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Speaking Minds
Interviews with Twenty Eminent Cognitive Scientists
By Peter Baumgartner, Sabine Payr PRINCETON UNIVERSITY PRESS
Copyright © 1995 Princeton University Press
All rights reserved.
ISBN: 978-0-691-03678-6
CHAPTER 1
PATRICIA SMITH CHURCHLAND
Take It Apart and See How It Runs
When I was a graduate student at Pittsburgh in 1966, we worked through Quine's book Word and Object. That book was one of the few things in philosophy that made any sense to me at that time, apart, of course, from Hume. Several other graduate students whom I came to know quite well were utterly contemptuous of the later Wittgenstein in particular and of so-called ordinary language philosophy in general. Their scoffing was typically directed toward specific claims, such as the private language argument, and they generally had very good arguments to support their criticism. And apart from seeming willfully obscure, Wittgenstein was at best insensitive to the possible role of scientific data in philosophical questions and, at worst, openly hostile to science. Thus the skepticism about conceptual analysis as a method for finding out how things are in the world, including that part of the world that is the mind, was germinating and taking root while I was at Pittsburgh. In Oxford from 1966 to 1969, by contrast, Wittgenstein was revered; and having taken a Quinean position on the a priori and on intentionality, I ended up making a nuisance of myself in Oxford by swimming in the other direction. Paul [Churchland] was most helpful around this time, because he was very straightforward. He thought we ought to approach mind questions in basically the same scientific spirit with which one approached other questions of fact. So instead of flailing around aimlessly analyzing concepts, I had some sense of direction. And so I tried to figure out what I could do in the philosophy of mind if it was not conceptual analysis. Because I am a materialist, it finally occurred to me that there might be a lot in neuroscience that might help answer the questions I was interested in—for example, questions about reasoning, decision making, and consciousness.
During the sixties and seventies most philosophers said, "No, no, no—studying the brain is a waste of time for philosophers. First, nothing much is known anyway; and second, even if a lot were known, it would be completely irrelevant." At the time I was deciding that philosophy seemed like a waste of time, Jerry Fodor's book The Language of Thought was published. In this book, Fodor is very clear: neuroscience is simply irrelevant to understanding psychological functions. Neuroanatomy and neurophysiology have nothing of significance to teach us about the nature of cognition.
I was convinced that Fodor was wrong, because, after all, the brain is the machine that does these things—the thinking and the feeling and the representing, and so on. It would be amazing if it turned out that the organization and mechanisms were not going to teach us anything about cognitive processes. My hunch in this direction also fit well with Paul's ideas about scientific realism and about the nonsentential nature of representations. So I decided to explore this hunch and find out whether Fodor was more likely to be wrong, or I was.
It was at this point that I realized I needed to study neuroscience systematically. I knew that I needed to know anatomy, and it is next to impossible really to learn anatomy from a book. You must have the actual 3-D object there, and you need to look at it from all angles. The faculty at the University of Manitoba Medical School were very welcoming. They thought it was enormously amusing to have a philosopher among the medical students, but they also took my general aims very seriously and wanted to talk about the philosophical issues. So I ended up doing experiments and dissections and observing human patients with brain damage in neurology rounds (from about 1975 to 1984). The first thing that really sunk in is how important it is to see something for yourself, not just read about what someone else says it looks like. Neurology rounds were fascinating because all the questions about consciousness and cognition were raised in this completely different context, and it made me think about everything in a different way.
So in a sense I was lucky. I was disgruntled intellectually so my mind was readied for a new slant, and I stumbled into neuroscience, which was exactly what I needed to give me that new slant.
Slowly I began to realize how much really was known about the brain. I was increasingly convinced that the way the brain is put together, the way individual cells operate and talk to one another, had to be important to macrofunctions like perception, imaging, thinking, and reasoning. This, shall I say, "tilt" to the neurosciences by people interested in cognition was by no means unique to Paul and me. Later I came to know other people who were moving in the same direction—people like David Rumelhart, James McClelland, Terry Sejnowski, and John Anderson. It was kind of a heretical thing to be thinking at that time, because the standard view was that of Artificial Intelligence: thinking is symbol manipulation according to rules. Thinking is like running a program; and if you want to understand cognition, you want to understand the program. Of course, a program needs hardware to run on, but looking at the hardware will not tell you much about the software it is running.
