STEVEN PINKER: Thank you. I'll have to begin by apologizing TO a number of you who may have come under false pretenses. I have an ad for tonight's forum that says that "Professor Pinker is going to argue that what people do is largely determined by their genes, but Professor Rose believes that human beings are able to shape their own lives." Actually, I DON'T believe that what people do is controlled by their genes. And i don't disagree with Professor Rose's statements that human beings are able to control our own lives, that organisms play an active role in their own destiny, and that we have the ability to construct our own futures. The question is not whether those statements are false. The question is whether those statements are BANAL.

OF COURSE we can control our own lives and control our own destinies. For me the question is: "What is it about our minds that ALLOWS us to control our own lives; in particular, that allows us to control our own lives in ways that are different from the way, say, a cat or a monkey can. That's what my book "How the Mind Works" is about, and tonight I'll briefly explain the approach I take in the book-sometimes called evolutionary psychology-and contrast it with what I take to be Professor Rose's approach.

As I said, I don't believe that behavior is controlled by the genes. I believe that behavior is controlled by beliefs and desire. Why did Bill just get on the bus? To answer that question, you don't have to put Bill's head in a brain scanner, and you certainly don't have to do DNA testing on him. Your best bet would be to ask him-and Bill might say something like, "I want to visit my grandmother, and I know that the bus will take me there." No answer will do as well as that one. If Bill hated the sight of his grandmother, or if he knew that the route had changed, his body would not be on that bus. Now this raises a problem. The beliefs and desires that are the best explanation for Bill's behavior are colorless, odorless, tasteless nothings; nonetheless they're as potent a cause of behavior as one billiard ball clacking into another. This is the ancient mind-body problem, and Professor Rose and I agree that the answer is to be sought in material terms; there isn't any immaterial soul or spook or spirit that magically pulls the levers of behavior.

One of the main points of How the Mind Works is that we can answer this question in material terms by interpreting beliefs and desires as a kind of computation. Roughly, beliefs are a kind of information, represented in the brain the way any piece of matter can represent information; desires are goals, that work in the same way as goal states in artificial intelligence programs; the mind, therefore, performs computation. It's not, of course, like the kind of computation done in a digital computer, for many reasons; rather, the elementary data representations and goal states that cause our behavior are implemented as neural networks and ultimately can be tied to the underlying neurophysiology.

Professor Rose, in his book Lifelines, argues strenuously against the doctrine of reductionism. My approach is most definitely not reductionist in the bad sense of trying to explain everything in terms of the smallest units of analysis. I believe that the psychological level of explanation, in terms of beliefs and desires, can be tied to a computational level, in terms of representation and processes, which in turn can be tied to the neural level, of synapses and neural firing. It IS reductionist in the good sense of not allowing a ghost in the machine; that is, any special process at the psychological level that can't be tied ultimately to the physical level. The reductionism I embrace simply states that the elementary units at one level of analysis can be translated into complicated interactions at the next level of analysis.

The next question that arises is WHY we have the kinds of thoughts and feelings that we do. I suggest an important source of information is in the process that gave rise to the brain, namely the evolutionary process, and in particular, the mechanism of natural selection. Let me explain.

How do we understand complex adaptive design in the living world? For example, the vertebrate eye is an intricately complex device, with a lens and a cornea that focus light on a light-sensitive layer of tissue, with an iris that opens and closes in response to the light level, and many other delicately arranged structures. For at least a century we've explained signs of apparent engineering design in the natural world by invoking Darwin's theory of natural selection-the only physical explanation of how good design could come about in the living world. There's no controversy that natural selection is a fundamental source of our understanding of the anatomy of the eye.

But of course the eye is useless without a BRAIN to receive the information coming in from the retina. The signals from the eye are not just dumped onto a blank slate. Rather, there are highly structured circuits that process the information coming from the eye. Now, there are countless signal processing operations that one could imagine being applied to the visual input in principle. But what the brain does is not just any old processing. For example, the visual system of the brain is not like a screen-saver, where it doesn't matter what pattern is displayed, as long as there is a pattern. Rather, we understand visual processing as having the function of constructing an accurate representation of the world: the objects that are out there, their 3-D arrangement, the material that the objects are made of, and so on. And this function is systematically related to the goal of perception, which is to keep the organism from falling off cliffs and bumping into walls and getting eaten by predators.

For over a century, perception has been understood within psychology in adaptationist terms: as a product of the process of natural selection. And perception is, by all accounts, the most successful part of psychology, the one that's closest to a rigorous science.

