---
title: Alan Turing
tags: [biography, theory, cryptography]
status: active
confidence: high
created: 2026-04-08
sources:
  - file: public-domain/turing-wikipedia-cc0.txt
    hash: placeholder
    size: 0
    ingested: 2026-04-08
aliases: []
---

# Alan Turing

Alan Mathison Turing (1912–1954) was an English mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist. He is widely considered to be the father of theoretical computer science and artificial intelligence.

## Turing Machine

In 1936, Turing published "On Computable Numbers, with an Application to the Entscheidungsproblem," introducing the concept of the **Turing machine** — an abstract model of computation that manipulates symbols on an infinite tape according to a set of rules. This model provided a rigorous definition of computation and remains the foundation of computer science theory.

## Wartime Contributions

During World War II, Turing worked at Bletchley Park and made decisive contributions to breaking German ciphers, including the Enigma machine. His Bombe electromechanical device, building on earlier Polish work, enabled the Allies to decrypt enormous volumes of enemy communications. Historians estimate this shortened the war by two to four years.

## Turing Test

In his 1950 paper "Computing Machinery and Intelligence," Turing proposed the imitation game — now known as the **Turing Test** — as a criterion for machine intelligence. A machine passes if an interrogator cannot reliably distinguish it from a human in a text conversation.

## Legacy

The [[von-neumann-architecture]] that underlies modern computers shares conceptual roots with Turing's stored-program ideas. Turing also influenced the development of [[programming-languages-overview]] by formalising what it means for a problem to be computable. The annual ACM Turing Award is named in his honour and is considered the "Nobel Prize of computing."

See also: [[internet-origins]] for later developments his theoretical work enabled.
