MIT made the first move: in 1956, the university invited one of its most famous alumni, Claude Shannon, to spend a semester back in Cambridge as a visiting professor. Returning to his graduate school haunts had something of a revivifying effect on Claude, as well as Betty. For one thing, the city of Cambridge was a bustle of activity compared to the comparatively sleepy New Jersey suburbs. Betty remembered it as an approximation of their Manhattan years, when going out to lunch meant stepping into the urban whirl.
Working in academia, too, had its charms. “There is an active structure of university life that tends to overcome monotony and boredom,” wrote Shannon. “The new classes, the vacations, the various academic exercises add considerable variety to the life here.” Reading those impersonal lines, one might miss the implication that Shannon himself had grown bored.
The work of teaching turned out to be a surprisingly pleasant change. A note from Shannon to a Bell Labs colleague gives a window into his new life as a professor:
I am having a very enjoyable time here at MIT. The seminar is going very well but involves a good deal of work. I had at first hoped to have a rather cozy little group of about eight or ten advanced students, but the first day forty people showed up, including many faculty members from M.I.T., some from Harvard, a number of doctorate candidates, and quite a few engineers from Lincoln Laboratory. . . .
I am giving 2 one and a half hour sessions each week, and the response from the class is exceptionally good. They are almost all following it at 100 percent. I also made a mistake in a fit of generosity when I first came here of agreeing to give quite a number of talks at colloquia, etc., and now that the days are beginning to roll around, I find myself pretty pressed for time. The people here are very interested in information theory, and there is a good deal of work going on both by the faculty and by graduate students specializing in that field.
The lecture audiences were as sharp as he might have hoped. “From the questions raised in the discussion period, I have a pretty favorable impression of the people attending,” Shannon told another correspondent. “So far lecturing has not become a chore. In fact, I rather enjoy it, but I expect after a month or two, the novelty will wear off.” It was, at least at the time, intellectually invigorating, not least because teaching was something Shannon had never done in any formal sense.
It was an opportunity, too, to glide across mathematics: freed of most professional obligations, Shannon was able to use each talk to dive deeply into a topic of personal interest. The “Seminar on Information Theory” in the spring term of 1956 served as a carousel for Shannon’s passions. In a lecture titled “Reliable Machines from Unreliable Components,” Shannon presented the following challenge: “In case men’s lives depend upon the successful operation of a machine, it is difficult to decide on a satisfactorily low probability of failure, and in particular, it may not be adequate to have men’s fates depend upon the successful operation of single components as good as they may be.” What followed was an analysis of the error-correcting and fail-safe mechanisms that might resolve such a dilemma.
In another lecture, “The Portfolio Problem,” Shannon pondered the implications for information theory of illicit gambling:
The following analysis, due to John Kelly, was inspired by news reports of betting on whether or not the contestant on the TV program “$64,000 Question” would win. It seems that one enterprising gambler on the west coast, where the program broadcast is delayed three hours, was receiving tips by telephone before the local telecast took place. The question arose as to how well the gambler could do if the communication channel over which he received the tips was noisy.
And so on, like this. The lectures drew packed houses, including many members of the faculty who were busy with cutting-edge research of their own. Shannon and his musings, it seems, were draw enough to pull even the stars at MIT away from their work.
When an offer came for a full professorship and a permanent move to Massachusetts, it was hard to decline. If he accepted, Shannon would be named a Professor of Communication Sciences, and Professor of Mathematics, with permanent tenure, effective January 1, 1957, with a salary of $17,000 per year (about $143,000 in 2017). For all the pull of university life, Shannon struggled with his choice. Bell Labs had been his professional home for more than fifteen years. It had been the site of his most productive years as a researcher and thinker. It had afforded him unheard-of intellectual freedom and supported him in his most audacious pursuits. But Shannon was an outlier within the Labs culture; his antics were tolerated, but it was only a matter of time, Shannon suspected, before he would wear out his welcome. As he wrote to his supervisor, Hendrik Bode, “It always seemed to me that the freedom I took [at the Labs] was something of a special favor.”
