7
None of this is to say that the brain works like a digital computer, that artificial intelligence will ever duplicate the human mind, or that computers are conscious in the sense of having first-person subjective experience.
None of this is to say that the brain works like a digital computer, that artificial intelligence will ever duplicate the human mind, or that computers are conscious in the sense of having first-person subjective experience.
Steven-Pinker-The-Blank-Slate 1
?
-- Margaret Mead (1935)37 Much of what is commonly called "human nature" is merely culture thrown against a screen of nerves,
? glands, sense organs, muscles, etc.
Or to the raw materials for a factory:
Human nature is the rawest, most undifferentiated of raw material.
-- Leslie White (1949)38 -- Margaret Mead (1928)39
? ? Our ideas, our values, our acts, even our emotions, are, like our nervous system itself, cultural products -- products manufactured, indeed, out of tendencies, capacities, and dispositions with which we were
born, but manufactured nonetheless.
-- Clifford Geertz (1973)41 {26}
Or to some other amorphous entity that can have many things done to it:
Cultural psychology is the study of the way cultural traditions and social practices regulate, express, transform, and permute the human psyche, resulting less in psychic unity for humankind than in ethnic
-- Clifford Geertz (1973)40 Man is the animal most desperately dependent upon such extragenetic, outside-the-skin control
? Or to an unprogrammed computer:
mechanisms, such cultural programs, for ordering his behavior.
? ? divergences in mind, self and emotion.
-- Richard Shweder (1990)42
? The superorganic or group mind also became an article of faith in social science. Robert Lowie (another Boas student) wrote, "The principles of psychology are as incapable of accounting for the phenomena of culture as is gravitation to account for architectural styles. "43 And in case you missed its full implications, the anthropologist Leslie White spelled it out:
? Instead of regarding the individual as a First Cause, as a prime mover, as the initiator and determinant
of the culture process, we now see him as a component part, and a tiny and relatively insignificant part at that, of a vast, socio-cultural system that embraces innumerable individuals at any one time and extends back into their remote past as well. . . . For purposes of scientific interpretation, the culture process may be regarded as a thing sui generis; culture is explainable in terms of culture. 44
In other words, we should forget about the mind of an individual person like you, that tiny and insignificant part of a vast sociocultural system. The mind that counts is the one belonging to the group, which is capable of thinking, feeling, and acting on its own.
The doctrine of the superorganism has had an impact on modern life that extends well beyond the writings of social scientists. It underlies the tendency to reify "society" as a moral agent that can be blamed for sins as if it were a person. It drives identity politics, in which civil rights and political perquisites are allocated to groups rather than to individuals. And as we shall see in later chapters, it defined some of the great divides between major political systems in the twentieth century. ~
The Blank Slate was not the only part of the official theory that social scientists felt compelled to prop up. They also strove to consecrate the Noble Savage. Mead painted a Gauguinesque portrait of native peoples as peaceable, egalitarian, materially satisfied, and sexually unconnected. Her uplifting vision of who we used to be -- and therefore who we can become again -- was accepted by such otherwise skeptical writers as Bertrand Russell and H. L. Mencken. Ashley Montagu (also from the Boas circle), a prominent public intellectual from the 1950s until his recent death, tirelessly invoked the doctrine {27} of the Noble Savage to justify the quest for brotherhood and peace and to refute anyone who might think such efforts were futile. In 1950, for example, he drafted a manifesto for the newly formed UNESCO that declared, "Biological studies lend support to the ethic of universal brotherhood, for man is born with drives toward co-operation, and unless these drives are satisfied, men and nations alike fall ill. "45 With the ashes of thirty-five million victims of World War II still warm or radioactive, a reasonable person might wonder how "biological studies" could show anything of the kind. The draft was rejected, but Montagu had better luck in the decades to come, when UNESCO and many scholarly societies adopted similar resolutions. 46
More generally, social scientists saw the malleability of humans and the autonomy of culture as doctrines that might bring about the age-old dream of perfecting mankind. We are not stuck with what we don't like about our current predicament, they argued. Nothing prevents us from changing it except a lack of will and the benighted belief that we are permanently consigned to it by biology. Many social scientists have expressed the hope of a new and improved human nature:
I felt (and said so early) that the environmental explanation was preferable, whenever justified by the
? ? ? ? data, because it was more optimistic, holding out the hope of improvement.
-- Otto Klineberg (1928)47
? Modern sociology and modern anthropology are one in saying that the substance of culture, or civilization, is social tradition and that this social tradition is indefinitely modifiable by further learning on the part of men for happier and better ways of living together. . . . Thus the scientific study of institutions awakens faith in the possibility of remaking both human nature and human social life.
-- Charles Ellwood (1922)48
Barriers in many fields of knowledge are falling below the new optimism which is that anybody can learn anything. . . . We have turned away from the concept of human ability as something fixed in the physiological structure, to that of a flexible and versatile mechanism subject to great improvement.
-- Robert Faris (1961)49
Though psychology is not as politicized as some of the other social sciences, it too is sometimes driven by a Utopian vision in which changes in child-rearing and education will ameliorate social pathologies and improve human welfare. And psychological theorists sometimes try to add moral heft to arguments for connectionism or other empiricist theories with warnings about the {28} pessimistic implications of innatist theories. They argue, for example, that innatist theories open the door to inborn differences, which could foster racism, or that the theories imply that human traits are unchangeable, which could we~aken support for social programs. 50
Twentieth-century social science embraced not just the Blank Slate and the Noble Savage but the third member of the
? ? ? ? trinity, the Ghost in the Machine. The declaration that we can change what we don't like about ourselves became a watchword of social science. But that only raises the question "Who or what is the 'we'? " If the "we" doing the remaking are just other hunks of matter in the biological world, then any malleability of behavior we discover would be cold comfort, because we, the molders, would be biologically constrained and therefore might not mold people, or allow ourselves to be molded, in the most socially salutary way. A ghost in the machine is the ultimate liberator of human will -- including the will to change society -- from mechanical causation. The anthropologist Loren Eiseley made this clear when he wrote:
The mind of man, by indetermination, by the power of choice and cultural communication, is on the verge of escape from the blind control of that deterministic world with which the Darwinists had unconsciously shackled man. The inborn characteristics laid upon him by the biological extremists have crumbled away. . . . Wallace saw and saw correctly, that with the rise of man the evolution of parts was to a marked degree outmoded, that mind was now the arbiter of human destiny. 51
The "Wallace" that Eiseley is referring to is Alfred Russel Wallace (1823-1913), the co-discoverer with Darwin of natural selection. Wallace parted company from Darwin by claiming that the human mind could not be explained by evolution and must have been designed by a superior intelligence. He certainly did believe that the mind of man could escape "the blind control of a deterministic world. " Wallace became a spiritualist and spent the later years of his career searching for a way to communicate with the souls of the dead.
The social scientists who believed in an absolute separation of culture from biology may not have literally believed in a spook haunting the brain. Some used the analogy of the difference between living and nonliving matter. Kroeber wrote: "The dawn of the social. . . is not a link in any chain, not a step in a path, but a leap to another plane. . . . [It is like] the first occurrence of life in the hitherto lifeless universe. . . . From this moment on there should be two worlds in place of one. "52 And Lowie insisted that it was "not mysticism, but sound scientific method" to say that culture was "sui generis" and could be explained only by culture, because everyone knows that in biology a living cell can come only from another living cell. 53 {29}
At the time that Kroeber and Lowie wrote, they had biology on their side. Many biologists still thought that living things were animated by a special essence, an elan vital, and could not be reduced to inanimate matter. A 1931 history of biology, referring to genetics as it was then understood, said, "Thus the last of the biological theories leaves us where we first started, in the presence of a power called life or psyche which is not only of its own kind but unique in each and all of its exhibitions. "54 In the next chapter we will see that the analogy between the autonomy of culture and the autonomy of life would prove to be more telling than these social scientists realized.
<< {30} >> Chapter 3
The Last Wall to Fall
In 1755 Samuel Johnson wrote that his dictionary should not be expected to "change sublunary nature, and clear the world at once from folly, vanity, and affectation. " Few people today are familiar with the lovely word sublunary, literally "below the moon. " It alludes to the ancient belief in a strict division between the pristine, lawful, unchanging cosmos above and our grubby, chaotic, fickle Earth below. The division was already obsolete when Johnson used the word: Newton had shown that the same force that pulled an apple toward the ground kept the moon in its celestial orbit.
