A bio-pic presents something of a puzzle for the thoughtful moviegoer who wants to sort out facts from the fictions that inevitably arise when compressing an entire life into two dramatically coherent and engaging hours. This is particularly the case when the film is about a historical figure as broadly accomplished and posthumously politicized as Alan Turing, who is the subject of “The Imitation Game,” an upcoming film based on Andrew Hodges’s excellent 1983 biography, “Alan Turing: The Enigma.” In the process of fashioning a film-ready version of Turing from the details of the real Turing’s life, the demands of truth are hardly up for a fair fight against the pressures of Hollywood.
Turing is viewed by many as the father of modern computer science, a status secured by his creation of the Turing Machine, an abstract model of the modern computer. He also made key contributions to the British effort, during the Second World War, to crack the German Army’s seemingly unbreakable Enigma code, an achievement that integrated mathematics, engineering, and a nascent effort in computer science, and which ultimately played a crucial role in shortening the war.
Great scientific achievements—even in the service of helping to win a war—don’t generally rate a movie treatment, but Turing’s personal life provided other narrative hooks. Turing was a gay man in England, where homosexual activity was criminalized until 1967. In 1952, he was convicted of “gross indecency” and sentenced to a probation that involved undergoing an extensive regimen of chemical castration, which that caused him to gain weight, become lethargic, and grow breasts. Two years later, at age forty-one, Turing was dead. Officials ruled that he had committed a Socrates-like suicide by eating an apple laced with cyanide.
“The Imitation Game” is made up of entwined personal and professional dramas, and the theme of imitation is, as the title suggests, the driving force of the film. For Turing (played by Benedict Cumberbatch), there is the imitation game practiced by any closeted gay man of the time. There is also an imitation game played by the British intelligence forces, who, having cracked the Enigma code, must imitate a clueless but believably lucky opponent and use the intercepted information judiciously so as not to give away their accomplishment—itself the product of a machine that imitates the actions of an extremely clever puzzle-solver. With this last imitation, “The Imitation Game” alludes to the Turing Test, in which a user having a conversation through a computer—something akin to a computer chat—tries to determine whether the correspondent on the other end is a person or a program. In an early formulation, the participant wasn’t trying to distinguish between human and machine, but between a man and a woman. This test was called “the imitation game.”
In the movie, Turing is obsessed with the creation of the code-cracking computer, not only to break Enigma but also because it is, to him, a first step in engineering a human brain and, with that, perhaps a soul. The latter motivation is amplified when Turing names the machine Christopher, after an adolescent object of affection—an invention of the movie that gives it a distracting and somewhat creepy resonance with “Frankenstein.” A biopic is not a documentary, and nobody likes a spoilsport who acts like it should be. But Turing’s appearance on the big screen does give us an opportunity to discuss his extraordinary scientific and mathematical legacy, on which the movie is built.
A fleshed-out version of the movie’s intellectual skeleton would reveal Turing’s other achievements, even if they present less cinematic narratives. Although the film focusses on Turing’s implementation of computational ideas, his early computing work was born of a decidedly non-applied problem, building on the great mathematician Kurt Gödel’s work toward understanding and codifying the power of formal reasoning (i.e., basic logic) to uncover and prove mathematical truths. Turing’s work in this area with his Princeton Ph.D. adviser, Alonzo Church, culminated in the Church-Turing Thesis, which addresses what kinds of numbers humans—or any machine that uses similar logic—can compute. Together, the thesis and the Turing Machine establish Turing as a founder of computability theory and theoretical computer science.
After the Second World War, Turing had hoped to lead the British effort to design a large digital computer, but his ambitious plans were not accepted. However, he continued to investigate the properties and possibilities of these modern computational engines. He was a pioneer in various areas of computational number theory, which have turned out to be important to recent efforts in modern digital cryptography. He also wrote early papers on cellular differentiation and speech encoding. One of his early mathematics papers explores the reliability of certain algorithms that would later be central to computations for things like the PageRank algorithm, on which Google’s search engine is based.
This is a sidewise connection to the subject of search, which makes an explicit appearance in Turing’s 1948 paper titled “Intelligent Machinery.” This pioneering and prescient work in artificial intelligence asks “whether it is possible for machinery to show intelligent behavior,” and confronts the challenges of “educating” a machine. In its simple mathematical models of networks of neurons, we find an anticipation of today’s work in neural networks and the larger area of machine learning, which is a part of robotics, data science, and other applications where computer-driven machinery is continually updating its decision processes based on new input. In the paper’s brief penultimate section, “Intelligence As An Emotional Concept,” Turing remarks judging intelligence is a largely subjective process. He proposes the game of trying to determine whether a hidden chess opponent is human or machine—the seed of a thought that later bloomed into the imitation game.
Toward the end of “Intelligent Machinery” Turing includes ruminations on search and thought. He writes, “Intellectual activity consists mainly of various kinds of search.” This is an oddly prophetic pronouncement—one that could be emblazoned on the walls of technology companies around the world today. Turing argues that the search process is central to epistemological and scientific discovery, and important in framing as well as pursuing mathematical, genetic, cultural, and intellectual problems. More precisely, perhaps he is outlining how his own mind works.
The searching mind can be tough to contain, which brings us back to the challenge of bringing full portrait of Turing to the screen. The tragedy of Turing’s life and death gives one set of guideposts for biographical exploration (and embellishment), but at the expense of examining some of his most important and lasting contributions to human history.
