A Conversatonwit Patrnica Churchiand NeilA. Campbell

Nervoussystems distinguish tions about the brain and that I needed to know the

iiSf,' .9X#. animals from all other king- nuts and bolts of the brain, what neurons were and jx i i X doms of life. And certain how they talked to each other. The more neuro- propertiesof thehuman brain science I knew, the more it seemed to me that we distinguishour speciesfrom really had the key to understanding the nature of the

all other animals. The human mind via neuroscience. This is not to say that we had Downloaded from http://online.ucpress.edu/abt/article-pdf/58/3/154/47484/4450104.pdf by guest on 29 September 2021 brain is, after all, the only a key that you could use independently of psychol- ii *1 11Pknown collection of matter ogy-behavioral descriptions-but that it was a cru- thattries to understanditself. cial element. l!!11 To most biologists,the brain I was always unconvinced by arguments that in and the mindare one and the addition to the brain, there is a nonphysical soul; and same; understandhow the it's the soul that makes decisions, the soul that feels brainis and how it and thinks. If you're unconvinced by that, then the Patricia Churchland organized works,and we'll understand nature of the brain and its organization have to be such mindfulfunctions as abstractthought and feelings. relevant in understanding these fundamental ques- Somephilosophers are less comfortablewith this mechanis- tions that philosophers are interested in. tic view of the mind, finding Descartes'concept of a mind-bodyduality more attractive. Patricia Churchland has Campbell: How did you then begin to learn neuro- takencenter stage in this debateabout the humanmind. science? Dr. Churchlandis a professorof philosophyat the Churchland:Well, I knew some basic biology, basic Universityof California,San Diego, and an adjunctpro- cell physiology and biochemistry, but I realized that I fessorat the SalkInstitute. Boundaries between the human- needed to know brain anatomy. By this time, I was a ities and the sciences dissolve as ProfessorChurchland faculty member at the University of Manitoba. So I attemptsto synthesizea philosophyof the mind basedon phoned the head of the anatomy department at the whatneuroscience is learningabout the brain.Her seminal University of ManitobaMedical School and explained bookin this new synthesisis Neurophilosophy: Toward my interests. He said, "Why don't you just come and a Unified Science of the Mind-Brain(MIT Press, 1986). take the basic neuroscience course with the medical Biologyis a multidisciplinaryadventure that integrates the students and do as much or as little as you want." I naturalsciences and connectsto the humanitiesand social did all the anatomy and the basic physiology, but that sciences.Neurophilosopher Patricia Churchland is helping wasn't enough. Then I got associated with a lab and makethose connections. learned the basic techniques, such as recording from single cells. But once you have a leg up, you start Campbell: What led you, as a philosopher, to neu- learning more on your own. roscience? Churchland:The questions I was interested in as a Campbell: So you started to bridge that neuroscience philosophy graduate student were really questions training to philosophy of the mind? about the human mind, about the nature of learning Churchland:At a certain point, it seemed to me that and perception, about what it is for something to be if the brain is the thing that does the thinking, the conscious, about the difference between the actions feeling, and the decision making, then we really have we call voluntary and actions we call involuntary- to pay attention to basic brain anatomy and physiol- the free-will problem. As time went on, it became ogy in order to answer some of the philosophical increasingly clear to me that these were really ques- questions. And some of the answers are going to be counterintuitive. Those ideas that seem very likely to us via introspection might well turn out to be false, NellA. Campbell is a MslslngScholar in the Departmentof Plant Sciences,at the Universityof California,Rlverside, CA 92521. just as in any other science. One theme in my book, Neurophilosophy,is that if you stick with your basic

