Science in Christian Perspective

The Relationship Between the 
Brain and the Mind
D. GARETH JONES
Department of Anatomy and Human Biology
University of Western Australia
Nedlands, West Australia

From: JASA 33 (December 1981): 193-202

Taken from Our Fragile Brains by D. Gareth Jones. Copyright 1980 by Inter- Varsity Christian Fellowship of the U.S.A. and used by permission of Inter- Varsity Press.

Mental Phenomena and the Brain

The "mind-body problem" concerns the way we think about states of consciousness on one hand and states of behavior on the other. What is the interaction between thoughts, feelings and the organ responsible for their expression, the brain? The problem, at heart, is how to hold together the obvious characteristics of people and their external behavior, and the not-so-obvious characteristics such as their internal mental states. Often the dilemma is expressed as the tension between the material and the immaterial, between brain and mind, between body and soul. Thought, feelings and beliefs are frequently described as constituting the mind; with increasing comprehension of brain mechanisms, however, they may seem to be products of physical brain processes rather than, or at least as much as, of an immaterial mind or spirit.

Although the mind-body problem is an old issue in philosophy, advances in the neurosciences over the past twenty or thirty years have forced the neuropsychologist to deal with it also. Manytopics, especially the split-brain and the brain-damage/personality paradigm, highlight the problem in a new way. Whether they help solve that longstanding dilemma is debatable.

The mind-body problem forces neuroscientists to consider not only their philosophical position on that question but also the nature of their science. Inevitably neuroscientists start from their knowledge of the brain as a physical entity, or of the individual as a group of observable behavior patterns. Once confronted by the possible existence of an immaterial mind, neuroscientists must assess the adequacy of their observable base of physical 

A danger of dualism is that once body and mind are separated, the mind 
can be dealt with as a separate entity.

phenomena. They must ask whether it alone provides an all embracing framework for a complete view of the individual person as a human being like themselves. By the very nature of the scientific endeavour, neuroscientists may find themselves drawn toward some form of materialist answer without analyzing the philosophical implications of such an answer.

Let us briefly review the major positions that have developed in the debate, starting inevitably with Rene Descartes and dualism. Descartes devoted some thought to neurobiological considerations along with his better known mathematical and philosophical studies. Living at a time when the natural sciences were being revolutionized by mechanistic thinking, Descartes compared the universe to a vast machine capable of being explained by purely mechanical laws. Everything, including man himself, was encompassed by these all-powerful explanatory principles. In arguing thus, Descartes was being true to his rationlism. Yet, unable to follow rationalism to its logical conclusion, he allowed one exception to his mechanical world view: the human mind.

Descartes, intent on doubting the evidence of the senses and calling in question even the validity of his perceptions of the world, felt able to fall back on the trustworthiness of his own consciousness. Hence the fundamental divide within dualism between the physical body and the nonphysical mind or consciousness, the former a prisoner of the mechanical world order but the latter the author of uniquely human characteristics such as rational thought and free choice. For Descartes it was the nonphysical mind which rendered a human being unique and which carried the marks of personhood. That nonphysical side of humans-the mind, soul or consciousness-was the critical one, constituting alongside the body, one of the two basic substances of the world.

The essence of classic dualism is the existence of body and mind as distinct substances. They were regarded by Descartes as totally interdependent, interacting aspects of a living being. If that is so, however, the way in which they interact becomes a problem. According to Descartes, the mind took up no space but acted on the body through the brain's pineal gland. The nonmaterial mind could thus influence physical happenings in the material brain. The hallmark of this view, interactionism, is the implicit suggestion that two different types of reality can affect one another.

Cartesian dualism was little challenged from Descartes's time in the seventeenth century until the late ninteenth century. The inherent difficulty of two different substances acting on each other, however, led some dualists to adopt an aberrant version of dualism, called parallelism: the mind and body are still distinct, but run along parallel tracks. To declare them independent proved a convenient way out of the interactionist dilemma, but opened the window to an influx of weird speculation. Without any control of each other, body and mind could go their own ways even to the extent of dispensing with the material body altogether.

