Alan Turing: The Father of Theoretical Computer Science and Artificial Intelligence

Alan Turing, according to Winston Churchill, made the single greatest contribution to the Allied victory in World War II. Churchill’s colleagues agreed. Without Turing, one stated, “I and many people are convinced that we would have lost the war.” Turing’s design for a computing device that could decipher enemy messages, written in the Nazi’s “unbreakable” Enigma codes, gave the Allies detailed, timely, and continuous access to German military plans, orders, and movements. What the Allies learned shortened the European conflict by at least two years, and possibly more, saving hundreds of thousands of lives — on both sides of the conflict — from still more battles, bombings, and the death camps of the Final Solution.

Often considered to be the father of both modern computing and the study of artificial intelligence, Turing, born in England on June 23, 1912, simply was one of the most brilliant and original minds of the last hundred years. There were a few computing devices before he published his seminal paper “On Computable Numbers” in 1936. These devices included the abacus, Babbage’s difference engine, and Hollerith’s tabulating machine. None of them, however, could perform more than one computational task at a time.

Turing was the first to conceptualize a machine that could compute anything that is computable simply by altering or changing its software instead of reworking its hardware or wiring. He envisioned a “universal programmable computer,” now called a mainframe or a desktop computer, a laptop, tablet or smartphone. To understand his contribution, just imagine our world without these devices and everything their programming provides. The Internet, online commerce, blogging, GPS, instant messaging, Angry Birds, Grindr, Grand Theft Auto and so much more share the basic concept. No wonder so many of Turing’s peers consider him to be the father of theoretical computer science and modern computing.

After the war, Turing’s contributions to the template of the modern world continued. In 1946, he was the first to detail the design of a stored-program computer. Two years later, he invented the LU decomposition method, used today to solve matrix equations and linear equations. In 1952, he predicted oscillating chemical reactions, not observed until the 1960s. The same year, he published his pioneering concepts of artificial intelligence. He provided a simple method, now known as the Turing Test, to determine whether or not a machine was “intelligent.”

A break-in at his home, also in 1952, ended his remarkable career. Turing reported the crime to the police, telling them the burglar might be an acquaintance of a young man with whom he was having an affair. At a time when convictions for homosexuality meant long jail sentences, professional ruin, and social ostracism, it was a grievous mistake. Given the more scandalous and salacious prospect of prosecuting an upstanding academic for his sex life, the police lost all interest in pursuing a petty criminal. Instead, they arrested Turing for “gross indecency,” the same charge that sent Oscar Wilde to Reading Gaol in 1895.

During his trial, Turing pleaded guilty to multiple counts of indecent acts. His defense? He saw nothing wrong with loving another man. Wilde received a brutalizing jail sentence, but the court gave Turing a choice: prison or probation after consenting to be castrated. Naturally wishing to avoid imprisonment, he agreed to be sterilized through a series of estrogen injections intended to “beef up his masculine urges and suppress his homosexuality.”

Not surprisingly, the treatment ruined his health and his life, causing major damage to his nervous system. He suffered from waves of depression and despair. His security clearance was revoked, although the government never explained how foreign agents could blackmail a publicly known homosexual into giving them state secrets by threatening to reveal his homosexuality. Turing tried to continue his research, but instead entered “a slow, sad descent into grief and madness” until his death two years later on June 7, 1954, sixteen days before his 42nd birthday.

In 2009, fifty-seven years after castrating Turing for being a gay man, Her Britannic Majesty’s Government apologized for what it did to him. Prime Minister Gordon Brown acknowledged that Turing’s treatment “was of course utterly unfair,” but also excused it, stating he “was dealt with under the law of the time.” No apology was made to the more than 50,000 other men convicted of same-sex intimacy with a consenting adult or to those who were terrorized, harassed, and humiliated for being gay and whose lives were ruined simply because they could not be themselves.

After a high-profile campaign supported by tens of thousands of people who believed that a mere apology was not enough, Turing was pardoned in 2013 under the Royal Prerogative of Mercy. Since 1945, only three other people in England and Wales have received such exoneration, granted because they were shown to be “conclusively innocent” of their convicted offense. Turing was not. The British government, for the first time, waived this requirement because of the “exceptional nature of Alan Turing’s achievements.” From a legal perspective, Turing’s conviction still stands. Debate continues over how the conviction could be overturned, but there is no debate in our minds that Turing merits inclusion on the Rainbow Honor Walk. (Editor’s Note: Last week, a biology theory Turing formulated 60 years ago was validated by researchers from the University of Pittsburgh and Brandeis University. His remarkable accomplishments continue to grow and to influence modern science and numerous other fields.)

Bill Lipsky, Ph.D., author of “Gay and Lesbian San Francisco” (2006), is a member of the Rainbow Honor Walk board of directors.