Conditioning, intervening, and decision

Abstract

Clark Glymour, together with his students Peter Spirtes and Richard Scheines, did pioneering work on graphical causal models (e.g. Spirtes et al., in Causation, prediction, and search, 2000). One of the central advances provided by these models is the ability to simply represent the effects of interventions. In an elegant paper (Meek and Glymour, in Br J Philos Sci 45: 1001–1021, 1994), Glymour and his student Christopher Meek applied these methods to problems in decision theory. One of the morals they drew was that causal decision theory should be understood in terms of interventions. I revisit their proposal, and extend the analysis by showing how graphical causal models might be used to address decision problems that arise in “exotic” situations, such as those involving crystal balls or time travelers.