Causal decision theory, context, and determinism

Abstract

AbstractThe classic formulation of causal decision theory (CDT) appeals to counterfactuals. It says that you should aim to choose an option that would have a good outcome, were you to choose it. However, this version of CDT faces trouble if the laws of nature are deterministic. After all, the standard theory of counterfactuals says that, if the laws are deterministic, then if anything—including the choice you make—were different in the present, either the laws would be violated or the distant past would be changed. And as several authors have shown, it's easy to transform this upshot of the standard theory of counterfactuals into full‐blown counterexamples to CDT. In response to these counterexamples, I argue here that the problem lies, not so much with CDT's guiding idea—that it's the expected causal consequences of your actions that matter for rational decision‐making—but with the fact that the classic formulation of CDT doesn't pay sufficient attention to the context‐sensitivity of counterfactuals. I develop a contextualist version of CDT which better accounts for this context‐sensitivity. And I show that my theory avoids the problems faced by the classic formulation of CDT in determinstic worlds.