Making computers think like people [fuzzy set theory]

Attempts to automate various types of human activity, from assembling an automobile to diagnosing a patient, have often been impeded by the gap between the way humans reason and the way computers are generally programmed. When making decisions, computers usually ask questions that have a clear-cut yes or no answer: “Does the temperature exceed 75.6°?” “Is Mary older than John?” Humans don't generally reason in such a precise manner. Rather, most human thinking deals with categories that shade into one another: “it's dangerous to drive on a very icy road” or “A complex circuit must be designed for high reliability.”