{"type":"ScholarlyArticle","title":"Indefinite Reasoning with Definite Rules","authors":[{"name":"L. Thorne McCarty","slug":"l-thorne-mccarty","given":"L. Thorne","family":"McCarty","affiliation":""},{"name":"Ron van der Meyden","slug":"ron-van-der-meyden","given":"Ron","family":"van der Meyden","affiliation":""}],"abstract":"In this paper we present a novel explanation of the source of indefinite information in common sense reasoning: Indefinite information arises from reports about the world expressed in terms of concepts that have been defined using only definite rules. Adopting this point of view, we show that first-order logic is insufficiently expressive to handle important examples of common sense reasoning. As a remedy, we propose the use of circumscribed definite rules, and we then investigate the proof theory of this more expressive framework. We consider two approaches: First, prototypical proofs, a special type of proof by induction, which yields a sound proof theory. Second, we describe cases in which there exists a decision procedure for answering queries, a particularly significant result because it shows that it is possible to have decidable query processing in circumscribed theories that are not equivalent to any first order theory.","doi":null,"url":"https://ijcai.org/proceedings/1991/131","pdf":"https://ijcai.org/proceedings/1991/0131.pdf","markdown":"https://ijcai.org/proceedings/1991/131.md","bibtex":"https://ijcai.org/proceedings/1991/bibtex/131","volume":{"slug":"1991","title":"Proceedings of the Twelfth International Joint Conference on Artificial Intelligence","short_title":"IJCAI 1991","url":"https://ijcai.org/proceedings/1991/","year":1991,"location":"Sydney, New South Wales, Australia","dates":"24-30 August 1991","editors":"John Mylopoulos and Ray Reiter","isbn":"","publisher":"International Joint Conferences on Artificial Intelligence","doi_prefix":""},"section":"Logic Programming","track":"Logic Programming","number":131,"pages":{"first":890,"last":895},"keywords":[],"videos":[],"references":[],"license_note":"Copyright International Joint Conferences on Artificial Intelligence."}