Book Review: One Jump Ahead: challenging human supremacy in checkers, by Jonathan Schaeffer
Leap of Faith
Man vs. Machine on the Checkered Battlefield
by Chris Lydgate
August 16, 1992, was a fateful day in the
history of artificial intelligence: It marked the first time a computer program
had ever challenged a human being for a world championship.
The challenger was a 400-pound slab of
silicon named Chinook.
The defending champion was a 65-year-old
college professor named Dr. Marion Tinsley.
The game was checkers.
In recent years, the ancient art of checkers
has gained a reputation as the Rodney Dangerfield of board games. Yet beneath
its surface simplicity lies a fierce struggle every bit as challenging as more
intellectually respectable pursuits such as chess. The game's deceptive
charm--plus the fact that other researchers had largely overlooked
it--persuaded Jonathan Schaeffer, a computer science professor at the
University of Alberta, to abandon his fledgling chess program and turn to
checkers instead. One Jump Ahead is his fascinating account of the
project, which began as a mere academic exercise but became an obsession to win
the world championship--and, more specifically, to defeat Tinsley.
Tinsley is such an intriguing character he
merits a biography of his own. The son of a Kentucky sheriff, he earned a
mathematics degree and became a professor at Florida State University in
Tallahassee. Following a religious experience, he moved across town to teach at
Florida A&M, a primarily black college, and spent his summers canvassing
door-to-door to win souls to his Baptist faith.
But beneath this gracious Southern exterior
lurked a colossus of the checkerboard. Since clinching the world championship
in 1952, Tinsley won every tournament he ever entered and every match he ever
played. He retired from checkers several times, only to return to the game
stronger than ever. Incredibly, during his 40-year reign, he lost only five
games. In Schaeffer's words, Tinsley was "as close to perfection as
humanly possible."
Tinsley was up against a formidable
opponent, however: Chinook boasted eight brains, a database of 85 billion
endgame positions and the ability to peer as many as 27 moves into the future.
A single keystroke could transform its personality from cautious to
swashbuckling, making it a difficult player to prepare against.
To non-combatants, Chinook may have seemed
like a boardgame Terminator, an indestructible automaton. But as Schaeffer's
book shows, its development was surprisingly haphazard. In fact, Chinook was
plagued by bugs: Its vaunted databases were riddled with holes; its knowledge
of checkers was surprisingly unsophisticated, at times almost laughably naive;
and when Schaeffer made last-minute corrections to the program, he often
accidentally introduced new errors. Far from being an infallible juggernaut,
Chinook comes across as a digital enfant terrible, capable of sparkling
brilliance and maddening blunders in the same game.
Held in London, the clash of the
checkerboard titans generated intense media coverage and was portrayed as a
battle between man and machine. Tinsley even cast the match in spiritual terms:
"I have a better programmer than Chinook," he told the Daily
Telegraph. "God gave me a logical mind." In the end, Tinsley
vanquished Chinook, thanks to flashes of brilliance and a mysterious computer
malfunction.
Schaeffer learned from his mistakes and
challenged Tinsley to a rematch in 1994. But the return bout was a puzzling
anti-climax: After six drawn games, Tinsley complained of an upset stomach,
withdrew from the match and forfeited the title. A few days later, doctors
discovered a malignant tumor in his pancreas. Tinsley died the next year,
leaving the cancer-proof computer as the world's reigning champ.
One Jump Ahead is not only gripping, it also raises many
provocative questions. Could Tinsley have beaten Chinook in the rematch? Are
computer programs destined to outplay humans in chess, go, bridge, and even
poker? Perhaps most important, what does Chinook's triumph imply for the future
of machine--and human--intelligence? After all, Chinook's strength lay in its
gigantic databases, which effectively reduced the game's creative subtleties to
a mechanical exercise in searching a catalog.
But Schaeffer makes a persuasive case that
we should not define computer intelligence by its similarity to the human
brain. Rather, he says, we should look at the results: Can a robotic program
excel at a task which, in humans, obviously requires imagination and
intelligence? The answer, at least in the case of Chinook, is a resounding
yes--and the implications must be correspondingly profound.
[First published in
Willamette Week, April 5, 2000]