We shall return to dualism in the next section when considering the viewpoint of contemporary neurophysiologist John Eccles. But before leaving dualism we should note one reason for its continuing influence up to the end of the last century and, in some quarters, up to the present: it seemed to offer support for the Christian belief in an immortal soul. Reflecting the Platonic concept of the soul, the classical form of that belief was strongly dualistic. A danger of dualism, however, is that once body and mind are separated, the mind can be dealt with as a separate entity. A modern consequence of dualism is that drug-induced perceptions and beliefs can be regarded as a valid-even a commendable-expression of reality. John Lilly is a modern exponent of parallelism. A perennial danger of that outlook is that the exaltation of mind takes place at the expense of the whole person.

The major difficulty with dualism is the unknowability of internal mental states if we have no way of analyzing them by way of behavioral or brain states. If mental states are not publicly observable, we cannot even be sure that we are justified in ascribing them to other people at all. The chasm between unknown internal states and known external ones makes information on how mental and brain states are to be linked difficult (some would say impossible) to obtain. It is far from clear whether any links between the two are of a causal nature; hence the possibility of parallelism.

The difficulties associated with dualism have led to an array of alternatives positions. The first alternative is, strictly speaking, a version of dualism with similarities to parrallelism. In epiphenomenalism, a nonmaterial mind is considered to exist but is an epiphenomenon or byproduct of physical events. Consequently, the conscious events of the mind are unable to influence the physical brain and its processes. The thoughts, moods and decisions of an individual, therefore, are powerless to influence that individual's actions.

Epiphenomenalism, like classic dualism, accepts an immaterial mind. On the other hand, like materialism, it locates the origin of mind in the material brain. It is a compromise that seems to exhibit the difficulties of both positions without satisfying exponents of either. The contention of epiphenomenalism that consciousness has no effect on the way the brain operates makes a mockery of human beliefs, actions and conscious choices. For anyone with a high view of the human person and human brain, epiphenomenalism is unsatisfactory.

A more rigorous alternative to dualism is behaviorism, with attempts to eliminate nonphysical mental states altogether by reducing them to patterns of behavior. That form of behaviorism is sometimes referred to as negative behaviorism, signifying that it is essentially a metaphysical doctrine rather than a straightforward psychological technique.

For a behaviorist, any talk about a mind is simply an inaccurate way of talking about human behavior. It is a form of linguistic confusion because the mind is neither a thing nor a substance, in the way the brain is a thing. Only the brain can be referred to in these terms; such terminology is inappropriate when referring to actions, thoughts, feelings and desires. If they are expressions of brain states, they are best described and analyzed using behavioral concepts.

By denigrating individual consciousness within a Skinnerian framework, behaviorism is driven to look for forces controlling individual behavior either in the physiological makeup of the individual or in that person's environment; hence the significance of conditioning as a technology of behavior. Since individuals are merely the sum of their behavior patterns, behaviorism has dispensed not only with consciousness and internal mental states, but also with human freedom, human dignity and human responsibility.

On the surface, behaviorism, with its simple reduction of mental states to actual or potential behavior, seems a welcome contrast to the tantalizing complexities of dualism. Yet its pitfalls are immense. The argument that all reference to the mind is simply a prescientific description of states of behavior is misleading. To say that "to be angry" means to behave in an angry way overlooks the possibility that someone may be angry but not show it. Further, the statement by itself explains nothing: angry behavior is angry behavior. Another difficulty is that we frequently appear to know more about our own mental states than other people do-a contradiction in terms if our mental states are nothing but patterns of behavior.

That mental states can, to some extent, be analyzed in behavioral terms is not open to question; that they can be completely analyzed in that manner, is. If they cannot be completely analyzed in behavioral terms, the issue of the nature of mental states remains. Apart from that dilemma, however, behaviorism can definitely be faulted for its loss of the wholeness and grandeur of the human person.

A third alternative to dualism is based on the presupposition that mental states are identical with brain states. The mind-brain identity theory is called central-state materialism. In its simplest expression it asserts that the goings-on in the mind are manifestations of physical happenings within the brain. Unlike behaviorism, it makes no attempt to deny the existence of consciousness or mental events; they are realities, but of the material brain rather than of an immaterial mind.

To equate the mind with the brain bypasses certain difficulties evident in epiphenomenalism and behaviorism. The self-evident phenomenon of consciousness is retained, and the problem of explaining how mind and brain interact does not arise. Central-state materialism has many attractive features to anyone aware of the dependence of conscious states on brain function.

