False Implications in Retroactive Choice Situations

What can time-travel cases tell us about rational choice? In particular, what can we learn about rational choice from what we may call retroactive choice situations, that is, from time-travel cases in which the circumstances where an agent makes a choice depend causally on the choice the agent makes? Such cases have been thought to call into question the dominant theory of rational choice among decision theorists, namely causal decision theory (CDT). In this paper, I consider two objections that retroactive choice situations appear to raise for CDT. The first objection, which I consider in part one, is familiar from the literature. It states that CDT has false implications in many retroactive choice situations. I argue that this objection is based on highly questionable assumptions. Then in part two of the paper I raise a new objection: I argue that that CDT cannot be applied in most retroactive choice situations, since in these situations it is impossible to evaluate one‟s options in the manner required by causal decision theory. Thus, anyone who maintains that CDT is the correct and complete theory of rational choice must claim that, in retroactive choice situations, rational guidance is impossible.