Aron Vallinder (Forethought Foundation, Oxford): “The Evidentialist’s Wager”

Suppose that an altruistic and morally motivated agent who is uncertain between evidential decision theory (EDT) and causal decision theory (CDT) finds herself in a situation in which the two theories give conflicting verdicts. We argue that even if she has significantly higher credence in CDT, she should nevertheless act in accordance with EDT. First, we claim that that the appropriate response to normative uncertainty is to hedge one’s bets. That is, if the stakes are much higher on one theory than another, and the credences you assign to each of these theories aren’t very different, then it’s appropriate to choose the option which performs best on the high-stakes theory. Second, we show that, given the assumption of altruism, the existence of correlated decision-makers will increase the stakes for EDT but leave the stakes for CDT unaffected. Together these two claims imply that whenever there are sufficiently many correlated agents, the appropriate response is to act in accordance with EDT.

Aron Vallinder is a research fellow at the Forethought Foundation in Oxford. Most of his research concerns ethical and empirical issues around the long-term future.