Probabilistic Inference

It is important to distinguish probabilistic reasoning from probabilistic inference. Probabilistic reasoning may concern the manipulation of knowledge of probabilities in the context of decision theory, or it may involve the updating of probabilities in the light of new evidence via Bayes theorem or some other procedure. Both of these operations are essentially deductive in character. Contrasted with these procedures of manipulating or computing with probabilities, is the use of probabilistic rules of inference rules that lead from one sentence or a set of sentences to another sentence, but do so in a way that need not be truth preserving. One could attempt to get along without probabilistic inference in AI, but it would be very difficult and unnatural. Instances of such rules are several classes of inference rules associated with statistics, and some rules discussed by philosophers. In artificial intelligence the rules that fall into this category are mainly default rules these are not generally construed probabilistic, but obviously default rules that more often lead you astray than to the truth would be poor ones.