154 THEAMERICAN BIOLOGY TEACHER, VOLUME 58, NO. 3, MARCH1996 intuitions about the way things must work in the understand. With the advent of artificialneural nets mind and don't take the route through neuroscience, that we can design on computers, we are beginning you are going to miss all the depth and the richness to get at least a conceptual frameworkfor making that that underlies the reality. This is partly an argument bridge between the individual neurons on the one for materialism-that there is only the brain-and hand and the systems on the other. We have a long partly an attempt to convince psychologists, who are way to go. So far, we can find really interesting also materialists, that it isn't enough to look just at propertiesof artificialneural nets when they're small: behavior. They learn from examples, and they find approxi- mately good answers when there is no precise an- swer to be found. They can do things fast. They can Campbell: Was it uncomfortable for you, coming have a kind of short-term memory. What we don't from a philosophy background, to challenge the understand is how you can get really interesting tradition of mind-body duality? effects out of big nets, or whether the nervous system Churchland:Not for me personally, because I don't takes lots of little nets and treats them as units of a big think that distinction of mind and body, or brain, net. ever seemed terribly plausible. I was always part of Take the case of categorization,for example. Some that traditionthat says that complexity is not predict- Downloaded from http://online.ucpress.edu/abt/article-pdf/58/3/154/47484/4450104.pdf by guest on 29 September 2021 regions of the brain seem to be specialized for han- able from looking at the constituents, but put them dling categories for natural things and others for together in certain ways, and you get these really manmade things. And within the regions specialized extraordinaryproperties. The mental properties for for manmade things, there is further categorization: perception, for knowledge, for learning, for memory, for example, tools that you use with your hands, and all had to come out of the complexity of the organi- other kinds of things like automobiles. We don't zation of matter. My own backgroundwas very much know how brains do this regionalization,so we don't in that line of thinking. The Darwinian perspective know how to make nets that can help us understand always seemed to me to be the key to making things it. Another key question about brains is how they get sensible. I don't find rejecting a nonphysical soul things done in time. How can an eagle intercept its personally wrenching, but I realize that some people prey? How can you catch an outfield fly? How you do. When students first encounter the thought that get the timing right is a majorissue for a lot of neural maybe there is only the brain-which means that network theory now. What we desperately need is when the brain dies, I die-it's something they have more understanding of neuroanatomyat the network to think through, not just in scientific terms but in level. very personal terms. They will sometimes ask me, doesn't it make you feel as if the world is a very bleak place or that there is no meaning to life? My response Campbell: Modeling neural nets on a computer is is that in lots of ways the idea of an afterlifedoes you one thing, but is the brain itself a type of computer? an enormous disservice. It gives you the idea that you Churchland:It's useful to think of the brain as a kind can defer lots of things and make it all come out right of computer because that allows you a frameworkfor later. I think if you take the view that the planet is the thinking about how individual neurons interact to thing to love and to care for and to see the future achieve a certain effect. Suppose you are trying to for-if you see that as a source of meaning and visually tracka given object and your head is turning value-you'll see that the other story doesn't help in as you walk. Viewing the brain as a kind of computer making life decisions and in feeling comfortable. It helps conceptualize the interactionbetween the neu- doesn't help particularlywith tragic situations and rons in the vestibular organ, which detects head death and the things that we all find deeply trou- movement, and the neurons that control eye move- bling. When students think about it in that context, ment. There are, however, many contrasts between they often do say, yeah, maybe you're right about the brain and a desktop computer. For example, in that, I'll just have to live it for awhile and see if I can. the brain the very elements that process perception are also elements that store information about what you perceive. It isn't that the memory is in one place If we view the mind functions as Campbell: major and the processing for perception is in another place. of the brain what emergent properties organization, The brain's style is parallel and analog computation. do we need to understand about neural complexity to explain these mental functions? Churchland:I think the majorarea we're missing is at Campbell: Do you think knowledge of the brain can the level of neural networks. Assuming that neurons enable us to build better computers or different form themselves into micronets, and micronets inter- kinds of computers? act with larger units, or macronets, it's really the Churchland:Yes, I really do. There is likely to be big properties at that larger level that we don't yet technologicalpayoff as we understand in more detail

