Our age is marked by the triumph of science. Greek philosophers may have been the first to raise questions about the nature of matter, living entities, knowledge, will, truth, beauty, and goodness. In recent centuries, however, philosophy has steadily been yielding ground, enthusiastically or reluctantly, to empirical science. Why speculate endlessly about the physical or biological world when you can carry out laboratory experiments, make precise measurements, test predictions, and revise proposed explanatory theories in light of findings? If there are material or psychic costs to this unflinchingly empirical approach, most of us have no desire to confront them (Cf. Joy, 2000).
Nowadays, most discussions of the territory where science and philosophy overlap take place in scholarly journals or on Internet sites. It is rare to encounter a full-length book in which scholars have the leisure to lay out their positions at length, undertake substantial interchanges with one another, and provide verbal and pictorial examples. In English I can only remember the 1978 discussion of The Self and Its Brain between philosopher Karl Popper and neuroscientist John Eccles. Of course, the genre itself does not guarantee genuine engagement on the part of the participants nor intellectual or literary rewards for the audience. In the late 1980s neuroscientist Jean-Pierre Changeux and mathematician Alain Connes conducted "Conversations on Mind, Matter, and Mathematics." The two debaters proceeded from such different premises and were sufficiently dismissive of one another that they resembled two French tankers passing one another at midnight.
In a contemporary debate, it is perhaps inevitable that philosophy will be on the defensive. Science has glamor, muscle, powerful theories and methods, dramatic findings and the promise of additional ones next week. Philosophy may tout its venerability, but it often appears preoccupied with the decidedly less sexy weapons of definitions, doubts, and "thought" (as opposed to "real") "experiments". Still, we should not expect philosophy to give up the struggle without a fight. With respect to issues of mind, Immanuel Kant argued that a science of psychology was impossible; Ludwig Wittgenstein ridiculed psychologists and philosophers who routinely spoke past one another. In our own day, Thomas Nagel has written persuasively about the impossibility of capturing experience ("What is it like to be a bat?"); Hubert Dreyfus has denigrated computer-based efforts to simulate human thought; and John Searle has issued similar indictments against artificial intelligence as he insists on the unique biological status of consciousness.
Indeed, when it comes to questions of human mind, consciousness and experience, philosophers retain one powerful weapon. Put bluntly, a good many of us still prefer to believe that there is something special about human beings, some properties that do not lend themselves to explanations in the same way that one can "explain" the structure of the universe or the anatomy of the cell. Copernicus marginalized our planet; Darwin marginalized our species; Freud marginalized our conscious and rational life. Many, if not, most of us still believe that as persons we retain a privileged relationship to religious beliefs, works of art, loves and hates, dreams and fantasies, and moral sentiments--in short, for want of a less clichéd term, the realm of the spirit. In that sense, when philosophers and scientists put on the gloves, we hope that the philosophers will strike at least a few powerful blows on behalf of the human part of human nature.
The two participants in the most recent debate of this genre could scarcely exhibit more impressive qualifications. Born in 1913, part of the same generation as Jean-Paul Sartre, Albert Camus, Claude Lévi-Strauss, and Raymond Aron, Paul Ricoeur is one of the most distinguished philosophers in the world. He has written on a wide range of topics, including the problem of justice, the nature of religious texts and belief, time and narrative, metaphor, psychoanalysis, the will, good and evil. For many years he taught in both France and the United States, including a decades-long relationship with the University of Chicago. His philosophical perspective features an emphasis on phenomenology (the close analysis of the world as perceived); hermeneutics (principles for studying and interpreting texts, notably Biblical ones); and reflectivity (introspection about the activities of the mind). He is a deeply learned scholar and, judging from the tone of his writings, a compassionate and religious person.
A generation younger than his debating opponent, Jean-Pierre Changeux (b. 1936) is one of the outstanding neuroscientists of our time. His own research has focussed on the structure and function of proteins, the nature of neurotransmitters, the early development of the nervous system, the rivalry among and eventual stabilization of neural connections, and, most recently, computer simulations of those connections. He became a celebrity among European intellectuals in the early 1980s with the publication of his Neuronal Man, a spirited book that attempted to ground age-old human issues on neuroscienctific principles and findings. After writing Neuronal Man, Changeux was challenged to explain how "his" man could ever become moral and, according to Changeux, he has never ceased to reflect on this question (p. 8). While continuing his teaching at the Collège de France and his research at the Institut Pasteur, he has also ranged widely: for six years he headed the National Advisory Committee on Bioethics; and he has served for many years as Chair of a high-level commission at the Louvre.
