Defeasible logic is a non-monotonic logic proposed by Donald Nute to formalize defeasible reasoning. In defeasible logic, there are three different types of propositions:
- strict rules
- specify that a fact is always a consequence of another;
- defeasible rules
- specify that a fact is typically a consequence of another;
- undercutting defeaters
- specify exceptions to defeasible rules.
A priority ordering over the defeasible rules and the defeaters can be given. During the process of deduction, the strict rules are always applied, while a defeasible rule can be applied only if no defeater of a higher priority specifies that it should not.
Famous quotes containing the word logic:
“There is no morality by instinct.... There is no social salvation—in the end—without taking thought; without mastery of logic and application of logic to human experience.”
—Katharine Fullerton Gerould (1879–1944)