EVOLUTION AND MODIFICATION OF PROBABILITY IN KNOWLEDGE BASES.

The assignment of certainties to rules, their modification and their interaction in chains of inference, are important issues in knowledge engineering. The authors argue that probability theory, because its results can be compared to the external world, is an appropriate model of certainty. The rich convergence results available in probability also allow rigorous updating of uncertainties. A simple modification of the Law of Large Numbers which provides updating of initial estimates of certainties is given. The independence requirements of probability also constrain the design of rule bases in ways which prove useful.