Nevertheless, it too has its drawbacks. It is easy to assert a oneness of the mind and brain but much more difficult to demonstrate what that identity specifically amounts to. J. Z. Young's attempts to do that necessitate a leap of faith to help bridge the gap between brain mechanisms and the meaning of human life. Such a leap may be tantamount to admitting that even if mind and brain processes are not identical, at the very least they provide clues to different aspects of human reality.

If one assumes that mind and brain are identical, what are the implications of that outlook for our view of human nature? Does it threaten the concept of human freedom by necessitating belief in determinism? In other words, acceptance of the validity of materialism precipitates a new discussion-that of determinism.

Neither dualism nor any of its alternatives provide a fully satisfying solution to the brain-mind controversy. Each illustrates some truth about the human person and human brain, yet each fails to hold the available data and insights in a manageable form. We would be tempted to dismiss all philosophical speculation and settle, for a formula solution if the stakes were not so high. With the dignity and worth of human beings in the balance, some way forward must be found.

D. Gareth Jones is Associate Professor and Head of the Department of Anatomy and Human Biology at the University of Western Australia. His research interests center on neurobiology, in which he is particularly concerned with developmental aspects of the synaptic connections between nerve cells. He has written three books and 100 papers on neurobiological topics. In addition, he is actively interested in biomedical ethics, especially in the neurobiological and genetic areas, and in creation-evolution issues. Besides Our Fragile Brains, Dr. Jones has written books on Teilhard de Chardin and genetic engineering. He is currently working on a book dealing with ethical issues in biomedicine.

dualism has fallen into such disrepute that no respectable philosopher-certainly no respectable neurobiologist-would give it serious consideration as being of anything but historical interest. Yet dualism has been propoun4ed in its classic form for at least twenty years by a respected and notable neurophysiologist, Sir John Eccles. What is more, his advocacy has become increasingly firm and vigorous over the years, coming to full fruition in the 1970s. Eccles leans heavily on the writings of Sir Karl Popper, particularly on the ideas expressed in Popper's threeworld philosophy. The interaction between Popper the philosopher and Eccles the neurobiologist resulted in a joint magnum opus, The Self and its Brain, lauding dualism and interactionism. Eccles has expressed his views in many speeches, articles and books, including the 1977-78 Gifford Lectures at the University of Edinburgh, published as The Human Mystery.

Eccles's enthusiasm for dualism appears to go back to another great neurophysiologist, Sir Charles Sherrington, whose own Gifford Lectures on the theme Man on his Nature were published in 1940. Sherrington was a dualist who felt the pangs of disconnectedness between brain and mind but found no answer to the dilemma of how the two cohere. Eccles also recognizes dualist aspirations in the writings of more recent scientists, notably physicists Erwin Schroddinger and Eugene Wigner, and ethologist W. H. Thorpe. Underlying the views of such thinkers is the primacy of our conscious experiences, which constitute for us primary or first-order reality. By contrast, the so-called objective or material world is a derivative or second-order reality. The world around us is known to exist only because we experience it. We are in a position to describe and understand the world only on account of our self-consciousness, which is another way of saying that our minds are primary in knowing.

Emphasis on the primacy of consciousness does not inevitably lead to the strident dualism advocated by Eccles. As we shall see in the next section, it forms the starting point of Donald MacKay's alternative notion of logical indeterminacy. For Eccles, however, the primacy of consciousness leads to a dualism diametrically opposed to what he describes as monist-materialism. The latter he sees as ushering in a world of chance and circumstance, with no meaning for life, no values, no freedom and no responsibility. Against this, he wishes to put forward a world view incorporating the mystery of our existence, its supernatural meaning and the fact that We are part of some great design' Beside being a dualist, therefore, Eccles is also a finalist ' believing that our individual lives have a role to play in some great unimaginable supernatural drama.