The debate is organized loosely around a set of topics: the contrast between knowledge and wisdom; the features of the neuroscientific approach; introspective approaches to knowledge; the nature of the neuronal model; issues of consciousess, morality, ethics, religion, violence, and the arts. No shortage of Big Questions and Ambitious Chapter Headings! Throughout these chapters, there are continuing sharp disagreements, as well as a surprising common set of intellectual points of reference. By the conclusion of the book, the reader has received considerable insight into how a major neuroscientist and major philosopher attack these enigmas which first occupied ancient Greeks. At the same time, as I'll argue later, both scholars wear blinders which obscure two promising rapprochements: one based on the distinctive contributions of different scholarly disciplines, the other based on the relations between universal (species-wide) and individual experience. Changeux reaches out to effect connections, but only on his terms; Ricouer fails to discern bridges across an epistemological chasm.
For the most part, and in distinction to other published controversies, including the Changeux-Connes encounter, the debate between these two formidable thinkers takes place in an atmosphere of good will. It is marked by genuine efforts on the part of both to listen carefully, react sympathetically, and build constructively across the disciplinary divide. One has the impression that the debaters may actually respect and like one another! Still, I cannot report that the debaters are evenly matched. Younger, and a more energetic debater, Changeux succeeds in setting the agenda, putting forth the arguments and evidence to which Ricoeur must react, and seeming more open to reconciliation. For his part, Ricoeur is mostly in a reactive mode; he is rarely able to wrest the attention of Changeux or the reader; and while he scores some telling points, he fails to make as strong a case as he could. This is unfortunate because philosophy continues to be indispensable for several of the topics at issue here.
From the opening salvo, Changeux wraps himself in the mantle of a steadily progressing neuroscience. At an early point in the discussion, he lays out five significant advances: 1) the demonstration that the central nervous system is capable not merely of reaction but also of anticipatory and intentional behavior; 2) the correlation between injuries to specific sites in the brain and the corresponding loss of specific cognitive or behavioral functions; 3) the emergence of imaging techniques, which allow us to observe what is actually occurring in regions of the brain in vivo; 4) the advent of electrophysiological techniques, which allow one to isolate with precision the activities of particular nerve cells; 5) the discovery of pyschotropic drugs--chemical agents that can change our moods--along with increased understanding of how these drugs operate. The resulting interchanges around these topic offer a succinct introduction to the positions of the principals.
Throughout this opening discussion, Changeux emerges as positive--and somewhat combative--in outlook, optimistic about the prospects of connecting matters of the mind to matters of the brain. At the same time, he makes it clear that understanding needs to grow out of solid mastery of empirical knowledge about the brain and respect for the principles of evolution. To Changeux's "lumping perspective," Ricoeur counterposes a "splitter's mentality." He continually underscores the importance of separate discourses, the limits of each science and of science in general, the privileged status of agency, intention, and meaning. He, too, believes in connection but of an entirely different sort: for Ricoeur, the important bonds reflect the holistic aspect of experience, a holism which is differentiated or dissected at its peril.
We can see these antinomies at work in any number of exchanges. When Changeux explains that the nervous system is active as well as reactive, Ricouer cautions that one should first speak of mental activities and not of the brain: "The discourse of the mental includes the neuronal and not the other way around." Changeux responds: "What we wish to do is to link up the two discourses (material and mental) with each other" (p. 44). Here as elsewhere, Changuex seeks to effect connections, while Ricoeur insists on the ontological separation of the two realms.
