give an effective action, just as the ‘identical’ nerve cells have an effective action. However the result of the transaction is that the purely material events of neural action are themselves sufficient for all brain—mind responses, hence the closedness of World 1 is preserved. This has been very well argued by Beloff (1976).
An outstanding characteristic of identity theories that centre around Feigl's (1967) brilliant formulation is the multiplication of names for theories that are almost indistinguishable. Not only are there the three names given above, but there are for example: emergent interactionism (Sperry, 1976, 1977); identistic panpsychism (Rensch, 1971); physicalism (Smart, 1963, 1978); biperspectivism (Laszlo, 1972); emergentistic materialism (Bunge, 1977).
In contrast to these materialist or parallelist theories are the dualist-interaction theories, as diagrammed at the bottom of Fig. 1-6. The essential feature of these theories is that mind and brain are independent entities, the brain being in World 1 and the mind in World 2, and that they somehow interact, as illustrated by the arrows in Fig. 1-7. Thus there is a frontier, as diagrammed in Fig. 1-7, and across this frontier there is interaction in both directions, which can be conceived as a flow of information, not of energy. Thus we have the extraordinary doctrine that the world of matter-energy (World 1) is not completely sealed, which is a fundamental tenet of physics, but that there are small ‘apertures’ in what is otherwise the completely closed World 1. On the contrary, as we have seen, closedness of World 1 has been safeguarded with great ingenuity in all materialist theories of the mind. Yet I shall now argue that this is not their strength, but instead their fatal weakness (cf. Popper and Eccles, 1977).
 1.3.3 Critical Evaluation of Brain—Mind Hypotheses
Great display is made by all varieties of materialists that their brain—mind theory is in accord with natural law as it now is. However, this claim is invalidated by two most weighty considerations.
Firstly, nowhere in the laws of physics or in the laws of the derivative sciences, chemistry and biology, is there any reference to consciousness or mind. Shapere (1974) makes this point in his strong criticisms of the panpsychist hypothesis of Rensch (1974) and Birch (1974) in which it was proposed that consciousness or protoconsciousness is a fundamental property of matter. Regardless of the complexity of electrical, chemical or biological machinery there is no statement in the ‘natural laws’ that there is an emergence of this strange non-material entity, consciousness or mind. This is not to affirm that consciousness does not emerge in the evolutionary process, but merely to state that its emergence is not reconcilable with the natural laws as at present understood. For example such laws do not allow any statement that consciousness emerges at a specified level of complexity of systems, which is gratuitously assumed by all materialists except panpsychists. Their belief that some primordial consciousness attaches to all matter, presumably even to atoms and subatomic particles (Rensch, 1971), finds no support whatsoever in physics. One can also recall the poignant questions by computer-lovers. At what stage of complexity and performance can we agree to endow computers with consciousness? Mercifully this emotionally charged question need not be answered. You can do what you like to computers without qualms of being cruel!
Secondly, all materialist theories of the mind are in conflict with biological evolution. Since they all (panpsychism, epiphenomenalism, and the identity theory) assert the causal ineffectiveness of consciousness per se, they fail completely to account for the biological evolution of consciousness, which is an undeniable fact. There is firstly its emergence and then its progressive development with the growing complexity of the brain. In accord with evolutionary theory only those structures and processes that significantly aid in survival are developed in natural selection. If consciousness is causally impotent, its development cannot be accounted for by evolutionary theory. According to biological evolution mental states and consciousness could have evolved and developed only if they were causally effective in bringing about changes in neural happenings in the brain with the consequent changes in behaviour. That can occur only if the neural machinery of the brain is open to influences from the mental events of the world of conscious experiences, which is the basic postulate of dualist-interactionist theory. As Sherrington (1940) states:
The influence of mind on the doings of life makes mind an effective contribution to life. We can seize then how it is that mind counts and has counted. That has been evolved seems to assure us that it has counted. How it has counted would seem to be that the finite mind has influenced its individual's ‘doing’.
