In recent years there has been a growing awareness that studies on quantum foundations have close relationships with other fields such as probability and information theory. In this talk I give another example of how such interdisciplinary work can be fruitful, by applying some of the lessons from quantum mechanics, in particular from Bell\'s theorem, to a debate on the philosophical foundations of decision theory. I argue that the basic assumptions of the popular causal decision theory -- which was developed partly in response to a puzzle proposed by the physicist William Newcomb and published by the philosopher Robert Nozick -- are analogous to the basic assumptions of a local hidden-variables theory in the context of Bell\'s theorem. Both have too strong a prejudice about the causal structure of the world: there are possible games the world can pose such that an agent who operates by those theories is constrained to choose losing strategies no matter what evidence he or she acquires.