Alan Turing was born June 23, 1912 in Paddington, London, the second child of Julius Mathison Turing and Ethel Sara Stoney.  His parents met while his father and his mother’s father were serving in Madras, India, as part of the Civil Service.  He and his brother were raised in other people’s homes while his parents continued their life in India.

A turning point in his life came when his best friend at Sherborne School, Christopher Marcom, died in 1930.  This led him to think about the nature of existence and whether or not it ends at death.

He went to King’s College of Cambridge in 1931, where he read books by von Neumann, Russell and Whitehead, Goedel, and so on.  He also became involved in the pacifist movement at Cambridge, as well as coming to terms with his homosexuality.  He received his degree in 1934, and stayed on for a fellowship in 1935.

The Turing Machine -- the first description of what would become the modern computer -- was introduced in a 1936 paper, after which he left for Princeton in the US.  There, he received his PhD in 1938, and returned to King’s College, living on his fellowship.

He began working with British Intelligence on breaking the famous Enigma Code by constructing code-breaking machines.  In 1944, he made his first mention of “building a brain.”

It should be noted that Turing was also an amateur cross-country runner, and just missed representing the UK in the 1948 Olympics!

In 1944, he became the deputy director  of the computing lab at Manchester University, where they were attempting to build the first true computer.  In 1950, he published a paper, "Computing Machinery and Intelligence," in Mind.  Turing saw the human brain as an "unorganized machine" that learned through experience.

Unfortunately, he was arrested and tried in 1952 -- for homosexuality!  He made no defense, but took an offer to stay out of jail if he would take estrogen injections to lower his supposedly overactive libido.  He lost security clearance because of his homosexuality as well.

He began working on pattern formation in biology -- what we would now call the mathematics of fractals -- and on quantum mechanics.  But on June 7, 1954, he committed suicide by ingesting cyanide -- making it look like an accident to spare his mother’s feelings.  He was 41.

Today, he is considered the father of Computer Science.  Let me let his biographer, Andrew Hodges, describe the famous Turing Machine:

His work introduced a concept of immense practical significance: the idea of the Universal Turing Machine. The concept of 'the Turing machine' is like that of 'the formula' or 'the equation'; there is an infinity of possible Turing machines, each corresponding to a different 'definite method' or algorithm. But imagine, as Turing did, each particular algorithm written out as a set of instructions in a standard form. Then the work of interpreting the instructions and carrying them out is itself a mechanical process, and so can itself be embodied in a particular Turing machine, namely the Universal Turing machine. A Universal Turing machine can be made do what any other particular Turing machine would do, by supplying it with the standard form describing that Turing machine. One machine, for all possible tasks.

It is hard now not to think of a Turing machine as a computer program, and the mechanical task of interpreting and obeying the program as what the computer itself does. Thus, the Universal Turing Machine embodies the essential principle of the computer: a single machine which can be turned to any well-defined task by being supplied with the appropriate program.

Additionally, the abstract Universal Turing Machine naturally exploits what was later seen as the 'stored program' concept essential to the modern computer: it embodies the crucial twentieth-century insight that symbols representing instructions are no different in kind from symbols representing numbers. But computers, in this modern sense, did not exist in 1936. Turing created these concepts out of his mathematical imagination. Only nine years later would electronic technology be tried and tested sufficiently to make it practical to transfer the logic of his ideas into actual engineering. In the meanwhile the idea lived only in his mind.

Quoted from Andrew Hodges’ “Alan Turing --- a short biography,” at https://books.byui.edu/-iCir

For much more on Turing, see the Turing Archive at https://books.byui.edu/-JwnE