Newton's theory that a single set of laws governed the motions of all objects in the universe was the first event in one of the great developments in human understanding: the unification of knowledge, which the biologist E. O. Wilson has termed consilience. 1 Newton's breaching of the wall between the terrestrial and the celestial was followed by a collapse of the once equally firm (and now equally forgotten) wall between the creative past and the static present. That happened when Charles Lyell showed that the Earth was sculpted in the past by forces we see today (such as earthquakes and erosion) acting over immense spans of time.
The living and nonliving, too, no longer occupy different realms. In 1628 William Harvey showed that the human body is a machine that runs by hydraulics and other mechanical principles. In 1828 Friedrich Wohler showed that the stuff of life is not a magical, pulsating gel but ordinary compounds following the laws of chemistry. Charles Darwin showed how the astonishing diversity of life and its ubiquitous signs of design could arise from the physical process of natural selection among replicators. Gregor Mendel, and then James Watson and Francis Crick, showed how replication itself could be understood in physical terms.
? ? ? ? ? ? ? ? ? ? ? The unification of our understanding of life with our understanding of matter and energy was the greatest scientific achievement of the second half of the twentieth century. One of its many consequences was to pull the rug out {31} from under social scientists like Kroeber and Lowie who had invoked the "sound scientific method" of placing the living and nonliving in parallel universes. We now know that cells did not always come from other cells and that the emergence of life did not create a second world where before there was just one. Cells evolved from simpler replicating molecules, a nonliving part of the physical world, and may be understood as collections of molecular machinery -- fantastically complicated machinery, of course, but machinery nonetheless.
This leaves one wall standing in the landscape of knowledge, the one that twentieth-century social scientists guarded so jealously. It divides matter from mind, the material from the spiritual, the physical from the mental, biology from culture, nature from society, and the sciences from the social sciences, humanities, and arts. The division was built into each of the doctrines of the official theory: the blank slate given by biology versus the contents inscribed by experience and culture, the nobility of the savage in the state of nature versus the corruption of social institutions, the machine following inescapable laws versus the ghost that is free to choose and to improve the human condition.
But this wall, too, is falling. New ideas from four frontiers of knowledge -- the sciences of mind, brain, genes, and evolution -- are breaching the wall with a new understanding of human nature. In this chapter I will show how they are filling in the blank slate, declassing the noble savage, and exorcising the ghost in the machine. In the following chapter I will show that this new conception of human nature, connected to biology from below, can in turn be connected to the humanities and social sciences above. That new conception can give the phenomena of culture their due without segregating them into a parallel universe. ~
The first bridge between biology and culture is the science of mind, cognitive science. 2 The concept of mind has been perplexing for as long as people have reflected on their thoughts and feelings. The very idea has spawned paradoxes, superstitions, and bizarre theories in every period and culture. One can almost sympathize with the behaviorists and social constructionists of the first half of the twentieth century, who looked on minds as enigmas or conceptual traps that were best avoided in favor of overt behavior or the traits of a culture.
But beginning in the 1950s with the cognitive revolution, all that changed. It is now possible to make sense of mental processes and even to study them in the lab. And with a firmer grasp on the concept of mind, we can see that many tenets of the Blank Slate that once seemed appealing are now unnecessary or even incoherent. Here are five ideas from the cognitive revolution that have revamped how we think and talk about minds.
The first idea: The mental world can be grounded in the physical world by the concepts of information, computation, and feedback. A great divide between {32} mind and matter has always seemed natural because behavior appears to have a different kind of trigger than other physical events. Ordinary events have causes, it seems, but human behavior has reasons. I once participated in a BBC television debate on whether "science can explain human behavior. " Arguing against the resolution was a philosopher who asked how we might explain why someone was put in jail. Say it was for inciting racial hatred. The intention, the hatred, and even the prison, she said, cannot be described in the language of physics. There is simply no way to define "hatred" or "jail" in terms of the movements of particles. Explanations of behavior are like narratives, she argued, couched in the intentions of actors -- a plane completely separate from natural science. Or take a simpler example. How might we explain why Rex just walked over to the phone? We would not say that phone-shaped stimuli caused Rex's limbs to swing in certain arcs. Rather, we might say that he wanted to speak to his friend Cecile and knew that Cecile was home. No explanation has as much predictive power as that one. If Rex was no longer on speaking terms with Cecile, or if he remembered that Cecile was out bowling that night, his body would not have risen off the couch.
For millennia the gap between physical events, on the one hand, and meaning, content, ideas, reasons, and intentions, on the other, seemed to cleave the universe in two. How can something as ethereal as "inciting hatred" or "wanting to speak to Cecile" actually cause matter to move in space? But the cognitive revolution unified the world of ideas with the world of matter using a powerful new theory: that mental life can be explained in terms of information, computation, and feedback. Beliefs and memories are collections of information -- like facts in a database, but residing in patterns of activity and structure in the brain. Thinking and planning are systematic transformations of these patterns, like the operation of a computer program. Wanting and trying are feedback loops, like the principle behind a thermostat: they receive information about the discrepancy between a goal and the current state of the world, and then they execute operations that tend to reduce the difference. The mind is connected to the world by the sense organs, which transduce physical energy into data structures in the brain, and by motor programs, by which the brain controls the muscles.
This general idea may be called the computational theory of mind. It is not the same as the "computer metaphor" of the mind, the suggestion that the mind literally works like a human-made database, computer program, or thermostat.
? ? ? It says only that we can explain minds and human-made information processors using some of the same principles. It is just like other cases in which the natural world and human engineering overlap. A physiologist might invoke the same laws of optics to explain how the eye works and how a camera works without implying that the eye is like a camera in every detail.
The computational theory of mind does more than explain the existence {33} of knowing, thinking, and trying without invoking a ghost in the machine (though that would be enough of a feat). It also explains how those processes can be intelligent -- how rationality can emerge from a mindless physical process. If a sequence of transformations of information stored in a hunk of matter (such as brain tissue or silicon) mirrors a sequence of deductions that obey the laws of logic, probability, or cause and effect in the world, they will generate correct predictions about the world. And making correct predictions in pursuit of a goal is a pretty good definition of "intelligence. "3
Of course there is no new thing under the sun, and the computational theory of mind was foreshadowed by Hobbes when he described mental activity as tiny motions and wrote that "reasoning is but reckoning. " Three and a half centuries later, science has caught up to his vision. Perception, memory, imagery, reasoning, decision making, language, and motor control are being studied in the lab and successfully modeled as computational paraphernalia such as rules, strings, matrices, pointers, lists, files, trees, arrays, loops, propositions, and networks. For example, cognitive psychologists are studying the graphics system in the head and thereby explaining how people "see" the solution to a problem in a mental image. They are studying the web of concepts in long-term memory and explaining why some facts are easier to recall than others. They are studying the processor and memory used by the language system to learn why some sentences are a pleasure to read and others a difficult slog.
And if the proof is in the computing, then the sister field of artificial intelligence is confirming that ordinary matter can perform feats that were supposedly performable by mental stuff alone. In the 1950s computers were already being called "electronic brains" because they could calculate sums, organize data, and prove theorems. Soon they could correct spelling, set type, solve equations, and simulate experts on restricted topics such as picking stocks and diagnosing diseases. For decades we psychologists preserved human bragging rights by telling our classes that no computer could read text, decipher speech, or recognize faces, but these boasts are obsolete. Today software that can recognize printed letters and spoken words comes packaged with home computers. Rudimentary programs that understand or translate sentences are available in many search engines and Help programs, and they are steadily improving. Face-recognition systems have advanced to the point that civil libertarians are concerned about possible abuse when they are used with security cameras in public places.
Human chauvinists can still write off these low-level feats. Sure, they say, the input and output processing can be fobbed off onto computational modules, but you still need a human user with the capacity for judgment, reflection, and creativity. But according to the computational theory of mind, these capacities are themselves forms of information processing and can be implemented in a computational system. In 1997 an IBM computer called Deep
{34} Blue defeated the world chess champion Garry Kasparov, and unlike its predecessors, it did not just evaluate trillions of moves by brute force but was fitted with strategies that intelligently responded to patterns in the game. Newsweek called the match "The Brain's Last Stand. " Kasparov called the outcome "the end of mankind. "
You might still object that chess is an artificial world with discrete moves and a clear winner, perfectly suited to the rule-crunching of a computer. People, on the other hand, live in a messy world offering unlimited moves and nebulous goals. Surely this requires human creativity and intuition -- which is why everyone knows that computers will never compose a symphony, write a story, or paint a picture. But everyone may be wrong. Recent artificial intelligence systems have written credible short stories,4 composed convincing Mozart-like symphonies,5 drawn appealing pictures of people and landscapes,6 and conceived clever ideas for advertisements.
