The Scientist as Rebel (34 page)

The most tragic episode of Wiener’s life happened in 1951 when he was fifty-seven years old and passionately involved in a collaboration with his friend Warren McCullough and a group of young colleagues that he called “the boys.” McCullough was a neurophysiologist who had moved from Illinois to MIT to work with Wiener. They planned to explore the connections between Wiener’s theory of feedback control and the functioning of living neurons and brains. “The boys” were a brilliant team, including Jerome Lettvin, who later became a leading experimental biologist. Margaret was insanely jealous of McCullough and his boys, and resolved to break up their friendship with Wiener.
At a dinner with some colleagues in Mexico, who reported the episode to Lettvin many years later, she informed Wiener that McCullough’s boys had seduced his daughter Barbara when she was a teenager staying at McCullough’s house.

This story had no basis in fact, but Wiener believed it. He made no attempt to verify the accusation, and immediately wrote an angry letter to the president of
MIT
dissolving all connection between himself and the McCullough team. From that day until the end of Wiener’s life, the contact remained broken. McCullough never knew why. The effect of the breach on McCullough and his boys was devastating. The effect on Wiener was also profound. His foray into biology, and his hopes for unifying cybernetics with biology, were at an end. Margaret achieved her objective, to cut him off from his friends and have him for herself.

The personal drama of the breach between Wiener and McCullough is the centerpiece of this biography, the event around which the rest of the narrative revolves. Perhaps the authors’ main purpose was to exorcise the Wiener family curse by exposing the family secrets to the light of day. Wiener is the dark hero, and Margaret is the dark villain. The book reads more like a novel than a conventional biography. And inevitably the reviewer wonders whether the story is true. Margaret is now the one who is accused and will never have a chance to answer her accusers. She never spoke with the authors, and left no friend behind to speak for her. The evidence against her is well documented and seems convincing. And still, the reviewer wonders. The evidence that Margaret claimed a seduction had taken place comes from a single informant, the late Arturo Rosenblueth, who told the story to Lettvin and others, ten years after the event. This is not the sort of evidence that would convict a murderer in a court of law. It is not likely, but possible, that Rosenblueth, who died in 1970, might have had ulterior motives for concocting the story.

This biography belongs to a genre that has recently become fashionable, emphasizing the baring of family secrets and the exposure of
human weaknesses. There has been a spate of books exposing the human weaknesses of Einstein, Madame Curie, and other scientific heroes. Such books are worth reading if they give us a balanced mixture of human drama with scientific substance. Many of them make no attempt at balance, giving us stories and scandals undiluted with science. The authors of this book have succeeded in bringing Wiener to life as a great figure in the world of science as well as a tragic hero in a domestic drama. They show him as he was, a mixture of Galileo and Othello. Because they are ignorant of mathematics, they cannot give the reader a detailed picture of what Wiener actually did. But they answer the crucial questions: what cybernetics was, what Wiener intended to do with it, and why it seems to have disappeared from the scene after Wiener’s death.

Wiener defined cybernetics to be “the entire field of control and communication theory, whether in the machine or in the animal.” The languages of communication theory are mathematical. To understand the history of cybernetics, it is important to understand that mathematical communication has two languages, which we call analog and digital. Analog communication describes the world in terms of continuously variable quantities such as electrical voltages and currents that can be directly measured. Digital communication describes the world in terms of zeros and ones, each zero or one representing a logical choice between two discrete alternatives. Analog communication is the language of analysis. Digital communication is the language of logic.

Wiener was fluent in both languages and intended cybernetics to include both. In 1940 he wrote a memorandum explaining in detail why digital language would be preferable for the computers whose existence he already foresaw. But his own contributions to communication theory happened to be written in analog language, for four reasons. First, his work as a pure mathematician had mostly been in analysis. Second, his practical experience with antiaircraft prediction
was concerned with analog measurements and analog feedback mechanisms. Third, his conversations with neurophysiologists had convinced him that the language of sensory-motor feedback signals in the brains of humans and animals is analog. Fourth, the transmission of signals by chemical hormones is evidence that the action of the brain is at least partly analog. For all these reasons, Wiener’s book
Cybernetics
, which summarized his thinking in 1948, was written in analog language. And for the last ten years of his life, as he traveled from country to country preaching the gospel of cybernetics, he used analog language almost exclusively. In spite of his original intentions, cybernetics became a theory of analog processes.

Meanwhile, also in 1948, Claude Shannon published his classic pair of papers with the title “A Mathematical Theory of Communication,” in
The Bell System Technical Journal
. Shannon’s theory was a theory of digital communication, using many of Wiener’s ideas but applying them in a new direction. Shannon’s theory was mathematically elegant, clear, and easy to apply to practical problems of communication. It was far more user-friendly than cybernetics. It became the basis of a new discipline called “information theory.” During the next ten years, digital computers began to operate all over the world, and analog computers rapidly became obsolete. Electronic engineers learned information theory, the gospel according to Shannon, as part of their basic training, and cybernetics was forgotten.

Neither Wiener nor von Neumann nor Shannon, nor anyone else in the 1940s, foresaw the microprocessors that would make digital computers small and cheap and reliable and available to private citizens. Nobody foresaw the Internet or the ubiquitous cell phone. As a result of the proliferation of digital computers in private hands, Wiener’s nightmare vision of a few giant computers determining the fate of human societies never came to pass. But other aspects of Wiener’s vision of the future are coming true. We see, as he predicted, millions of skilled human workers displaced by machines and sinking
into poverty. We see the basis of the wealth of nations moving from the manufacture of goods to the processing of information. We see the beginnings of an understanding of the mysteries of the human brain. We still have much to learn from Wiener’s vision.