I believe that this logic can be extended. We obviously don't just see the world, but actively INTERPRET it. Just as there exist complex perceptual faculties that construct an interpretation of the world from a retinal image, there exist complex COGNITIVE faculties. I think we're equipped, for example, with intuitions about the physical world, which allow us to understand inanimate objects; with an intuitive sense of biology, which allows us to figure out how the living world works; with an intuitive psychology, which allows us to be social creatures and interpret other people's behavior in terms of their beliefs and desires; with a sense of number and a sense of space; and with a language faculty that ties us together socially and allows us to exchange information.

I review in the book a variety of kinds of evidence for these different faculties of the mind. One kind of evidence is the sheer engineering complexity that goes into mental feats that we take for granted. Human engineers have not been able to design robots that duplicate common sense and visual perception and motor control and language, because the kinds of things the brain does are so sophisticated that we are only beginning to figure out how they work. A second source of evidence is cross-cultural ethnographic surveys. The faculties that I argue for can be seen in the behavior of people in all cultures. A third source of evidence is precocious development in the infant. There are ingenious experimental methodologies that have discovered that babies have a precocious understanding that the world is made up of objects and minds and living things. Finally, there is evidence from neural dissociations-the results of studies from the neuropsychology lab showing that our different intuitions about living things versus physical objects versus other people can be dissociated in neurological disease-where a patient, say, preserves the ability to name living things, but loses the ability to name man-made objects, or vice versa.

Of course, people aren't like Mister Spock, pure intellects that reason abstractly about the world. In addition to our beliefs, we have DESIRES: emotions that guide our behavior. And as with the case of perception, many of the emotions have long been profitably analyzed as adaptations. Fear for example has been studied for many years, and since the time of Walter Cannon in the '30s, it's been recognized as an adaptation that prepares an organism to cope with danger. Evidence includes the fact that the universal stimuli for fear are ancestral dangers such as heights, venomous animals, confinement, and deep water; the fact that the physiological component of such as the release of adrenalin and an increase in heartrate, prime the organism to cope with a danger by fleeing or otherwise dealing with it; the fact that fear can be shown to be tied to ecologically measurable dangers-animals that evolve on islands without predators lose their sense of fear and are therefore sitting ducks when the islands are invaded by predators. Similarly, sexual desire is uncontroversially an adaptation. It is no mystery why most people would rather make love with an attractive partner than to get a slap on the belly with a wet fish. Sexual desire leads causally to reproduction.

In How the Mind Works, I argue that similar analyses can profitably be applied to other emotions. I think we have well-engineered neural systems for emotions of disgust, happiness, anger, guilt, love of children, love of spouses, love of siblings, and so on.

How does one argue that these emotions really do have a biological function? In the case of fear, we can appeal to the laws of physics: it's a physical fact that a body that falls off a cliff will tend not to live to reproduce. In the case of social emotions we have to look to another body of knowledge to make the argument, and very often is the analysis of inclusive fitness and reciprocity, which can be summed up in Richard Dawkins' metaphor of the selfish gene. To simplify: if you want to ask why people have built into them a love of their family, their children, their parents, and their siblings, the answer is that any gene that fosters such emotions would be protecting and nurturing copies of itself inside the loved one. Just as a gene for fear can be selected because it's less likely to end up at the bottom of a cliff, a gene for love of children can be selected because it's more likely to end up in the body of grandchildren, and therefore to end up with us today.

Now Professor Rose, in his book Lifelines, argues strenuously against the expression "a gene for x", such as a gene for love of family. He makes a number of points I completely agree with, such as that genes don't cause behavior in any linear or direct sense. What I mean by "a gene for X," and what ALL evolutionary theorists mean by "a gene for X," is simply a gene that, in comparison with its alternative allele, averaged over the other genes that it appears with in bodies, and averaged over the environments in appears in, probablistically leads to more behavior X-say, being solicitous to one's children. That's all that "a gene for X" means, and that definition is completely consistent with all of the arguments about genetics in Lifelines. It does not imply that genes directly cause behavior; it's simply a shorthand.

A second caveat is that the idea of the selfish gene does not imply that people are deep down fundamentally selfish. Genes are not the unconscious mind. The way to interpret the expression "selfish gene" is that it's useful to calculate the effects of genes on their own fate by thinking of them as metaphorically selfish. Sometimes the most (metaphorically) selfish thing that a gene can do is to build an organism that's unselfish. So there's no contradiction between saying that selfish genes are part of the explanation for why we have the emotions that we do, and that some of the emotions themselves don't have a trace of selfishness in them.

The third caveat is that I certainly don't believe that everything that we do or feel is adaptive. Professor Rose refers to "ultra-Darwinians" and "Darwinian fundamentalists" who believe that every trait of an organism is adaptive. The ultra-Darwinian is a mythical creature; there aren't any. I believe that SOME aspects of what we think and feel are adaptive; I don't believe that ALL aspects of what we think and feel are adaptive. In particular, in the book I argue that such momentous human activities as dreams, religion, art, music, written language, school math, and school science are not adaptations, but instead are by-products of adaptations.