7
None of this is to say that the brain works like a digital computer, that artificial intelligence will ever duplicate the human mind, or that computers are conscious in the sense of having first-person subjective experience. But it does suggest that reasoning, intelligence, imagination, and creativity are forms of information processing, a well- understood physical process. Cognitive science, with the help of the computational theory of mind, has exorcised at least one ghost from the machine.
A second idea: The mind cannot be a blank slate, because blank slates don't do anything. As long as people had only the haziest concept of what a mind was or how it might work, the metaphor of a blank slate inscribed by the environment did not seem too outrageous. But as soon as one starts to think seriously about what kind of computation enables a system to see, think, speak, and plan, the problem with blank slates becomes all too obvious: they don't do anything. The inscriptions will sit there forever unless something notices patterns in them, combines them with patterns learned at other times, uses the combinations to scribble new thoughts onto the slate, and reads the results to guide behavior toward goals. Locke recognized this problem and alluded to something called "the understanding," which looked at the inscriptions on the white paper and carried out the recognizing, reflecting, and associating. But of
? ? ? ? ? ? ? course explaining how the mind understands by invoking something called "the understanding" is circular.
This argument against the Blank Slate was stated pithily by Gottfried Wilhelm Leibniz (1646-1716) in a reply to Locke. Leibniz repeated the empiricist motto "There is nothing in the intellect that was not first in the senses," then added, "except the intellect itself. "8 Something in the mind must be innate, if it is only the mechanisms that do the learning. Something has to see a world of objects rather than a kaleidoscope of shimmering pixels. Something has to infer the content of a sentence rather than parrot back the exact wording. {35} Something has to interpret other people's behavior as their attempts to achieve goals rather than as trajectories of jerking arms and legs.
In the spirit of Locke, one could attribute these feats to an abstract noun -- perhaps not to "the understanding" but to "learning," "intelligence," "plasticity," or "adaptiveness. " But as Leibniz remarked, to do so is to " [save appearances] by fabricating faculties or occult qualities,. . . and fancying them to be like little demons or imps which can without ado perform whatever is wanted, as though pocket watches told the time by a certain horological faculty without needing wheels, or as though mills crushed grain by a fractive faculty without needing anything in the way of millstones. "9 Leibniz, like Hobbes (who had influenced him), was ahead of his time in recognizing that intelligence is a form of information processing and needs complex machinery to carry it out. As we now know, computers don't understand speech or recognize text as they roll off the assembly line; someone has to install the right software first. The same is likely to be true of the far more demanding performance of the human being. Cognitive modelers have found that mundane challenges like walking around furniture, understanding a sentence, recalling a fact, or guessing someone's intentions are formidable engineering problems that are at or beyond the frontiers of artificial intelligence. The suggestion that they can be solved by a lump of Silly Putty that is passively molded by something called "culture" just doesn't cut the mustard.
This is not to say that cognitive scientists have put the nature-nurture debate completely behind them; they are still spread out along a continuum of opinion on how much standard equipment comes with the human mind. At one end are the philosopher Jerry Fodor, who has suggested that all concepts might be innate (even "doorknob" and "tweezers"), and the linguist Noam Chomsky, who believes that the word "learning" is misleading and we should say that children "grow" language instead. 10 At the other end are the connectionists, including Rumelhart, McClelland, Jeffrey Elman, and Elizabeth Bates, who build relatively simple computer models and train the living daylights out of them. 11 Fans locate the first extreme, which originated at the Massachusetts Institute of Technology, at the East Pole, the mythical place from which all directions are west. They locate the second extreme, which originated at the University of California, San Diego, at the West Pole, the mythical place from which all directions are east. (The names were suggested by Fodor during an MIT seminar at which he was fulminating against a "West Coast theorist" and someone pointed out that the theorist worked at Yale, which is, technically, on the East Coast. )12
But here is why the East Pole-West Pole debate is different from the ones that preoccupied philosophers for millennia: neither side believes in the Blank Slate. Everyone acknowledges that there can be no learning without innate circuitry to do the learning. In their West Pole manifesto Rethinking Innateness, {36} Bates and Elman and their coauthors cheerfully concede this point: "No learning rule can be entirely devoid of theoretical content nor can the tabula ever be completely rasa"13 They explain:
There is a widespread belief that connectionist models (and modelers) are committed to an extreme form of empiricism; and that any form of innate knowledge is to be avoided like the plague. . . . We obviously do not subscribe to this point of view. . . . There are good reasons to believe that some kinds of prior constraints [on learning models] are necessary. In fact, all connectionist models necessarily make some assumptions which must be regarded as constituting innate constraints. 14
The disagreements between the two poles, though significant, are over the details: how many innate learning networks there are, and how specifically engineered they are for particular jobs. (We will explore some of these disagreements in Chapter 5. )
A third idea: An infinite range of behavior can be generated by finite combinatorial programs in the mind. Cognitive science has undermined the Blank Slate and the Ghost in the Machine in another way. People can be forgiven for scoffing at the suggestion that human behavior is "in the genes" or "a product of evolution" in the senses familiar from the animal world. Human acts are not selected from a repertoire of knee-jerk reactions like a fish attacking a red spot or a hen sitting on eggs. Instead, people may worship goddesses, auction kitsch on the Internet, play air guitar, fast to atone for past sins, build forts out of lawn chairs, and so on, seemingly without limit. A glance at National Geographic shows that even the strangest acts in our own culture do not exhaust what our species is capable of. If anything goes, one might think, then perhaps we are Silly Putty, or unconstrained agents, after all.
But that impression has been made obsolete by the computational approach to the mind, which was barely conceivable in the era in which the Blank Slate arose. The clearest example is the Chomskyan revolution in
? ? ? ? ? ? ? ? ? ? language. 15 Language is the epitome of creative and variable behavior. Most utterances are brand-new combinations of words, never before uttered in the history of humankind. We are nothing like Tickle Me Elmo dolls who have a fixed list of verbal responses hard-wired in. But, Chomsky pointed out, for all its open-endedness language is not a free-for-all; it obeys rules and patterns. An English speaker can utter unprecedented strings of words such as Every day new universes come into existence, or He likes his toast with cream cheese and ketchup, or My car has been eaten by wolverines. But no one would say Car my been eaten has wolverines by or most of the other possible orderings of English words. Something in the head must be capable of generating not just any combinations of words but highly systematic ones. {37}
That something is a kind of software, a generative grammar that can crank out new arrangements of words. A battery of rules such as "An English sentence contains a subject and a predicate," "A predicate contains a verb, an object, and a complement," and "The subject of eat is the eater" can explain the boundless creativity of a human talker. With a few thousand nouns that can fill the subject slot and a few thousand verbs that can fill the predicate slot, one already has several million ways to open a sentence. The possible combinations quickly multiply out to unimaginably large numbers. Indeed, the repertoire of sentences is theoretically infinite, because the rules of language use a trick called recursion. A recursive rule allows a phrase to contain an example of itself, as in She thinks that he thinks that they think that he knows and so on, ad infinitum. And if the number of sentences is infinite, the number of possible thoughts and intentions is infinite too, because virtually every sentence expresses a different thought or intention. The combinatorial grammar for language meshes with other combinatorial programs in the head for thoughts and intentions. A fixed collection of machinery in the mind can generate an infinite range of behavior by the muscles. 16 Once one starts to think about mental software instead of physical behavior, the radical differences among human cultures become far smaller, and that leads to a fourth new idea: Universal mental mechanisms can underlie superficial variation across cultures. Again, we can use language as a paradigm case of the open-endedness of behavior. Humans speak some six thousand mutually unintelligible languages. Nonetheless, the grammatical programs in their minds differ far less than the actual speech coming out of their mouths. We have known for a long time that all human languages can convey the same kinds of ideas. The Bible has been translated into hundreds of non-Western languages, and during World War II the U. S. Marine Corps conveyed secret messages across the Pacific by having Navajo Indians translate them to and from their native language. The fact that any language can be used to convey any proposition, from theological parables to military directives, suggests that all languages are cut from the same cloth.