INTERVIEWWITH PATRICIA CHURCHLAND 155 how neuranets function and how they solve prob- right about the strategythat people invoke when they lems. That is, how do they manage to be so flexible? say it's important to be in touch with your feelings. How, with so few neurons, can a bee solve problems Suppose you come into a convenience store and you that are really highly complicated?In general, I think sense something is not right. I certainlywouldn't say the flexibility and the capacity to generalize that we that it is a completely reliableclue, but it's something see with brains, and don't see in the very brittle worth relying on and taking a closer look. architectureof artificialcomputers, are things we will understand as we get more of the story of the brain. Campbell: Is that part of what we mean by being conscious? Campbell: Do you think it's possible to build ma- Churchland: Yes, but it is probably not the most chines that think? fruitful place to begin an experimental entry to that Churchland:I think in principle it is. Since we are a problem. Some people have the idea that before you machine that thinks, and evolution built us, then yes. can study consciousness, you need a nice, precise, Whether we can mimic the brain using the kinds of clean definition of what consciousness is. I want to electronic components that we are now using de- resist that. Clean, nice, precise definitions are what

pends on the nature of the problem. It might turn you get afteryou've done the science and you've got Downloaded from http://online.ucpress.edu/abt/article-pdf/58/3/154/47484/4450104.pdf by guest on 29 September 2021 out, as I suspect it will, that getting the timing right is an established, well-tested theory. Before you have a not just a matter of connecting neurons up in the good theory, often what you have to do is grope right sort of way. The individual neurons that are so around with good examples, where we generally connected have their own timing propertiesadjusted. agree that it is an example of the phenomenon we They've got certain patterns of specific protein chan- want to study. Doctors and most lay people are pretty nels, and such factors are going to affect spiking good at telling when somebody is in a coma or frequency and duration of hyperpolarization,and all vegetative state of consciousness. We're pretty good of those kinds of things are going to be part of what at telling when somebody is in deep sleep and when goes into getting the timing right. So if what we want he or she is awake-and that's a big difference in to do is get the timing right, we may have to mimic consciousness. These are good examples-good start- what neurons actually do down to the level of mem- ing points. When you're in deep sleep, you're not brane proteins. aware of things, even though you may do some things that are somewhat intelligent. For example, you move a lot in deep sleep and you navigate Campbell: All of which depends on learning more around the bed. Even if you're in a relatively novel about how the brain itself works. Are we getting bed and there are other people in the bed, you closer to understanding consciousness, memory or generally manage not to fall out, etc. We can tell emotions? when people are in REM sleep, which seems to be Churchland:We have made progress on a number of differentfrom both of those other states. So here is an majorquestions-certainly on the learning and mem- experimentalentry point: What happens in the brain ory front, and on the interconnectedness of reason when somebody is in deep sleep, and awake, and in and emotion. Researchershave studied the idea that REMsleep? emotion and feelings-the ones that we often call gut feelings, the feeling of uneasiness or that something is wrong-help bias decision-making in ways that Campbell: Why do we sleep? allow us to make choices we normally consider Churchland:There's been interesting recent work on purely rational. It looks as if limbic structures,such as the anatomy and physiology of sleep. But why we the amygdala, play an extremely important role in need to sleep remains puzzling. Undoubtedly sleep this biasing, and that the projections from the limbic plays some criticalrole or other. We do a lot of it, and structures to frontal structures are very, very impor- we like it. People, by and large, like to sleep, and tant. The main point is that in situations requiring a show serious problems when sleep-deprived. There certain amount of analysis, such as being able to must be a significant reason why the brain does it. predict a complex event, you need not just frontal Some people think that it has to do with restorationof cortex but input from the limbic structures that are basic neurotransmitters,and that it's fundamentallya cued, in turn, from the viscera, the skin, and so forth. metabolic issue. That's quite possible, but not estab- I think that is tremendously interesting. It shows us lished. The startling thing that people discovered that for demanding common-sense problems deter- many years ago, however, is that your cortical neu- mining what, in the general sense, is relevant and rons are not quiet in deep sleep; they're going like what isn't-you've got to have the emotions in- blazes. There's very little difference between overall volved. That is very revealing about the way we neural activity when you're in deep sleep and overall actually work. It may mean that there is something neural activity when you are conscious. Both deep

156 THEAMERICAN BIOLOGY TEACHER, VOLUME 58, NO. 3, MARCH1996 sleep and REM sleep are quite puzzling because we mental issues such as poverty and drug-use. We shall incur a survival risk in both. We're terriblyvulnerable want to be prepared in a very dispassionate, careful while asleep. Evolution has put a good deal into this and wise way to reconsider the institution of punish- strategy-but exactly why, it's hard to say. ment.

