The story of Alan Turing

Alan Turing stands at the crossroads of genius and tragedy — a man whose abstract thoughts reshaped the concrete world. He deciphered the secrets of machines, of numbers, even of war — yet remained a mystery to the very society he helped protect. Today, we look not just at what he achieved, but at who he was — and what was lost when the world failed to see his worth.

Before the Enigma

Early life

Alan Mathison Turing was born in Warrington Lodge in Paddington, London on 23 June 1912.

His father, Julius Mathison Turing, was a government official of the ICS (Indian Civil Service), and his mother, Ethel Sara Stoney, became a housewife after her marriage. Alan Turing also had an elder brother, John Turing.

Due to their father's work in India, Alan and John seldom saw their parents until 1926, when Julius Turing resigned from his position in the Madras Presidency government. In 1922, Alan Turing was sent to a preparatory boarding school, Hazelhurst, in Sussex. During this time, Alan Turing developed a deep interest for nature and science. He watched the daisies grow, developed an interest in chemistry, and also enjoyed the book “Natural Wonders Every Child Should Know.”

In 1926, fourteen-year-old Alan started learning at Sherborne School, Dorset, in southwest England.

He got very bad reports in English and Latin, but a little bit better in math and science. In 1927, Alan was capable of solving advanced problems without having studied even elementary calculus. In 1928, he encountered and understood Albert Einstein’s work. He also managed to deduce Einstein’s questioning of Newton’s laws of motion.

Christopher Morcom

That same year, Alan Turing met Christopher Morcom in his science classes—a brilliant student who shared his deep enthusiasm for science. They quickly became close friends, and Alan was in love with Christopher, but it was unrequited.

In 1929, Christopher won a scholarship to Trinity College, and Alan Turing won a scholarship to King’s College in 1931. Tragically, on 13 February 1930, Christopher Morcom passed away because of tuberculosis at the age of 18. Christopher’s death had a profound and lasting impact on Alan Turing. Christopher was not only Alan’s first close friend but also his first love — a loss that left a lasting emotional wound. His departure left Alan scarred—a quiet, enduring pain that shadowed him for the rest of his life. In a letter to his mother, Alan wrote, “I feel sure that I shall meet Morcom again somewhere & that there will be some work for us to do together, as I believed there was for us to do here.”

After his death, Alan Turing believed in the survival of the spirit after death. In 1932, when visiting the Morcom family at their home (the Clock House), Alan wrote “Nature of Spirit”, an essay about his belief in spirits after death.

Academic formation

From February 1931 to November 1934, Turing was an undergraduate student at King’s College, Cambridge, studying mathematics. He was awarded first-class honors in mathematics there.

In 1934, Alan wrote his dissertation titled “On the Gaussian Error Function,” in which he proved a version of the central limit theorem.

By the spring of 1935, Turing had started his master’s course (Part II) at Cambridge, and he completed it in 1937. Later in 1935, Turing was elected a Fellow of King’s College. On 28 May 1936, Turing finished and submitted his seminal paper titled “On Computable Numbers, with an Application to the Entscheidungsproblem” which is also called “Turing’s proof.”

In the article, Alan Turing introduced the concept of the “Turing machine”, a theoretical model for algorithmic computation. He also proposed the idea of a Universal Turing Machine, capable of simulating any other computing machine.

That’s the foundation of modern computing.

He also proved that the Halting Problem is undecidable, which is the beginning of modern computational theory.

From 1936 to 1938, Alan studied under Alonzo Church, one of the foremost logicians of the 20th century.

In June 1938, he obtained his PhD from Princeton University.

If you are interested in any of these articles, I'll put them all in the description.

Achievements

Durring the War

During the Second World War, Alan Turing worked at Hut 8, a section of the Government Code and Cypher School (GC&CS) at Bletchley Park. He played a pivotal role in breaking German ciphers. And his contributions laid the foundation for his legendary status, as historian Asa Briggs stated: “You needed exceptional talent, you needed genius at Bletchley, and Turing’s was that genius".

From September 1938, he collaborated with Gordon Welchman, co-developer of the Bombe.

Then, they had a meeting in July 1939 near Warsaw, where the Polish Cipher Bureau shared details of the Enigma machine’s rotor wiring and decryption techniques. After that, they developed a more comprehensive solution. Their approach focused on fixing the vulnerable indicator system of Polish encryption, which the Germans had modified in May 1940. Turing created a more adaptable method using crib-based decryption and designed the functional specifications for the bombe, an improvement over the Polish Bomba.

This machine is designed to replace the traditional and inefficient method of breaking codes by hand, which is not effective for quickly deciphering messages. While the German Enigma machine could change its settings every 24 hours, resulting in 103 sextillion possible combinations each day, the Bombe was able to determine the locations of the Naval Enigma faster than ever, overcoming the limitations of existing manual methods.