Chomsky proposed that the generative grammars of individual languages are variations on a single pattern, which he called Universal Grammar. For example, in English the verb comes before the object (drink beer) and the preposition comes before the noun phrase (from the bottle). In Japanese the object comes before the verb (beer drink) and the noun phrase comes before the preposition, or, more accurately, the postposition (the bottle from). But it is a significant discovery that both languages have verbs, objects, and pre- or postpositions to start with, as opposed to having the countless other conceivable kinds of apparatus that could power a communication system. And it is even more significant that unrelated languages build their phrases by assembling a head (such as a verb or preposition) and a complement (such as a noun {38} phrase) and assigning a consistent order to the two. In English the head comes first; in Japanese the head comes last. But everything else about the structure of phrases in the two languages is pretty much the same. And so it goes with phrase after phrase and language after language. The common kinds of heads and complements can be ordered in 128 logically possible ways, but 95 percent of the world's languages use one of two: either the English ordering or its mirror image the Japanese ordering. 17 A simple way to capture this uniformity is to say that all languages have the same grammar except for a parameter or switch that can be flipped to either the "head- first" or "head-last" setting. The linguist Mark Baker has recently summarized about a dozen of these parameters, which succinctly capture most of the known variation among the languages of the world. 18
Distilling the variation from the universal patterns is not just a way to tidy up a set of messy data. It can also provide clues about the innate circuitry that makes learning possible. If the universal part of a rule is embodied in the neural circuitry that guides babies when they first learn language, it could explain how children learn language so easily and uniformly and without the benefit of instruction. Rather than treating the sound coming out of Mom's mouth as just an interesting noise to mimic verbatim or to slice and dice in arbitrary ways, the baby listens for heads and complements, pays attention to how they are ordered, and builds a grammatical system consistent with that ordering. This idea can make sense of other kinds of variability across cultures. Many anthropologists sympathetic to social constructionism have claimed that emotions familiar to us, like anger, are absent from some cultures. 19 (A few anthropologists say there are cultures with no emotions at all! )20 For example, Catherine Lutz wrote that the Ifaluk (a Micronesian people) do not experience our "anger" but instead undergo an experience they call song. Song is a state of dudgeon triggered by a moral infraction such as breaking a taboo or acting in a cocky manner. It licenses one to shun, frown at, threaten, or gossip about the offender, though not to attack him physically. The target of song
? ? ? ? ? ? ? ? experiences another emotion allegedly unknown to Westerners: metagu, a state of dread that impels him to appease the song-ful one by apologizing, paying a fine, or offering a gift.
The philosophers Ron Mallon and Stephen Stich, inspired by Chomsky and other cognitive scientists, point out that the issue of whether to call Ifaluk song and Western anger the same emotion or different emotions is a quibble about the meaning of emotion words: whether they should be defined in terms of surface behavior or underlying mental computation. 21 If an emotion is defined by behavior, then emotions certainly do differ across cultures. The Ifaluk react emotionally to a woman working in the taro gardens while menstruating or to a man entering a birthing house, and we do not. We react emotionally to someone shouting a racial epithet or raising the middle finger, but {39} as far as we know, the Ifaluk do not. But if an emotion is defined by mental mechanisms -- what psychologists like Paul Ekman and Richard Lazarus call "affect programs" or "if-then formulas" (note the computational vocabulary) -- we and the Ifaluk are not so different after all. 22 We might all be equipped with a program that responds to an affront to our interests or our dignity with an unpleasant burning feeling that motivates us to punish or to exact compensation. But what counts as an affront, whether we feel it is permissible to glower in a particular setting, and what kinds of retribution we think we are entitled to, depend on our culture. The stimuli and responses may differ, but the mental states are the same, whether or not they are perfectly labeled by words in our language.
And as in the case of language, without some innate mechanism for mental computation, there would be no way to learn the parts of a culture that do have to be learned. It is no coincidence that the situations that provoke song among the Ifaluk include violating a taboo, being lazy or disrespectful, and refusing to share, but do not include respecting a taboo, being kind and deferential, and standing on one's head. The Ifaluk construe the first three as similar because they evoke the same affect program -- they are perceived as affronts. That makes it easier to learn that they call for the same reaction and makes it more likely that those three would be lumped together as the acceptable triggers for a single emotion.
The moral, then, is that familiar categories of behavior -- marriage customs, food taboos, folk superstitions, and so on -- certainly do vary across cultures and have to be learned, but the deeper mechanisms of mental computation that generate them may be universal and innate. People may dress differently, but they may all strive to flaunt their status via their appearance. They may respect the rights of the members of their clan exclusively or they may extend that respect to everyone in their tribe, nation-state, or species, but all divide the world into an in-group and an out-group. They may differ in which outcomes they attribute to the intentions of conscious beings, some allowing only that artifacts are deliberately crafted, others believing that illnesses come from magical spells cast by enemies, still others believing that the entire world was brought into being by a creator. But all of them explain certain events by invoking the existence of entities with minds that strive to bring about goals. The behaviorists got it backwards: it is the mind, not behavior, that is lawful.
A fifth idea: The mind is a complex system composed of many interacting parts. The psychologists who study emotions in different cultures have made another important discovery. Candid facial expressions appear to be the same everywhere, but people in some cultures learn to keep a poker face in polite company. 23 A simple explanation is that the affect programs fire up facial expressions in the same way in all people, but a separate system of "display rules" governs when they can be shown. {40}
The difference between these two mechanisms underscores another insight of the cognitive revolution. Before the revolution, commentators invoked enormous black boxes such as "the intellect" or "the understanding," and they made sweeping pronouncements about human nature, such as that we are essentially noble or essentially nasty. But we now know that the mind is not a homogeneous orb invested with unitary powers or across-the-board traits. The mind is modular, with many parts cooperating to generate a train of thought or an organized action. It has distinct information-processing systems for filtering out distractions, learning skills, controlling the body, remembering facts, holding information temporarily, and storing and executing rules. Cutting across these data-processing systems are mental faculties (sometimes called multiple intelligences) dedicated to different kinds of content, such as language, number, space, tools, and living things. Cognitive scientists at the East Pole suspect that the content-based modules are differentiated largely by the genes;24 those at the West Pole suspect they begin as small innate biases in attention and then coagulate out of statistical patterns in the sensory input. 25 But those at both poles agree that the brain is not a uniform meatloaf. Still another layer of information-processing systems can be found in the affect programs, that is, the systems for motivation and emotion.
The upshot is that an urge or habit coming out of one module can be translated into behavior in different ways -- or suppressed altogether -- by some other module. To take a simple example, cognitive psychologists believe that a module called the "habit system" underlies our tendency to produce certain responses habitually, such as responding to a printed word by pronouncing it silently. But another module, called the "supervisory attention system," can override it and focus on the information relevant to a stated problem, such as naming the color of the ink the word is printed in, or thinking up an action that goes with the word. 26 More generally, the interplay of mental systems can
? ? ? ? ? ? ? ? explain how people can entertain revenge fantasies that they never act on, or can commit adultery only in their hearts. In this way the theory of human nature coming out of the cognitive revolution has more in common with the Judeo- Christian theory of human nature, and with the psychoanalytic theory proposed by Sigmund Freud, than with behaviorism, social constructionism, and other versions of the Blank Slate. Behavior is not just emitted or elicited, nor does it come directly out of culture or society. It comes from an internal struggle among mental modules with differing agendas and goals.
The idea from the cognitive revolution that the mind is a system of universal, generative computational modules obliterates the way that debates on human nature have been framed for centuries. It is now simply misguided to ask whether humans are flexible or programmed, whether behavior is universal or varies across cultures, whether acts are learned or innate, whether we are essentially good or essentially evil. Humans behave flexibly because they are
{41} programmed: their minds are packed with combinatorial software that can generate an unlimited set of thoughts and behavior. Behavior may vary across cultures, but the design of the mental programs that generate it need not vary. Intelligent behavior is learned successfully because we have innate systems that do the learning. And all people may have good and evil motives, but not everyo~ne may translate them into behavior in the same way.
The second bridge between mind and matter is neuroscience, especially cognitive neuroscience, the study of how cognition and emotion are implemented in the brain. 27 Francis Crick wrote a book about the brain called The Astonishing Hypothesis, alluding to the idea that all our thoughts and feelings, joys and aches, dreams and wishes consist in the physiological activity of the brain. 28 Jaded neuroscientists, who take the idea for granted, snickered at the title, but Crick was right: the hypothesis is astonishing to most people the first time they stop to ponder it. Who cannot sympathize with the imprisoned Dmitri Karamazov as he tries to make sense of what he has just learned from a visiting academic?
Imagine: inside, in the nerves, in the head -- that is, these nerves are there in the brain . . . (damn them! ) there are sort of little tails, the little tails of those nerves, and as soon as they begin quivering . . . that is, you see, I look at something with my eyes and then they begin quivering, those little tails . . . and when they quiver, then an image appears . . . it doesn't appear at once, but an instant, a second, passes . . . and then something like a moment appears; that is, not a moment -- devil take the moment! -- but an image; that is, an object, or an action, damn it! That's why I see and then think, because of those tails, not at all because I've got a soul, and that I am some sort of image and likeness.