Bell Labs, understandably, didn’t see it that way. They made a counteroffer, with a generous increase in Shannon’s salary. But, in the end, it wasn’t enough to sway him. His letter of resignation was a thoughtful weighing of industry against the academy. “There are certainly many points of superiority at Bell Labs,” Shannon writes. “Perhaps most important among these is the freedom from teaching and other duties with a consequent increase in time available for research.” Shannon acknowledged, too, that Bell Labs was offering him more money than MIT, “although the differential was not great in my case and, at any rate, I personally feel other issues are much more important.”
Bell Labs’ somewhat remote location in New Jersey was a complicating factor in its own right. “The essential seclusion and isolation of Bell Labs has both advantages and disadvantages. It eliminates a good many time-wasting visitors, but at the same time prevents many interesting contacts. Foreign visitors often spend a day at Bell Laboratories but spend six months at MIT. This gives opportunities for real interchange of ideas.” Bell Labs matched and even exceeded MIT in the caliber of its thinking, Shannon allowed. But in the end, “the general freedom in academic life is, in my view, one of its most important features. The long vacations are exceedingly attractive, as is also the general feeling of freedom in hours of work.” The two institutions are “roughly on par,” which meant there was no one decisive factor pulling Shannon to MIT—only a certain restlessness on Shannon’s part after spending more than a decade and a half in a single institution. “Having spent fifteen years at Bell Labs,” Shannon writes, “I felt myself getting a little stale and unproductive and a change of scene and of colleagues is very stimulating.”
Yet Shannon’s associations with Bell Labs were, in the end, too strong for the Labs to simply sever all ties. Shannon was kept on the payroll. As the Labs’ president, Bill Baker, later told Henry Pollak, “Shannon is one of the great people for which Bell Labs is known and going to be known. I will not take the chance of his ever being in poverty.” Pollak would later joke that this was in keeping with the Bell Labs spirit: “There were two kinds of researchers at Bell Labs: those who are being paid for what they used to do, and those who are being paid for what they were going to do. Nobody was paid for what they were doing now.” Perhaps in hopes of a return tour, Shannon’s office was kept for him, his nameplate still gracing the closed door.
After accepting the MIT offer, the Shannons left for Cambridge via California—a year-long detour for a fellowship at Stanford’s Center for Advanced Study in the Behavioral Sciences. Prestigious as the appointment was, the Shannons mainly treated it as an excuse to see the country. They made the leisurely drive through the West’s national parks to California, and back, in a VW bus. Like many an East Coast professor before and since, Shannon marveled at Palo Alto and was said to have wondered aloud about how faculty there were able to finish any work in such luscious surroundings. Not long after, he recommended the same itinerary to a colleague: “You are going to God’s country. All you need is a great white apron, a chef’s hat, and a barbecue, and you’ll be all set.”
Before setting off for the West, though, Claude and Betty purchased a house at 5 Cambridge Street in Winchester, Massachusetts, a bedroom community eight miles north of MIT. Once their California year was complete, they returned to their new home. In Winchester, the Shannons were close enough to campus for a quick commute but far enough away to live an essentially private life. They were also living in a piece of history—an especially appropriate one in light of Shannon’s background and interests.
Built in 1858, the house was constructed for Ellen Dwight, a great-granddaughter of a genius tinkerer of an earlier era, Thomas Jefferson. Originally seated on twelve acres, its design was inspired by Monticello. Encircled by “a three-sided verandah with segmental openings and chamfered posts,” the house was a stately three stories at the crest of a “broad expanse of lawn reaching down to the wooded shore of Upper Mystic Lake.” Toward the end of Shannon’s life, it was added to the National Register of Historic Places, with the citation noting its “panoramic views of the lake and distant hills,” as well as a sumptuous interior:
The focal point of the plan is the first floor octagonal room. It contains a parquet floor said to be laid in a pattern identical to a floor at Monticello. The elaborate yellow marble fireplace surround has acanthus leaf, waterleaf and egg and dart moldings. Ceilings of the first story are approximately twelve feet in height; the ceilings are embellished with ornate plaster moldings around the perimeter. Windows of the lower story are full-length six-light windows, which when raised, provide egress to the verandah. The right parlor/library has a green marble fireplace.
