A Theory of Commonsense Knowledge

What is commonly called "commonsense knowledge" may be viewed as a collection of "dispositions": propositions with implied fuzzy logic.

Abstract

The theory outlined in this paper is based on the idea that what is commonly called commonsense knowledge may be viewed as a collection of dispositions, that is, propositions with implied fuzzy quantifiers. Typical examples of dispositions are: Icy roads are slippery. Tall men are not very agile. Overeating causes obesity. Bob loves women. What is rare is expensive, etc. It is understood that, upon restoration of fuzzy quantifiers, a disposition is converted into a proposition with explicit fuzzy quantifiers, e.g., Tall men are not very agile→Most tall men are not very agile. Since traditional logical systems provide no methods for representing the meaning of propositions containing fuzzy quantifiers, such systems are unsuitable for dealing with commonsense knowledge. It is suggested in this paper that an appropriate computational framework for dealing with commonsense knowledge is provided by fuzzy logic, which, as its name implies, is the logic underlying fuzzy (or approximate) reasoning. Such a framework, with an emphasis on the representation of dispositions, is outlined and illustrated with examples.