I was also quite simply captured by neuroscience itself. I thought it was absolutely fascinating. Once I had done as much as the medical students do, I took graduate courses in neurophysiology, and ultimately I became attached to Larry Jordan's neurophysiology lab, which was focused primarily on the spinal cord mechanisms for locomotion. That was a tremendously rewarding experience for me for several reasons. First, it taught me some basic things about neuroscientific techniques, especially concerning what you can and cannot do, and how to interpret results, what to be skeptical about, and so forth. So that was invaluable. Second, it was not the lab I had expected to be in because, after all, it was aimed at studying locomotion, and I was not especially interested in locomotion. I thought the "juicy" topics were memory, perception, consciousness—why should I be interested in how animals move? The lab taught me why I should be. Gradually it dawned on me, mainly by talking to Jordan, that for evolutionary reasons, cognition is closely tied to motor control, since adaptive movement is critical in survival. You might learn a lot about cognitive functions, at least in their general character, by looking at cognition from the perspective of an organism needing to feed, fight, flee, and reproduce (Paul Maclean's "four Fs"). The lab thus shifted my thinking, so the conceptual profit from being in the lab was also valuable. Once I got rolling, I began to have the opportunity to talk to people like Rodolfo Llinas and Francis Crick, who taught me simply an enormous amount—both about details and about how to think about the problems: which ones are interesting, which ones might be tackled successfully relative to experimental limitations.
What was the idea behind this attraction to neuroscience at a time when people were still stuck with the idea that the architecture did not matter?
I suppose I was bloody-minded, but it just seemed obvious to me that the brain and its mechanisms and structure were relevant. It seemed obvious to me that you can learn a lot about visual perception by understanding the eye, the retina, and so on. One of the books I read early on that I think had a major impact on me was Richard Gregory's book, Eye and Brain. It was a very important book because on the one hand he discussed the psychophysics of visual perception—the phenomenology and behavioral parameters of perception of motion, color, depth, and so on—but he also tied it to the physiology, to the extent that it was known. In Gregory's book, you could begin to see—but only begin, because so much is still unknown—that the physiology can tell you a lot about how we see. Consequently, when I read the functionalists' claim that the brain is irrelevant, I thought it was a bit outrageous. It did not seem real to me, in a funny kind of a way. And of course I did not have any stake in the orthodoxy, because I was not part of the "inner circle" in Boston. So I could afford to say, "Ha! That's a bunch of baloney!" and strike out on my own. In Manitoba I had a truly marvelous freedom to move in whatever direction I wanted to.
From way, way back, my take on how the world works was rather mechanistic, in the sense that I generally assumed that if you wanted to understand how something worked, you should try to take it apart and see how it runs. Maybe it's because I grew up on a farm, and as a kid I had to solve, as a matter of daily life, a lot of practical problems. If an irrigation pump did not work or a cow was having trouble calving, we had to figure out how the thing worked and do what we could to fix it. It seemed reasonable to me that taking something apart and finding out the causal connection between the parts would reveal a lot about how the thing as a whole worked. This seemed true not only for artifacts such as engines but also for the hearts and gizzards that I took apart after cleaning the chickens. I also knew that simply taking a gizzard apart was not enough—that the inner structure and all the little stones could give you a clue, but you also got clues from seeing what it was connected to, the relation to the gut and to the mouth, what the chicken ate, and so forth. What Jerry Fodor's book did for me was crystallize the functionalist assumption—namely, that the brain was at the implementation level and cognition was at the program level. By putting his views so clearly, Fodor allowed me to begin to feel my way toward a different approach. I could understand the basic point that the same program could be run on different machines, but I suppose I was always dubious that cognition could be understood as analogous to a program. You must understand that in the beginning most of my ideas were pretty hazy, and I guess lots still are; but I just could not see how knowing about the brain could fail to shed light on cognitive processes.
Paul and I discussed such questions endlessly. In the summer of 1971 we were crossing the prairies in an old car to reach British Columbia, a trip that takes about four days. Shortly after we entered the province of Saskatchewan, Paul began to try out a new idea of his, namely that representations in general might not be at all like sentences. As Paul sized it up, we use a theory to explain behavior in terms of beliefs that p and desires that p and so on, but this may be as mistaken as "commonsense" ideas about the earth being stationary and spirits causing the tides. He argued that sensory representations and maybe even most cognitive representations were not best understood on the model of sentences such as p and q. Hence content, intentionality, meaning, and the whole pudding had to be rethought from scratch. As a matter of principle I took the opposite view, and at first I could not really understand what on earth he was getting at. We argued and argued about it during the entire four days, and by the time we reached Vancouver, I thought, I bet he's right.
