Artificial Intelligence, Logic, and Formalising Common Sense

This chapter is about the relations among artificial intelligence (AI), mathematical logic, and the formalisation of common‐sense knowledge and reasoning. Common‐sense knowledge includes the basic facts about events (including actions) and their effects, facts about knowledge and how it is obtained, facts about beliefs and desires. One path to human‐level AI uses mathematical logic to formalise common‐sense knowledge in such a way that common‐sense problems can be solved by logical reasoning. It seems that fourth‐level systems require extensions to mathematical logic. One kind of extension is formalised nonmonotonic reasoning, first proposed in the late 1970s. McCarthy discusses several formalisations, proposing those based on nonmonotonic reasoning as improvements of earlier ones. The project of formalising common‐sense knowledge and reasoning raises many new considerations in epistemology and also in extending logic.