Finally the most telling criticism of all materialist theories of the mind is against its key postulate that the happenings in the neural machinery of the brain provide a necessary and sufficient explanation of the totality both of the performance and of the conscious experience of a human being. For example the willing of a voluntary movement is regarded as being completely determined by events in the neural machinery of the brain, as also are all other cognitive experiences. But as Popper states (Popper, 1972, Chapt. 6).
According to determinism, any theory such as say determinism is held because of a certain physical structure of the holder - perhaps of his brain. Accordingly, we are deceiving ourselves and are physically so determined as to deceive ourselves whenever we believe that there are such things as arguments or reasons which make us accept determinism. In other words, physical determinism is a theory which, if it is true, is unarguable since it must explain all our reactions, including what appear to us as beliefs based on arguments, as due to purely physical conditions. Purely physical conditions, including our physical environment make us say or accept whatever we say or accept.
This is an effective reductio ad absurdum. This stricture applies to all of the materialist theories. So perforce we turn to dualist-interactionist explanations of the brain—mind problem, despite the extraordinary requirement that there be effective communication in both directions across the frontier shown in Fig. 1-7.
Necessarily the dualist-interactionist theory is in conflict with present natural laws, and so is in the same ‘unlawful’ position as the materialist theories of the mind. The differences are that this conflict has always been admitted and that the neural machinery of the brain is assumed to operate in strict accordance to natural laws except for its openness to World 2 influences.
Moreover, as stated by Popper (Popper and Eccles, 1977, Diaogue XII), the interaction across the frontier in Fig. 1-7 need not be in conflict with the first law of thermodynamics. The flow of information into the modules could be effected by a balanced increase and decrease of energy at different but adjacent micro-sites, so that there was no net energy change in the brain. The first law at this level ‘may be valid only statistically’.
1.4 Recent Proposals by Neuroscientists in Relation to the Brain—Mind problem
After this introductory survey I turn to some recent theoretical developments that have been proposed in relation to scientific studies on the brain. We can assimilate these various theories into the framework of Fig. 1-6.
Sherrington was the pioneer in the endeavour to reinstate the conscious mind as an effective agent in controlling brain activity, and so to contradict the basic beliefs of behaviourism and scientific materialism. Already in his Rede Lecture (Sherrington, 1933), he had proposed the dualism of mental experience and brain and their interaction. In his Gifford Lectures of 1937 and 1938, here in Edinburgh, he made this brain—mind problem the central theme, building up and elaborating a great structure of dualist-interactionism (Sherrington, 1940; Eccles and Gibson, 1979, Chap. 7).
Later I developed Sherrington's ideas especially in relation to the known anatomical and physiological properties of the neocortex (Eccles, 1951b, 1953).
As early as 1952, Sperry had published on the relationship of brain to mind, and from 1965 to the present time he has progressively developed a brain—mind theory that he calls emergent-interactionism. This theory has some very subtle aspects that I and others (e.g. Popper) find elusive. Nevertheless, it was of great importance that a brain scientist with a deservedly great reputation should develop an hypothesis that was in conflict with the materialist monism of the behaviourist establishment. I will discuss his theory in relation to its expression in one of his most recent publications (Sperry, 1976) and give quotations therefrom. In a more recent paper (Sperry, 1977) there is a similar account.
The essential postulates of his theory are initially the orthodox anatomy and physiology of the neocortex with their emergent phylo-genetic development. On this basis he postulates an operational derivation of the conscious properties which are assumed to have causal potency in regulating the course of the brain events. He states that
‘the subjective conscious experience becomes an integral part of the brain process’ and that
‘the mental events are causes rather than correlates. In this respect our view can be said to involve a form of mental interactionism, except that there is no implication of dualism or other parallelism in the traditional sense. The mental forces are direct causal emergents of the brain process’.