In detail, Alan Turing designed this machine with multiple drums that represent Enigma rotors, similar to having several Enigma machines connected together, which allows for quick checking of potential settings.

He also wrote two papers discussing mathematical approaches, titled The Applications of Probability to Cryptography and Paper on Statistics of Repetitions.

Besides him, Gordon Welchman, co-developer of the Bombe, also made a major contribution by developing the "diagonal board" technique. It helped the Bombe automate its process more effectively by using a system of interconnected circuits that exploited the reciprocal nature of the Enigma's plugboard settings.

By accelerating the process of breaking the day’s Enigma settings, Turing’s invention allowed staff to decode messages quickly and pass on vital intelligence for immediate action. Intelligence gathered before the Battle of El Alamein in 1942 contributed significantly to the victory of this Egyptian campaign, which proved to be a turning point in the North African theater of World War II. Additionally, the use of Bombe machines in cryptanalysis had a considerable impact on various land, sea, and air campaigns. For instance, the German U-boat was employed by Germany to target and destroy Allied ships en route to the UK, which were essential for supplying resources to sustain the war effort. By utilizing the Bombe, the UK was able to easily locate German submarines, allowing them to defend against and attack these threats.

Turing's invention represented the first mass production of a specialized cryptanalytic machine. This innovation marked the beginning of the industrialization of codebreaking, and the intelligence it provided was crucial to the Allies' success in World War II. These machines played a significant role in the operation at Bletchley Park. There is no doubt that Turing was a hero in the UK; he saved the country from collapse and countless lives.

Jack Good, a colleague of Turing, remarked on Turing's unique qualities while working with him. Turing was known for his eccentricity at Bletchley Park, where he was nicknamed "Prof.":

"In the first week of June each year, he would get a bad attack of hay fever, and he would cycle to the office wearing a service gas mask to keep the pollen off. His bicycle had a fault: the chain would come off at regular intervals. Instead of having it mended, he would count the number of times the pedals went around and would get off the bicycle in time to adjust the chain by hand. Another of his eccentricities is that he chained his mug to the radiator pipes to prevent it from being stolen."

Peter Hilton also shared his experience working with Turing in Hut 8 in his "Reminiscences of Bletchley Park" from A Century of Mathematics:

... Alan Turing was such a genius, and those, like myself, who had the astonishing and unexpected opportunity, created by the strange exigencies of the Second World War, to be able to count Turing as a colleague and friend will never forget that experience, nor can we ever lose its immense benefit to us.

After the War

Automated Computing Engine (ACE)

In 1945, Alan Turing introduced a visionary idea: that computers should not be limited to number-crunching but should serve as universal machines capable of handling a wide range of symbolic tasks—such as mathematics, logic, chess, and data processing.

His design for the Automatic Computing Engine (ACE) was taken up by the National Physical Laboratory (NPL) in Teddington. However, the project quickly ran into trouble. The technology of the time couldn’t meet his storage requirement of 6,000 bytes, and the engineers from wartime codebreaking teams were no longer available to begin development swiftly.

Although the NPL issued press releases in 1946 celebrating the design as a major British innovation, nothing was built in 1947 or 1948. Bureaucratic delays and Turing’s resignation in 1948 meant that many of his early ideas—including one of the first attempts at a programming language—were lost.

Turing’s inability to publicize his wartime achievements, combined with his quiet nature and a tendency to move quickly on to new ideas, also meant his reputation suffered. Had he published more on practical computing, he might have received greater recognition.

Ironically, after his departure, new leadership at the NPL allowed the project to move forward. In 1950, the Pilot ACE—a smaller version of Turing’s original design—was finally completed, proving the strength of his original vision.

Although the complete version of Turing's original ACE was never built, his concept has had a significant influence on the modern computers we use daily.

Turring test

Turing's idea all came from one question that humans are still struggling with even today: Could a computer think?

This question has sparked a lot of debate over the years. People often fear the possibility that one day, computers might become so intelligent that they take over the world. But to be clear, Turing’s idea wasn’t about domination or replacing humans. He was simply curious—could a machine, which has no life or emotions, think in the way humans do?

To explore this, Turing introduced what is now known as the Turing Test.

The test is based on a simple game involving three participants: a human judge, another human, and a machine. All three communicate through text, so the judge doesn’t know who is who. The goal of the machine is to convince the judge that it is the human. If the judge cannot reliably tell which is which, then the machine is said to have passed the test.

This test doesn't prove that the machine actually "thinks" like a human, but it does challenge the idea that thinking must be linked to being human. It shifts the question from “Can machines think?” to “Can machines act like they think?”

Some people claim that certain AIs have already passed the Turing Test. For example, in 2014, a chatbot called Eugene Goostman was said to have passed it by pretending to be a 13-year-old boy from Ukraine. However, this result was controversial.