The motives of Eccles and Popper are, from a Christian perspective, exemplary. They are intent on viewing human beings as ends in themselves, with meaning, values, purpose and responsibility. In starting from the self-consciousness of individuals, they insure that individuals will not be reduced to partial materialistic components and thereby lose their personhood. For such strong premises we are grateful. But when Eccles and Popper proceed beyond basic principles there is cause for concern. Their defense of human dignity and meaning rests on an explicit dualism between the self and the brain; the self-conscious mind is described as acting on the neural centers of the brain, thereby modifying the dynamic spatio-temporal patterns of the neural events. If such interactionism par excellence should fail as an explanatory principle, human dignity and meaning are placed in serious jeopardy. The issue is not simply whether dualism and interactionism can be justified, therefore, but whether this is an appropriate way to defend human significance.

Karl Popper's three-world view, developed in the early 1970s, is depicted in Figure 1. World 1 is the world of physical objects and states. It comprises, therefore, inorganic matter, the whole of biology and the material substratum of all manmade artefacts. World 2 is the realm of states of consciousness; it is the world each of us knows firsthand, containing our ongoing experiences of perception, thinking, emotions, imaginings and memories. Of particular significance in Popper's philosophical scheme is World 3, the world of knowledge in the objective sense. Encompassed by that world are all the records of human culture expressed in scientific, literary and artistic thoughts, plus the theoretical systems comprising scientific problems and the critical arguments generated by the discussion of those problems. World 3 is the world of human intellectual endeavor, a world of culture and storage.

The uniqueness of man, according to Eccles, is that he not only exists in World 1, the world of matter and energy, but can also realize his existence in World 2, the world of self-awareness. It is their World 2 existence that bestows a soul on human beings. Human experience does not stop at World 2, however, because human beings utilize their World 2 knowledge to create yet another world, that of culture (World 3). In that third world human greatness manifests itself with the rise of cultures and civilizations. What we are is dependent on World 3 in which we have been immersed, and on the effectiveness with which we have utilized our opportunities to make the most of our brain potentialities.

At the level of the individual, Eccles argues that the brain in World I and the world of culture in World 3 are both necessary for the development of the conscious self in World 2 (Fig. 1). Eccles goes beyond expression of the three-world view, however, to contend that such interaction is not sufficient to explain the uniqueness of our personal self. The explanation must lie outside the field of scientific inquiry; the coming-into-existence of each unique self is the result of a supernatural creation of the soul.

In taking up that position, Eccles has already committed himself to a strong dualist position on the brain-mind problem. He regards brain and mind as independent entities, with the brain in World I and the mind in World 2 (Fig. 1). What is more, they are thought to interact, as outlined in Figure 2, across the World 1 -World 2 interface. Eccles concludes that the world of matter and energy, including the brain (World 1), is not completely sealed off from the world of experience and subjective experiences (the mind, World 2). Their interaction allows the mind to influence the brain or, more specifically, the self-conscious mind to influence the neuronal machinery of the brain.

In working out his position, Eccles postulates that the self-consaious mind influences neural events in special areas of the neocortex which he terms the haiyon brain. These areas can perhaps be compared to the pineal gland in Descartes's scheme of things. To substantiate a dualistinteractionist view, there must be loopholes or crevices in World 1 (the brain) enabling it to be modified by World 2 (conscious experience). Eccles's loopholes are provided by the liaison brain (Fig. 2).

Two issues immediately arise. Is it the mind or the brain that is responsible for the unity of conscious experience? What is the evidence for the existence of a liaison brain?

Eccles categorically asserts that the unity of conscious experience is provided by the self-conscious mind and not by the neuronal machinery of the liaison brain. His reason appears to be the inadequacy of any neurophysiological theory in that regard. Eccles rejects the notion that the selfconscious mind is in liaison with single nerve cells, contending instead that liaison occurs with groups of nerve cells in the cerebral cortex known as modules. The liaison modules are found principally in the dominant left hemisphere, particularly the linguistic areas, because in split-brain subjects consciousness is principally located in the left hemisphere with its speech centers. The prefrontal lobe of the dominant hemisphere is also, in Eccles's eyes, a highly probable liaison site, since memory storage and retrieval may be located there. A brain-mind interactionist position is also suggested, Eccles claims, by physiological evidence of a readiness potential and by work on the subjective correlates of cortical stimulation.