? glands, sense organs, muscles, etc.
Or to the raw materials for a factory:
Human nature is the rawest, most undifferentiated of raw material.
-- Leslie White (1949)38 -- Margaret Mead (1928)39
? ? Our ideas, our values, our acts, even our emotions, are, like our nervous system itself, cultural products -- products manufactured, indeed, out of tendencies, capacities, and dispositions with which we were
born, but manufactured nonetheless.
-- Clifford Geertz (1973)41 {26}
Or to some other amorphous entity that can have many things done to it:
Cultural psychology is the study of the way cultural traditions and social practices regulate, express, transform, and permute the human psyche, resulting less in psychic unity for humankind than in ethnic
-- Clifford Geertz (1973)40 Man is the animal most desperately dependent upon such extragenetic, outside-the-skin control
? Or to an unprogrammed computer:
mechanisms, such cultural programs, for ordering his behavior.
? ? divergences in mind, self and emotion.
-- Richard Shweder (1990)42
? The superorganic or group mind also became an article of faith in social science. Robert Lowie (another Boas student) wrote, "The principles of psychology are as incapable of accounting for the phenomena of culture as is gravitation to account for architectural styles. "43 And in case you missed its full implications, the anthropologist Leslie White spelled it out:
? Instead of regarding the individual as a First Cause, as a prime mover, as the initiator and determinant
of the culture process, we now see him as a component part, and a tiny and relatively insignificant part at that, of a vast, socio-cultural system that embraces innumerable individuals at any one time and extends back into their remote past as well. . . . For purposes of scientific interpretation, the culture process may be regarded as a thing sui generis; culture is explainable in terms of culture. 44
In other words, we should forget about the mind of an individual person like you, that tiny and insignificant part of a vast sociocultural system. The mind that counts is the one belonging to the group, which is capable of thinking, feeling, and acting on its own.
The doctrine of the superorganism has had an impact on modern life that extends well beyond the writings of social scientists. It underlies the tendency to reify "society" as a moral agent that can be blamed for sins as if it were a person. It drives identity politics, in which civil rights and political perquisites are allocated to groups rather than to individuals. And as we shall see in later chapters, it defined some of the great divides between major political systems in the twentieth century. ~
The Blank Slate was not the only part of the official theory that social scientists felt compelled to prop up. They also strove to consecrate the Noble Savage. Mead painted a Gauguinesque portrait of native peoples as peaceable, egalitarian, materially satisfied, and sexually unconnected. Her uplifting vision of who we used to be -- and therefore who we can become again -- was accepted by such otherwise skeptical writers as Bertrand Russell and H. L. Mencken. Ashley Montagu (also from the Boas circle), a prominent public intellectual from the 1950s until his recent death, tirelessly invoked the doctrine {27} of the Noble Savage to justify the quest for brotherhood and peace and to refute anyone who might think such efforts were futile. In 1950, for example, he drafted a manifesto for the newly formed UNESCO that declared, "Biological studies lend support to the ethic of universal brotherhood, for man is born with drives toward co-operation, and unless these drives are satisfied, men and nations alike fall ill. "45 With the ashes of thirty-five million victims of World War II still warm or radioactive, a reasonable person might wonder how "biological studies" could show anything of the kind. The draft was rejected, but Montagu had better luck in the decades to come, when UNESCO and many scholarly societies adopted similar resolutions. 46
More generally, social scientists saw the malleability of humans and the autonomy of culture as doctrines that might bring about the age-old dream of perfecting mankind. We are not stuck with what we don't like about our current predicament, they argued. Nothing prevents us from changing it except a lack of will and the benighted belief that we are permanently consigned to it by biology. Many social scientists have expressed the hope of a new and improved human nature:
I felt (and said so early) that the environmental explanation was preferable, whenever justified by the
? ? ? ? data, because it was more optimistic, holding out the hope of improvement.
-- Otto Klineberg (1928)47
? Modern sociology and modern anthropology are one in saying that the substance of culture, or civilization, is social tradition and that this social tradition is indefinitely modifiable by further learning on the part of men for happier and better ways of living together. . . . Thus the scientific study of institutions awakens faith in the possibility of remaking both human nature and human social life.
-- Charles Ellwood (1922)48
Barriers in many fields of knowledge are falling below the new optimism which is that anybody can learn anything. . . . We have turned away from the concept of human ability as something fixed in the physiological structure, to that of a flexible and versatile mechanism subject to great improvement.
-- Robert Faris (1961)49
Though psychology is not as politicized as some of the other social sciences, it too is sometimes driven by a Utopian vision in which changes in child-rearing and education will ameliorate social pathologies and improve human welfare. And psychological theorists sometimes try to add moral heft to arguments for connectionism or other empiricist theories with warnings about the {28} pessimistic implications of innatist theories. They argue, for example, that innatist theories open the door to inborn differences, which could foster racism, or that the theories imply that human traits are unchangeable, which could we~aken support for social programs. 50
Twentieth-century social science embraced not just the Blank Slate and the Noble Savage but the third member of the
? ? ? ? trinity, the Ghost in the Machine. The declaration that we can change what we don't like about ourselves became a watchword of social science. But that only raises the question "Who or what is the 'we'? " If the "we" doing the remaking are just other hunks of matter in the biological world, then any malleability of behavior we discover would be cold comfort, because we, the molders, would be biologically constrained and therefore might not mold people, or allow ourselves to be molded, in the most socially salutary way. A ghost in the machine is the ultimate liberator of human will -- including the will to change society -- from mechanical causation. The anthropologist Loren Eiseley made this clear when he wrote:
The mind of man, by indetermination, by the power of choice and cultural communication, is on the verge of escape from the blind control of that deterministic world with which the Darwinists had unconsciously shackled man. The inborn characteristics laid upon him by the biological extremists have crumbled away. . . . Wallace saw and saw correctly, that with the rise of man the evolution of parts was to a marked degree outmoded, that mind was now the arbiter of human destiny. 51
The "Wallace" that Eiseley is referring to is Alfred Russel Wallace (1823-1913), the co-discoverer with Darwin of natural selection. Wallace parted company from Darwin by claiming that the human mind could not be explained by evolution and must have been designed by a superior intelligence. He certainly did believe that the mind of man could escape "the blind control of a deterministic world. " Wallace became a spiritualist and spent the later years of his career searching for a way to communicate with the souls of the dead.
The social scientists who believed in an absolute separation of culture from biology may not have literally believed in a spook haunting the brain. Some used the analogy of the difference between living and nonliving matter. Kroeber wrote: "The dawn of the social. . . is not a link in any chain, not a step in a path, but a leap to another plane. . . . [It is like] the first occurrence of life in the hitherto lifeless universe. . . . From this moment on there should be two worlds in place of one. "52 And Lowie insisted that it was "not mysticism, but sound scientific method" to say that culture was "sui generis" and could be explained only by culture, because everyone knows that in biology a living cell can come only from another living cell. 53 {29}
At the time that Kroeber and Lowie wrote, they had biology on their side. Many biologists still thought that living things were animated by a special essence, an elan vital, and could not be reduced to inanimate matter. A 1931 history of biology, referring to genetics as it was then understood, said, "Thus the last of the biological theories leaves us where we first started, in the presence of a power called life or psyche which is not only of its own kind but unique in each and all of its exhibitions. "54 In the next chapter we will see that the analogy between the autonomy of culture and the autonomy of life would prove to be more telling than these social scientists realized.
<< {30} >> Chapter 3
The Last Wall to Fall
In 1755 Samuel Johnson wrote that his dictionary should not be expected to "change sublunary nature, and clear the world at once from folly, vanity, and affectation. " Few people today are familiar with the lovely word sublunary, literally "below the moon. " It alludes to the ancient belief in a strict division between the pristine, lawful, unchanging cosmos above and our grubby, chaotic, fickle Earth below. The division was already obsolete when Johnson used the word: Newton had shown that the same force that pulled an apple toward the ground kept the moon in its celestial orbit.
Newton's theory that a single set of laws governed the motions of all objects in the universe was the first event in one of the great developments in human understanding: the unification of knowledge, which the biologist E. O. Wilson has termed consilience. 1 Newton's breaching of the wall between the terrestrial and the celestial was followed by a collapse of the once equally firm (and now equally forgotten) wall between the creative past and the static present. That happened when Charles Lyell showed that the Earth was sculpted in the past by forces we see today (such as earthquakes and erosion) acting over immense spans of time.
