My Developing Understanding of Roger Wolcott Sperry's Philosophy

Clinical Professor of Neurological Surgery University of Southern California and Adjunct Professor of Psychology University of California at Los Angeles and Visiting Professor of Computation and Neural Science California Institute of Technology, U.S.A.
(Received II February 1995; accepted 17 June 1995)

Abstract - Reviewed are some of the dramatic experimental results and penetrating analyses characterizing the career of Roger Sperry. These require that we seriously consider his opinions regarding matters not yet testable, especially regarding the brain/mind relationships. His opinions include first, that a worthwhile understanding of brain function requires a biological explanation of consciousness; second, that mental properties described by him as "overall pattern effects in brain dynamics" can govern neuronal traffic at the cellular level by virtue of "mental forces'; and third, that further development of this outlook can provide a scientific basis for moral values. Discussion here is restricted to the first two of these points, urging that most criticisms of them arise largely from semantic confusions inherited from our past. Particular emphasis is placed on distinguishing mind from soul, thus totally separating the brain-on to-mind mapping problem from the nexus problem inherited from Descartes. Taken here is a physicalist position regarding mind, together with agnosticism regarding the nonmaterial. ©1998 Elsevier Science Ltd. All rights reserved

Key Words: consciousness, split-brain, epistemics.

People interested in Roger Sperry's work have often asked, among other questions: what specifically is the relation alluded to by Sperry (e.g., Sperry, 1969) between the split-brain results and Sperry's view of consciousness as a "holistic systemic property [which is] a dynamic emergent of brain activity" (Sperry, 1992). More often people ask: "How can Sperry maintain that his view is a form of mentalism but not dualism?" (Sperry, 1980). Similarly, "How can he be a mind-brain interactionist and still claim to be a monist?" For some years my responses to these questions had to be, "I don't know-except that there have been many times in the past when Roger turned out to be right." With the passage of time and some further development of my own philosophy, there have come some answers to these questions. Concurrently, with exposition of these answers, I shall indicate rare places where I differ. As might be expected, after forty years oflearning so much from and with him, my beliefs derive substantially from his. Hence, I begin with an attempt to convey my veneration for Roger's scientific ability as well as some feeling for his droll, often oblique and rogatory discourse.

