Who was Alan Turing and why should you care

This post will not give a full biography of Alan Turing (23 June 1912 – 7 June 1954). For more on Turing head to Wikipedia. I will be summarising what’s important to me.

For a full biography read the book Alan Turing: The Enigma or the YouTube vid below (27 min). The Imitation Game – the movie is highly recommended.

Introduction

Alan Turing, a name synonymous with the foundations of computer science and artificial intelligence, remains an iconic figure in both scientific and cultural spheres. Born on June 23, 1912, in London, Turing displayed an exceptional aptitude for mathematics and logic from a young age. His work at King’s College, Cambridge, led to the development of the Turing machine concept, a cornerstone of computational theory and the precursor to modern computing. Turing’s most notable contributions emerged during World War II, where his pioneering work in cryptanalysis, particularly in breaking the German Enigma code, was instrumental in the Allied war effort. Despite his monumental scientific achievements, Turing faced personal challenges and legal prosecution for his homosexuality, a reflection of the societal norms of his time. His untimely death in 1954 left a legacy that extends beyond his scientific genius, symbolising a pivotal moment in the struggle for LGBTQ+ rights. Today, Turing is celebrated not only as a father of computer science but also as a symbol of resilience and the ongoing pursuit of justice and equality. Turing IQ was estimated to be of 185 (0.01% of the population). Turing’s personal life was marked by tragedy. He was prosecuted for homosexual acts in 1952, which were criminal offences in the UK at the time. He was chemically castrated and died in 1954 from cyanide poisoning, which was ruled a suicide. Turing’s death and the preceding criminal conviction have been widely condemned. In 2009, the British government formally apologized for the treatment Turing received, and in 2013, he was posthumously pardoned by Queen Elizabeth II.

Early Life and Education of Alan Turing

Childhood and Family Background:

• Birth and Family: Alan Turing was born on June 23, 1912, in Maida Vale, London, to Julius Mathison Turing, a member of the Indian Civil Service, and Ethel Sara Turing, daughter of a railway engineer. Turing’s family background was one of scientific and mathematical inclination.
• Early Indications of Genius: Turing showed signs of high intelligence at a very young age, with a specific talent in mathematics and science. His abilities were evident despite some educational challenges, such as his struggles with traditional schooling methods.

Schooling:

• Sherborne School: Turing’s formal education began at Sherborne School, a prestigious independent school in Dorset. He joined in 1926, where he initially struggled due to the school’s emphasis on classical studies over science and mathematics.
• Academic Pursuits: Despite these challenges, Turing continued to focus on mathematics, teaching himself advanced topics. His natural aptitude for the subject became increasingly apparent, and he was eventually recognised for his talents by his teachers.

Higher Education:

• King’s College, Cambridge: Turing enrolled at King’s College, Cambridge, in 1931. Here, he studied mathematics and was awarded a first-class honours degree in 1934. His academic prowess was remarkable, and he was elected a fellow of King’s College in 1935, at the age of just 22.
• The Princeton Years: Turing furthered his studies at Princeton University in the United States from 1936 to 1938. Under the supervision of American mathematician Alonzo Church, Turing’s work at Princeton was integral to his development. He earned his Ph.D. with a dissertation on the central limit theorem in probability theory.

Early Academic Achievements:

• Ground-breaking Work in Computability: Turing’s time at Cambridge and Princeton was crucial in shaping his future contributions. It was during this period that he developed the concept of the Turing machine, which became a foundational model for the theory of computation and algorithms.

Influence of Early Education on Later Work:

• Formation of Theoretical Foundations: Turing’s early education, particularly his self-driven study of advanced mathematical concepts, laid the groundwork for his later revolutionary work in computation and artificial intelligence.
• Development of Logical Thinking: The rigorous mathematical training he received, combined with his natural inclination towards problem-solving and logical analysis, played a critical role in his contributions to codebreaking during World War II and his subsequent pioneering work in computer science.

Contribution to Computability Theory:

The Turing Machine Concept:

• Foundation of Modern Computing: In 1936, Alan Turing introduced the concept of the Turing machine in his paper “On Computable Numbers, with an Application to the Entscheidungsproblem.” This theoretical construct is a fundamental model of computation that can simulate any algorithm’s logic. It is the basis for understanding the limits of what can be computed and the design of modern computers.
• Universal Machine: Turing’s idea of a “universal machine” that could take a program as input and execute it was ground-breaking. This concept laid the groundwork for the modern programmable computer.