The living and nonliving, too, no longer occupy different realms. In 1628 William Harvey showed that the human body is a machine that runs by hydraulics and other mechanical principles. In 1828 Friedrich Wohler showed that the stuff of life is not a magical, pulsating gel but ordinary compounds following the laws of chemistry. Charles Darwin showed how the astonishing diversity of life and its ubiquitous signs of design could arise from the physical process of natural selection among replicators. Gregor Mendel, and then James Watson and Francis Crick, showed how replication itself could be understood in physical terms.
? ? ? ? ? ? ? ? ? ? ? The unification of our understanding of life with our understanding of matter and energy was the greatest scientific achievement of the second half of the twentieth century. One of its many consequences was to pull the rug out {31} from under social scientists like Kroeber and Lowie who had invoked the "sound scientific method" of placing the living and nonliving in parallel universes. We now know that cells did not always come from other cells and that the emergence of life did not create a second world where before there was just one. Cells evolved from simpler replicating molecules, a nonliving part of the physical world, and may be understood as collections of molecular machinery -- fantastically complicated machinery, of course, but machinery nonetheless.
This leaves one wall standing in the landscape of knowledge, the one that twentieth-century social scientists guarded so jealously. It divides matter from mind, the material from the spiritual, the physical from the mental, biology from culture, nature from society, and the sciences from the social sciences, humanities, and arts. The division was built into each of the doctrines of the official theory: the blank slate given by biology versus the contents inscribed by experience and culture, the nobility of the savage in the state of nature versus the corruption of social institutions, the machine following inescapable laws versus the ghost that is free to choose and to improve the human condition.
But this wall, too, is falling. New ideas from four frontiers of knowledge -- the sciences of mind, brain, genes, and evolution -- are breaching the wall with a new understanding of human nature. In this chapter I will show how they are filling in the blank slate, declassing the noble savage, and exorcising the ghost in the machine. In the following chapter I will show that this new conception of human nature, connected to biology from below, can in turn be connected to the humanities and social sciences above. That new conception can give the phenomena of culture their due without segregating them into a parallel universe. ~
The first bridge between biology and culture is the science of mind, cognitive science. 2 The concept of mind has been perplexing for as long as people have reflected on their thoughts and feelings. The very idea has spawned paradoxes, superstitions, and bizarre theories in every period and culture. One can almost sympathize with the behaviorists and social constructionists of the first half of the twentieth century, who looked on minds as enigmas or conceptual traps that were best avoided in favor of overt behavior or the traits of a culture.
But beginning in the 1950s with the cognitive revolution, all that changed. It is now possible to make sense of mental processes and even to study them in the lab. And with a firmer grasp on the concept of mind, we can see that many tenets of the Blank Slate that once seemed appealing are now unnecessary or even incoherent. Here are five ideas from the cognitive revolution that have revamped how we think and talk about minds.
The first idea: The mental world can be grounded in the physical world by the concepts of information, computation, and feedback. A great divide between {32} mind and matter has always seemed natural because behavior appears to have a different kind of trigger than other physical events. Ordinary events have causes, it seems, but human behavior has reasons. I once participated in a BBC television debate on whether "science can explain human behavior. " Arguing against the resolution was a philosopher who asked how we might explain why someone was put in jail. Say it was for inciting racial hatred. The intention, the hatred, and even the prison, she said, cannot be described in the language of physics. There is simply no way to define "hatred" or "jail" in terms of the movements of particles. Explanations of behavior are like narratives, she argued, couched in the intentions of actors -- a plane completely separate from natural science. Or take a simpler example. How might we explain why Rex just walked over to the phone? We would not say that phone-shaped stimuli caused Rex's limbs to swing in certain arcs. Rather, we might say that he wanted to speak to his friend Cecile and knew that Cecile was home. No explanation has as much predictive power as that one. If Rex was no longer on speaking terms with Cecile, or if he remembered that Cecile was out bowling that night, his body would not have risen off the couch.
For millennia the gap between physical events, on the one hand, and meaning, content, ideas, reasons, and intentions, on the other, seemed to cleave the universe in two. How can something as ethereal as "inciting hatred" or "wanting to speak to Cecile" actually cause matter to move in space? But the cognitive revolution unified the world of ideas with the world of matter using a powerful new theory: that mental life can be explained in terms of information, computation, and feedback. Beliefs and memories are collections of information -- like facts in a database, but residing in patterns of activity and structure in the brain. Thinking and planning are systematic transformations of these patterns, like the operation of a computer program. Wanting and trying are feedback loops, like the principle behind a thermostat: they receive information about the discrepancy between a goal and the current state of the world, and then they execute operations that tend to reduce the difference. The mind is connected to the world by the sense organs, which transduce physical energy into data structures in the brain, and by motor programs, by which the brain controls the muscles.
This general idea may be called the computational theory of mind. It is not the same as the "computer metaphor" of the mind, the suggestion that the mind literally works like a human-made database, computer program, or thermostat.
? ? ? It says only that we can explain minds and human-made information processors using some of the same principles. It is just like other cases in which the natural world and human engineering overlap. A physiologist might invoke the same laws of optics to explain how the eye works and how a camera works without implying that the eye is like a camera in every detail.
The computational theory of mind does more than explain the existence {33} of knowing, thinking, and trying without invoking a ghost in the machine (though that would be enough of a feat). It also explains how those processes can be intelligent -- how rationality can emerge from a mindless physical process. If a sequence of transformations of information stored in a hunk of matter (such as brain tissue or silicon) mirrors a sequence of deductions that obey the laws of logic, probability, or cause and effect in the world, they will generate correct predictions about the world. And making correct predictions in pursuit of a goal is a pretty good definition of "intelligence. "3
Of course there is no new thing under the sun, and the computational theory of mind was foreshadowed by Hobbes when he described mental activity as tiny motions and wrote that "reasoning is but reckoning. " Three and a half centuries later, science has caught up to his vision. Perception, memory, imagery, reasoning, decision making, language, and motor control are being studied in the lab and successfully modeled as computational paraphernalia such as rules, strings, matrices, pointers, lists, files, trees, arrays, loops, propositions, and networks. For example, cognitive psychologists are studying the graphics system in the head and thereby explaining how people "see" the solution to a problem in a mental image. They are studying the web of concepts in long-term memory and explaining why some facts are easier to recall than others. They are studying the processor and memory used by the language system to learn why some sentences are a pleasure to read and others a difficult slog.
And if the proof is in the computing, then the sister field of artificial intelligence is confirming that ordinary matter can perform feats that were supposedly performable by mental stuff alone. In the 1950s computers were already being called "electronic brains" because they could calculate sums, organize data, and prove theorems. Soon they could correct spelling, set type, solve equations, and simulate experts on restricted topics such as picking stocks and diagnosing diseases. For decades we psychologists preserved human bragging rights by telling our classes that no computer could read text, decipher speech, or recognize faces, but these boasts are obsolete. Today software that can recognize printed letters and spoken words comes packaged with home computers. Rudimentary programs that understand or translate sentences are available in many search engines and Help programs, and they are steadily improving. Face-recognition systems have advanced to the point that civil libertarians are concerned about possible abuse when they are used with security cameras in public places.
Human chauvinists can still write off these low-level feats. Sure, they say, the input and output processing can be fobbed off onto computational modules, but you still need a human user with the capacity for judgment, reflection, and creativity. But according to the computational theory of mind, these capacities are themselves forms of information processing and can be implemented in a computational system. In 1997 an IBM computer called Deep
{34} Blue defeated the world chess champion Garry Kasparov, and unlike its predecessors, it did not just evaluate trillions of moves by brute force but was fitted with strategies that intelligently responded to patterns in the game. Newsweek called the match "The Brain's Last Stand. " Kasparov called the outcome "the end of mankind. "
You might still object that chess is an artificial world with discrete moves and a clear winner, perfectly suited to the rule-crunching of a computer. People, on the other hand, live in a messy world offering unlimited moves and nebulous goals. Surely this requires human creativity and intuition -- which is why everyone knows that computers will never compose a symphony, write a story, or paint a picture. But everyone may be wrong. Recent artificial intelligence systems have written credible short stories,4 composed convincing Mozart-like symphonies,5 drawn appealing pictures of people and landscapes,6 and conceived clever ideas for advertisements.