Getting to know him

It is not a simple matter to do justice to Roger Sperry's many achievements or to the full gamut of emotions I experienced during our many years of interaction. It may be best for me to tell a few anecdotes which will hopefully reflect my impression of Roger's genius, style, and dour demeanor.
The first time I saw Roger was when he gave a Sigma Xi lecture at Caltech over forty years ago. He lucidly described and dramatically illustrated the discriminative ability of cats with various alterations of visual cortex. A former Biology Division chairman has said that it was the best scientific talk he ever heard. I was not then in a position to make such an evaluation. Perhaps I can convey my own feelings when I heard that talk, by telling about a time some years ago when I was trying to teach my elder daughter how to evaluate wine and how to distinguish good wine from not as good. She swirled it, sniffed it, rolled some around in her mouth and said, "Nobody has to tell me that's good!" That's the way I felt about Roger's talk. And that's the way I have continued to feel about Roger Sperry for the ensuing forty years.
My next personal contact with Roger was in 1955 when I was a graduate research assistant to Caltech's Professor Anthony Van Harreveld; his lab and office were just down the hall from Roger's. Those split-brain cats made a profound impression on everybody. It was for me the most influential scientific experiment that I have ever seen or known about. It set the course of my life.1
Three years later, having trained in general surgery, I returned to Van Harreveld, this time as a post-doc in neurophysiology. During that time Roger and I become better acquainted. It was necessary for me to go up and down the hall of the third floor in Kerkhoff several times a day. Most of the time when I would pass by Roger's office, the door would be open. Sometimes he would be reading or doodling on a pad. Sometimes he would be sitting back with his feet on the desk, apparently staring off into space. Then, one day, he was gone--into the lab. Not long after, we had a third floor seminar concerning the work of Attardi and Sperry on optic nerve regeneration. The slides were sections of goldfish brain, stained a bluish-black except for the regenerating fibers. The regenerating fibers, snaking their way through the neuromatous jumble of the optic chiasm were stained a brilliant pink. Around the front of the optic lobe they went, and then they drove abruptly into their intended targets. It was spectacular! Unfortunately, when this work was published, in Exp. Neurol., the pictures were reproduced in black and white. That was in 1963, five years after appearance of the abstract in Anat. Record in 1958. Such a long delay was not unusual for Roger. He often kept papers on his desk for a long time, for several reasons. One was that he liked to have some idea of how the follow-up experiments were developing before finalizing the discussion of the earlier paper. He did not always delay. One day he said, "We have to send this [olfactory] paper in immediately." Why? "Because I have just refereed a paper with a similar experiment in rats. People know that with human subjects, we can do in a few weeks what would take many months in rats. If we delay, people might think that I got the idea when refereeing the rat paper." Roger seemed to think of everything. I idolized him and hung on his every word, of which there were not very many.
Which leads to another story from that time. A group of us were out carousing all New Year's Eve. We eventually returned to Roger and Norma's home up in Altadena just in time for an early New Year's Day breakfast. I volunteered to make some scrambled eggs. Somewhere I had read that Worcestershire sauce would pep up scrambled eggs. Unfortunately, I had neglected to take note of the appropriate amount. When the eggs were served they were a homogeneous tan color. After my first bite, I was mortified, and horrified at the thought of what Roger might think. Another minute went by as Roger took a second and then, thoughtfully, a third bite. He then turned to me and said, "Joe, these are scrambled eggs."
A year later, 1960, I was working at the County Hospital. I took to him an essay on epilepsy entitled, "A Rationale For Splitting the Human Brain." His laconic comments included, "Maybe you should change the title." Also, "Look up those papers by Akelaitis." When I did, it appeared that the callosal surgery by Van Wagenen twenty years before had actually turned out better than was then (about 1960) the prevailing medical opinion (Bogen, 1997). This led eventually to a nearly thirty year joint effort. I like to think of it as a collaboration although in fact, our teacher-student relationship persisted throughout.
While I was at the County Hospital, one of my projects involved some behavioral experiments with rats, with results I could not understand. It seemed to me that if anybody could help it would be Roger. I brought my data up to the Institute. After some technical comments he mumbled, "If you keep working with that you might come up with something dramatic."
Roger Sperry's facility for "coming up with something dramatic," time after time, in a variety of contexts, was not simply because he kept in mind the value of a decisive, counterintuitive result. Nor was it only because he was an expert experimentalist. Nor only because he was at the same time a creative and highly disciplined presenter. Essential was his being among the deepest, the most profound, neurothinkers of our time.
On one occasion, after members of an NIH site visit team had left, I asked Roger what he had said to influence their decision. "Three of the five were psychologists," he replied. "I said that this was the only psychology program at Caltech and ifit were not supported there wouldn't be any." This was not simply a ploy. Roger sometimes dryly alluded to being surrounded by molecularists plugging away without any interest in what he called "the big problems. "He meant by this both problems of society and problems identified by psychologists, requiring physiological answers.
Roger's emphasis on psyche and consciousness was long present in his thoughts. This emphasis become progressively more evident in his writing. He felt his first paper to assert forcefully what he called the "Central Issue" was the "Platt piece," that is, his chapter in New Views of the Nature of Man (Sperry, 1965). In this chapter he asserted that the Central Issue is the nature of consciousness and that a correct model of brain function could not be constructed "without including consciousness in the causal sequence." He urged what he called a Mentalist position which meant that, "overall pattern effects in brain dynamics" direct and govern neuronal traffic. He suggested that his Mentalist position illuminated the problem of free will by embedding selfdetermination firmly in the flow of physical forces. He believed that he was offering, "an objective, explanatory model of brain function [that] affirms age old humanist values" while at the same time opening established moral values to "the free winds of scientific skepticism and inquiry."
Roger continued along this path ever more energetically so that by 1980 almost all of his writing was devoted to the Central Issue of consciousness. Specifically, he continued to dispute "the idea that the objective physical brain process is causally complete in itself without reference to conscious or mental forces" (Sperry, 1980).
Even by 1970, Roger had become widely recognized for the above views and was attracting much philosophic attention, both pro and con.
It was then, in 1970, that Oliver Zangwill, Professor of Psychology at Cambridge, the premier psychologist in England and possibly in the English-speaking world, came to Caltech for the entire month of August, at Sperry's invitation. Oliver was bent on seeing the splitbrain patients for himself, and Roger wanted Oliver's reaction to his efforts to bring science into the humanities, and vice versa.
After several weeks of socializing with Oliver, I was emboldened to ask him, "What are you telling Roger?" "I'm a bit concerned," he confided, "that if he goes on in this vein it is likely to diminish the impact of his many marvelous achievements."
"How did he react to that?" I asked.
"Very little," was the stiff-lipped reply.
Oliver Zangwill's prediction was fulfilled by the time Sperry was honoured with a party at Caltech in 1982 for having brought to the Biology Department its fourth Nobel Award. Those who had not known him early on assumed that "he's gone religious like so many old folks." By 1990, even those Caltech professors who had been his friends for nearly forty years had given up trying to defend or even to understand "the philosophy of his later years" as one of them put it.
Contributory to the unhappiness at Caltech was Roger's habitual obliquity. Hardly helpful were his cryptic comments to senior professors, twice in my presence, on the inability of quantum mechanics to save a world terribly threatened by technology and "development," a world that was, as he put it, "going to hell in a handbasket. "
Part of the problem was the failure of most people to distinguish (or even to care to distinguish) epistemology from ontology; and most failed to make a distinction between Mind and Spirit. Roger was an epistemologic dualist, indeed twice over, as I hope to explain below. First, it is necessary to make clear in what way he was not a dualist.

