Newell and Simon's Logic Theorist: Historical Background and Impact on Cognitive Modeling

Abstract

Fifty years ago, Newell and Simon (1956) invented a “thinking machine” called the Logic Theorist. The Logic Theorist was a computer program that could prove theorems in symbolic logic from Whitehead and Russell's Principia Mathematica. This was perhaps the first working program that simulated some aspects of peoples' ability to solve complex problems. The Logic Theorist and other cognitive simulations developed by Newell and Simon in the late 1950s had a large impact on the newly developing field of information-processing (or cognitive) psychology. Many of the novel ideas about mental representation and problem solving instantiated in the Logic Theorist are still a central part of the theory of cognitive psychology, and are still used in modeling the complex tasks studied in human factors psychology. This paper presents some of the theoretical precursors of the Logic Theorist, describes the principles and implementation of the program, and discusses its immediate and long-term impacts.