7
None of this is to say that the brain works like a digital computer, that artificial intelligence will ever duplicate the human mind, or that computers are conscious in the sense of having first-person subjective experience. But it does suggest that reasoning, intelligence, imagination, and creativity are forms of information processing, a well- understood physical process. Cognitive science, with the help of the computational theory of mind, has exorcised at least one ghost from the machine.
A second idea: The mind cannot be a blank slate, because blank slates don't do anything. As long as people had only the haziest concept of what a mind was or how it might work, the metaphor of a blank slate inscribed by the environment did not seem too outrageous. But as soon as one starts to think seriously about what kind of computation enables a system to see, think, speak, and plan, the problem with blank slates becomes all too obvious: they don't do anything. The inscriptions will sit there forever unless something notices patterns in them, combines them with patterns learned at other times, uses the combinations to scribble new thoughts onto the slate, and reads the results to guide behavior toward goals. Locke recognized this problem and alluded to something called "the understanding," which looked at the inscriptions on the white paper and carried out the recognizing, reflecting, and associating. But of
? ? ? ? ? ? ? course explaining how the mind understands by invoking something called "the understanding" is circular.
This argument against the Blank Slate was stated pithily by Gottfried Wilhelm Leibniz (1646-1716) in a reply to Locke. Leibniz repeated the empiricist motto "There is nothing in the intellect that was not first in the senses," then added, "except the intellect itself. "8 Something in the mind must be innate, if it is only the mechanisms that do the learning. Something has to see a world of objects rather than a kaleidoscope of shimmering pixels. Something has to infer the content of a sentence rather than parrot back the exact wording. {35} Something has to interpret other people's behavior as their attempts to achieve goals rather than as trajectories of jerking arms and legs.
In the spirit of Locke, one could attribute these feats to an abstract noun -- perhaps not to "the understanding" but to "learning," "intelligence," "plasticity," or "adaptiveness. " But as Leibniz remarked, to do so is to " [save appearances] by fabricating faculties or occult qualities,. . . and fancying them to be like little demons or imps which can without ado perform whatever is wanted, as though pocket watches told the time by a certain horological faculty without needing wheels, or as though mills crushed grain by a fractive faculty without needing anything in the way of millstones. "9 Leibniz, like Hobbes (who had influenced him), was ahead of his time in recognizing that intelligence is a form of information processing and needs complex machinery to carry it out. As we now know, computers don't understand speech or recognize text as they roll off the assembly line; someone has to install the right software first. The same is likely to be true of the far more demanding performance of the human being. Cognitive modelers have found that mundane challenges like walking around furniture, understanding a sentence, recalling a fact, or guessing someone's intentions are formidable engineering problems that are at or beyond the frontiers of artificial intelligence. The suggestion that they can be solved by a lump of Silly Putty that is passively molded by something called "culture" just doesn't cut the mustard.
This is not to say that cognitive scientists have put the nature-nurture debate completely behind them; they are still spread out along a continuum of opinion on how much standard equipment comes with the human mind. At one end are the philosopher Jerry Fodor, who has suggested that all concepts might be innate (even "doorknob" and "tweezers"), and the linguist Noam Chomsky, who believes that the word "learning" is misleading and we should say that children "grow" language instead. 10 At the other end are the connectionists, including Rumelhart, McClelland, Jeffrey Elman, and Elizabeth Bates, who build relatively simple computer models and train the living daylights out of them. 11 Fans locate the first extreme, which originated at the Massachusetts Institute of Technology, at the East Pole, the mythical place from which all directions are west. They locate the second extreme, which originated at the University of California, San Diego, at the West Pole, the mythical place from which all directions are east. (The names were suggested by Fodor during an MIT seminar at which he was fulminating against a "West Coast theorist" and someone pointed out that the theorist worked at Yale, which is, technically, on the East Coast. )12
But here is why the East Pole-West Pole debate is different from the ones that preoccupied philosophers for millennia: neither side believes in the Blank Slate. Everyone acknowledges that there can be no learning without innate circuitry to do the learning. In their West Pole manifesto Rethinking Innateness, {36} Bates and Elman and their coauthors cheerfully concede this point: "No learning rule can be entirely devoid of theoretical content nor can the tabula ever be completely rasa"13 They explain:
There is a widespread belief that connectionist models (and modelers) are committed to an extreme form of empiricism; and that any form of innate knowledge is to be avoided like the plague. . . . We obviously do not subscribe to this point of view. . . . There are good reasons to believe that some kinds of prior constraints [on learning models] are necessary. In fact, all connectionist models necessarily make some assumptions which must be regarded as constituting innate constraints. 14
The disagreements between the two poles, though significant, are over the details: how many innate learning networks there are, and how specifically engineered they are for particular jobs. (We will explore some of these disagreements in Chapter 5. )
A third idea: An infinite range of behavior can be generated by finite combinatorial programs in the mind. Cognitive science has undermined the Blank Slate and the Ghost in the Machine in another way. People can be forgiven for scoffing at the suggestion that human behavior is "in the genes" or "a product of evolution" in the senses familiar from the animal world. Human acts are not selected from a repertoire of knee-jerk reactions like a fish attacking a red spot or a hen sitting on eggs. Instead, people may worship goddesses, auction kitsch on the Internet, play air guitar, fast to atone for past sins, build forts out of lawn chairs, and so on, seemingly without limit. A glance at National Geographic shows that even the strangest acts in our own culture do not exhaust what our species is capable of. If anything goes, one might think, then perhaps we are Silly Putty, or unconstrained agents, after all.
But that impression has been made obsolete by the computational approach to the mind, which was barely conceivable in the era in which the Blank Slate arose. The clearest example is the Chomskyan revolution in
? ? ? ? ? ? ? ? ? ? language. 15 Language is the epitome of creative and variable behavior. Most utterances are brand-new combinations of words, never before uttered in the history of humankind. We are nothing like Tickle Me Elmo dolls who have a fixed list of verbal responses hard-wired in. But, Chomsky pointed out, for all its open-endedness language is not a free-for-all; it obeys rules and patterns. An English speaker can utter unprecedented strings of words such as Every day new universes come into existence, or He likes his toast with cream cheese and ketchup, or My car has been eaten by wolverines. But no one would say Car my been eaten has wolverines by or most of the other possible orderings of English words. Something in the head must be capable of generating not just any combinations of words but highly systematic ones. {37}
That something is a kind of software, a generative grammar that can crank out new arrangements of words. A battery of rules such as "An English sentence contains a subject and a predicate," "A predicate contains a verb, an object, and a complement," and "The subject of eat is the eater" can explain the boundless creativity of a human talker. With a few thousand nouns that can fill the subject slot and a few thousand verbs that can fill the predicate slot, one already has several million ways to open a sentence. The possible combinations quickly multiply out to unimaginably large numbers. Indeed, the repertoire of sentences is theoretically infinite, because the rules of language use a trick called recursion. A recursive rule allows a phrase to contain an example of itself, as in She thinks that he thinks that they think that he knows and so on, ad infinitum. And if the number of sentences is infinite, the number of possible thoughts and intentions is infinite too, because virtually every sentence expresses a different thought or intention. The combinatorial grammar for language meshes with other combinatorial programs in the head for thoughts and intentions. A fixed collection of machinery in the mind can generate an infinite range of behavior by the muscles. 16 Once one starts to think about mental software instead of physical behavior, the radical differences among human cultures become far smaller, and that leads to a fourth new idea: Universal mental mechanisms can underlie superficial variation across cultures. Again, we can use language as a paradigm case of the open-endedness of behavior. Humans speak some six thousand mutually unintelligible languages. Nonetheless, the grammatical programs in their minds differ far less than the actual speech coming out of their mouths. We have known for a long time that all human languages can convey the same kinds of ideas. The Bible has been translated into hundreds of non-Western languages, and during World War II the U. S. Marine Corps conveyed secret messages across the Pacific by having Navajo Indians translate them to and from their native language. The fact that any language can be used to convey any proposition, from theological parables to military directives, suggests that all languages are cut from the same cloth.