Why do I think that this is a valuable approach? In the book I show that it has led to new understanding of dozens of topics in psychology. It's spawned an enormous amount of new research in the psychology laboratory, in ethnographic research, and in many other areas, which I don't have time to review now. One such finding was alluded to in the newspaper ad for this forum: there's new evidence that many aspects of what parents do in bringing up their children have no long-term effects on the personality of the children. It's a finding that was predicted by evolutionary theory, and I think it's one of the most important findings in the history of psychology. I can't say any more about it now, but if there's curiosity I can address it in the question period.

Finally, I'd like to talk about the alternative approach suggested by Professor Rose. In Lifelines, Professor Rose suggests that 20th century biology is rotten at the core. It's determinist and reductionist, and is inspired by, and helps to prop up, capitalism and patriarchy. Most of the scientific content of the book itself is a lucid and fascinating overview of the spectacular discoveries of 20th century biology, and Professor Rose presents alternative interpretations of many of those discoveries.

However, as he points out, the discoveries themselves were all done under the standard determinist, reductionist paradigm of biology that he rejects. And many of the arguments in the book try to convince us that scientists such as James Watson, Francis Crick, and Louis Wolpert are not properly interpreting their own discoveries. I find it hard to escape the feeling that much of Professor Rose's approach just REDESCRIBES standard biology with new jargon: words like "autopoiesis" and "homeodynamics" and "self-construction."

I think that there's something conspicuously missing from Professor Rose's approach. It's the sense of AHA! The sense that there's a new insight into problems such as How the Mind Works, a sense that something formerly mysterious is now comprehensible, a question that inspires research that turns up surprising new findings.

I think this is especially noticeable in the discussions in the book on the human mind and human behavior. The book contains many discussions of hypotheses about human psychology, but virtually all of them are negative: Richard Dawkins and E. O. Wilson are WRONG, WRONG, WRONG!! I scoured the book for anything positive: any new hypothesis about How the Mind Works. In the entire book, I only came up with two. One of them is the suggestion that racism is a cause of schizophrenia, on page 104. This hypothesis is not based, as far as I can tell, on any theory or research, but rather is a consequence of a certain political view. I think it's fair to say that there is no evidence whatsoever that it is true.

The other suggestion is from page 68, in which Professor Rose talks about the metaphors and analogies that we use in science, a point that I completely agree with. But then he says that "the metaphors and analogies that we find attractive are laden with cultural values and expectations that come from outside our science. They inevitably-inevitably!-reflect our experience as directors of companies, or as sacked workers, as men executives, or women child-carers, as white racists, or black footballers. That is they are not and cannot be free from ideology."

Now this raises three questions in my mind. One is: if the ideas that we find attractive are "inevitable," how can that be reconciled with his idea that "we play an active part in our own destiny?" That seems to be an area in our destiny where, according to Professor Rose, we DON'T play an active part. It seems to me to be a strikingly DETERMINISTIC thesis.

The second question is, what is the evidence that this is the case? I don't know of any, but I know of some evidence that it's NOT the case. One field that I'm familiar with, evolutionary psychology, has been attractive to all kinds of people, from members of the British aristocracy to sons of Marxist labor leaders, and it is attractive to men and women in equal numbers. Furthermore I do know of one quantitative study of whether one's social class and social background affect one's acceptance of scientific ideas, namely the data from Frank Sulloway on acceptance versus resistance to revolutionary ideas in science. Sulloway actually looked at scientific revolutions such as Darwinism, and found that there was no correlation between social class and one's willingness to accept new scientific ideas.

Finally there's a political dimension to Professor Rose's claim. Lifelines, from beginning to end, talks about the harmful political consequences that Professor Rose sees in the attempts to relate biology to psychology. The Holocaust is mentioned in the very first paragraph, and throughout the book we are reminded of the way in which these ideas have been distorted by the Nazis and other racists in the 19th and 20th centuries. And Professor Rose adds, "this history cannot be transcended."

But there have, unfortunately, been several holocausts in this century. Some of them have taken place in the Soviet Union, China, and Cambodia, and many of them can be clearly related to the idea that opinions are a product of one's social class, and therefore, rather than being debated, the proponents of them should be "reeducated" or worse. I don't think this necessarily taints the particular opinions, but it is only fair to bring into a discussion that tries to criticize the ideas of the other side for their supposed political implications.

So if these two hypotheses about the mind are the best that Professor Rose's "dialectical biology" can do, I would like to suggest that it is not a particularly promising way to understand How the Mind Works. Thank you.