Physical symbol system

The physical symbol system hypothesis was formulated by Newell and Simon (1963) as the result of success of GPS (General Problem Solver) and subsequent programs as models of cognition.

It states that "a physical symbol system has the necessary and sufficient means of general intelligent action."

What this means is that any system (human or machine) exhibiting intelligence must operate by taking physical patterns (symbols), combining them into structures (expressions) and manipulating them (using processes) to produce new expressions.

The hypothesis has been criticized strongly by various parties, but is a core part of AI research. A common critical view is that the hypothesis seems appropriate for higher-level intelligence such as playing chess, but less appropriate for commonplace intelligence such as vision.