Computers Thought

This is a case study in problem-solving, representing part of a program of research on complex information-processingsystems. We have specified a system for finding proofs of theorems in elementary symbolic logic, and by programming a computer to these specifications, have obtained empirical data on the problem-solving process in elementary logic. The program is called the Logic Theory Machine (LT); it was devised to learn how it is possible to solve difficult problems such as proving mathematical theorems, discovering scientific laws from data, playing chess, or understanding the meaning of English prose. The research reported here is aimed at understanding the complex processes (heuristics) that are effective in problem-solving. Hence, we are not interested in methods that guarantee solutions, but which require vast amounts of computation. Rather, we wish to understand how a mathematician, for example, is able to prove a theorem even though he does not know when he starts how, or if, he is going to succeed. This focuses on the pure theory of problem-research solving (Newell and Simon, 1956a). Previously we specified in detail a program for the Logic Theory Machine; and we shall repeat here only as much of that specification as is needed so that the reader can understand our data. In a companion study (Newell and Shaw, 1957) we consider how computers can be programmed to execute processes of the kinds called for by LT, a problem that is interesting in its own right. Similarly, we postpone to later Papers a discussion of the implications of our work for the psychological theory of human thinking and problem-solving. Other areas of application 109 !