Brain Storm

Dr. Rosenblueth is a specialist in neurophysiology, the field (the dust jacket assures us) “most likely to provide hard answers to the central questions of perception, sensation, volition, and the nature of human knowledge,” since “a nonneurological epistemology can only be impressionistic.” Dr. Rosenblueth is not the first to feel that the task of interpreting the world had better be undertaken by those who know something about it. Experimental scientists are the natural philosophers.

Into his short and gracefully written book he compresses, without strain, an account of his philosophical position on all the matters just mentioned and more. The language, except for terms belonging to his specialty, is nontechnical, or no more technical than that of Descartes, Locke, and Berkeley. Indeed the book reads almost as a sequel to their arguments, minus the theology. How easily, with the change of a term or two, one could slip the following sentences into one of Berkeley’s dialogues as a contribution from a not-yet-persuaded believer in matter: “We postulate the existence of this material universe in order to account for certain recurrences or regularities in our sensations or perceptions. We also accept the postulate because, although we have the feeling that we can evoke or direct voluntarily some of our mental processes, others, those whose origin we attribute to material objects, we can neither evoke nor suppress at will.”

What is Dr. Rosenblueth’s position? It is, as the above quotation shows and as he repeatedly affirms, dualistic: a dualism with a Cartesian starting point, though a professedly un-Cartesian conclusion. (1) There are mental processes and events, such as thoughts and sensations, of which alone we can have direct and certain knowledge. (2) Each specific mental event has a neurophysiological correlate (a specific spatiotemporal pattern of neuronal activity). (3) Our brains and, generally, our bodies form part of a material universe, but (4) the only knowledge we can have of material things is knowledge of their abstract structures. (An instance of an “abstract structure” would be the structure which is common to all the following related things: a certain heard sequence of musical notes; the score which the musician followed; the air vibrations produced by his playing; the grooving of the gramophone record.) (5) The “secondary qualities” of taste, smell, color, sound, and felt hardness, smoothness, roughness, etc., which we attribute to material things, do not really belong to them, but are purely mental. (6) The only causality is physical and there is no mind-matter interaction in either direction.

The author cites evidence from his specialty as his grounds for adopting (2) and (4). Since he rests his point about “abstract structures” on features of the actual physical layout and working of the human organism, it seems either that he must exempt the human body from his conclusion that we have a merely abstract structural knowledge of the material universe—a somewhat arbitrary exemption—or that we must gloss the talk of abstract structures by referring to a set of “primary qualities” not so very different from Locke’s “bulk, figure, motion and number.” The fact that Dr. Rosenblueth seems frequently to equate the point about abstract structures with the denial that material things have secondary qualities suggests that the second alternative is what he really means, at any rate most of the time.

There is also a puzzle about what Dr. Rosenblueth really means by the denial of interactionism. His language is frequently enough interactionist. He speaks more than once of physical stimuli giving rise to sensations, of sensations being elicited by or attributable to material processes. He speaks also of conscious processes leading to behavior, of types of behavior that become comprehensible only if we are to assume that they are accompanied or determined by mental experiences. Merely to replace these causal idioms, as Dr. Rosenblueth does when he remembers, with the terms “concomitance,” “correlation,” “association,” etc., will not stop us asking whether he thinks mental events are ever causally necessary or sufficient conditions of physical events or vice versa.

Dr. Rosenblueth’s view, if I have understood him rightly, is this. First, as regards interaction in which events that happen to the body are supposed to have an effect on mental states, he argues that causal dependence implies temporal priority of cause over effect, but sensations or perceptions are simultaneous with their physical correlates and therefore not caused by them; though the latter are caused by other material events. Even if we accept this, however, the argument gives us no reason for denying that mental events may be caused by the antecedent physical causes of their physical correlates. So it gives us no reason for surrendering, for example, our naive conviction that our sensation of pain was caused by stubbing our toe. Nor does it seem that anything of consequence in Dr. Rosenblueth’s physics or his metaphysics is imperiled by the admission that sense-experience has physical causes.

The case is rather different with interactionism in the other direction, from mind to body. Here there really is something which Dr. Rosenblueth wants to deny, namely that mind can intervene in the purely physical causal chains which lead to bodily movement, that the “mental state we call will” (which is itself simply an “awareness of a characteristic mental process or state”) can ever initiate what we call voluntary activities. He argues that any such supposed intervention would be a violation of the laws of physics and gives technical reasons for thinking that the suggestions of those who toyed with the thought of the will exerting an influence on the cerebral processes within the range of the indeterminacy of quantum physics were at best baseless and at worst nonsensical.

Dr. Rosenblueth’s position is, I take it, that the complete causal story regarding those events in the physical world which constitute human behavior in its physical aspect could in principle be told without any reference to the mental. We need never invoke a link between the mental and the physical, since the neurophysiological correlates of mental states are sufficient (and necessary) to carry the causal burden. Dr. Rosenblueth does not really say quite enough to ease the anxieties of those who might conclude that, if not a mark of delusion, it could only be whimsical to continue to talk of voluntary action at all. Indeed what he does say seems likely, if anything, to confirm those anxieties: “…if one accepts, as I do, that our feeling of freedom of choice is a mental event and defines, as I do, voluntary movements as those which are preceded or attended by the mental state which we call will, the denial [of free will] disappears.”

