[Humanist] 23.607 why chess for AI
Humanist Discussion Group
willard.mccarty at mccarty.org.uk
Fri Jan 29 07:31:08 CET 2010
Humanist Discussion Group, Vol. 23, No. 607.
Centre for Computing in the Humanities, King's College London
Submit to: humanist at lists.digitalhumanities.org
Date: Thu, 28 Jan 2010 11:21:02 -0600
From: amsler at cs.utexas.edu
Subject: Re: [Humanist] 23.597 why chess for AI
In-Reply-To: <20100126063420.43BAC49297 at woodward.joyent.us>
Chess has an interesting history in AI. It was more a case of trying
to explore the limits of reasoning by machine than anything else--or
at least forcing opponents of the idea that machines could "think" to
clarify what they meant.
Most famously, there was a gauntlet thrown down by those who said, "A
computer could never defeat a human at chess"; later refined to "A
computer could never defeat a grand master at chess". It became a
demonstration task for the computer folks. However, as with many other
tasks, the solution revealed that computers and human beings are
At first the task was simply to build computer programs that could
play chess, i.e., make legal moves. This became a standard artificial
intelligence graduate course class assignment by the late 1960s, to
teach students about game playing techniques. Once computers played
"legal" chess there were a variety of approaches to improving their
game. Some pursued modeling the strategies of human chess experts.
However, it soon became apparent that there was another strategy
available through brute force. I.e., the computer could simply look
ahead to see what the consequences of EVERY move were. And then, the
consequences of every countermove by its opponent, and the
consequences of every counter-countermove to those moves.... all the
way through to a checkmate. Once this strategy was determined to be
solely limited by the computing capacity of the machine it was
apparent that a computer could eventually beat human players--all that
had to be done was to build it. Additional criteria were added to the
challenge, such as requiring the machine to make its moves in real
time, in a real chess match.
Frankly, it seemed a bit silly because it was very much like
questioning whether a locomotive could outrace a horse and anyone
claiming that it would never happen clearly didn't understand how
So, what finally happened is that computer folks decided to build
special purpose hardware to play chess. This is always available as an
option when general purpose computing is too slow. (However,
surprisingly, it is often a short-lived necessity, as general purpose
computers eventually overtake the capability of the
special-hardware--which cannot economically continue to be developed
since it only does one task). The "chess machine" was created with the
sole purpose of playing chess using look-ahead to greater depths than
any human could reach.
An interesting sidenote was that once all these circumstances were set
up, i.e., computer engineers figured out how to build and run special
hardware to play chess in real time against real chess masters, the
human chess masters began to interpret the machine's performance as
evidence of it having a personality. I suppose this was an integral
part of their strategy in playing against human chess players that
gave them a means to see further ahead by guessing what moves their
opponent would favor---but I can't but help find it misplaced
inference when used against a machine. True, the problem of being able
to see all the way to the end of the game was too difficult for even
the best hardware of the day, so effort was put into improving the
software to not have the computer waste its time with analysis of
legal but dumb moves that no chess expert would execute, but the
principle that this was a finite game that had a computable end really
meant eventually there was no doubt of the computer's eventual mastery
of the problem and no reason to believe in "personality" being a factor.
So, when it became apparent that all but grand masters could easily be
beaten by a computer playing chess, it became a matter of finding a
use for this capability. The obvious answer was to market a
chess-playing computer for human players to test their skill
against--and that was done, with graded levels of expertise so it
could be played and beaten at each level.
I guess the humanist lesson is that one shouldn't assume all tasks
performed by human beings REQUIRE "thinking", just because we use
"thinking" to do them.
The computer that plays chess well doesn't "think" any more than the
toaster-oven that cooks food using a timer to shut off when done
"thinks" about the food being done. "Thinking" is thus a rather vague
term that has swept up a number of tasks humans perform that could
readily be done without "thought" at all.
The questions that remain are still challenging. How can we decide
when a task cannot be performed by "reasoning" alone. In hindsight, I
believe we've gotten considerably more sophisticated in our
understanding of the boundary between "reasoning" and "thinking". Of
course, the mathematical understanding of game theory and the
realization that many 'games' are completely solvable by reasoning
alone, advanced our understanding of where the boundary was.
The movie "Wargames" is instructive. In it a computer programmed to
fight a nuclear war is hacked into by a kid thinking it's a harmless
game-playing machine with this novel game called "thermonuclear war".
The computer doesn't know or care that it's about to launch a real
nuclear war using the hardware it controls. In the end, it runs a
massive number of scenarios in terms of the outcome and (in a
Hollywood ending) "learns" that "thermonuclear war" is an odd game,
because as it says, "The only way to win is not to play" and then
suggests a nice game of chess instead. Learning of this kind is still
a mystery in AI. I.e., recasting the problem intitially given as an
instance of a high-level concept.
More information about the Humanist