Yet the connections stressed by Changeux necessarily emanate from the brain. At one point, Ricouer concludes from direct inference that "I see with my eyes." Changeux counters "I wouldn't go so far as to say that I see with my eyes. Instead I would say that I need my eyes in order to see. One speaks, for example, of the 'eye' of a connoissuier of art. But one really ought to speak of his brain, which is to say of his memory of the painting he has seen and of his ability to judge how a work that he contemplated compares with others that he has committed to memory." Donning the perspective of the phenomenologist, with a touch of the quibbling lawyer, Ricoeur proceeds, "One is right to speak of the connoisseur's eye rather than his brain... I see with my eyes, because my eyes belong to my bodily experience, whereas my brain does not belong to my bodily experinece. It is an object of science. That is to say that the 'with' does not function in the same way when I see with my eyes and when I think with my cortex" (p. 49).
As the discussion turns to brain imaging, Ricoeur introduces another objection. He asserts that the physical notion of the image differs from an image in the sense of imagining "that is something different--it implies absence, the unreal" (p. 53). Like a chess master invading Ricoeur's territory, Changeux speculates that one could have done a PET scan of Theresa of Avila's brain during her mystical ecstacies. Such scans might have revealed whether she had hallucinations and whether she was the victim of epileptic fits. When Changeux notes that Pascal also had hallucinations, Ricoeur rejoins: "When he [Pascal] said 'Joy, joy, tears of joy!' that was something entirely different. To use the notion of hallucination in a categorical way amounts to having a rich neuronal discourse and an impoverished psychological discourse" (p. 57).
One might think that Changeux would concede the point, but he does not. Instead he goes on to suggest that Pascal's own unpublished Mémorial, which contains the phrase to which Ricoeur referred, suggests that he had a condition called "temporal lobe epilepsy." Pascal's powerful memories probably were located in the temporal lobe and were recalled during a crisis. The content of the memories move us "because it attests to human experience that the organization of the human brain allows us to organize in memory" (p. 57). Ricoeur's final words--those of the hermeneuticist and the phenomenologist combined--emphasize that we must turn to the statements of the patient--"in other words, an account, a fragment of discourse" (p. 57).
In another fascinating example, based on recordings from single cells, Changeux describes cells that respond to color as seen by the subjects. Contrary to what most researchers would have predicted, these cells respond not to the absolute wave lengths of the color but rather to color as it remains despite changes in the composition of the light. These cells convincingly confirm Hermann von Helmholtz's classical demonstration of the constancy of colors: "in all conditions in which the subject sees red, for example, the neurons that correspond to this color are activated" (p. 60). Ricoeur predictably interrupts to add, "what we are going to call 'color' in mental language." Conceding the point, Changeux stresses that we are now able to make an exact connection between actual mental experience and recorded physiological activity. Not satisfied, Ricoeur asks whether it is proper to "identify" mental experience with observed neuronal activity; and he goes on to question the correspodence between the experimental field, on the one hand, and the view that the subject holds about himself and his brain, on the other. Undeterred, Changeux declares "this function is precisely established by the subject's own view of his perception of colors." In other words, phenomenological experience confirms the operation of color-constant cells.
Thus the opening salvos in the debate, based on Changeux's laboratory experiments and Ricoeur's critique thereof. In the pages that follow, Ricouer puts forth his two strongest line of arguments. The first has to do with artificiality. The scientist is condemned to draw inferences from situations that are inherently contrived and unrepresentative of experience "in the whole." As Ricoeur puts it:
He goes on to say formal approaches to ordinary experiences eventually bring us to "one's heart of hearts--a forum in which one speaks to oneself. The heart of hearts has its own particular status that it would appear you will never succeed in explaining in your science" (p. 69). But Changeux still retains the rhetortical high ground: "Why do you say 'never'? I cannot imagine any scientist saying 'I will never succeed in understanding...It is now possible to critically examine the way our heart of heart functions and to inquire into its private deliberations" (p. 69).
Ricoeur's second argument has to do with intentions and meanings. Once one enters the world of human experience, one is wrapped up in a discourse of beliefs, desires and meanings. This tapestry of integrated notions has undoubted significant to a person embedded in a historical and cultural context, but it remains beyond the access of the distanced, tool-dependent external observer of cells firing in various regions of the nervous system. Speaking critically of the cognitive sciences, Riceour declares:
Changeux responds that it is possible to obtain physical facts about subjective psychological states and that a physics of introspection might even be possible. He chronicles the advances that have been made in understanding linguistic and other symbol systems. Yet, to my way of thinking, he skirts around the territory of intentions and meaning, rather than entering the heartland which Ricoeur so cherishes.
