The cognitive science perspective on the mind views thought as information processing. More specifically, this information processing is not merely arbitrary computation; it typically involves deriving new information from existing information. For example, visual perceptual analysis and categorization are viewed as taking low-level information about the pattern of light incident at the retina, and creating a representation of information about objects in the environment, their movements, interrelationships and causal powers. Speech production involves mapping from representations of an intention (the message to be conveyed), to a detailed set of information providing instructions to the tongue, lips and voice box. To take a final example, problem solving involves taking the information given in a problem, and mapping on to a representation of the ...