The details of these arguments are beyond the scope of this paper, but they are all open to alternative interpretations by neurophysiologists. The areas of the cerebral hemisphere-designated liaison areas have no morphological distinguishing features from nonliaison areas. It must be admitted that since no one has any idea what to look for, a scientific approach is valueless at present. But that is precisely the difficulty with the liaison brain concept: it expresses in semiscientific language an idea that is essentially ascientific. It must be questioned, therefore, whether the "liaison brain" really does belong to World 1, as Eccles suggests-or to World 2.

How successful has Eccles been in reinterpreting Cartesian dualism in contemporary neuroscientific terms? More important, does he provide grounds for recommending such strong dualism to Christians? Has he given us an alternative to materialistic monism?

Excellent as his intentions are, it is doubtful that Eccles has succeeded in his quest. The inevitably debatable nature of his neurophysiological interpretations is reminiscent of the constantly recurring "God-of-the-gaps" syndrome. The interface between the mind/self/soul and the brain shifts from one brain region or set of nerve cells to another as the scientific evidence and its interpretation shift. There is no escape from that dilemma, as long as one is dealing with the scientific domain. Eccles, who once staked his claim for an interface in the synapse, is now prepared to stake it elsewhere. Any specific location must, by the nature of the situation, prove temporary.

The fundamental problem of dualism is the feasibility of one sort of substance acting on another sort of substance. If the mind/self/soul acts on modules of nerve cells as modules act on each other, is the mind/self/soul something like a module? Alternatively, if the mind/self/soul acts in an inexplicable way, does it become an inexplicable entity? That is where Descartes had to leave the problem. In spite

Material substrates                                scientific problems
    of human creativity                             critical arguments
        of tools 
        of machines 
        of books 
        of works of art 
         of music

The brain is subject to scientific scrutiny because it is publicly observable; the mind or soul is not open to such investigation and hence can never receive scientific support. Proof that the mind or soul either is or is not influencing the brain is almost impossible to obtain. Either way, it needs to be demonstrated that the brain does or does not possess some device for receiving influences from the mind. Eccles attempts to demonstrate that such a device does exist, bringing us back to the equivocal status of the whole exercise. On the other hand, there is ample evidence that human behavior is caused by neural events; the evidence that every neural event is caused by some physical event is not conclusive, but neither can it be ignored.

A final difficulty with the strong dualism of Eccles and Popper is perhaps surprising. The fact is that radical dualism is in danger of overlooking the human person. It tries to uphold the meaning of human existence not so much at the personal level as at the level of brain-mind interaction. True, Eccles uses as his starting point our awareness of our conscious selves. But that awareness becomes lost amid his neuroscientific justification of how and where the self-conscious mind exerts its control over the brain. It may be that any emphasis on the separation of brain and mind, of body and soul, misses the crucial, intimate relationship we, as people, have to our bodies. The form of dualism advocated by Eccles may simply be misplaced.

Before leaving contemporary dualism we should consider two other example from the ranks of neuroscientists. Wilder Penfield, one of the most influential neurosurgeons of this century, made major contributions to the localization of function in the cerebral hemispheres in the 1930s

Perceptions

Figure 2. Information flow diagram for brain-mind interaction, as postulated by Eccles. Reprinted, by permission, from J. C. Eccles, Facing Reality (1970).

and '40s. Like Eccles, Penfield was influenced by Sherrington's ideas on the relationship between the brain and mind, but an explicitly dualistic position emerged only gradually throughout his long life. Penfield's dualism is expressed most clearly in The Mystery of the Mind, published in 1975 when he was eighty-five years old.

For Penfield the mind is aware of what is going on, it focuses attention, reasons and makes decisions, but has no memory of its own. It can put decisions into effect by activating nerve cell mechanisms situated in what Penfield terms the highest brain-mechanism, a region of grey matter in the upper reaches of the brain stem. The highest brainmechanism, therefore, functions as the messenger between the mind and other brain-mechanisms. It serves as the mind's executive, its normal action constituting the physical basis of the mind.

Penfield was drawn to this view by his experience with patients displaying a variety of brain lesions. In particular he was impressed by attacks of epileptic automatism, in which a patient becomes unconscious but continues to act as an automaton. Penfield recognized in that situation a dissociation between the functions of the automatic sensory-motor mechanism and the highest brain-mechanism. He surmised that the highest brain-mechanism might go out of action during such attacks, depriving the patient of the functions of the mind.

