Part Two


One of the central metaphors of the third culture is computation. The computer does computation and the mind does computation. To understand what makes birds fly, you may look at airplanes, because there are principles of flight and aerodynamics that apply to anything that flies. That is how the idea of computation figures into the new ways in which scientists are thinking about complicated systems.

At first, people who wanted to be scientific about the mind tried to treat it by looking for fundamentals, as in physics. We had waves of so-called mathematical psychology, and before that psychologists were trying to find a simple building block — an "atom" — with which to reconstruct the mind. That approach did not work. It turns out that minds, which are brains, are extremely complicated artifacts of natural selection, and as such they have many emergent properties that can best be understood from an engineering point of view.

We are also discovering that the world itself is very "kludgey"; it is made up of curious Rube Goldberg mechanisms that do cute tricks. This does not sit well with those who want science to be crystalline and precise, like Newton's pure mathematics. The idea that nature might be composed of Rube Goldberg machines is deeply offensive to people who have a strong esthetic drive — those who say that science must be beautiful, that it must be pure, that everything should be symmetrical and deducible from first principles. That esthetic has been a great motivating force in science, since Plato.

Counteracting it is the esthetic that emerges from this book — the esthetic that says the beauties of nature come from the interaction of mind-boggling complexities, and that it is complexity essentially most of the way down. The computational perspective — machines made out of machines made out of machines — is on the ascendant. There is a lot of talk about machines in this book.

Marvin Minsky is the leading light of AI — that is, artificial intelligence. He sees the brain as a myriad of structures. Scientists who, like Minsky, take the strong AI view believe that a computer model of the brain will be able to explain what we know of the brain's cognitive abilities. Minsky identifies consciousness with high-level, abstract thought, and believes that in principle machines can do everything a conscious human being can do.

Roger Schank is a computer scientist and cognitive psychologist who has worked in the AI field for twenty years. Like Minsky, he takes the strong AI view, but rather than trying to build an intelligent machine he wants to deconstruct the human mind. He wants to know, in particular, how natural language — one's mother tongue — is processed, how memory works, and how learning occurs. Schank thinks of the human mind as a learning device, and he thinks that it is being taught in the wrong way. He is something of a gadfly; he deplores the curriculum-based, drill-oriented methods in today's schools, and his most recent contributions have been in the area of education, looking at ways to use computers to enhance the learning process.

The philosopher Daniel C. Dennett is interested in consciousness, and his view of it, similar to Minsky's, is as high-level, abstract thinking. He is known as the leading proponent of the computational model of the mind; he has clashed with philosophers such as John Searle who maintain that the most important aspects of consciousness — intentionality and subjective quality — can never be computed. He is the philosopher of choice of the AI community. In his more recent work, he has turned to what he calls "Darwin's dangerous idea"; he is squarely in the ultra Darwinist camp of George C. Williams and Richard Dawkins, and he has with great energy mustered a serious critique of the scientific ideas of Stephen Jay Gould.

Nicholas Humphrey, a research psychologist who twenty years ago breathed life into the newly developing field of evolutionary psychology with his theory about "the social function of intellect," here discusses his more recent ideas on the nature of phenomenal consciousness. Unlike Dennett, who sees the role of philosophers as disabusing people of their "primitive" ideas about the nature of consciousness, Humphrey believes that we should take these primitive intuitions at face value. If people say that the problem is what it "feels like" to be conscious, then the problem is indeed to explain "feeling." Humphrey and Dennett are a pair of bookends. Some regard Humphrey as a "romantic scientist," more interested in storytelling than in getting at the scientific facts. But he would probably not agree that there is a hard and fast line between facts and stories.

Francisco Varela, an experimental and theoretical biologist, studies what he terms "emergent selves" or "virtual identities." His is an immanent view of reality, based on metaphors derived from self-organization and Buddhist-inspired epistemology rather than on those derived from engineering and information science. He presents a challenge to the traditional AI view that the world exists independently of the organism, whose task is to make an accurate model of that world — to "consult" before acting. Varela's nonrepresentationalist world — or perhaps "world-as- experienced" — has no independent existence but is itself a product of interactions between organisms and environment. He first became known for his theory of autopoiesis ("self production"), which is concerned with the active self-maintenance of living systems whose identities remain constant while their components continually change. Varela is tough to categorize. He is a neuroscientist who has become an immunologist. He is well informed about cognitive science and is a radical critic of it, because he is a believer in "emergence" — not the vitalist idea promulgated in the 1920s (that of a magical property that emerges inexplicably from lower mechanical operations) but the idea that the whole appears as a result of the dynamics of its component parts. He thinks that classic computationalist cognitive science is too simplemindedly mechanistic. He is knowledgeable and romantic at the same time.

The experimental psychologist Steven Pinker is a unifier, someone who ties a lot of big ideas together — from evolutionary theory to consciousness to the language "instinct." He has studied visual cognition and language acquisition in the laboratory, and was one of the first to develop computational models of how children learn the words and grammar of their first language. He has merged Chomskyan ideas about the innate character of language with Darwinian explanations, such as adaptation and natural selection. Pinker wrote one of the most influential critiques of neural-network models of the mind. He takes the position that even the simplest tasks that humans perform — picking up a pencil, responding to a color, recognizing a friend's face — are extraordinary engineering feats and beyond the capabilities of any current software designers. He believes that the brain has to have a set of specialized tools and that there is no one general-purpose learning machine capable of duplicating its feats.

The mathematical physicist Roger Penrose attempts to link the quantum and the classical world in physics. He believes that a lot of what the brain does is what you could do on a computer, but he posits that the actions of consciousness are something different. To allow for the brain's capacity to know mathematical truth, he thinks, physics must include a noncomputable element, which he surmises will emerge in a theory of quantum gravity. This leads many of his colleagues to wonder if he is a physicist gone astray. Indeed, his international best-seller, The Emperor's New Mind, is considered by some of them to be The Emperor's New Book. Yet the reading public had a very different reaction — the book reached the #7 position on the New York Times' best-seller list. Why? It is a tour de force through the realm of physics and is filled with pages of mathematical formulas and equations. In claiming that the human mind is not equatable to a machine, Penrose obviously said what many people wanted to hear: they may well have bought the book as a talisman in support of that which they would have be true. Among his scientific colleagues there is less backing for what many consider to be a radical theory. Yet Penrose retains their respect, because of his utter honesty and inquiring mind. In Shadows of the Mind, his sequel, he addresses the scientific arguments concerning his theories of mind in a rigorous fashion.

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Excerpted from The Third Culture: Beyond the Scientific Revolution by John Brockman (Simon & Schuster, 1995) . Copyright 1995 by John Brockman. All rights reserved.