How could Sperry be a mentalist but not a dualist?

My answer to this question is based on the difference between epistemology and ontology. I hope to make clear that Roger was an epistemologic dualist but not an ontologic dualist. Ontology is the study of being, that is, of what exists. A common claim of neuroscientists is that there is only one fundamental substance or element: matter (or energy). The official position of the Roman Catholic Church (and many other churches) is that there are two fundamental elements: matter and Spirit. This view is probably held by an overwhelming majority of mankind-it is ontologic dualism (Fig. 1a) It is this kind of dualism which Roger denied. That is, he frequently asserted that without brain, there could be no mind. He considered himself a monist because, "Monism... says 'no' to an independent existence of conscious mind apart from a functioning brain" (Sperry, 1980).

Two kinds of epistemologic dualism

Roger was an epistemologic dualist twice over, that is, in two different ways. By "epistemology" is meant the study (logos) of epistemics: the means for acquiring knowledge. That is, how do we come to know what we know? The first duality concerns the acquisition of our abilities to understand the outside world; we acquire those abilities in two ways. The first source of knowledge is our phylogenetic history-that is, our brains come equipped with wired-in organizational principles, including rules for making choices and weighing evidence, even for weighing consequences of contemplated actions. Roger championed this view. As Hamilton (1994) put it, he "showed conclusively that neural connections are reestablished under genetic control following experimental interruption, and also, by implication, during embryonic development." But there is a second source of understanding: namely, experience. Roger was fully aware of the importance of ontogenetically acquired information, including rules for weighing evidence and consequences. He went so far as to say,"... our educational system, as well as science in general, tends to neglect the nonverbal form of intellect. What it comes down to is that modern society discriminates against the right hemisphere" (Sperry, 1973; 1974).
That nature and nurture both enable our behavior is surely now understood and believed by readers of this journal. What seems not as widely understood is the second epistemologic duality, that mentation (that is, thoughts and feelings) serves as a subjective (or direct) knowledge source that needs to be consulted independently of and in addition to our objective knowledge of brain processes. Although Roger himself saw this duality as so obvious as to require no defense, a widespread attitude in the natural sciences makes appropriate here some explication of what we mean by "mind."

