Showing papers on "Commonsense reasoning published in 1985"

Computing circumscription

Abstract: Circumscription is a transformation of predicate formulas proposed by John McCarthy for the purpose of formalizing non-monotonic aspects of commonsense reasoning. Circumscription is difficult to implement because its definition involves a second-order quantifier. This paper presents metamathematical results that allow us in some cases to replace circumscription by an equivalent first-order formula.

Formal Theories of the Commonsense World

Abstract: This volume is a collection of original contributions about the core knowledge in fundamental domains. It includes work on naive physics, such as formal specifications of intuitive theories of spatial relations, time causality, substance and physical objects, and on naive psychology.

Syllogistic reasoning in fuzzy logic and its application to usuality and reasoning with dispositions

Abstract: A fuzzy syllogism in fuzzy logic is defined as an inference schema in which the major premise, the minor premise, and the conclusion are propositions containing fuzzy quantifiers. A basic fuzzy syllogism in fuzzy logic is the intersection/product syllogism. Several other basic syllogisms are developed that may be used as rules of combination of evidence in expert systems. Among these is the consequent conjunction syllogism. Furthermore, it is shown that syllogistic reasoning in fuzzy logic provides a basis for reasoning with dispositions, that is, with propositions that are preponderantly but not necessarily always true. It is also shown that the concept of dispositionality is closely related to the notion of usuality and serves as a gateway to what might be called a theory of usuality, a theory that may eventually provide a computational framework for commonsense reasoning.

The Structures of Everyday Life

Abstract: This note descends from a talk I gave at the AI Lab's Revolving Seminar series in November 1984K I offer it as an informal introduction to some work I've been doing over the last year on common sense reasoning. Four themes wander in and out. 1) Computation provides an observation vocabulary for introspection. With a little wolk, you can learn to exhume your models of everyday activities. Tnis method can provide empirical grounding for computational theories of the central systems of mind. 2) The central systems of mind arise in each of us as a rational response to the impediments to living posed by the laws of computation. One of these laws is that all search problems (theorem proving for example) are intractable. Another is that no one model of anything is good enough for all tasks. Reasoning from these laws can provide theoretical grounding for computational theories of the central systems of mind. 3) Mental models tend to form mathematical lattices under the relation variously called subsumption or generalization. Your mind puts a lot of effort into maintaining this lattice because it has so many important properties. One of these is that the more abstract models provide a normalized decomposition of world-situations that greatly constrains the search for useful analogies.

Taxonomic reasoning

Abstract: In formalizing knowledge for common sense reasoning, one often needs to partition some domain. An instance of this from the Blocks World is the statement "All blocks are either held, on the table, or on another block." Although we can write this axiom in predicate calculus or in clause form for input to a theorem prover, such representations are highly space inefficient. In this paper we present a generalized clause form that allows for the compact representation of arbitrary partitions, along with a set of corresponding inference rules. Additionally, a theorem prover implementing these rules is described that demonstrates their utility with certain kinds of common sense rule bases.

Reasoning Using Exclusion. An Extension of Clausal Form.

Abstract: : In formalizing knowledge for common sense reasoning, one often needs to partition some domain. An instance of this from the block's world is the statement 'All blocks are one of held, on the table, or on another block.' Although we can write such an axiom in predicate calculus using the standard logical connectives, or in clause form as input to a resolution theorem prover, such representations are highly space inefficient. A generalized clause form is presented that allows for the compact representation of arbitrary partitions, along with a set of corresponding inference rules whose soundness and refutation completeness are proven. Additionally, an implementation of a subset of these rules is described that demonstrates their utility with certain kinds of common sense rule bases. (Author)

The use of modal default reasoning in information systems

Abstract: In describing a real, complex world it is practically impossible to represent all the facts about it. Moreover, quite a large number of these facts are “soft” (i.e. doubtful or not verified). In this paper, we propose the use of the language of modal default logic as a tool for knowledge representation, this being a solution to both the problems mentioned above. This approach appears to be very fruitful in modelling common sense reasoning. We discuss these representational problems, giving an example of an experimental information system that was implemented using the OL-resolution proving method for a certain class of S5 modal theories. All suggested solutions are applied in this system.

A Formalization of Commonsense Reasoning Based on Fuzzy Logic

Abstract: The basic idea underlying the approach outlined in this paper is that commonsense knowledge may be regarded as a collection of dispositions, that is, propositions which are preponderantly, but not necessarily always, true. Technically, a disposition may be interpreted as a proposition with implicit fuzzy quantifiers, e.g., most, almost all, usually, often etc. For example, a disposition such as Swedes are blond may be interpreted as most Swedes are blond For purposes of inference from commonsense knowledge, the conversion of a disposition into a proposition with explicit fuzzy quantifiers sets the stage for an application of syllogistic reasoning in which the premises are allowed to be of the form Q A’s are B’s whereA and B are fuzzy predicates and Q is a fuzzy quantifier. In general, the conclusion yielded by such reasoning is a proposition which may be converted into a disposition through the suppression of fuzzy quantifiers.

Representing Mutually Exclusive Knowledge in a Property Hierarchy for a Reasoning System in Clinical Gynecology

Abstract: The education and practice of clinical medicine can benefit significantly from the use of computational assistants. This article describes the development of a prototype system called SURGES (Strong/University of Rochester Gynecological Expert System) for representing medical knowledge and then applying this knowledge to suggest diagnostic procedures in medical gynecology. The paper focuses on the representation technique of property inheritance, which facilitates the simple common sense reasoning required to enable execution of the more complex medical inferences. Such common sense can be viewed as a collection mundane inferences, which are the simple conclusions drawn from knowledge that an exclusive or (XOR) relation (i.e., mutual exclusion) holds among a number of facts. The paper discusses the use of a property hierarchy for this purpose and shows how it simplifies knowledge representation in medical artificial intelligence (AIM) computer systems.

Circumscribing Circumscription: A Guide to Relevance and Incompleteness

Abstract: : Intelligent agents in the physical world must work from incomplete information due to partial knowledge and limited resources. An agent copes with these limitations by applying rules of conjecture to make reasonable assumptions about what is known. Circumscription, proposed by McCarthy, is the formalization of a particularly important rule of conjecture likened to Occam's razor. That is, the set of objects that is consistent with what is known. This paper examines closely the properties and the semantics underlying circumscription, considering both its expensive power and its limitations. In addition we study circumscription's relationship to several related formalisms, such as negation by failure, the closed world assumption, default reasoning and Planner's THNOT. In the discussion a number of extensions to circumscription are proposed, allowing one to tightly focus its scope of applicability. In addition, several new rules of conjecture are proposed based on the notions of relevance and minimality. Finally, a synthesis between the approaches of McCarthy and Konolige is used to extend circumscription, as well as several other rules of conjecture, to account for resource limitations. Keywords: Circumscription, Commonsense reasoning, Non-Monotonic logic, Resource limitations, Relevance, Completeness.