Proceedings of the AAAI Conference on Artificial Intelligence, 5
Deliberation typically involves the formation of a plan or intention from a set of values and beliefs. I suggest that deliberation, or "practical reasoning," is a form of normative reasoning and that the understanding and construction of reasoning systems that can deliberate and act intentionally presupposes a theory of normative reasoning. The language and semantics of a deontic logic is used to develop a theory of defeasible reasoning in normative systems and belief systems. This theory may be applied in action theory and to artificial intelligence by identifying expressions of values, beliefs, and intentions with various types of modal sentences from the language.