For Penfield, as for Eccles, belief in a distinct and purposeful mind proved a buttress against the inroads of materialism. Its mystery intrigued him, and even if we find his arguments unconvincing, it is hard to escape the sense of the wonder at human thought and the complexity of the neural machinery that comes through in his writings. His awe at the potential of the human intellect and the subtleties of behavior of a brain-damaged patient demands a serious response on our part.

R. W. Sperry is one of the foremost exponents of splitbrain studies. Sperry has also written extensively in the brain-mind area. Although not a dualist in the classic sense exemplified by Eccles and Penfield, he fits best within that general category.

Like Eccles and Penffeld, Sperry wants to reject both behaviorism and materialism. More specifically, he rejects theories of consciousness that interpret subjective experience as an epiphenomenon, or parallel correlate of brain activity, or is identical to neural events.

Sperry advocates a form of emergence, in which consciousness is an emergent property of brain activity. Conscious phenomena are different from, more than, and not reducible to neural events, although they are built of neural and other physicochemical events. He sees value in a description of the neural events generating conscious experience, while denying that such a description can arrive at a complete understanding of consciousness. Most important within Sperry's system is his view that the emergent properties forming the mind are capable of controlling normal brain processes.

Is it the mind or the brain that is responsible for the unity of conscious experience?

Sperry, recognizing that no direct empirical proof exists, argues that his position is more credible than the behaviorist-materialist position. The difference between himself and Eccles is in the absence of a specific dualist interaction in Sperry's system. Instead, conscious experience influences the brain by virtue of the hierarchical organization of the nervous system and in the power exerted by a whole over its parts. From Sperry's perspective, mind moves matter in the brain in much the same way that an organism moves its component organs and cells.

Sperry leans heavily on the rule played by subjective conscious experience in an appreciation of brain function. The significance of that role, in his eyes, is that the value-rich, qualitative world of inner, conscious, subjective experience is reinstated into the domain of science. He is thus able to introduce into neuroscience what he calls humanistic thinking, leading to an erasure of the distinction between objective facts and subjective values.

Sperry's approach to the brain-mind issue, therefore, is part of a much broader issue-that of introducing values into science. Intent on deriving an ethical framework from science, Sperry sets about demonstrating that human values are inherent properties of brain activity and hence amenable to scientific investigation. That assumption leads him to propose a value system built on the orderly design of evolving nature.

Sperry's view seems to be a curious amalgam of materialism and dualism. Although he claims to be strongly antimaterialist, the emergent mind of his scheme is entirely a product of neural events. Once mind has emerged, however, it assumes the dominant role in driving the brain, being the essential directive force of brain processes. The mind is seen as being above the brain processes even though they are described as mutually interdependent. Since Sperry's holism arises from material forces within the brain, his stance-unlike that of Eccles-is thoroughly antisupernatural. If an emergent scheme is eclectic, allowing arbitrary values to be introduced into it, it seems to provide no surer way to a humane society than materialism.

Another difficulty with emergence reflects its dualistic leanings. Even if conscious experience does emerge from neural organization, the mode of control then exercised by consciousness remains unexplained. Either we are back at the interaction problem, or consciousness adds nothing to the wholeness generated by the brain itself.

In the end we are not fully satisfied with Sperry's position, although we agree on the importance of subjective conscious experience. A longing for holism is exemplary, but Sperry's rejection of a Christian outlook limits his horizons to the materialism that so distresses him. What Sperry has overlooked is the contribution that can be made by adopting more than one perspective to the wholeness of the human person. The brain-mind problem, like the science-values issue, should be viewed from different viewpoints. When that is done, previously unrecognized aspects may appear. It is to such a "perspectivalist" approach that we now turn.

Dualists take subjective experience seriously but sometimes stumble over its implications. Brain scientist Donald MacKay suggests that we start from our immediate experience of what it is like to be a person. Our primary data constitute a flood of conscious experiences such as seeing, hearing, thinking, meeting people. Taken together, these data form the ground on which all our knowledge must rest. Alongside these data one also has other characteristics, so that being a person means being identifiable to other persons as a tangible body and having specific conscious experiences like those of other persons.