Campbell: Do you see potential medical applications Campbell:Unifying brain and mind may seem like a of neurophilosophy? reasonable objective to most biologists. Why are Churchland: Insofar as I see neurophilosophy as a some of your philosophy colleagues uncomfortable part of the general discipline of neuroscience and with this synthesis you call neurophilosophy? insofar as I see neuroscience as having a major Churchland:There are a number of differentreasons. medical benefit, then yes. There are still a number of Partof it is that, in general, science discovers that the serious medical problems we haven't quite gotten a realitybehind the appearancesis quite differentfrom grip on. One is schizophrenia, another is Alzhei- what we thought. Aristotle thought, for pretty good mer's, and another is Parkinson's. In all of those reasons, that an object is not going to keep moving cases we have palliatives for treating people to make unless you keep a force applied to it. Giving that up those diseases slightly less awful, but we are a long based on the Newtonian frameworkmeans accepting Downloaded from http://online.ucpress.edu/abt/article-pdf/58/3/154/47484/4450104.pdf by guest on 29 September 2021 way from enabling a person to have a normallife and a very different picture of the nature of kinetics. a normal death. When you realize that about 1% of Similarly, thinking that species come into being via the population has schizophrenia, and something Darwinian evolution rather than at the moment of like 15% over age 65 suffer from Alzheimer's, and creation is, for some people, very counterintuitive. I something comparable for Parkinson's, it is really think some people worry that the next step is that important to understand these diseases. I think the science is going to say, "You aren'twhat you thought answers will come out of further understanding of you were." I think lots of us find that hard. It's one basic neuroscience. thing to have a counterintuitivetheory of motion but do I want a counterintuitive theory of myself? We Campbell: Will a better understanding of the mind may suppose, wrongly I think, that there can't be a also raise ethical issues? If, for example, there are counterintuitive theory of me because I'm the best dysfunctions in areas of the brain that are involved authority for how I work. Additionally, some people in judgment, in distinguishing between right and think that if science is applied to humans, then the wrong, what are the implications of that? Do we dignity of humans is at risk. I take a more optimistic hold people accountable for their behavior if they view. Some of the very damaging superstitions we have these kinds of dysfunctions? have about humans may actually be replaced by Churchland:That's a very delicate question, and the much more caring, more humanitarianhypotheses or interface between neurophilosophy and the legal approaches. Historically, this has been the pattern. system and ethics in general is going to be tremen- For example it is really much more humanitarianto dously important. I suspect we shall want to rethink have a pharmacologicaltreatment for a schizophrenic the nature of punishment. In dealing with criminal than to put that person on a dung pile in order to behavior, we need to understand, first of all, what chase the demons out. As for other puzzles about our interventions are efficacious-what produces the de- universe, a scientific understanding of the mind will sired result. It might turn out that certain interven- actually promote humanitarian values rather than tions might be more efficacious and less costly than detractfrom them. Superstitionand irrationalismare locking people up for long periods of time. Then you the enemies of science, and often the enemy of want to look at those interventions and ask, now humanity too. what might be the social and ethical consequences of Perhaps what worries some philosophers is that using those alternative forms of changing behavior? the questions about the mind have been their prop- Are they humane? Are they consistent with our basic erty for a long time. It's a turf matter. On the other ideas about what is fair and what is reasonable and hand, the coming generation of graduate students what preserves human dignity? My guess is that we and young faculty in philosophy finds it obvious that will find alternativeforms of rehabilitationthat satisfy scientific data on the brain are relevant to our under- those criteria and have a real effect on changing standing of the mind. A leading criticof neurophilos- behavior. For example, some erratic and impulsive ophy makes an argument something like this: "Un- people behave entirely differentlyif you put them on doubtedly the brain is probably all there is, but you Prozac. Having said that though, it is really important will never explain consciousness, the painfulness of to emphasize that we shouldn't expect a quick bio- pain, and so forth in terms of neurons, in terms of logical fix for all of our social ills. Some components sheerly physical processes." Why not? "Because I of social disruption are clearly connected to environ- cannot imagine such an explanation." My response

