CHESS-PLAYING PROGRAMS AND THE PROBLEM OF COMPLEXITY

Man can solve problems without knowing how he solves them. We shall try to assess recent progress in understanding and mechanizing man's intellectual attainments by considering a single line of attack Chess is the intellectual game par excellence. Such characteristics mark chess as a natural arena for chine, attempts at mechanization. If one could devise a successful chess ma one would seem to have penetrated to the core of human intellectual endeavor. The history of chess programs is an example of the attempt to conceive and cope with complex mechanisms. We return to the original orientation: Humans play chess, and when they do they engage in behavior that seems extremely complex, intricate, and successful. Consider, for example, a scrap of a player's (White's) running comment as he analyzes the position in Figure 1: « Are there any other threats? Knight to Bishop 5 threatening the Queen, and also putting more pressure on the King's side because his Queen's Bishop can come over after he moves his Knight Notice that his analysis is qualitative and functional. He wanders from one feature to another, accumulating various bits of information that will be available from time to time throughout the rest of the analysis. They need not play in exactly the same way; close simulation of the human is not the immediate issue. Complexity of response is dictated by the sponse task, not by idiosyncrasies of the human re mechanism. There is a close and reciprocal relation between complexity and com On the one hand, the complexity of the systems we can specify depends on the language in which we must specify them. Being human, we have only limited capacities for processing information.