Thus, if not the heart of hearts, at least the heart of the debate, laid out in the first part of the book. The remaining pages explore these clashing epistemological positions with reference to a succession realms of human experience. In each case--consciousness, religion, morality, ethics, arts--Changeux looks for biological clues: from the behavior of animals, the impaired functions of individuals who suffer from brain disease, correlations between blood flow or electrophysiological patterns and behavioral states, findings about genetic or psychological functioning, linguistic and artistic products. For example, when it comes to morality, Changeux cites animals who resist hurting those conspecifics who have assumed a position of vulnerability; when it comes to consciousness, he focuses on experiments where human beings deny knowledge of a situation and yet can be shown to have apprehended aspects of the situation unconsciously; when it comes to the arts, Changeux identifies features of works that command attention across higher organisms and patterns of emotions which predictably accompany such reactions.
In each case, Ricoeur raises kindred objections to these attempts to "naturalize" the human condition. While recognizing that there may be intimations of human behaviors in the activities of animals, he will not accept "commonality of origins" as evidence that these activities can be described, let alone justified, in terms of such commonality; they must always be explicated in terms of their place within a meaningful human community. He refuses to conflate actions based on instincts with actions based on a sense of responsibility; that latter sense can only emanate from conscious human agents, operating in a voluntary matter within a network of rights and responsibilities. Commenting on Franz de Waal's demonstration that adult chimpanzees care for a handicapped infant, Ricoeur pointedly insists "we always interpret animal behaviors from a human perspective" (p. 191).
The two men clash in the arena of religion. Ricoeur, personally a religious man, has devoted decades to the study of the major Western religious traditions. In his view, much of what is most worthy in life comes from our religious beliefs, experiences, and teachings. Changeux, for his part, sees religious traditions as scientifically unsupportable, responsible for much of the hatred and violence of the historical and contemporary worlds. Whereas Ricoeur deems religion a fundamental aspect of human experience, Changeux sees it as increasingly anachronistic in a world in which we should seek biological (not mystical) explanations of human good and evil, and should try to use that knowledge to build a harmonious world. Their exchange here is as acrid as any in the book:
In a book punctuated by such different viewpoints, it is noteworthy that both authors draw on certain scholarly authorities. For starters, both invoke René Descartes, who first posited the divide between body/matter and spirit/mind, and who modelled methods of introspection for the understanding of the mind. Ricoeur emphasizes the independence of two realms of discourse, while Changeux argues that "we have arrived at the moment in history when it has become possible to link them up." Changeux claims that in unpublished texts, Descartes had called for this rapprochement as a means of constituting "men who resemble us" (p. 35). Moreover, he goes on, Descartes had proposed the same hierarchy of organization of cerebral functions, and modes of reciprocal regulation between levels of organization, that he himself favors. For his part, Ricoeur dwells on the fact that Descartes' famous dualism allowed successors to develop a philosophy of bodily subjectivity. This general philosophy led ultimately to a phenomenology of subjective corporeal experience--the Merleau-Ponty tradition with which Ricoeur identifies.
The debaters also draw on a well-known contemporary scholar, the paleontologist and evolutionary theorist Stephen Jay Gould. Ricoeur quotes with approval Gould's claim that there is nothing inevitable about the appearance of man on earth, no reason to think that our species represents any kind of progress in which we can take pride and whose origins we can discern in our predecessors. Gould's work emboldens Ricoeur to assert that our search for evolutionary antecedents for morality (and other human virtues) is misguided. We must provide a moral order--nature cannot do so (p. 181).