MacKay sees in that description of a person a dualism of two different kinds of data about ourselves. There are data of our own experience as conscious agents, and data about our correlated brain activity and brain states. Put more simply, the first is the I-story, what we see and believe; the second is the brain-story, the corresponding processes going on within our brains. Every aspect of our conscious experience, anything we believe or see or hear, will be represented by a particular configuration in the state of our brains. From that it follows that a change in our experience will be accompanied by a change in the state of our brains. This is a basic assumption of brain science, although we still know very little about the actual organization of the brain under changing circumstances.

If we accept that assumption for the purpose of argument, what follows from it? It has often been suggested that the two must be causally related, that is, the I-story must cause the brain-story or vice versa. MacKay's contribution comes in at just that point. He does not deny that such a causal connection may occur, but contends that it is implausible and unnecessary.

Instead of viewing the two sets of events as rivals, so that one must be right and the other wrong, MacKay suggests that we view them as complementary aspects of human behavior. "These events," he writes, "admit of analysis at the mechanical level in terms of nerve cells and their interactions, and also not only admit of but demand analysis in terms of their significance as the activity of a conscious being whose thoughts and desires and decisions can determine his behavior."

Taking his argument further, MacKay tackles the problem of determinism. If a "superscientist" were able to specify every aspect of the machinery of an individual's brain, would that individual be correct to believe all the specifications he was told about the state of his brain? In other words, may a point be reached one day when by analyzing an individual's brain a scientist would be able to tell that individual what he would believe at some future time?

Or, to be more exact, what he would be correct to believe? If so, freedom of action and responsibility would become mere illusions.

MacKay contends there is a logical fallacy in that argument. If an individual were to believe what he was told about the state of his brain, his belief would have a major consequence: the state of his brain would be immediately changed by introduction of that new factor (belief). Therefore, he would be mistaken to believe what he was told, because that description would be out of date. Thus no complete specification of a brain's mechanism can exist which would be equally correct whether or not the person concerned believed it. The point of the argument is that an observer's prediction would be valid only if he did not inform the individual being observed of his prediction.

The brain is subject to scientific scrutiny because it is publicly observable; the mind or soul is not open to such investigation and hence can never receive scientific support.

Could the time ever come when allowance can also be made for the new factor? MacKay says no: even if it becomes possible to produce a specification which is incorrect at the moment but will become correct when it is believed, there would still be a difficulty. The difficulty is that the individual concerned would be under no obligation actually to believe it. If he did believe it, it would be correct; but if he did not believe it, it would be incorrect. And there is no reason why he should believe it. Consequently, MacKay contends, there can never be produced a specification of a person's brain, however sophisticated, that would have an unconditional claim to his assent.

The consequence is that, even if the human brain turns out to be as mechanical as the solar system, predictions about it will always differ from predictions about the solar system. Although predictions about the latter may have an unconditional claim to our assent, predictions about our brains do not-because we are under no obligation to believe them. The future state of our brains is indeterminate for us until we have decided on a course of action or belief. It is indeterminate not just in the sense of being unknown, but because a future specification does not exist which is inevitable for us until we have made up our minds.

MacKay argues that there are thus no mechanistic grounds for excusing our actions. We are responsible beings. MacKay spells out the crux of that responsibility, decision making. "A decision," he says, "is an action whose future form depends on what you believe about the situation in a way that makes it indeterminate for you until you have made up your mind: indeterminate, not just in the sense of unknown to you, but in the sense that there does not exist a specification of the outcome which is inevitable for you until you make up your mind: until, in other words, you determine what the form shall be."

Human decision making provides a basis of freedom even in a mechanistic universe. We are free and responsible, not in spite of the way our brain works or because of the way our brain works, but because freedom of action is a demonstrable logical fact. MacKay's principle of logical indeterminacy applies even in a physically determinate universe, although of course it is far from certain that the universe is physically determinate. MacKay's point is that, even if such an extreme situation were to prevail, his principle would continue to hold.

A crucial point for MacKay's stance is that the I-story (mind-story) and the brain-story are correlates of one another and not translations of one another. That means that the I-story can be indeterministic and the brain-story deterministic without mutual contradiction. The reason is that the two statements are descriptions of different aspects of an event, one referring to people with brains and the other to the brains of the people. When considering the question of freedom, it is important to distinguish between people and brains-because it is people, and not brains, who are free. Conversely, it is brains, and not people, which may be machines.