Many experts argued that the test was too short, and that Eugene’s success relied more on tricks and confusion than real intelligence. By pretending to be a young, non-native speaker, the bot was allowed to make strange or unclear replies without raising suspicion.

In reality, most AI systems today are still very far from true human-like thinking. They can generate impressive answers, but they don’t understand the world like humans do. So while some chatbots may seem smart, they haven’t truly passed the test in the deep, original sense that Turing imagined.

Tragedy

To begin with, I think we should look back at the reason for Alan Turing’s death. Labouchere Amendment was section 11 of the Criminal Law Amendments Act 1885.

This absurd law has resulted in many people being convicted and punished for homosexual acts.

In 1951, while walking in Manchester, Alan Turing met Arnold Murray, a 19-year-old unemployed man. They began a personal relationship—a connection between two individuals. However, after Turing’s house was robbed, he reported the crime to the police. During questioning, he admitted to his relationship with Murray. That act of honesty sealed his fate.

At that time, homosexuality was still illegal in the United Kingdom. Instead of being treated with gratitude for his wartime achievements, Turing was arrested and charged with “gross indecency” under a law from 1885. Rather than stand trial, Turing followed legal advice and pled guilty. The court offered him a choice: prison or probation with mandatory hormone treatment—essentially, chemical castration.

He chose the treatment in the hope of preserving his freedom. However, the cost was enormous. For a year, Turing underwent regular injections of synthetic estrogen—a drug that weakened his body, eliminated his libido, and caused breast development. Although his sharp mind remained intact, the spark in him began to dim. He became isolated, humiliated, and alienated from the life he once had.

The punishment didn’t end there. The government stripped him of his security clearance, effectively ending his cryptographic work. During the Cold War era, being gay was viewed as a national security risk. The brilliant mind that had outwitted Nazi machines was now seen as a danger. Turing, once a trusted guardian of national secrets, became a whisper in academic circles.

Despite everything, he tried to carry on. He continued his research, consulted a psychiatrist, and even found temporary happiness abroad. But the emotional scars ran deep. In June 1954, just two years after his conviction, Turing was found dead in his home. He had consumed cyanide, and a half-eaten apple lay beside his bed.

The official verdict was suicide. Some believe he laced the apple with poison, drawing a parallel to the death scene from Snow White, his favorite story. Others think it may have been accidental—perhaps from cyanide fumes in his home laboratory. There was no note, no warning—just a quiet end to a life once filled with brilliance.

Turing's mother never believed that he took his own life, and scholars continue to debate the truth. Regardless of how he died, one fact remains: Alan Turing was broken not by failure, but by injustice. A war hero was punished for love. A pioneer of modern computing was brought low not by enemies, but by prejudice.

It took decades for the world to acknowledge the full extent of this tragedy. In 2009, the British government formally apologized, and in 2013, the Queen granted him a posthumous pardon. However, these gestures came far too late.

Alan Turing should have been honored in life, not just in memory. He gave humanity a future, while society repaid him with silence, shame, and sorrow.

Final thoughts

Recognition and apologies

In the past, the UK caused immense tragedy for Alan Turing, destroying the life of one of the greatest geniuses simply because of who he was. However, today, they have taken many steps to make amends for their past mistakes. An official apology for the treatment of Alan Turing was formally made by UK Prime Minister Gordon Brown in 2009, representing the government

In 2013, Queen Elizabeth II granted a royal pardon to Alan Turing.

In 2017, the UK passed legislation informally known as "Turing Law" which extended justice beyond Turing himself. “Turing Law” is Section 166 of the Policing and Crime Act 2017, which pardons men who were convicted under the Labouchere Amendment.

In 2021, Alan Turing was chosen to appear on the new £50 banknote. The note features not only his portrait, but also mathematical formulas from his groundbreaking work in computing.

There’s even an institute named after him - the Alan Turing Institute. It’s the UK’s national institute for data science and artificial intelligence, established in 2015.

There’re also two statues of Alan Turing, one in Sackville Garden and one in Bletchley Park.

A legacy

Alan Mathison Turing gave the world so much — a mind that shaped the course of war, the birth of computer science, and a future he would never live to see. His brilliance was undeniable. His contributions, immeasurable. And yet, society turned its back on him. Not because of what he did, but because of who he was. A man who saved millions of lives, only to be treated by silence, isolation and injustice.

His story is a tragedy — but it is also a legacy.

Today is June 23rd — Alan Turing’s birthday. It’s also the month he died. And it’s Pride Month. June, in all its weight and meaning, now carries more than just history. It carries memory. It carries responsibility. It carries names like his.

It’s time to look back, to remember people like Alan Turing - the ones who built the foundation of our world, but were denied by society. Pride Month is often seen as a celebration of freedom, personal identity, and love. But it is also a tribute. Not just for those who live openly today, but for those who never could. To remember Alan Turing is to remind ourselves that brilliance should never be punished — and that love, in any form, should never be a crime.

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