Responding to this "reading" of a shared authority (pp. 182 ff), Changeux first chides Ricoeur for, on the one hand, rejecting any Divine hand in evolution and yet, on the other, alluding constantly to the "Great Code" of the Bible. Next, Changeux stresses that the great variety of nature, including the brains of earlier hominids, probably played an important role in the origin of the human species. He says that Gould has underestimated the difficulties posed for evolutionary genetics by the undeniable increase in the complexity of the brain over the last four million years. The genetic differences are small in light of the enormous differences in computing power of our species. Finally, Changeux challenges Gould's contention that cultural changes are founded on Lamarckian inheritance--in the current jargon, on the transmission of memes. In Changeux's view, this resorting to wholly cultural explanations ignores the extent to which long-term memory and storage reflect mechanisms of selection that are biologically determined, on the one hand, and yet also reflect random factors, on the other. As the neuroscientist sees it, there are underappreciated biological aspects to the spread of culture.
The historical figure who comes close to dominating the discourse turns out be a most surprising "mystery guest"--the 17th century Dutch philosopher Baruch Spinoza. Living a bit later than Descartes, Spinoza took the position that mind and body were actually part of a single substance, which, in pantheistic fashion, he called, alternately, Nature and God. On Spinoza's account, we know the universe in its infinite variety through physical extension and through thought. The Dutch philosopher went on to privilege reason which allows human beings to be active agents and virtuous beings.
Both debaters are enamored of Spinoza, and in splendid hermeneutic--if not deconstructionist--fashion, each is able to find in this philosophical ancestor the seeds of his own intellectual enterprise. Ricoeur acknowledges that Spinoza sought a unity of mind and body but only at the most transcendental level--that of God (p. 20). He claims that Spinoza was actually interested in the difference between the illusory freedom of a Cartesian arbiter ("I think and therefore I am"), and a richer freedom that results from following a system of laws, and that yields wisdom and bliss (pp. 24, 201). And so Ricoeur asserts "I do not see a way of passing from one order of discourse to the other: either I speak of neurons, and so forth, in which case I find myself in a certain language, or I speak of thoughts, actions, and feelings that I connect with my body, to which I stand in a relation of posesssion, of belonging" (p. 15). He states, defiantly, "[your discourse] does not move us an inch nearer to a renewal of Spinoza's unity of substance" (p. 31).
For Changeux, on the other hand, Spinoza was the philosopher who extended insights about nature to man and to the "human soul" (p. 23). The neuroscientist asks, "why posit a discontinuity of discourse when objective knowledge of what determines our behavior holds out the prospect of greater wisdom, perhaps even greater freedom?" He goes on to argue that Spinoza sought to create a single discourse "with the same rigor of method as geometry" (p. 29). And, as if discovering in the Sephardic grinder of lenses an early draft of a chapter from Neuronal Man, Changeux quotes his master as saying "Men's judgment is a function of the disposition of the brain" (p. 201).
At the end, we confront two gaps that these thinkers are unable to bridge. There is the disciplinary gap: the gap between the practicing scientist, who believes that the tools of his trade will allow him to progress, if not completely illuminate, the deepest questions of human existence; and the practicing philosopher, who remains convinced of the parochiality of science and who prefers to employ his own tools: the close study and analysis of experience, the careful interpretation of sacred and secular texts, and the capacity for reflection and for reflection upon reflection. Complementarily, there is the discourse gap: one discourse that describes human behavior and thought from an external vantage point, and a second discourse that describes human activity from within, as the realized experience of the mind, the spirit, the soul. Changeux believes in continuity--one can proceed from one to the other; Ricoeur believes in a fundamental discontinuity--one will never be able to span this gap, for it reflects inherently alien universes.
I approached this book ambivalently. As a social scientist with ties to both cognitive science and neuroscience, I have a professional faith that major philosophical questions have been, and will continue to be, illuminated by scientific work. No terrain should be declared "off-limits" to scientists. And I am impressed by the scientific advances described by Changeux. At the same time, I have equally strong links to the world of humanistic scholarship and practice. Much of my work has focussed on the nature of artistic expression and experience, and I have little doubt that the core of the arts lies remote from current scientific understanding and even scientific promissory notes. I also believe in the indispensability of cultural and historical studies and do not see them ever replaced by a natural or social scientific stance. Indeed, I am suspicious of reductionist efforts, whether in the hands of a physical materialist or an evolutionary psychologist.
I wish, therefore, that the debate had treated two loosely related dimensions which, I believe, constitute a fairer test of the perennial struggle between science and philosophy. These dimensions--"forms of explanation" and "insight into individual entities"--should both be viewed as continua.
