Newcomb's problem

Abstract

Like Skyrms (1990), who transfers the equilibrium concept from game theory to rational decision theory and who uses it for modelling the dynamics of rational deliberation, I transfer a concept of game theory, namely the concept of a game against nature, to rational decision theory and wish to use it for providing a foundation for Skyrms' (1980, 1982, 1984) causal decision theory. Furthermore, like Brams (1983) I use the concept of a game against nature for defending a certain solution to Newcomb's problem as rational, namely taking both boxes. This concept which has to be distinguished from the concept of games with two or more decision makers explains why there are different recommendations (cf. Spohn in press) in a 1-shot Newcomb's problem vs. in a finitely iterated Newcomb's problem. Furthermore, the concept of a game against nature explains why the predictor's high reliability and why the predictor's perspective are irrelevant for providing a solution to Newcomb's problem. Moreover, if the decision maker conceives Newcomb's problem as a game against nature in contrast to a game with two or more decision makers, he takes a certain perspective, so that this approach of rational decision theory stresses the decision maker's perspective. Additionally, while the decision maker's belief in Newcomb's problem as a game against nature is rational, the decision maker's belief in Newcomb's problem as a game with two decision makers isn't non-permissible irrational.