But then he goes on to speak of
‘the holistic conscious properties … of the brain process. These special mental properties have not been described objectively as yet in any form. They are holistic configurational properties that have Yet to be discovered. We predict that, once they have been discovered and understood, they will be best conceived of as being different from and more than the neural events of which they are composed’.
It seems that Sperry is here postulating that there are holistic configurational properties of mental events that are composed of neural events of a lower order. The dilemma arises because he avoids dualism by not giving the mental events an independence from neural events, yet at the same time he gives the mental events a causal influence on the neural events in a typical dualist-interactionist manner, stating that ‘the brain physiology determines the mental effects and mental phenomena in turn have causal influence on the neurophysiology’. I find it difficult to accept Sperry's rejection of dualism, because this rejection seems in conflict with his proposal of the most important operational considerations on brain—mind interaction and the derivations therefrom. There will be further references to his theory in Lectures 6 and 7. Already there has been consideration of his theory of emergent interactionism in relation to problems of consciousness in the hemispheres of the commissurotomized brain. The rejection of dualism leads to the only alternative position, namely a very sophisticated identity hypothesis (cf. Fig. 1-6) relating to the
emergent holistic properties of high order cerebral processes, and further that these emergent phenomena will be seen to play a potent causal role in brain function that cannot be accounted for in terms merely of the neurophysiologic and neurochemical events as these are traditionally conceived (Sperry. 1976).
I wonder if the spatio-temporal patterning of modular actions that are now being proposed (Szentágothai, 1978 a, b, 1979; Eccles, 1979a; Chaps. 2, 3 and 4 below) would qualify as the emergent holistic properties of the neocortex.
Very recently a theory of emergentist materialism has been proposed with great display (Bunge, 1977; Bunge and Llinás, 1978) that in most features is almost the same as the emergent interactionism just described that Sperry has been proposing since 1965. Unfortunately these authors make no reference to Sperry. It is also regrettable that their attack on dualist-interactionism reveals that they are ignorant of its essential features. Bunge and Llinás (1978) apparently believe that according to dualist-interactionism the mind is independent of the brain and not in interaction with it! Otherwise how could they ask?
How is it possible that an aloof nonphysical mind can be so mercilessly demurred by such a relatively simple molecule as the lysergic acid diethy1 amide? How is it that physical parameters which change the functional properties of the brain change the faculties of the mind?
They are refuting an extraordinary dualist-interactionism of their own invention! And again (Bunge, 1977):
Unlike dualism, which digs an unbridgeable chasm between man and beast, emergentist materialism jibes with evolutionary biology, which-by exhibiting the gradual development of the mental faculties along certain lineages-refutes the superstition that only Man has been endowed with a mind.
Contrast this arrogant claim with the open discussion in the preceding section on the Unity of Consciousness and Commissurotomy; as well as many later discussions in these lectures. Here is an example of the extravagant overselling that Bunge (1977) indulges in:
emergentist materialism is the only philosophy of mind that enables a breakthrough in the scientific investigation of the mind-body (or rather brain-rest of the body) problem - and that defends neuroscience against obstruction by obsolete philosophies and idealogies.
All this is very impressive for the layman, but why write this in a scientific publication that is distributed to neuroscientists who have been getting on quite well these many years before Bunge arrived in 1977? Nevertheless there are some redeeming features amongst all this pomposity:
For example, rather than say that love can color our reasonings, we may say that the right brain hemisphere affects the left one, and that sex hormones can act upon the cell assemblies that do the thinking.
This seems to suggest that Bunge gets all tangled up with love, and why omit the hypothalamus? And so we leave him, but reference can be made to MacKay's (1978) criticism and devaluation.
