A justification-based approach to causal reasoning

Abstract

This article provides a formal framework for dealing with two common concepts in causal reasoning, namely causal/evidential support and causal independence. We focus our attention on the phenomenon of explaining away that plays an important role in analyzing and understanding both concepts. In order to provide a qualitative account of the explaining away phenomenon, we present a justification-based approach that uses circumscription to obtain the minimality of causes. We give a logical formulation of causal and evidential support in terms of a justification change with respect to a circumscriptive theory and show how the definition provides desirable interactions between causal and evidential support. Also, we give a qualitative analysis of causal independence in terms of justification, by restricting it to be expressed only in terms that are considered relevant to the independence query. In both attempts of logical formulation, the notion of justification and the circumscriptive encoding of causal relationship among events provide a flexible and yet rigorous framework. © 1994 John Wiley & Sons, Inc.