INTERVIEWWITH PATRICIA CHURCHIAND 157 is, that's an argument from ignorance. It concludes real answers, although as we get the answers, the what we cannot know from what we do not know. So questions may transform themselves. For example, what if you can't imagine a future science? That's a Harvey studied blood circulation looking for where fact about your imagination. That's not a fact about the animal spirits were concocted, and he came out what science can and can't discover. Arguments saying, sorry chaps, they are not concocted in the about what some individual at some point in history heart. In fact there are no animal spirits at all. The cannot imagine are not very revealing. heart is a pump for blood. Similarly, we might start with questions and end up saying, sorry, we were Campbell: Are your colleagues in psychology more actually asking the wrong question because we had comfortable with neurophilosophy than many phi- certain assumptions that were wrong. losophers are? Churchland:Yes, by and large I would say psychol- ogists are, though for some psychologists it's a Campbell: As neurophilosophy brings the brain and wrench. Curiously, part of the heritage of behavior- mind closer, how will this change how we view ism was the assumption that the only thing that ourselves as a species? Churchland: To begin with, we are learning how

matters in getting explanations is the behavior; the Downloaded from http://online.ucpress.edu/abt/article-pdf/58/3/154/47484/4450104.pdf by guest on 29 September 2021 brain itself need not enter into it. According to some much similaritythere is between our brains and the cognitive psychologists, there is the computational brains of other mammals. Moreover many general level and the hardware level, and you can solve the features of our behavior are rooted in our evolution- computationalissues of how perception, for example, ary past via evolution of the brain. Brainshave many might occur without worrying too much about the properties they have because humans emerged from hardware. Their idea is that we want to understand the struggle to survive. At the same time, there are things at the level that you would if you were trying things that make our brains different from the brains to understand MicrosoftWord rather than at the level of other mammals. Just as there are things chimpan- of the hardware. It would be nice if this logic applied zees can do that we can't do, there are things we can because it's hard to understand the bits and pieces of do that they can't do. It would be nice to know what the brain. But the fact is, brain organizationis the key the neural differences are, but they appear to be to behavior. Ideas about how the computation works subtle-not just a matter of more neurons. One depend on knowing something about the hardware hypothesis is that what allows for greaterintelligence since the hardware puts powerful constraints on is slowing the rate at which the nervous system computation. After all, the brain is an evolved ma- matures. In our case brain immaturityis extended for chine; it's not going to look like what an engineer an unusually long time. Crucially,what the develop- would design. There are all kinds of wonderful tricks ing brain learns earlier can be useful in teaching the and strategies in perception, for example, that begin brain later. The general idea is that developmental to emerge once you really know more about the delays enable us to do more complicated things. So neural hardware. it's not that we're rational,and other animals are not; it's a quantitative difference partly related to the Campbell: As a scholar who works at the intersec- developmental timing that prolongs brain develop- tion of philosophy and science, do you have an ment. That understanding might even have the effect opinion on how scientists generally differ from of allowing people to have more regard for other philosophers in their approach to problems? species and less of the attitude that, "We are the Churchland: Yes. I think scientists expect to make greatest, so we get to squash all the others." Evolu- progress and some philosophers expect not to make tion doesn't startfrom scratch. It has to be gradual, to progress. What the scientists will say is, yes that's a some degree. A small differencein some aspect of an hard problem, let's find where we can get into it, then organism can make the thing as a whole look like it's maybe things will look a little different and then we got vastly different properties. Our brains are so can make more progress. At least within the philo- similar to chimpanzee brains, but some relatively sophical tradition of, say, the last 50 years, that's not small difference in developmental timing magnifies really been the take on problems. What some philos- into very different properties. My guess is that the ophers like to do is wallow in the great complicated- study of brain development and child psychology are ness of the problems. My take on it is that philosophy where the really big action is going to be in neuro- of the mind poses real problems for which we can get science in the next few decades.

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