John Shedletsky March 14, 2003 Prof Henry Lowood STS145 Case Study
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John Shedletsky March 14, 2003 Prof Henry Lowood STS145 Case Study On the Romance of Regicide: The Turk, Kasparov, and Deep Blue “Chess is beautiful enough to waste your life for,” the oft-quoted aphorism of Dutch Grandmaster Hans Rees, most succinctly describes the human obsession with the ancient game of kings. For centuries, the act of playing chess has been upheld as the very paragon of intellectual activity. Voltaire said, “Chess is the game which reflects most honor on human wit,” and Goethe called chess “The touchstone of intellect” (Spaans). The first internationally recognized World Champion of the game, Paul Morphy, echoes these sentiments, “Chess is eminently and emphatically the philosopher's game.” (ChessVille) The deep strategic nuances of the game has kept players enamored with the game for centuries and more books have been written about chess than all other games combined. It is the game’s reputation as both a strategically deep system and as a thinking man’s activity that originally made the idea of a mechanized chess player an intriguing notion. There is a romantic appeal to building machines to do battle with the mind of man that has propelled computer chess from humble beginnings to the 1997 defeat of world champion Garry Kasparov to IBM’s Deep Blue. The seminal paper in the field of computer chess was written by Claude Shannon in 1949 and since then generations of chess programmers have looked to it for inspiration (Atkinson 39). It was about this time in the United States that the nascent field of artificial intelligence looked ready to burst forth with revolutionary thinking machines. Such was the enthusiasm of the time that Herbert Simon (an AI researcher and Carnegie Mellon and a Nobel laureate in Economics) and Allen Newell suggested in 1958 that, “Within ten years a digital computer will be the world’s chess champion, unless the rules bar it from competition” (7). In this great era of exploration, researchers were looking for model problems to develop new AI techniques with that, they hoped, would eventually lead to a mathematical model of conscious decision making – the true artificial intelligence that the world has yet to witness. In 1950, an abbreviated version of Claude Shannon’s paper was printed in Scientific American, making the case for the use of chess as a model system to be used for this purpose. “The investigation of a chess-playing program is intended to develop techniques that can be used for more practical applications,” he wrote. “The chess machine is an ideal one to start with for several reasons. The problem is sharply defined, both in the allowed operation and the ultimate goal. It is neither so simple as to be trivial or too difficult for satisfactory solution. And such a machine could be pitted against a human opponent, giving a clear measure of the machine’s ability in this kind of reasoning.” (48) For these reasons, the idea of building a machine that could play chess better than any man became one of the holy grails in the field of artificial intelligence (Bynum, 215). Surprisingly, the romance of chess-playing machines begins centuries before Claude Shannon or even before the computer. At first, computer chess was the realm of dreamers. In 1770, Baron Wolfgang von Kempelen constructed an automaton composed a manikin sitting cross-legged on a four by two by three foot wooden cabinet, sporting a handsome turban. The automaton was capable of playing chess. Though Kempelen never gave his creation a name, it was known throughout Europe as “The Turk” (Standage, 23). The Turk had an illustrious and prolific playing career. When first built it was displayed at the court Austrian Empress Marie Theresa in Vienna to the empress’s delight. In 1783, after a tour through Russia, the Turk was again exhibited in Vienna for Emperor Joseph II. The same year the machination beat Benjamin Franklin in a game played in Paris. Two years later, while the Turk was touring Prussia, Fredrick the Great played it a game and lost. Perhaps the most famous game the Turk ever played was against Napoleon Bonaparte at Schonburnn during the Wagram campaign in 1809, checkmating the emperor in 24 moves. In 1820, the Turk sailed west to America where it visited New York, Boston and Philadelphia. In Philadelphia, the excitement caused by the Turk resulted in the formation of the first American chess club there. Charles Carroll, one of the original signers of the Declaration of Independence, played the Turk in 1827 (Wall). Edgar Allen Poe wrote about the Turk on two separate occasions, once in 1836 in an analytical essay describing how the machine worked, and again in 1850, when the machine was featured in a short story called Von Kempelen and His Discovery (Standage, 211). The Turk’s celebrated 85 year career came in an end in 1854 when it was destroyed in a great fire that