Alan Turing: Thinking Up Computers
The Cambridge University Mathematician Laid the
Foundation for the Invention of Software
BusinessWeek,
May 10, 2004
By Andy Reinhardt in Paris
The Great Innovators
As part of its anniversary celebration, BusinessWeek
is presenting a series of weekly profiles for the greatest innovators of the
past 75 years. Some made their mark in science or technology; others in
management, finance, marketing, or government. In late September, 2004,
BusinessWeek will publish a special commemorative issue on Innovation.
The rarefied world of early 20th-century mathematics
seems light years away from today’s PCs and virtual-reality video games. Yet
it was a 1936 paper by Cambridge University mathematician Alan M. Turing that
laid the foundation for the electronic wonders now crowding into every corner
of modern life. In a short and eventful life, Turing also played a vital role
in World War II by helping crack Germany’s secret codes—only to be
persecuted later for his homosexuality.
A shy, awkward man born into the British upper middle
class in 1912, Turing played a seminal role in the creation of computers. To
be sure, many other people contributed, from mathematicians Charles Babbage
and Ada Lovelace in the 1830s to Herman Hollerith—whose tabulating company
became IBM (IBM )—at the turn of the century. But it was Turing who made the
critical conceptual breakthrough, almost as an aside in a paper he wrote while
in his 20s. Attempting to resolve a long-standing debate over whether any one
method could prove or disprove all mathematical statements, Turing invoked the
notion of a “universal machine” that could be given instructions to
perform a variety of tasks. Turing spoke of a “machine” only abstractly,
as a sequence of steps to be executed. But his realization that the data fed
into a system also could function as its directions opened the door to the
invention of software. “He is the one who found the underlying reason why an
automatic calculating device can do so many things,” says Martin Davis,
professor emeritus of computer science at New York University and a visiting
scholar at the University of California at Berkeley.
As basic as Turing’s notion seems today, it was radical
in the mid-1930s. But before the first programmable computers were built,
Turing got diverted into the war effort. He worked for five years at Bletchley
Park, north of London, with dozens of Britain’s brightest minds. Through
endless hours and logical deduction, they unraveled the Enigma code used by
the Germans to send messages to field commanders and U-boats.
Turing was himself an enigma. He adored maps and chess as
a child and survived the brutal boarding school system by withdrawing into
eccentricity. Later he found solace in distance running. Turing realized young
that he was attracted to other men, but homosexuality was outlawed. So he
lived a secret life, torn by inner battles between the mind and body. As long
as he was useful to the government, officials overlooked his sexuality, says
his biographer, Oxford mathematics research fellow Andrew Hodges. After the
war, Turing became more overt in his relationships and was convicted in 1952
of “gross indecency.” He was subjected to injections of female hormones,
ostensibly to quell sexual desires, and shunned as a security risk. In 1954,
at 41, he died suddenly, almost certainly by suicide from eating a
cyanide-laced apple.
Turing didn’t live to see the revolution he unleashed.
But he left an enormous legacy. In 1950 he proposed a bold measure for machine
intelligence: If a person could hold a typed conversation with “somebody”
else, not realizing that a computer was on the other end of the wire, then the
machine could be deemed intelligent. Since 1990 an annual contest has sought a
computer that can pass this “Turing Test.” Nobody has yet taken the
$100,000 purse. Turing would no doubt be delighted that engineers the world
over are still trying.
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