Davidson is wrong, Fodor is wrong, Putnam is wrong. Most people are looking at the problem of representation in the wrong way because they are looking at it as tied to language, as languagelike. Language is probably not necessary for representing the world, and probably lots of what we call reasoning does not involve anything languagelike either.
Since we seemed to agree on what was wrong, the next question was, What is right? How does the mind-brain represent the world? How can we go about finding out how it represents the world? What will such a theory look like? We both knew that a priori reflection would not tell us much. And we agreed with Quine that there is no first philosophy, no fundamental difference between philosophy and science. So against the backdrop of these rather radical ideas, studying neuroscience was almost inevitable. In many ways it was Paul's willingness to pick something up, turn it around, and look at it from an entirely different perspective that was absolutely crucial in encouraging and making respectable my naturalistic impulses. We also just thought it was enormous fun.
Which sciences do you think play an important role in cognitive science?
Experimental psychology, linguistics, and psychophysics, because they help specify what exactly are the capacities of humans and other animals, and they can also say something about the interconnections between those capacities. Neuropsychology, because by studying patients with brain damage, we get a far deeper perspective on the scope and limits of psychological capacities. Neuroanatomy, because you have to understand the basic components of nervous systems (neurons) and their specific patterns of connectivity. Neurophysiology, because you have to know how neurons work, and how neurons respond as a function of what other neurons are saying to them, and what transmitters cause them to do, what hormones and modulators cause them to do. Computational neuroscience, because a network model constrained by neuroscience is an important tool for seeing what interactive and dynamic effects can be generated by a circuit. Modeling is an important source of ideas and hypotheses, but it is in no sense a replacement for experimental neuroscience or experimental psychology. Modeling is important because representations generally appear to be highly distributed across many cells, and to understand how properties emerge from networks, computer models can be useful. Developmental psychology, because it is critical to understand how capacities come into existence and change over time and on what their development depends. Developmental neurobiology, because we need to understand how the timetable for capacity development links up to the timetable for brain development. Molecular biology, because we need a perspective on genetic specification and plasticity. Philosophy, because we badly need to synthesize and theorize and ask the questions everyone else is either too embarrassed or too focused or too busy to ask.
Are there neuroscientists currently involved in cognitive science?
Absolutely. In many domains, particularly memory, sensory systems, and attention, there are projects that involve many of the aforementioned fields. For example, I can think of at least five vision labs that do both the psychophysics of vision as well as visual system physiology and anatomy. Patricia Goldman-Rakic is a striking example of a neuroanatomist whose physiological research into working memory has uncovered particular cellular responses during a task requiring holding of spatial information for a few seconds, and these responses appear likely to be an important piece in the puzzle of working (short-term) memory. Fuster does related work, but with working memory for visual patterns rather than spatial location. Mark Konishi's work on the auditory capacity and auditory system of the barn owl is surely one of the stunning success stories of cognitive neuroscience. Several graduate students in the Philosophy Department are doing joint work in neuroscience, and at least six others are doing joint work with psychologists and some with computer scientists. It seems to be just part of the ethos of UCSD that cross-disciplinary projects are encouraged.
Was it coincidence that you are here, where neuroscience is so strong?
The cognitive neuroscience community here was an important attraction as we were considering moving to San Diego. It is large, diverse, and lively. At some point or other, everybody passes through, so there is lots of contact, and that means there is the opportunity to learn a lot and keep abreast of new developments. There is also considerable interest and activity in computational neuroscience, so I feel very much at home. I am an adjunct at the Salk Institute, and I currently work in Terry Sejnowski's laboratory. The lab has tea every afternoon, and various people drop by—often Francis Crick, and some of the visual psychologists, such as Ramachandran—and we discuss everything from consciousness and free will to apparent motion to the NMDA receptor.
(Continues...)
Excerpted from Speaking Minds by Peter Baumgartner, Sabine Payr. Copyright © 1995 Princeton University Press. Excerpted by permission of PRINCETON UNIVERSITY PRESS.
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