MacKay's concern throughout is to demonstrate that any denial of human responsibility on the basis of the assumed physical determinateness of the brain is based on a logical error. Hence the positive scientific theory that all physical events are determined by physical causes does not, he argues, imply the negative metaphysical belief that the immediate future of a human agent is inevitable. It follows that, even if an individual's action is predictable by observers, there would be no ground for denying that individual's responsibility for it.

We are free and responsible, not in spite of the way our brain works or because of the way our brain works, but because freedom of action is a demonstrable logical fact.

It is evident that MacKay, unlike Eccles, does not seek gaps in physical causality within the brain. Conscious activity is embodied in the brain activity that physically determines what our bodies do. The mental and the physical are in no sense rivals, therefore, but are complementary aspects of our consciousness. Beside the primacy of conscious experience, MacKay stresses the necessity to attach the significance of human identity to a person as a whole rather than to an artificially isolated body or brain.

MacKay's defense of human freedom on the basis of logical indeterminacy has attracted the attention of many philosophers. If legitimate, it provides a means of circumventing the seemingly intractable problems of dualism and the potentially dehumanizing tendencies of materialism.

A major question posed by MacKay's argument is the meaning of the term freedom. Stephen Evans, in his book Preserving the Person, considers that MacKay's argument can be interpreted in two ways. According to the first, an individual is free as long as he is kept in ignorance of the observer's predictions about his future actions. The individual is free in the sense that he has alternatives he could choose if different conditions prevailed. In that instance, the freedom of the individual lies in his lack of knowledge of the particular prediction made by the observer. The second interpretation entails a more rigorous meaning of freedom, namely, that no logical specifications exist of an individual's beliefs about a subject on which he is at present undecided. An individual's future belief is indeterminate, since any prediction about that belief might change it. Believing is not merely a physical happening, therefore; it includes a normative element about what ought to be believed. If that is true, an individual reflecting on the causes of his beliefs may proceed to alter those beliefs, the implication being that beliefs are not just events to be causally determined and predicted. They result from rational reflection and hence may be free because of the nature of such reflection. If so, an onlooker as well as the individual may agree that beliefs of that type are free.

Evans favors the second alternative interpretation of MacKay's argument as a basis for human freedom. Both the potential strengths and weaknesses of MacKay's position seem to lie in its purely logical level. Although MacKay demonstrates the pitfalls of materialism and points the way, to a viable alternative to both it and dualism, many find his argument hard to follow. The meaning of freedom may be one issue that needs clarification. It is clear that MacKay believes that freedom is real and not an illusion.

MacKay appears to be saying that, if a future outcome is indeterminate for an individual, that individual has the power to determine the outcome, and therefore is free. Freedom of that kind underlies human responsibility. MacKay has put forward a very strong argument that there are future beliefs that are indeterminate for the individual. What is less clear is whether this implies that such beliefs are determinable by the individual.

MacKay's logical argument fits well with his Christian presuppositions. It is a clearing operation for working out the meaning and consequences of belief in human freedom and dignity. MacKay has shown that man cannot be written off as a being for whom all future thoughts, actions and decisions are inevitable. Having established that, the task is now to demonstrate what human freedom entails and the uses to which it needs to be put.

In a sense, our discussion has brought us a long way from the brain-mind debate. Yet the direction we have traveled has been almost an inevitable one for a Christian. We dare not isolate a person's brain from the remainder of the body and personality as though it were a detachable piece of luggage. To reach a person-centered conclusion one must start from man as a person, not from man as a brain.

Many discussions of brain-mind relationships bypass a holistic view of human beings, then find it impossible to break free of the bonds of reductionism. To confine one's perspective of the mind to specific regions of the brain demeans the value of human significance, regardless of the conclusions reached. A proper level at which to contemplate the brain-mind debate is that of humans as choosing, deliberating, valuing and purposeful beings. From vantage point, the primacy of our own consciousness is a valid piece of evidence. Our sense of freedom and purpose is an essential ingredient of any discussion on the human brain and what has traditionally been termed the human mind.