The house would figure prominently in Shannon’s public image. Nearly every story about him, from 1957 on, situated him at the house on the lake—usually in the two-story addition that the Shannons built as an all-purpose room for gadget storage and display, a space media profiles often dubbed the “toy room,” but which his daughter Peggy and her two older brothers simply called “Dad’s room.”
The Shannons gave their home a name: Entropy House. Claude’s status as a mathematical luminary would make it a pilgrimage site for students and colleagues, especially as his on-campus responsibilities dwindled toward nothing.
Even at MIT, Shannon bent his work around his hobbies and enthusiasms. “Although he continued to supervise students, he was not really a co-worker, in the normal sense of the term, as he always seemed to maintain a degree of distance from his fellow associates,” wrote one fellow faculty member. With no particular academic ambitions, Shannon felt little pressure to publish academic papers. He grew a beard, began running every day, and stepped up his tinkering.
What resulted were some of Shannon’s most creative and whimsical endeavors. There was the trumpet that shot fire out of its bell when played. The handmade unicycles, in every permutation: a unicycle with no seat; a unicycle with no pedals; a unicycle built for two. There was the eccentric unicycle: a unicycle with an off-center hub that caused the rider to move up and down while pedaling forward and added an extra degree of difficulty to Shannon’s juggling. (The eccentric unicycle was the first of its kind. Ingenious though it might have been, it caused Shannon’s assistant, Charlie Manning, to fear for his safety—and to applaud when he witnessed the first successful ride.) There was the chairlift that took surprised guests down from the house’s porch to the edge of the lake. A machine that solved Rubik’s cubes. Chess-playing machines. Handmade robots, big and small. Shannon’s mind, it seems, was finally free to bring its most outlandish ideas to mechanical life.
Looking back, Shannon summed it all up as happily pointless: “I’ve always pursued my interests without much regard to financial value or value to the world. I’ve spent lots of time on totally useless things.” Tellingly, he made no distinction between his interests in information and his interests in unicycles; they were all moves in the same game.
Robert Gallager, decades later, would offer a comment that captures what many leading minds at the time likely thought of Shannon’s private whimsies: “These were things that normal, outstanding scientists did not do!” Gallager was a Shannon disciple, and the remark was delivered with affection and only mock outrage, but it isn’t too hard to imagine Shannon’s more skeptical contemporaries wondering what the legend of Bell Labs could possibly have been thinking. His arrival at MIT, after all, carried with it great expectations. He had been awarded a named chair, tenure, and a position in two different departments, mathematics and engineering. “He was really lionized. He was going to be the luminary that led the electrical engineering department into the future of information theory,” said Trenchard More, a former Shannon student.
Initially, it seems, Shannon’s mere presence at MIT was powerful. It was a mark of distinction to have someone like him on the faculty, and he was useful in drawing energetic graduate students who might otherwise have gone elsewhere. Len Kleinrock, a graduate student of Shannon’s from that era, recalled the impact of Shannon’s arrival on his own decision making about graduate programs: “If I’m going to spend three or four years doing a PhD, I’m going to choose the best professor I can think of, and I want to do something with impact. The best professor, I knew, was Shannon.”
Kleinrock wasn’t the only one: graduate students in information theory were abuzz at the possibility of working with the inventor of their field. But the reality may have been somewhat less luminous. The few dissertation advisees he took on at MIT saw him infrequently. Asked to take on more students, he once responded, “I can’t be an advisor. I can’t give advice to anybody. I don’t feel the right to advise.” And it wasn’t just Shannon’s reticence: asking someone like Shannon for help induced anxiety in even the most capable. For Gallager, who began graduate study at MIT in the same year that Shannon joined the faculty, there was the small problem of asking a living legend to pencil him in:
I was in such awe of him that I could hardly bring myself to speak to him! . . . He had very few doctoral students, and I think part of the reason was that, if you were at MIT with a colossal figure like Shannon around, you had to have a pretty big ego to ask someone like Shannon to supervise you!