Turning first to "forms of explanation," scholars dating back to the 17th century philosophers agree that it makes sense to think of human psychology as consisting of a set of ordered components. Closest to neuronal analysis, and most powerfully shared with other animals, are our capacities to sense and to perceive. I fully expect that science can provide reasonably complete explanations of these capacities. One can proceed to order other capacities, including those of concept formation and categorization, linguistic and other forms of communication, all the way across the continuum to religious, moral, and artistic systems. The sciences of experimental psychology, linguistics, and evolutionary psychology can provide insight into these broader-gauged capacities. Yet as one proceeds along the continuum, the explanatory power of basic sciences is steadily attenuated, and one needs increasingly to bring to bear other disciplinary tools, including those of semiotics (symbol analysis), ethics, and aesthetics. Indeed, at the "right" end of the continuum, cogent accounts can only be put forth if they draw heavily on historical and cultural studies (anthropology, literary analysis). It is not that religious beliefs or aesthetic standards and experiences stand apart from atoms and neurons; rather, it is that the most powerful and persuasive accounts will succeed only if they bring to bear the insights of humanistic studies.
Where I differ from many scientists, including, I believe, Changeux, is in my belief that there is nothing privileged about the most basic atomic or neuronal level; the great chain of being, the braid of consilience, if you will, simply reflects different points along a single continuum.
Continuum A: The Disciplines (through philosophical analysis)
To put this in terms of the debate, there is no gulf between behavior and soul; nor is there a need to insist in two unjoinable discourses. There is rather a continuum: at each point, a somewhat different blend of disciplines and discourses must be drawn upon. Cultural and historical factors are needed to explain the expression of genes in different contexts; gene analysis is needed to reveal historical and cultural potentialities; philosophy is needed (as in the present analysis) to define and identify these different perspectives. That is why we have universities!
The other neglected space, mentioned only in passing in the debate, is the nature of individual creations and experiences. We share many properties with our fellow humans; indeed, as often noted, we even share nearly all of our genes with chimpanzees. And yet each of us--even identical twins, as Changeux has pointed out elsewhere (1999)--has a different nervous system. Each of us is interestingly different from every other member of homo sapiens, and indeed, from the way in which we ourselves were years ago and will (if we are lucky) be years hence. More importantly, the works of art that affect us are revealingly different from one another. We do not listen to Beethoven in order to secure the same experiences as we seek from Mozart or Stravinsky. Moreover, what is distinctive about the opening bars of Mozart's 40th symphony is what makes it intriguing, and why we may choose to listen to it or program it, rather than to the (equally beautiful) openings of the 39th or the 41st symphonies. Paraphrasing the composer Arnold Schoenberg, "style" is what cuts across the works of a person or era; "idea" is what makes each distinctive and precious. I do not believe that science will ever be able to capture either form of individuality (the person or the work); nor, despite phenomenology and hermeneutics, do I think that this individuality can be adequately illuminated by philosophical tools. But I do not deplore this state of affairs--I rejoice in it.
Noting that scientific explanations lose potency as we move to the right, we can depict two continua of individuality as follows:
Continuum B: The Person
Continuum C: The Work
Finally, a word about consciousness. For centuries, philosophers have cherished the privileged area of consciousness--the peculiarly human (and perhaps higher animal) capacity to feel and to think, and to be aware of our feelings and our thoughts, and how, so to speak, they feel. But in recent years, cognitive- and neuroscientists have at least begun an assault on this fortress; and for the first time, we have genuinely searching discussions of "the feeling of what happens" (Chalmers 1996, Damasio 1999, Dennett 1991, Searle 1992). From my point of view, consciousness is no more or less privileged than the other areas under discussion here--the true, the beautiful, and the good. Moreover, aspects of consciousness will lend themselves readily to the kinds of scientific experimentation and analysis prescribed by Changeux, while others will call for the sorts of historical and cultural studies that emanate from humanists like Riceour. To expect science or history of philosophy ever to explain my or your peculiar consciousness as you read and reflect on these words is, however, a fool's errand: as Einstein once quipped, "the purpose of chemistry is not to recreate the taste of the soup."
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