26 Jun 2012

Decoding the legacy of Alan Turing


  • Alan Turing. Photo: King's College, Cambridge Digital Archives
    Alan Turing. Photo: King's College, Cambridge Digital Archives 
  • Alan Turing with contemporaries at King's College, Cambridge. Photo: King's College, Cambridge Digital Archives
    Alan Turing with contemporaries at King's College, Cambridge. Photo: King's College, Cambridge Digital Archives
The birth centenary of the legendary mathematical and computing genius was on June 23
Every now and then, random computer and web applications ask us to prove that we are indeed human. This popular and ubiquitous security test, widely known as Captcha, requires us to enter characters that we are shown to convince the system that we’re not code. Technologists know this as a reverse Turing test.
Short for ‘Completely Automated Public Turing test to tell Computers and Humans Apart’, Captcha is the converse of the Turing test, devised by legendary mathematical and computing genius Alan M. Turing.

Turing’s theory

Turing’s theory in the Thirties, long before computers existed as we know it, was that if a human was to interact with a machine, and if he was convinced that the machine’s response was that of a human’s, then the computing system would have passed the Turing test.
On Saturday, as the world celebrates the birth centenary of this legendary genius, one wonders if the world of technology and logic would have been the same without his groundbreaking contributions.
His life, packed with creative and scientific breakthroughs, met with a tragic end at the age of 41. To merely call him the ‘Father of theoretical computer science’ is to dismiss him with an easy cliche of a tribute.


Turing’s most well-known and celebrated achievement, perhaps the one easiest understood, was the work he did with Britain’s codebreaking centre when he cracked German code ‘Enigma’ during World War II. His contribution there was significant for the electromechanical crypt-analysis machine he devised, the Bombe, which helped the Allies listen to German secrets.

Tragic end

However, his contribution to his country, and towards the understanding of computer science and technology, did not stop his conviction in 1952. He was convicted for homosexuality, and put through chemical castration (treatment with female hormones) before he died of cyanide poisoning, widely believed to have been a suicide.
This tragic end to a remarkable life, one that is remembered not only for his contributions to technology as we know it today, but also for the philosophical pursuit of understanding the human mind, was acknowledged and recognised 56 long years later, when British Prime Minister Gordon Brown made a formal public apology for the way the British government treated him after the war.

Years of campaigning

The unequivocal apology was the culmination of intense campaigning by scientists, technologists, academics and leading public figures.
Though it took over five decades for the government to officially acknowledge both his genius and his contribution to the outcome of World War II, the scientific community had for decades spent time and effort to decode his seminal work, which touches upon a range of mathematical and computational fields from algorithms and cryptology to artificial intelligence and biological and life sciences.
As early as in the Sixties, the scientific community instituted an award, considered the highest distinction in computer science, in his name: the Association for Computing Machinery’s Turing Award.
Worldwide, scientists and technologists have planned a number of programmes to be held through the year, to mark his birth centenary.

Google doodle

In a fitting tribute on Saturday morning, Google marked his 100th birth anniversary with one of its creative doodles. A whole generation of tech enthusiasts, who may not have familiarised themselves with the pioneering works of Turing, learnt through this interactive model, what Turing’s contribution was all about. What Google’s Turing Machine does is give you a binary series to match by creating a short programme using the buttons provided at the bottom. On getting it right, the letters of the grey Google logo get filled with colour.

His contributions

Turing’s most widely impacting contribution is perhaps the introduction of two key concepts — of algorithms and computing machines — that he outlined in his paper on ‘Computable Number’ in 1936, while at King’s College, Cambridge.
His inventions and theoretical understanding of computational logic have, over the years, paved the way for researchers in a wide range of fields.

The Bombe

Turing’s work was first noticed when he devised the Bombe, after which he headed to the National Physical Laboratory where he created among the first designs for a stored computer program called the Automatic Computing Engine.
A complex machine, this laid the foundation for the first pilot electronic computer built in Britain around 1951. His basic design was used in several computers and computing technologies, from mainframes to the world’s first personal computer that came over three decades later.

The Turing machine

Turing’s most lasting contribution, however, was the Turing machine. A machine or computational method, he proposed that a long piece of tape could be used to write simple instructions, allowing the machine to read an instruction at a time. The machine could then use one of its coded algorithms to process these instructions.
Why was this important? This was pathbreaking simply because till then the idea of a stored programme, reading and processing multiple instructions had not been conceived.
This theoretical understanding is what makes Turing the father of theoretical computation, and the pioneer of computing technology as we know it today. Going through the list of technologies and scientific projects that Turing either completed, contributed to or left unfinished, it is difficult to not be amazed at his genius.
Diverse interests
From speech encryption to his fascinating work where he was trying to understand the structure of plant petals and seeds, and the adherence of sunflower petals to the Fibonacci sequence, Turing was one whose genius, and inquisitiveness, knew no bounds.
His lesser-known achievements are as fascinating to read about as his lasting contributions; for instance, did you know that back in 1950, as part of work on artificial intelligence, Turing wrote the first-ever chess computer programme ‘Turbochamp’.
Though it took a few other scientists, and a couple more years for the first successful chess program to be played on the computer, the video of the game he played, back in 1952, as the program, against his colleague Alick Glennie is an all-time favourite of tech enthusiasts. The program, and Turing, lost to Glennie in 29 moves.

No comments: