PROBABILISTIC LOGIC.

The article discusses about "probabilistic logic" which is typically used to refer to systems of logic that permit the attachment of probabilities to the premises and the conclusion of an argument. Systems of probabilistic logic vary with respect to how the uncertainty associated with the premises of an argument is propagated to the conclusion. The worlds in a given set are equivalent with respect to the truth values of the sentences. The sets of possible worlds are mutually exclusive and exhaustive. Nilsson's method for identifying the sets of possible worlds which involves constructing a semantic tree is discussed.