a proposition asserting that a necessary and sufficient condition for a computational system to exhibit general intelligent action is that it be a physical symbol system. “Necessary” means that any physical system that exhibits general intelligence will be an instance of a physical symbol system. “Sufficient” means that any physical symbol system can be organized further to exhibit general intelligent action. This hypothesis has been a driving factor for much research in artificial intelligence and cognitive science. [proposed in 1976 by U.S. cognitive and computer scientist Allen Newell (1927–1992) and Herbert A. Simon]