devastated Philadelphia. The Turk, of course, was merely a brilliant illusion, not a brilliant chess-playing machine. Though the doors of its cabinet could be opened to demonstrate that there was only machinery inside, a small chess master could be squeezed into a secret compartment and control the automaton’s moves. Over the course of its long history, the Turk was occupied by no fewer than 15 masters of the game (Wall). Von Kempelen very pointedly never claimed that the Turk was actually playing chess for itself (Standage). Considering the power of some of Turk’s more historical opponents, this was no doubt a wise decision. As the Industrial Revolution trundled on and people became more familiar with what a machine could and could not be expected to do, that the Turk was an elaborate hoax became the prevailing opinion. But this did not dispel the Turk’s mystique. The very idea that a machine could be constructed that would play chess was the most compelling aspect of the Turk’s novelty – it set the imagination on fire. At the time of the Turk’s demise, ideas regarding the creation of honest chess automata had already been engendered. Charles Babbage, a man born before his time, was consumed for much of his life by a powerful vision of programmable computing machines. Today he is recognized as one of the grandfathers of the Digital Age. Limited by technology in Victorian England, his greatest invention, the Difference Engine, an enormous mechanical calculator, was not actually constructed until 1996 (Swade). On March 6, 1819 Babbage saw the Turk play in the Spring Gardens on one of its tours to London (Standage, 140). A year later, he actually sparred with the device, losing to it in about an hour. Babbage began to consider whether it was possible to create a machine capable of playing games of skill, specifically chess (among others), and even considered constructing several to fund the construction of the Difference Engine. Though he wrote about game playing algorithms, he never attempted to construct an automaton. In his memoirs, Babbage relates how he causally polled people about whether or not they thought machines could ever exist that could play games of skill. They answered, unequivocally, no. Never. The technology required to build true chess playing machines did not yet exist, but during and after the Turk’s reign, many chess automatons were built. The romance of the idea that a machine could hold its own in a province previously exclusive occupied by man almost had a life of its own. Plans and designs and algorithms for chess-playing automata were made, but never built. There are a few notable exceptions. Around 1890, Spanish inventor Leonardo Torres y Quevedo built a series of mechanisms that could autonomously play a subgame of chess against a human opponent. When completed the automaton could play a technically perfect king and rook versus king endgame (the simplest chess endgame). The device was very fancy and involved an electromagnet that would move pieces across the board, lights that would go off it an illegal move was entered, and a phonograph that would yell “Checkmate!” in Spanish when the machine won. The device remains in perfect working order and is on display at the Polytechnique University in Madrid (Atkinson, 22). Another notable advance in mechanized chess was Alan Turing’s “Paper Machine” that he experimented with in the late 1939s. Not having access to an actual computer, Turing wrote down simple search and move evaluation moves onto a couple dozen pieces of paper and would painstakingly play games against fellow academics by executing all of the instructions by hand. Turing’s chess program performed dismally against opponents, but it was the first time that all of the algorithms related to chess programming were put together in one place and used to play a game (Newborn, 28, 1996). The foundation for computer chess was being laid. In terms of Game Theory, the chess is a game of perfect information. Everything about the state of the board is known by both players of the game at all times. If one player makes a brilliant move, it is because his opponent didn’t see it coming in time to counter it. From any position in the game, there are a finite number of moves that any player can make, and a finite number of moves his opponent may make in return. Thus, from the starting position there is a widely branching game tree that represents all possible moves and counter-moves that can be played. The approach that nearly all chess programs take to finding the move to make in any particular position is to search this tree of moves and countermoves, applying various heuristics that good players use to evaluate each position (axiomatic rules of thumb like having knights in the center is good or an uncastled king is bad) and choosing the first in a sequence of moves that result in the best position for the program if it is assumed that both sides play perfectly (according to these heuristics).