Our modern use of the word "mind"

David Hubel, in 1984, pointed out to me that, "the word Mind is obsolete." The reason for this is that as physiological studies of brains have given us an increasing understanding of how brains work, we need less and less recourse to the common sense or folk psychology which speaks of what is on people's minds, that people make up their minds, that people can be of two minds, and the like. David said, "It's like the word 'sky' for modern astronomers." In his Foreword (Hubel, 1991) to a book about Sperry he wrote:
We may then wisely keep the word mind, with all its present richness and fuzziness, for everyday use and substitute a new word for scientific purposes, just as astronomers speak of the universe and we keep the sky for everyday use.

I went to my astronomer friend, Arthur Vaughan (who helped design the highly successful camera correction for the flawed Hubble telescope). I asked him, "Do astronomers use the word 'sky'?" "Yes," he replied, and mentioned a number of usages including "the stars are in the sky." Also, they speak of "an area of the sky" [a solid angle], and they also commonly refer [fully aware that it is geocentric] to "the brightest star in the northern sky," that is, Sirius. "And they read Sky and Telescope," he added.
Similarly, many psychologists read the journal Mind and Behavior, and most find useful the concept of "mental states". Those who use such terms (including Sperry) generally intend that "mind" is a four-letter word synonymous with "mentation" which is itself a shorthand way of referring to a collection of processes rather than being the name of a thing. As long ago as 1844, Wigan spoke of, "the emotions, sentiments and faculties which we call in the aggregate, mind" (chapter I I).
A difficulty with Mind is that it carries an excess of historical baggage. First, the word seems to imply the existence of a thing. Moreover, it is often implied that it is a nonmaterial thing. But for us it need not bother us any more than the word "sky" bothers contemporary astronomers. If for them the word "sky" no longer implies a rotating, crystal dome in which the stars are imbedded, we need no longer imply by "mind" either that it is a thing, or that it is transparent to introspection or that it is independent of brain.
If mentation were not a subject worthy of study in its own terms, then, except for what was once called "physiological psychology,'" psychology as a whole would appear to be a hoax. We can be quite sure that Sperry would not accept that psychology is a hoax. Nor would Lehman et al. (1993) when they showed that a computational architecture [SOAR] based onAI and cognitive psychology could provide insights into language, leading them to conclude: "Cognitive Science need not be split forever into its core disciplines of AI, Linguistics and Cognitive Psychology" (p. 58).
Whereas mentation is worthy of study in its own terms, this does not mean on its own terms. Psychologically derived concepts at odds with anatomy or physiology make up what can be called "anencephalic psychology"-as in some of J. Fodor's assertions.
According to Fodor (1983), input systems are highly modular, including that they are "encapsulated," i.e., not subject to "top down" or other outside influences (p. 66). By contrast, he wrote:

. . . in the case of central processes you get an approach to universal connectivity (p. 119) [where] neural connectivity appears to go every which way and the form/function correspondence appears to be minimal (p. 118).

The facts are: first, input systems are definitely subject to a wide variety of downward (including cerebrofugal as well as mesencephalofugal) controls. Second, intracerebral connections are far from either universal or random, and they are often meaningfully interpretable.

As Hopfield (1991) said:
Our understanding of biological computation and its origins must come through studying the relations between computation and its underlying hardware, not computation as a logical structure.

Mentalistic materialism

To understand Sperry's philosophy it is essential to understand that speaking of Mind carries no implication of ontologic dualism. One can be both a materialist ontologically and a mentalist epistemologically. A materialist is one who explicitly denies Spirit. A very emphatic, current advocate of materialism is Paul M. Churchland (1989; 1995). He sees no conflict between his materialism and what he calls "autoconnected epistemic pathways."

Each one of us has a peculiar access to exactly one's own sensations, that no other creature has [because] each individual gets information. . . via a specific set of neuronal pathways that only he has. [Thus] each person has a self-connected way of knowing about his own current physical condition, a way of knowing that will function successfully independently. . . of whatever scientific knowledge he might or might not possess (1995, pp. 273-277).

The philosopher Owen Flanagan prefers to describe his own view as "naturalism" rather than as materialism or physicalism. He wrote:

Naturalism is the view that the mind-brain relation is a natural one. Mental processes are just brain processes (Flanagan, 1992, p. xi).