Chomsky proposed that the generative grammars of individual languages are variations on a single pattern, which he called Universal Grammar. For example, in English the verb comes before the object (drink beer) and the preposition comes before the noun phrase (from the bottle). In Japanese the object comes before the verb (beer drink) and the noun phrase comes before the preposition, or, more accurately, the postposition (the bottle from). But it is a significant discovery that both languages have verbs, objects, and pre- or postpositions to start with, as opposed to having the countless other conceivable kinds of apparatus that could power a communication system. And it is even more significant that unrelated languages build their phrases by assembling a head (such as a verb or preposition) and a complement (such as a noun {38} phrase) and assigning a consistent order to the two. In English the head comes first; in Japanese the head comes last. But everything else about the structure of phrases in the two languages is pretty much the same. And so it goes with phrase after phrase and language after language. The common kinds of heads and complements can be ordered in 128 logically possible ways, but 95 percent of the world's languages use one of two: either the English ordering or its mirror image the Japanese ordering. 17 A simple way to capture this uniformity is to say that all languages have the same grammar except for a parameter or switch that can be flipped to either the "head- first" or "head-last" setting. The linguist Mark Baker has recently summarized about a dozen of these parameters, which succinctly capture most of the known variation among the languages of the world. 18
Distilling the variation from the universal patterns is not just a way to tidy up a set of messy data. It can also provide clues about the innate circuitry that makes learning possible. If the universal part of a rule is embodied in the neural circuitry that guides babies when they first learn language, it could explain how children learn language so easily and uniformly and without the benefit of instruction. Rather than treating the sound coming out of Mom's mouth as just an interesting noise to mimic verbatim or to slice and dice in arbitrary ways, the baby listens for heads and complements, pays attention to how they are ordered, and builds a grammatical system consistent with that ordering. This idea can make sense of other kinds of variability across cultures. Many anthropologists sympathetic to social constructionism have claimed that emotions familiar to us, like anger, are absent from some cultures. 19 (A few anthropologists say there are cultures with no emotions at all! )20 For example, Catherine Lutz wrote that the Ifaluk (a Micronesian people) do not experience our "anger" but instead undergo an experience they call song. Song is a state of dudgeon triggered by a moral infraction such as breaking a taboo or acting in a cocky manner. It licenses one to shun, frown at, threaten, or gossip about the offender, though not to attack him physically. The target of song
? ? ? ? ? ? ? ? experiences another emotion allegedly unknown to Westerners: metagu, a state of dread that impels him to appease the song-ful one by apologizing, paying a fine, or offering a gift.
The philosophers Ron Mallon and Stephen Stich, inspired by Chomsky and other cognitive scientists, point out that the issue of whether to call Ifaluk song and Western anger the same emotion or different emotions is a quibble about the meaning of emotion words: whether they should be defined in terms of surface behavior or underlying mental computation. 21 If an emotion is defined by behavior, then emotions certainly do differ across cultures. The Ifaluk react emotionally to a woman working in the taro gardens while menstruating or to a man entering a birthing house, and we do not. We react emotionally to someone shouting a racial epithet or raising the middle finger, but {39} as far as we know, the Ifaluk do not. But if an emotion is defined by mental mechanisms -- what psychologists like Paul Ekman and Richard Lazarus call "affect programs" or "if-then formulas" (note the computational vocabulary) -- we and the Ifaluk are not so different after all. 22 We might all be equipped with a program that responds to an affront to our interests or our dignity with an unpleasant burning feeling that motivates us to punish or to exact compensation. But what counts as an affront, whether we feel it is permissible to glower in a particular setting, and what kinds of retribution we think we are entitled to, depend on our culture. The stimuli and responses may differ, but the mental states are the same, whether or not they are perfectly labeled by words in our language.
And as in the case of language, without some innate mechanism for mental computation, there would be no way to learn the parts of a culture that do have to be learned. It is no coincidence that the situations that provoke song among the Ifaluk include violating a taboo, being lazy or disrespectful, and refusing to share, but do not include respecting a taboo, being kind and deferential, and standing on one's head. The Ifaluk construe the first three as similar because they evoke the same affect program -- they are perceived as affronts. That makes it easier to learn that they call for the same reaction and makes it more likely that those three would be lumped together as the acceptable triggers for a single emotion.
The moral, then, is that familiar categories of behavior -- marriage customs, food taboos, folk superstitions, and so on -- certainly do vary across cultures and have to be learned, but the deeper mechanisms of mental computation that generate them may be universal and innate. People may dress differently, but they may all strive to flaunt their status via their appearance. They may respect the rights of the members of their clan exclusively or they may extend that respect to everyone in their tribe, nation-state, or species, but all divide the world into an in-group and an out-group. They may differ in which outcomes they attribute to the intentions of conscious beings, some allowing only that artifacts are deliberately crafted, others believing that illnesses come from magical spells cast by enemies, still others believing that the entire world was brought into being by a creator. But all of them explain certain events by invoking the existence of entities with minds that strive to bring about goals. The behaviorists got it backwards: it is the mind, not behavior, that is lawful.
A fifth idea: The mind is a complex system composed of many interacting parts. The psychologists who study emotions in different cultures have made another important discovery. Candid facial expressions appear to be the same everywhere, but people in some cultures learn to keep a poker face in polite company. 23 A simple explanation is that the affect programs fire up facial expressions in the same way in all people, but a separate system of "display rules" governs when they can be shown. {40}
The difference between these two mechanisms underscores another insight of the cognitive revolution. Before the revolution, commentators invoked enormous black boxes such as "the intellect" or "the understanding," and they made sweeping pronouncements about human nature, such as that we are essentially noble or essentially nasty. But we now know that the mind is not a homogeneous orb invested with unitary powers or across-the-board traits. The mind is modular, with many parts cooperating to generate a train of thought or an organized action. It has distinct information-processing systems for filtering out distractions, learning skills, controlling the body, remembering facts, holding information temporarily, and storing and executing rules. Cutting across these data-processing systems are mental faculties (sometimes called multiple intelligences) dedicated to different kinds of content, such as language, number, space, tools, and living things. Cognitive scientists at the East Pole suspect that the content-based modules are differentiated largely by the genes;24 those at the West Pole suspect they begin as small innate biases in attention and then coagulate out of statistical patterns in the sensory input. 25 But those at both poles agree that the brain is not a uniform meatloaf. Still another layer of information-processing systems can be found in the affect programs, that is, the systems for motivation and emotion.
The upshot is that an urge or habit coming out of one module can be translated into behavior in different ways -- or suppressed altogether -- by some other module. To take a simple example, cognitive psychologists believe that a module called the "habit system" underlies our tendency to produce certain responses habitually, such as responding to a printed word by pronouncing it silently. But another module, called the "supervisory attention system," can override it and focus on the information relevant to a stated problem, such as naming the color of the ink the word is printed in, or thinking up an action that goes with the word. 26 More generally, the interplay of mental systems can
? ? ? ? ? ? ? ? explain how people can entertain revenge fantasies that they never act on, or can commit adultery only in their hearts. In this way the theory of human nature coming out of the cognitive revolution has more in common with the Judeo- Christian theory of human nature, and with the psychoanalytic theory proposed by Sigmund Freud, than with behaviorism, social constructionism, and other versions of the Blank Slate. Behavior is not just emitted or elicited, nor does it come directly out of culture or society. It comes from an internal struggle among mental modules with differing agendas and goals.
The idea from the cognitive revolution that the mind is a system of universal, generative computational modules obliterates the way that debates on human nature have been framed for centuries. It is now simply misguided to ask whether humans are flexible or programmed, whether behavior is universal or varies across cultures, whether acts are learned or innate, whether we are essentially good or essentially evil. Humans behave flexibly because they are
{41} programmed: their minds are packed with combinatorial software that can generate an unlimited set of thoughts and behavior. Behavior may vary across cultures, but the design of the mental programs that generate it need not vary. Intelligent behavior is learned successfully because we have innate systems that do the learning. And all people may have good and evil motives, but not everyo~ne may translate them into behavior in the same way.
The second bridge between mind and matter is neuroscience, especially cognitive neuroscience, the study of how cognition and emotion are implemented in the brain. 27 Francis Crick wrote a book about the brain called The Astonishing Hypothesis, alluding to the idea that all our thoughts and feelings, joys and aches, dreams and wishes consist in the physiological activity of the brain. 28 Jaded neuroscientists, who take the idea for granted, snickered at the title, but Crick was right: the hypothesis is astonishing to most people the first time they stop to ponder it. Who cannot sympathize with the imprisoned Dmitri Karamazov as he tries to make sense of what he has just learned from a visiting academic?
Imagine: inside, in the nerves, in the head -- that is, these nerves are there in the brain . . . (damn them! ) there are sort of little tails, the little tails of those nerves, and as soon as they begin quivering . . . that is, you see, I look at something with my eyes and then they begin quivering, those little tails . . . and when they quiver, then an image appears . . . it doesn't appear at once, but an instant, a second, passes . . . and then something like a moment appears; that is, not a moment -- devil take the moment! -- but an image; that is, an object, or an action, damn it! That's why I see and then think, because of those tails, not at all because I've got a soul, and that I am some sort of image and likeness.
