Alan Turing

In 1936, Turing published a paper that is now considered the founding document of computer science. He introduced the "Turing machine," a theoretical model that could simulate any algorithmic process. By proving that some problems are "undecidable"—meaning no machine could ever solve them—he established the mathematical boundaries of computation.

This work was remarkably visionary because it decoupled the concept of a computer from the hardware. While his contemporaries were building machines for specific tasks, Turing’s "Universal Machine" proved that a single device could perform any task if provided with the right program. This remains the fundamental logic of every smartphone and laptop today.

During the war, Turing led "Hut 8" at Bletchley Park, the unit responsible for breaking the German naval Enigma ciphers. He didn't just break codes manually; he engineered a solution. He developed the bomba, an electromechanical device that could scan through thousands of Enigma settings to find the key.

This work produced "Ultra" intelligence, which allowed the Allies to track U-boats in the Battle of the Atlantic. Historians estimate that his team's work shortened the war by at least two years, saving millions of lives. Because his work was protected by the Official Secrets Act, his pivotal role in the Allied victory remained unknown to the public for decades.

At age 16, Turing formed a deep intellectual and emotional bond with a schoolmate named Christopher Morcom. When Morcom died suddenly of tuberculosis in 1930, Turing was devastated. He coped by obsessing over how a human "spirit" could survive the death of the physical body.

This trauma drove Turing’s interest in the "mechanism" of the mind. He spent years writing to Morcom’s mother, exploring the idea that the brain is a machine that "holds" a spirit. This search for a bridge between the physical and the metaphysical eventually evolved into his pioneering work on Artificial Intelligence and the question of whether a machine could ever truly possess a mind.

In his later years, Turing pivoted from computers to biology. He was fascinated by how a simple embryo develops into a complex organism with stripes, spots, or limbs. In 1952, he published "The Chemical Basis of Morphogenesis," proposing that biological patterns emerge from the interaction of two diffusing chemicals.

His mathematical models predicted oscillating chemical reactions that wouldn't actually be observed in a laboratory until the 1960s. This work laid the groundwork for modern mathematical biology, suggesting that the "chaos" of life is actually governed by elegant, predictable mathematical rules.

Despite his wartime heroism, Turing was prosecuted in 1952 for "gross indecency" due to his homosexuality. To avoid prison, he submitted to "chemical castration"—hormone injections designed to suppress his libido. Two years later, he died of cyanide poisoning at age 41; while officially ruled a suicide, some believe it may have been an accidental lab mishap.

The "appalling way" he was treated eventually led to a massive shift in British law. In 2013, he received a posthumous royal pardon from Queen Elizabeth II. This paved the way for the 2017 "Alan Turing Law," which retroactively pardoned thousands of other men convicted under historical anti-homosexuality legislation.