Kleinrock put it perhaps more succinctly: “I always felt honored and a bit awkward that he’d be willing to work with me.”
Somewhat inadvertently, Shannon played into this perception and kept himself at a remove from the normal comings and goings of academic life. He didn’t join academic committees, jockey for status within his department, or even show up to his office with any regularity. What interaction he did have with his fellow faculty members usually took the form of dropping by unannounced at their lectures. One professor, Hermann Haus, remembered a lecture of his that Shannon attended. “I was just so impressed,” Haus recalled, “he was very kind and asked leading questions. In fact, one of those questions led to an entire new chapter in a book I was writing.”
Shannon lectured as well, dressed in coat and tie, as was expected of all MIT professors in those days, and occasionally flicking a piece of chalk in the air with one hand while answering student questions (and, impressively, never dropping the chalk). Once he was on faculty full-time, the lectures, it seems, received mixed reviews. Some students found them engaging and found Shannon to be just as good as advertised. “His classes were like a delicious meal! You’d go there, and the stuff he was giving you, it was clean, it was intuitive. It was good mathematics and it had impact,” observed Kleinrock. For some, watching Shannon think out loud in a classroom setting would prove one of the defining moments of their academic lives.
Yet whatever challenges a genius might face explaining himself were evidently on full display in Shannon’s lectures. The professor may have been enjoying himself, but some in his audience struggled to follow his train of thought. Dave Forney, then a student in the orbit around Shannon, observed that the quality of his talks depended almost entirely on the substance of the problem he had chosen to focus on that day. “For some problems, he had good results. For others, he made no progress beyond formulating the problem,” said Forney, who added, “it was great for graduate students looking for a thesis topic.”
In a way, even students who were fond of his lectures understood that they were, for Shannon, less a chance to impart specific information than to think out loud, to gather together MIT’s finest and share some problem of personal interest. “He didn’t teach that many classes,” Kleinrock recalled. “I don’t think he enjoyed it that much. He did it well, but I think he wanted to get the word out to this cadre of PhD students. Once he had taught them, he was happy working with them but not to continue teaching in that way to every generation.” Or, as Gallager remembered:
He was not the sort of person who would give a class and say “this was the essence of such and such.” He would say, “Last night, I was looking at this and I came up with this interesting way of looking at it.” He’d say it with a sly grin, and he’d come back with this absolutely beautiful thing.
This, then, was “Professor Shannon”: too brilliant to be understood, or ignored. He was, by that point, more inspiration than instructor. Or, as one student put it, “We all revered Shannon like a god.”
There were a lucky few students who managed to find a place at the deity’s elbow. And for those who made it into Shannon’s confidence, there were trips to the Winchester house and a standing invitation to bring him interesting problems. Kleinrock described his first interaction with Shannon: “He said, ‘Why don’t you come to my house next Saturday and visit with me?’ and I said, ‘Terrific.’ You know, here I was, this lowly graduate student, I couldn’t believe he had invited me to his house! . . . I remember telling my colleagues, ‘I’m going to Shannon’s house!’ ”
Shannon became a whetstone for others’ ideas and intuitions. Rather than offer answers, he asked probing questions; instead of solutions, he gave approaches. As Larry Roberts, a graduate student of that time, remembered, “Shannon’s favorite thing to do was to listen to what you had to say and then just say, ‘What about . . .’ and then follow with an approach you hadn’t thought of. That’s how he gave his advice.” This was how Shannon preferred to teach: as a fellow traveler and problem solver, just as eager as his students to find a new route or a fresh approach to a standing puzzle.
