A philosophical basis for knowledge acquisition

Abstract

Knowledge acquisition for expert systems is a purely practical problem to be solved by experiment, independent of philosophy. However the experiments one chooses to conduct will be influenced by one's implicit or explicit philosophy of knowledge, particularly if this philosophy is taken as axiomatic rather than as an hypothesis. We argue that practical experience of knowledge engineering, particularly in the long term maintenance of expert systems, suggests that knowledge does not necessarily have a rigorous structure built up from primitive concepts and their relationships. The knowledge engineer finds that the expert's knowledge is not so much recalled, but to a greater or lesser degree “made up” by the expert as the occasion demands. The knowledge the expert provides varies with the context and gets its validity from its ability to explain data and justify the expert's judgement in the context . We argue that the physical symbol hypothesis with its implication that some underlying knowledge structure can be found is a misleading philosophical underpinning for knowledge acquisition and representation. We suggest that the “insight” hypothesis of Lonergan (1958) better explains the flexibility and relativity of knowledge that the knowledge engineer experiences and may provide a more suitable philosophical environment for developing knowledge acquisition and representation tools. We outline the features desirable in tools based on this philosophy and the progress we have made towards developing such tools.