Each time I publish a review in
The New York Review
, I receive a bimodal set of responses. First come the responses from nonexpert readers who write to tell me how much they like the review. Second come the responses from expert readers who write to correct my mistakes. I am grateful for both categories of response, but I learn much more from the second category. It is inevitable that I make mistakes when writing about fields in which I am not an expert, and I rely on the experts to set the record straight.

This review gave me an unusually rich collection of responses in both categories. I am especially grateful to those who wrote to correct my mistakes. I have responded to their criticisms by deleting some statements and judgments that were either untrue or unfair.

GREAT SCIENTISTS COME
in two varieties, which Isaiah Berlin, quoting the seventh-century-
BC
poet Archilochus, called foxes and hedgehogs. Foxes know many tricks, hedgehogs only one. Foxes are interested in everything, and move easily from one problem to another. Hedgehogs are interested only in a few problems which they consider fundamental, and stick with the same problems for years or decades. Most of the great discoveries are made by hedgehogs, most of the little discoveries by foxes. Science needs both hedgehogs and foxes for its healthy growth, hedgehogs to dig deep into the nature of things, foxes to explore the complicated details of our marvelous universe. Albert Einstein was a hedgehog; Richard Feynman was a fox.

Many readers are more likely to have encountered Feynman as a storyteller, for example in his book
Surely You’re Joking, Mr. Feynman
!,
¹
than as a scientist. Not many are likely to have read his great textbook
The Feynman Lectures on Physics
,
²
which was a best seller among physicists but was not intended for the general public. Now we have a collection of his letters, selected and edited by his daughter, Michelle.
³
The letters do not tell us much about his science. For readers who are not scientists, it is important to understand that foxes may be as creative as hedgehogs. Feynman happened to be young at a time when there were great opportunities for foxes. The hedgehogs, Einstein and his followers at the beginning of the twentieth century, had dug deep and found new foundations for physics. When Feynman came onto the scene in the middle of the century, the foundations were firm and the universe was wide open for foxes to explore.

One of the few letters in the collection that discusses Feynman’s science was written to his former student Koichi Mano. It describes the fox’s way of working:

“The ‘grander’ problems of quantum theory” were only one item in a long list of Feynman’s activities.

The phrase “the ‘grander’ problems of quantum theory” refers to the great work for which he received a Nobel Prize in 1965: inventing the pictorial view of nature which he called “the space-time approach.” This work began in 1947 as a modest enterprise, to calculate accurately the fine details of the hydrogen atom for comparison with the findings of some new experiments that had been done at Columbia University. To do the calculation, Feynman invented a new
way of describing quantum processes, using pictorial diagrams instead of equations to represent interacting particles. The “Feynman diagrams” that he invented for a particular calculation caused a revolution in physics. The diagrams were not only a useful tool for calculation but a new way of understanding nature. Feynman’s basic idea was simple and general. If we want to calculate a quantum process, all we need to do is to draw stylized pictures of all the interactions that can happen, calculate a number corresponding to each picture by following some simple rules, and then add the numbers together. So a quantum process is just a bundle of pictures, each of them describing a possible way in which the process can happen.

Feynman’s diagrams gave us a simple visual representation of quantum processes not only for hydrogen atoms but for everything else in the universe. Within twenty years after they were invented, these diagrams became the working language of particle physicists all over the world. It is difficult now to imagine how we used to think about fields and particles before we had this language. A new book by the MIT historian David Kaiser,
Drawing Theories Apart: The Dispersion of Feynman Diagrams in Postwar Physics
,
⁴
gives a lively account of the spread of the diagrams, describing how they were transmitted around the world. The diagrams spread like a flu epidemic. Each new generation of young scientists became infected with the Feynman disease and then infected others with whom they came into personal contact. The Feynman epidemic lasted longer than a flu epidemic, because the incubation period was measured in years rather than in days. Many of the older scientists remained immune, but their influence waned as the new language became universal.

After Feynman’s work on the diagrams was done, a year went by before it was published. He was willing and eager to share his ideas in conversation with anyone who would listen, but he found the job of
writing a formal paper distasteful and postponed it as long as he could. His seminal paper, “Space-Time Approach to Quantum Electrodynamics,”
⁵
might never have been written if he had not gone to Pittsburgh to stay for a few days with his friends Bert and Mulaika Corben. While he was in the Corbens’ house, they urged him to sit down and write the paper, and he made all kinds of excuses to avoid doing it. Mulaika, who was a liberated woman with a forceful personality, decided that drastic measures were needed. She was one of the few people who could stand up to Feynman in a contest of wills. She locked him in his room and refused to let him out until the paper was finished. That is the story that Mulaika told me afterward. Like other Feynman stories, it may have been embellished in the telling, but to anyone who knew both Mulaika and Feynman it has the ring of truth.

People who knew Feynman as a friend and colleague were astonished when this collection of his letters appeared. We never thought of him as a letter writer. He was famous as a great scientist and a great communicator, but his way of communicating with the public was by talking rather than writing. He talked in a racy and informal style, and claimed to be incapable of writing grammatical English. His many books were not written by him but transcribed and edited by others from recordings of his talks. The technical books were records of his classroom lectures, and the popular books were records of his stories. He preferred to publish his scientific discoveries in lectures rather than in papers.