Abstract: The invention is directed to an inference mechanism to execute human logical and fuzzy thought including intuitive thought. The mechanism consists of two independent engines. One engine is a frame inference engine based on human logical thought. The other engine is a fuzzy reasoning engine base on human fuzzy thought. The mechanism utilizes a common domain control to connect the two engines. After reading in the domain by the fuzzy reasoning engine, the engine draws inferences and writes the fuzzy reasoning result. The conventional inference engine operates in accordance with the results in the domain.For intuitive thought, for example, a procedure (model) is introduced for realizing an operation or a situation of an object. The frame engine commences execution of the procedure (model). The procedure (model) predicts objectives states under a present condition and outputs a predicted performance value requiring fuzzy reasoning on the domain.