http://www.cs.unm.edu/~high/future.html
Symbolic AI is a top-down approach to the engineering of intelligent behavior. The physical-symbol hypothesis of Newell and Simon (1972) suggests (correctly, I believe) that human thought can be fully described in terms of the manipulation of abstract symbols, embodied as states in the physical world. The common (mis)interpretation (incorrect, I believe) is that symbols are discrete entities like those found in computer programming languages (e.g. OBJECT = BIRD, COLOR = BLUE). This is a bias due to both the computer scientist's special perceptual system but also the basic human perceptual system. That mind has a physical basis is apparent. That this physical basis can be construed as a processing of physical symbols seems acceptable, but only if we allow a loose definition of the word "symbol."
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