Visits with Shannon generated their own folklore, and his suggestions during those sessions stayed with his students even decades after the fact. One anecdote, from Robert Gallager, captures both the power and subtlety of Shannon’s approach to the work of instruction:
I had what I thought was a really neat research idea, for a much better communication system than what other people were building, with all sorts of bells and whistles. I went in to talk to him about it and I explained the problems I was having trying to analyze it. And he looked at it, sort of puzzled, and said, “Well, do you really need this assumption?” And I said, well, I suppose we could look at the problem without that assumption. And we went on for a while. And then he said, again, “Do you need this other assumption?” And I saw immediately that that would simplify the problem, although it started looking a little impractical and a little like a toy problem. And he kept doing this, about five or six times. I don’t think he saw immediately that that’s how the problem should be solved; I think he was just groping his way along, except that he just had this instinct of which parts of the problem were fundamental and which were just details.
At a certain point, I was getting upset, because I saw this neat research problem of mine had become almost trivial. But at a certain point, with all these pieces stripped out, we both saw how to solve it. And then we gradually put all these little assumptions back in and then, suddenly, we saw the solution to the whole problem. And that was just the way he worked. He would find the simplest example of something and then he would somehow sort out why that worked and why that was the right way of looking at it.
Other visitors, though, found themselves occasionally beaten to the punch by a mind that had mapped much of the terrain they were still only beginning to explore. Irwin Jacobs, an MIT student of that era and later the founder of Qualcomm, recalled: “People would go in, discuss a new idea, and how they were approaching it—and then he’d go over to one of his filing cabinets and pull out some unpublished paper that covered the material very well!”
Unlike traditional mid-century husbands and fathers, Shannon spent many of his days around the house. Of her many memories of her father, that would prove a distinctive one for Shannon’s daughter, Peggy: “He did a lot of work at home so he would only go into the office to teach and to meet with graduate students, but if he didn’t have to be there, he didn’t spend much time at MIT. So my sense growing up was that he was around a lot. It was different from a lot of working people.” Entropy House became his office; students dropped by, seeking feedback on projects but just as often looking to see what the Sage of Winchester had cooked up at his in-home laboratory. Even more conventional professors and old Bell Labs hands would make the trek to Winchester, and Shannon would walk them from room to room, all the while showing off his collection of contraptions and oddities. Guests were impressed by his collection of books, his two-story invention-room-cum-mechanic-shop, and the stunning array of gizmos and gadgets in the house.
It wasn’t only Shannon’s constant presence in the house, or the collection of electromechanical ephemera, that set him apart from other fathers. The Shannons were peculiar in the way that only a family headed by two mathematical minds might be. For instance, when it came time to decide who would handle the dishes after dinner, the Shannons turned to a game of chance: they wound up a robotic mouse, set it in the middle of their dining room table, and waited for the mouse to drop over one of the edges—and thus select that evening’s dishwasher.
Then there were the spontaneous moments of math instruction. At a party hosted by the Shannons, young Peggy Shannon was in charge of the toothpicks. She was carrying a box of them on the house’s verandah—and then dropped it by accident, spilling its contents onto the porch. Her father, standing nearby, paused, took stock of the mess, and then said, “Did you know, you can calculate pi with that?” He was referring to Buffon’s Needle, a famous problem in geometric probability: it turns out that when you drop a series of needles (or toothpicks) on an evenly lined floor, the proportion of needles falling across a line can be used to estimate pi with surprising accuracy. Most important, Peggy remembered, her dad wasn’t angry with her for the mess.
The Shannon household coalesced around the parents’ passions: chess and music became family pastimes, and stock picking and tinkering were a part of everyday life. Shannon took his children to circus performances. Alice in Wonderland, the favorite of many a mathematician, was in the air; Shannon especially enjoyed quoting from “Jabberwocky.” When it came to challenging math assignments, Peggy was regularly pointed in her father’s direction, even though, as she admits, this was overkill; anyone in the household, including her two older brothers, could have helped. He was, by her account, a patient teacher, though he often went on tangents that betrayed his own inclinations. He complained about the educational fad of the “New Math” and would digress on concepts like imaginary numbers well past the point of helping his daughter finish her homework.
