Alan Turing: The Enigma

I finished reading Andrew Hodges’ book Alan Turing: The Engima, otherwise known as the definitive biography of mathematician, computer scientist, and code breaker Alan Turing. I was inspired to read the book in part because I’ve been reading lots of AI-related books this year¹ and in just about every one of those books, Alan Turing is mention in some form. In addition, I saw the film The Imitation Game, and indeed this is the book that inspired it. I bought the 2014 edition of the book — with The Imitation Game cover — during a recent visit to the National Cryptology Museum.

The author is Andrew Hodges, who at that time was a mathematics instructor at the University of Oxford (he’s now retired). He maintains a website where he commemorates Alan Turing’s life and achievements. I encourage the interested reader to check it out. Hodges has the qualifications to write about the book, being deeply versed in mathematics. He also appears to be gay himself.²

After reading the book, my immediate thoughts relating to the positive aspects of the books are:

• The book is organized chronologically and the eight chapters are indicated with date ranges. Thus, for a biography of this size, it is relatively straightforward to piece together a mental timeline of Alan Turing’s life.

• The book is detailed. Like, wow. The edition I have is 680 pages, not counting the endnotes at the back of the book which command an extra 30 or so pages. Since I read almost every word of this book (I skipped a few endnotes), and because I tried to stay alert when reading this book, I felt like I got a clear picture of Turing’s life, along with what life must have been like during the World War II-era.

• The book contains quotes and writings from Turing that show just how far ahead of his time he was. For instance, even today people are still utilizing concepts from his famous 1936 paper On Computable Numbers, with an Application to the Entscheidungsproblem and his 1950 paper Computing Machinery and Intelligence. The former introduced Turing Machines, the latter introduced the famous Turing Test. Fortunately, I don’t think there was much exaggeration of Turing’s accomplishments, unlike the The Imitation Game. When I was reading his quotes, I often had to remind myself that “this is the 1940s or 1950s ….”

• The book showcases the struggles of being gay, particularly during a time when homosexual activity was a crime. The book actually doesn’t seem to cover some of his struggles in the early 1950s as much as I thought it would be, but it was probably difficult to find sufficient references for this aspect of his life. At the very least, readers today should appreciate how much our attitude towards homosexuality has improved.

That’s not to say there weren’t a few downsides. Here are some I thought of:

• Related to what I mentioned earlier, it is long. It too me a month to finish, and the writing is in “1983-style” which makes it more difficult for me to understand. (By contrast, I read both of Richard Dawkins’ recent autobiographies, which combine to be roughly the same length as Hodges’ book, and Dawkins’ books were much easier to read.) Now, I find Turing’s life very interesting so this is more of a “neutral” factor to me, but I can see why the casual reader might be dissuaded from reading this book.

• Much of the material is technical even to me. I understand the basics of Turing Machines but certainly not how the early computers were built. The hardest parts of the book to read are probably in chapters six and seven (out of eight total). I kept asking to myself “what’s a cathode ray”?

To conclude, the book is an extremely detailed overview of Turing’s life which at times may be technically challenging to read.

I wonder what Alan Turing would think about AI today. The widely-used AI undergraduate textbook by Stuart Russell and Peter Norvig concludes with the follow prescient quote by Turing:

We can only see a short distance ahead, but we can see plenty there that needs to be done.

Earlier scientists have an advantage in setting their legacy in their fields since it’s easier to make landmark contributions. I view Charles Darwin, for instance, as the greatest biologist who has ever lived, and no matter how skilled today’s biologists are, I believe none will ever be able to surpass Darwin’s impact. The same goes today for Alan Turing, who (possibly along with John von Neumann) is one of the two preeminent computer scientists who has ever lived.

Despite all the talent that’s out there in computer science, I don’t think any one individual can possibly surpass Turing’s legacy on computer science and artificial intelligence.