Those who seek a more substantial reassurance may find it without much difficulty, though they may be better equipped to do so if they carry a little non-natural philosophy in their baggage. There is, after all, not a shadow or breath of a hint of the possibility of displacing, or reducing to physical and neurophysiological terms, our voluntaristic explanations of what, in a way not quite Dr. Rosenblueth’s, we actually identify as human actions. And, for those who need them, there are hints in his book, if not in plenty at least in modest profusion, as to why not.

While there is, he writes, evidence of a “high degree of localization of function in the cortex” and we can “safely infer that the cerebral cortex plays a fundamental role in the nervous activities correlated to some conscious events,” yet “the physiological correlates of mental states probably include the activity of nervous elements in many more regions of the brain than those which these localizations might suggest.” “Most, if not all, conscious processes probably require the organized activity of myriads of neurons.” “It is likely that the neurological correlate of even the simplest mental state involves a large number, thousands of millions, of neurons.” Even the simplest.

Moreover, “human beings acquire new conditionings throughout their lives, and they learn, and retain memories. The functional connections of the neurons in our brains are modified by all these processes. The neuronal reactions of our brains to a given stimulus are therefore determined, not only by whatever innate neuronal connections we may possess, but also by our previous experiences and the traces which they leave in our nervous systems…. These experiences include our intercommunications with other human beings…. These deterministic influences are not included in physics, which is not concerned with the specific properties of the specific material aggregates of our brains; but they do not run counter to any of its laws.”

Not much prospect, then, of finding the neurophysiological correlate of John’s noticing that Jenny was embarrassed by the mention of Richard’s name or the deterministic laws which led thence to his adroit diversion of attention from her. These complexes of pattern and of law, granted their existence, would not be such as a neurophysiological investigation alone could ever lead us to isolate and study. The point is, I think, implicit in the last sentence of Dr. Rosenblueth’s I have quoted, but it is more general. If the intricacy of correspondence is raised to a sufficiently high level, the correspondence itself is without any actual significance for us, it is inefficacious, playing no part in any of our games. So the human and voluntaristic style of explanation of behavior must continue to impose its own indispensable pattern, and there is no reason to feel anything but (if we like) wonder and satisfaction at the existence of the whole intricate neurophysiological mechanism, itself an indispensable vehicle. We are better off without either the simplistic dream of interactionism which Dr. Rosenblueth repudiates or the no less simplistic conception of mental states which he does not.

None of this implies any denial of the interest and importance of the investigation of the role of the brain in behavior. Dr. Delgado, a writer who places a lower value on conciseness and a higher value on rhetoric than Dr. Rosenblueth, offers, in Physical Control of the Mind (optimistically subtitled Toward a Psychocivilized Society), an interesting assemblage of anecdotal and photographically illustrated material concerning the electrical stimulation of the brain (ESB) in monkeys, cats, and men. He notes how motor activity can be controlled (“Your electricity is stronger than my will,” one subject remarked), aggression stimulated, anxiety diminished or increased. He notes, too, as far as behavior of any complexity is concerned, the relative coarseness of correlation and control. You can stimulate aggressiveness in, say, a female monkey; but just what form her aggressive behavior will take is a matter of a pre-existing social order and already established individual relations.

All this is well enough. But Dr. Delgado is not concerned only to inform us on these points. He has other lessons to teach, and the weight of experimental information is greatly overbalanced by that of general hortatory reflection on the evolution of species, the place of man in history, the nature of human happiness and human society, our present predicament, our future prospects, and the relevance to all these of ESB. He is a little, and naturally, divided in his mind about this last. His predominant mood is one of optimism before what he conceives to be the glorious prospect of a beneficent transformation of the general human condition opened up by the possibility of physical control of the mind. Aware, however, that his enthusiasm may not be universally shared, he interrupts its flow from time to time to remind us, somewhat inconsistently, of the very severe restraints on the use of these techniques which would, at present, be considered desirable in any civilized society.

Nothing in either the matter or the form of Dr. Delgado’s practical reasoning inspires confidence. Platitude (“A knife is neither good nor bad; but it may be used by either a surgeon or an assassin”) and jocosity (“Of course there is no physical impediment to the acquisition of half a dozen wives—at least until the law or the ladies catch up”) are pardonable; and perhaps one should not be worried overmuch by an author’s committing himself to the proposition that “words, concepts, information…circulate through the nervous system.” But one may reasonably be chilled at the suggestion of a quaint survival in “Primitive man probably derived pleasure from looking at the changing beauty of nature, which retains its fascination to the present day” and experience a yet deeper uneasiness at the recommendation of “governmental action declaring ‘conquering the human mind’ a national goal at parity with conquering of poverty or landing a man on the moon.”

It is a relief to turn from these overheated pages to the long, cool, and scholarly study by Robert M. Young of the history, during the nineteenth century, of investigation into the relation between mental function and the brain. Anyone with the slightest acquaintance with the cultural history of the period must have been amused and puzzled by the interest obviously taken by the educated classes, around the early middle of the century, in the pseudo-science of phrenology. Mr. Young fairly and firmly “places” its surprising role in both the history of the concept of cerebral localization and in the development of psychology as a biological science.

His book as a whole seems a model for the writing of the history of science. As, perhaps, a good historian of science must be, he is much more than a historian. Of the continuing and current conceptual problems of psychology he shows an awareness which neurophysiologists who write on mind and brain might be encouraged, by reading his book, to share. As regards the relation of human behavior to the physiology of the organism he is surely not overstating the case when he writes, in conclusion, that “historical, philosophical and conceptual studies in the interpretation of man’s place in nature have a more important part to play than has hitherto been assumed.”