Wh yW eN eed Many Knowledge Representation Formalisms

Against advocates of particular formalisms for representing all kinds of knowledge, this paper argues that different formalisms are useful for different purposes. Different formalisms imply different inference methods. The history of human science and culture illustrates the point that very often progress in some field depends on the creation of a specific ne wf ormalism, with the right epistemological and heuristic power .T he same has to be said about formalisms for use in artificial intelligent systems. W en eed criteria for evaluating formalisms in the light of the uses to which the ya re to be put. The same subject matter may be best represented using different formalisms for different purposes, e.g. simulation vs e xplanation. If dif ferent notations and inference methods are good for different purposes, this has implications for the design of expert systems.