Narrator: What can we learn about thinking from a game of chess? One challenging approach has been made by mathematician, Alex Bernstein, based on this ancient, intellectually demanding game with it.s complex moves and it.s endlessly varying patterns of play. If chess had been played at the rate of a million games a second, since the beginning of recorded time, only a small fraction of all the possible games would yet have been played.
No human being can play a perfect game of chess and neither can any conceivable machine. To find out how good a game of chess a machine might play, Mr. Bernstein and his collaborators prepared a chess-playing program for the IBM 704, a digital computer that has performed one billion calculations in a single day in computing the orbit of an artificial satellite. The chess-playing program is given to the 704 on a reel of magnetic tape.
On the chessboard itself the moves are made by Mr. Bernstein for both players. As he makes a move, he communicates it to the machine. The machine prints out the position of all the pieces. It.s own and its opponents, to correspond with the chessboard on every move. In calculating its moves, the machine considers the board square by square. Is the square occupied? By whose man? Is it under attack? Can it be defended? Can it be occupied? All this has taken a long time by computer standards. One-tenth of a second. Now the computer proceeds to select its move. It has about 30 possible moves.
After asking eight preliminary questions about each of them, it selects seven of the 30 for further analysis. It tests each of the seven through four moves ahead, considering its opponents. possible replies and its own possible counter responses in each case. It examines twenty eight hundred positions in eight minutes. Now the machine prints out its move. It elects to take the opponent.s knight with its own bishop. Mr. Bernstein takes the machine.s bishop with his queen. The move is recorded. But the machine rejects the move as illegal. The difficulty is an incorrect coding, which is corrected.
The game continues with the machine playing methodically and tirelessly. It.s never absent-minded and never makes an obvious blunder. In individual moves, it often plays like a master. In a complete game, it can defeat an inexperienced player, but can be outwitted by a good one. This game has gone up to the 21st move. Mr. Bernstein attacks strongly, threatening the machine.s knight with his castle. He records the move. The machine.s response is a useless pawn move. Its unprotected knight is lost to Mr. Bernstein.s castle. The machine recognizes its position as hopeless and resigns.
After losing a game, the machine will still make the same moves again and lose in the same way. Some day, though not soon, Mr. Bernstein feels, a program may be designed that will enable the computer to profit by its own mistakes and improve its chess game on the basis of its experience against human opponents.