MIT, and its limited pressures on Shannon, also offered him the chance to step back from day-to-day work on information theory and observe the landscape of the still-coalescing digital world. Those years, said Thomas Kailath, who studied under Shannon, were something of “a golden age of information theory at MIT”—one in which Shannon played the role of godfather and network node, if no longer a central participant. Even if they had no direct contact with Shannon, a generation of new minds were brought into the field, with Shannon’s work piquing their curiosity. As Anthony Ephremides, a later information theorist, put it, “The intellectual content of his approach was so appealing that many people who had inclinations to go in different directions said, ‘Wow, I like this! This is a beautiful way of looking at this process about which I knew nothing, so let me find out more.’ ”
That more relaxed role might have seemed an indulgence, except that Shannon had, for all his humor and insouciance, been phenomenally productive by the time he left Bell Labs for MIT. Even with his aversion to writing things down, the famous attic stuffed with half-finished work, and countless hypotheses circulating in his mind—and even when one paper on the scale of his “Mathematical Theory of Communication” would have counted as a lifetime’s accomplishment—Shannon still managed to publish hundreds of pages’ worth of papers and memoranda, many of which opened new lines of inquiry in information theory. That he had also written seminal works in other fields—switching, cryptography, chess programming—and that he might have been a pathbreaking geneticist, had he cared to be, was extraordinary.
Yet Shannon had also come to accept that his own best days were behind him. “I believe that scientists get their best work done before they are fifty, or even earlier than that. I did most of my best work while I was young,” Shannon said. This belief in an implicit age cap on mathematical genius was hardly unique to Shannon. As the mathematician G. H. Hardy famously wrote, “no mathematician should ever allow himself to forget that mathematics, more than any other art or science, is a young man’s game.”
While there have been notable exceptions to that rule, Shannon was convinced that he would not be one of them. His Bell Labs colleague Henry Pollak recalls visiting Shannon at home in Winchester to bring him up to date on a new development in communications science. “I started telling him about it, and for a brief time he got quite enthused about this. And then he said, ‘Nuh-uh, I don’t want to think. I don’t want to think that much anymore.’ It was the beginning of the end in his case, I think. He just—he turned himself off.”
But if Shannon turned off the most rigorous part of his mind, he also freed himself to take a bird’s-eye view of the emerging Information Age that his work had made possible. A crucial legacy of that work was the redirection of his colleagues’ efforts. The old era had ended, one in which communications scientists were divided by medium, locked into fields of specialization whose gains did not shed any obvious light on one another.
“For everybody who built communication systems, before [Shannon], it was a matter of trying to find a way to send voice, trying to find a way to send data, like Morse code,” recalled Gallager. “The thing that Claude said is that you don’t have to worry about all those different things.” Now their worries had a far more productive outlet: the coding, storage, and transmission of bits. “Once all the engineers were doing that, they start making this enormously rapid progress, start finding better and better ways of digitizing things and of storing and of communicating these very simple objects called binary digits, instead of these very complicated things like voice waveforms. If you look at it that way, Shannon is really responsible for the digital revolution.”
And even though the revolution had begun to pass him by, Shannon’s lectures at MIT and his talks around the country became a survey of the world to come. At a talk at the University of Pennsylvania in 1959, for instance, he said,
I think that this present century in a sense will see a great upsurge and development of this whole information business . . . the business of collecting information and the business of transmitting it from one point to another, and perhaps most important of all, the business of processing it—using it to replace man at semi-rote operations at a factory . . . even the replacement of man in the things that we almost think of as creative, things like mathematics or translating languages.
If words like that seem self-evident and unremarkable to us today, it’s worth remembering that Shannon was speaking more than a quarter century before the birth of the World Wide Web, and at a time when virtually all computers were still room-sized. To talk about “the information business” then was to talk about a world that was still more fantasy than fact.
So while it’s a commonplace to say that Shannon’s best thinking was over by 1948, that criticism might lead us to overlook a rich body of work, one marked by a playfulness of mind that was Shannon’s lifelong calling card. Wish away the dilettante who spent the bulk of his later life on chess, machines, and juggling, and you’d also wish away the curious genius who invented information; it came, all of it, from the same place.