On analogy with information systems engineering MacKay (1978) proposes that
the direct correlate of conscious experience is the self-evaluating supervisory or ‘metaorganizing’ activity of the cerebral system that determines norms and priorties and organizes the internal state of readiness to reckon with the sources of sensory stimulation. On this view, although all the modules of the cerebral cortex could normally participate in the loops of information-flow to and from the supervisory system, their activity in isolation would not be the direct correlate if our conscious experience. This view would take the concept of conscious human agency as primary, and recognize an irreducible duality in the two kinds of correlated data we have about it: (a) the data of our conscious experience, and (b) the data obtained from observation of our brain workings. The essential condition is that our conscious form-determining activity must be embodied in, rather than running alongside, the brain activity that physically determines (at the energetic level) what our bodies do.
I have much sympathy with this effort of MacKay to preserve the causal effectiveness of human agency without coming into conflict with the first law of thermodynamics, but I fail to understand it in terms of the properties of neurones and neurone assemblages. What is the neural status of the postulated ‘supervisory system’, and where is it located?
It is surprising to find that panpsychism is still alive. Rensch (1971, 1974) has developed this philosophy at great length and with a wealth of detail from his knowledge of biology and Birch (1974) also expressed a panpsychist philosophy. Rensch repeatedly states that dualist-interactionism is contrary to the fundamental laws of physics, but, as pointed out above, Shapere (1974) criticizes Rensch's hypothesis on the grounds of its incompatibility with physics. Rensch (1971, p. 272) expresses an extraordinary panpsychism where he considers ‘the evolution of consciousness from protopsychical elements to self-consciousness’ by a series of stages from elementary particles up eventually to higher organisms with ‘sensation, memory, stream of consciousness’.
The varieties of identity theory expressed by Barlow (1972) and Doty (1975) have already been described (Popper and Eccles, 1977, Chap. E7) and conform to the brief description given above in relation to Fig. 1-6. Their views may be taken as typical of the great majority of neuroscientists (cf. Mountcastle, 1978b). Uttal (1978) has given an authoritative account of the brain—mind problem that is based on the identity theory of Feigl. He flatly rejects dualistinteractionism.
Creutzfeldt and Rager (1978) base a dualist interpretation of the problems relating consciousness to brain events on a sophisticated philosophical analysis that stems from Kant and Husserl. They do not consider in detail the neural events that could be related to mental events, but make some important general statements:
Our reason cannot accept any attempt to reduce experience of the human self to neurophysiological facts and to establish a monism of information.
If neurophysiology as a science cannot explain phenomena such as perception, experience, consciousness or free will, we ask how indeed they can be envisaged. The only way of looking at them is to reflect upon the context in which they appear.
We should always keep in mind that even a complete knowledge of the connectivities and operation of the brain - if this is at all possible cannot explain the phenomena of our life experience. Even the most complete scientific image of our conscious experience is bound to be a mere image and not the experience itself.
These general statements will be of great value as we explore various aspects of the human psyche in these lectures.
Lorenz (1977) has also presented valuable insights into the brain—mind problem - or body-soul problem as he calls it:
What matters here is solely the fact that the gulf between the physical and the spiritual is of a fundamentally different kind from that between the organic and the inorganic, and that between man and the animals. These latter gulfs represent transitions, and each owes its existence to a unique event in the evolution of the world. Not only can both be bridged by a theoretical continuum of intermediate forms, but we also know that these transitional forms have indeed existed at specific moments in time… The ‘hiatus’ between soul and body, on the other hand, is indeed unbridgeable, albeit perhaps ‘only for us’, - … that is, with the cognitive apparatus at our disposal. Yet I do not believe that this is a limitation imposed just by the present state of our knowledge, or that even a utopian advance of this knowledge would bring us closer to a solution of the problem. The autonomy of personal experience and its laws cannot in principle be explained in terms of chemical and physical laws or of neuro-physiological structure, however complex.
Here is a clear recognition of the duality of mind and matter. There are some neuroscientists (Kety, 1969; Thorpe, 1974; Penfield, 1975) who subscribe to a dualist-interactionist philosophy such as that expressed by Popper and Eccles (1977). Thorpe in particular has presented a philosophy almost identical with that which I will be developing in Lecture 2.
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