Elsewhere he emphasized, with approval, one of the essential concepts of cognitive neuroscience:

Any science, therefore, that fails to talk about mental events and processes will not be remotely adequate (Flanagan, 1991, p. 259).

Here, bluntly stated, is one of Roger Sperry's basic claims, an assertion, as Oliver Zangwill realized, that was almost guaranteed to offend many of his Caltech colleagues.

Distinguishing mind from spirit

Objections to "mind" arise because of the ancient usage which has long considered mind much the same as spirit or soul. For centuries the concepts have commonly been used synonymously. According to Clarke and O'Malley (1968), the conflation (lumping together) of mind and soul was especially evident in the work of Descartes of whom they say:

Plato had divided the soul into three parts, the vegetative in the abdomen, the sensitive in the heart, and like Pythagoras, the reasoning or rational soul [i.e., the mind] in the brain, but Descartes' solution was to consider the body as a machine and thus dispense with the first two. The third portion of the soul or mind, which in man controlled the bodily machine was in the pineal body (p. 470).

What Descartes said was not exactly that the soul was in the pineal, but that it controlled the brain via the pineal.

... although the soul is joined to the whole body, there is, however, a certain part in which it exercises its functions more particularly than in all the others (Clarke and O'Malley, 1968, p. 471).

We can see the lingering influence of Descartes in the German word "Seele" which is commonly translated "soul" (Sasse et al., 1976) although by many persons it has been translated "psyche." And the term "Seelenblindheit" has usually been translated as "mind blindness" (Benton and Tranel, 1963) or "psychic blindness" (GrOsser & Landis, 1991). Moreover, the German phrase "mit ganzer Seele" means "with all my heart." The previously mentioned German/English dictionary (Sasse et al., 1976) also translates Geist as "spirit, mind, ghost" as well as translating Gemuüt as "mind, soul, heart." This conflation of soul, mind and heart by representing them with a single word is not restricted to European languages. The Chinese character", has meant all three: heart, mind and spirit' (Karlgren, 1974).
Onto logic dualism was the creed of many past creators of neuroscience. Fritsch and Hitzig (1870) were prominent pioneers in cortical localization. Summing up some experimental results, they said:

... one might express himself thus: there was some motor connection between the soul [Seele] and the muscle, while the connection from muscle to soul was somewhere interrupted.

This quotation is from the translation by Gerhardt von Bonin (1960, p. 96). In the translation by Wilkins (1965, p. 27) the word "psyche" is used instead of "soul"; this is a crucial, conflationary change.

The foregoing conflation, in both East and West, of mind with soul is vestigial of an ancient ignorance; we can do better. Deconflating "mind" from "soul" enables us to consider mind strictly as a result of physical (brain) processes, leaving to metaphysics the concept of soul. I have not been able to identify the first neurothinker to insist upon this separation but such a separation is unmistakable when we come to William James (1890, Vol. I, p. 350):

The reader who finds any comfort in the idea of the Soul, is, however, perfectly free to continue to believe in it; for our reasonings have not established the non-existence of the Soul; they have only proved its superfluity for scientific purposes.

This view of James, to which I subscribe, is illustrated in
It deserves repeating that to speak of a "brain/mind relation" means that we obtain information from our own mentation which needs to be compared with information about brain states. That is, for the foreseeable future, our knowledge of what goes on inside brains will come from two sources, first person introspection and third person observation. This is epistemologic dualism but is onto logically neutral; it is compatible with either ontologic dualism or monism, including materialism.
One way to illustrate the difference between sources of knowledge is to consider the split-brain patient LB. LB reads the split-brain literature, has studied his own brain MRI, and has often discussed the right/left hemisphere differences. His talking left hemisphere has a great deal of indirect information about his own right hemisphere.4 What his left hemisphere does not have is the extent of direct knowledge of his right hemisphere contents that most of our left hemispheres have of our right hemispheres. As Sperry (1969) put it:

About the only instrument known at present by which one brain can plug into and read out directly the conscious experience of another brain, is the corpus callosum (p. 534).

