## Review: A Mind at Play: How Claude Shannon Invented the Information Age by Jimmy Soni and Rob Goodman

I am somewhat embarrassed to say that, until now, I never knew all that much about Claude Shannon personally. I, of course, knew that he ostensibly “invented” information theory and I’d read sections of some of his more important work. But aside from routinely using Shannon entropy in calculations, he never much crossed my mind. So I was more than a little surprised to discover that, until now, no one had ever published a biography of Shannon. There were a few books that discussed Shannon in the broader context of the history of information theory, but none that focused solely on him. Jimmy Soni and Rob Goodman’s biography, *A Mind at Play: How Claude Shannon Invented the Information Age* (Simon & Schuster, 2017, $27.00, list price) thus fills a much-needed gap in the history of science, technology, and culture.

I have to admit that the book started off a bit rocky. Early on the authors spent a little too much time quoting Walter Isaacson and James Gleick (who have both written books on the history of information theory) and not enough time checking some simple facts. For instance, in describing the home-built telegraph on Shannon’s childhood farm in Gaylord, Michigan, they describe communication on the system as taking place at “lightspeed”. While this is a common mistake of the general public (though one that continually perplexes me), one would think that authors digging deeply into the history of a technology would understand it a bit better. At times they also try just a bit too hard to turn a memorable phrase (“A digital watch is nothing like the sun; an analog watch is the memory of a shadow’s circuit around a dial.”) That said, the book did noticeably improve, and I soon found myself engrossed.

Shannon was a remarkable man. Though he is known for information theory, he made seminal contributions to a wide variety of fields including what was perhaps the first mathematical analysis of the topic. Early on in his career, in a meeting with Hermann Weyl at the Institute for Advanced Study in Princeton, where Shannon would spend a year on a fellowship, he a few rather prescient comments. As Soni and Goodman write,

What if the mathematical model for a message sent over telephone or telegraph wires had something in common with the models for the motion of elementary particles? What if the content of any message and path of any particle could be described not as mechanical motions, or as randomized nonsense, but as random-

lookingprocesses that obeyed laws of probability—what physicists called “stochastic” processes? Think of the “fluctuations in the price of stocks, the ‘random walk’ of a drunk in a sidewalk”—think, for that matter, of a clarinet solo—happenings that were less than fixed by more than chance: maybe “intelligence” and electrons were alike in that way, taking haphazard walks within probability’s bounds. That got Weyl’s attention.

Truth be told, I don’t know who first came up with the idea of a quantum walk but this exchange with Weyl in 1940 seems to come tantalizingly close. Unfortunately, at this point, Soni and Goodman immediately jump to discussing Shannon’s interactions with Einstein. That highlights my only other complaint about the book: it’s a little too “breezy.” More than once I was disappointed that there wasn’t just a bit more depth.

That said, I do think the authors did an admirable job capturing Shannon as a person and, as the book progressed, they included more material culled from interviews with Shannon’s family. In particular, I think they did a good job capturing that grey area between engineering and pure math and science. That seems to have been the area Shannon inhabited. He was a brilliant mathematician who could think in highly abstract ways and yet he was also an inveterate tinkerer who could build amazingly useful devices (and not-so-useful devices: he once built a flame-throwing trumpet) with his own hands in his basement workshop. Sadly, today’s society has little use for this sort of person. It’s a testament to the values of those times that Shannon spent a good portion of his career at the phone company. As the authors note

By the time Shannon joined Bell Labs, the curious mix of techniques, talent, culture, and scale had turned the modest R&D wing of the phone company into a powerhouse of discovery. It was an institution that churned out inventions and ideas at an unheard-of rate and of unimaginable variety. In [Jon] Gertner’s words, “to consider what occurred at Bell Labs … is to consider the possibilities of what large human organizations can accomplish.”

At one time robust and vibrant R&D departments that valued knowledge for its own sake were more common. In addition to AT&T and Western Electric, who jointly ran Bell Labs, GE, Westinghouse, IBM, Xerox, and others had large R&D arms that routinely made ground-breaking discoveries, many of which won Nobel Prizes. Eight Nobel Prizes have been awarded for work performed at Bell Labs alone. While there certainly appears to be a reasonable investment in R&D at places such as Microsoft, Google, and others, one wonders if they have the freedom to do what was done at places like Bell Labs. But that’s a topic for another post.

In short, I found Soni and Goodman’s biography of Claude Shannon to be very good. It certainly had its rough spots and I had some quibbles, particularly near the beginning, but the majority of the book was engrossing in the way any good biography should be. It is well worth a read and Claude Shannon, with his flame-throwing trumpet and unusual juggling experiments, is a worthy subject.

As a final note, if you ever find yourself in Cambridge, Massachusetts, look for Shannon’s grave in Mount Auburn Cemetery and be sure to check the back of the headstone. Hidden from view by a bush is an inscription of his famous entropy formula. It is well-known in the physics community that Ludwig Boltzmann’s headstone at the Vienna Zentralfriedhof has his entropy formula carved on the front. It seems very much in character that Shannon’s would be carved on the back of his own.