The Entscheidungsproblem and Computability:

• Addressing Hilbert’s Problem: Turing’s work was in response to David Hilbert’s Entscheidungsproblem, which asked whether a general algorithm could exist to determine the truth or falsity of any mathematical statement. Turing showed that no such universal algorithm could exist, a conclusion reached independently at around the same time by Alonzo Church, leading to the Church-Turing thesis.
• Church-Turing Thesis: The Church-Turing thesis posits that any function that can be computed algorithmically can be computed by a Turing machine. This thesis is a fundamental principle in computer science and establishes a framework for understanding computational processes and their limitations.

Impact on Computer Science and Mathematics:

• Foundation of Theoretical Computer Science: Turing’s work is the bedrock of theoretical computer science. It has influenced the development of complexity theory, algorithm design, and the understanding of artificial intelligence.
• Informing Modern Algorithms: Turing’s theoretical framework informs the development of algorithms in all areas of computer science, from cryptography to machine learning.

Legacy and Recognition:

• Enduring Influence: Turing’s contributions to computability theory continue to influence modern computing and the philosophical understanding of what it means to compute.
• Turing Award: In his honour, the Turing Award, often referred to as the “Nobel Prize of Computing,” is awarded annually by the Association for Computing Machinery (ACM) to individuals for significant contributions to the field of computer science.

Relevance to Modern Technology:

• Influence on Software Development: The principles laid out by Turing underpin much of modern software engineering and computational theory.
• Role in Advancements in AI: Turing’s conceptual groundwork has been pivotal in advancements in artificial intelligence, particularly in understanding the theoretical limits and capabilities of AI systems.

In essence, Alan Turing’s contribution to computability theory not only resolved a significant mathematical problem of his time but also established the theoretical foundations for the field of computer science. His conceptualisation of the Turing machine and the universal machine model has profoundly impacted the development of modern computers and continues to be a critical reference point in the ongoing evolution of computational technology and artificial intelligence.

World War II and Cryptanalysis

Alan Turing’s work during World War II in the field of cryptanalysis was of monumental importance. His innovative methods in breaking the Enigma code not only had a direct and significant impact on the outcome of the war but also established foundational principles in the field of cryptography that resonate to this day. The secrecy surrounding his work during his lifetime has since given way to widespread recognition of his critical contributions to the Allied war effort and the broader field of computer science.

Role at Bletchley Park:

• Recruitment and Codebreaking: During World War II, Alan Turing was recruited to join the Government Code and Cypher School at Bletchley Park, the British codebreaking centre. Here, he played a pivotal role in deciphering the coded messages of the Axis powers, particularly those encrypted with the German Enigma machine.
• Team Leadership: Turing led a team at Hut 8, the section responsible for German naval cryptanalysis. He was instrumental in developing techniques for faster decryption of Enigma messages, which was crucial for the Allied war effort.

Development of Cryptanalytic Techniques:

• The Bombe Machine: Turing’s most significant contribution was the development of the Bombe, an electromechanical machine designed to expedite the breaking of Enigma-encrypted messages. This device significantly enhanced the speed and efficiency of codebreaking operations at Bletchley Park.
• Algorithmic Approach: Turing applied his mathematical and logical expertise to develop algorithms for codebreaking. His systematic approach transformed the art of cryptanalysis into a science, laying the groundwork for modern cryptographic techniques.

Impact on the War:

• Shortening the War: The work done by Turing and his team at Bletchley Park is widely credited with shortening the duration of the war in Europe. By some estimates, their efforts may have shortened the war by as many as two to four years, saving countless lives.
• Strategic Advantages: The intelligence gathered through Turing’s cryptanalysis, codenamed “Ultra,” provided the Allies with significant strategic advantages. It was instrumental in several key Allied victories, including the Battle of the Atlantic.

Secrecy and Post-War Recognition:

• Highly Classified Work: The work at Bletchley Park remained a closely guarded secret for many years after the war, with its full significance only becoming widely known in the 1970s.
• Posthumous Recognition: Turing’s contributions to the war effort and cryptanalysis were not fully acknowledged during his lifetime due to the classified nature of the work. However, he has been posthumously recognised as one of the most important figures in the Allied victory in World War II.

Legacy in Cryptography:

• Foundational Work in Modern Cryptography: Turing’s work during World War II laid the foundation for modern cryptography. His approaches and methodologies continue to influence the field.
• Inspiration for Future Cryptanalysts: Turing’s legacy in cryptanalysis extends beyond his wartime achievements, inspiring generations of cryptanalysts and security experts.