Physicalism vs materialism

Many people use the terms "physicalism" and "materialism" interchangeably. I find it helpful to distinguish them. Roger Sperry was a physicalist and most of his students are physicalists, as am I. That is, we believe as said by Doty (this issue), "mind derives exclusively from brain." This means, as I stated elsewhere (Bogen, 1995b): a small subset of cerebral processes maps onto (not just "into") mentation. The word "onto" means that the target of the mapping is exhausted by the mapping, so that nothing is left over.
As Haugeland (1980) put it, "The central intuition is that 'fixing' the physical fixes everything, or that nothing [mental] could have been otherwise without something physical having been otherwise." This is a clear description of physicalism; it asserts nothing about the absence or possibility of non-material influences on brain (and subsequently on mind). By contrast, materialism is not only physicalistic but goes on to explicitly deny any non material influences (Fig. Ib). However, not only is the concept of a non-material soul non-falsifiable; more important, controversy over such matters is an unnecessary diversion from the goal of relating mind to brain. Hence, I remain publicly agnostic with respect to anything non-material. (Bogen, 1995a), (Fig. lc).
It needs to be emphasized that for a physicalist to believe in mind (or a brain/mind relation) means that such a person is, like me, a mentalistic physicalist. To consider this self-contradictory is to remain the victim of the centuries-old dualistic idea that mind is of a different, non-physical substance.
In view of the "near completeness" of physics, how something without spatial extent (e.g., the Soul) could affect brain is, and has long been a problem: it is sometimes called the "nexus problem." But this is not the same as the "mapping problem," i.e., how brain produces mind. Some superlative scientists (e.g., Sperry, 1980; Edelman, 1992; Crick, 1994) have explicitly denied ontologic dualism, thus denying the existence of any nexus problem. Others (e.g., Popper and Eccles, 1977; MacKay, 1980; Eccles, 1994) being dualists, have explicitly explored the nexus problem. Unclear is how either attitude, whatever other virtues they possess, contributes to the mapping problem. Many people have mistakenly conflated these two problems.5
Another distinction worth noting is a difference between physicalism and either complete determinism or total reductionism. No one now knows how a subset of brain states specifically maps onto mental states; but it is surely not one-to-one for each individual brain state (Sperry, 1952). A variety of distinguishable brain states likely correspond to a small number of mental states, in a many-to-few mapping. Within the network described by Hopfield (1982), "The flow is not entirely deterministic, and the system responds to an ambiguous starting slate by a statistical choice between the memory states it most resembles". This is one example of a probabilistic many-to-few mapping; such a brain-on to-mind mapping would impose some limitation on the reverse, a mind-to-brain reduction.


What distinguishes Sperry's view from most physicalist approaches which do recognize mind is the great importance he attached to the influence back onto brain of mentation. This can be called "retroaction," being half of what Sperry himself called "monistic interactionism" and described as follows:

... the individual nerve impulses and associated elemental excitatory events are obliged to operate within larger circuit-system configurations [which] have their own dynamics in cerebral activity [and] govern the flow of nerve impulse traffic by virtue of their encompassing emergent properties... Obviously, it also works the other way around, that is, the conscious properties of cerebral patterns are directly dependent on the action of the component neural elements... The neurophysiology, in other words, controls the mental effects, and the mental properties in turn control the neurophysiology (1969).

I have attempted to illustrate Sperry's retroactionism (half of his "monistic interactionism") by the arrow in Fig. I d from mind to cerebrum.
What could be the mechanism of retroaction? Could it be some form of electric or magnetic fields constraining neuronal action? Roger himself produced evidence against this view (Sperry, Miner and Myers, 1955). And more recent experience with magnetic resonance apparatuses show little if any influence on brain function by repetitive radio frequency pulses superimposed on quite strong magnetic fields. We know single cells or entire circuits can be controlled by "overall pattern effects in brain dynamics" such as sleep or generalized seizures. I believe that Roger had in mind patterns, more differentiated and more local, which are as yet unidentified. If Roger was right, finding answers to the retroaction problem would be a basic contribution to our understanding of brain/mind relations.

Acknowledgements - Thanks for generous advice from G. M. Bogen, F. Colburn, M. C. Corballis, D. Galin, C. R. Hamilton, T. Richey, and G. Rico.


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