Related to: Counterfactual Mugging, The Least Convenient Possible World

MBlume said:

What would you do in situation X?" and "What would you like to pre-commit to doing, should you ever encounter situation X?" should, to a rational agent, be one and the same question.

Applied to Vladimir Nesov's counterfactual mugging, the reasoning is then:

Precommitting to paying $100 to Omega has expected utility of $4950.p(Omega appears). Not precommitting has strictly less utility; therefore I should precommit to paying. Therefore I should, in fact, pay $100 in the event (Omega appears, coin is tails).

To combat the argument that it is more likely that one is insane than that Omega has appeared, Eliezer said:

So imagine yourself in the most inconvenient possible world where Omega is a known feature of the environment and has long been seen to follow through on promises of this type; it does not particularly occur to you or anyone that believing this fact makes you insane.

My first reaction was that it is simply not rational to give $100 away when nothing can possibly happen in consequence. I still believe that, with a small modification: I believe, with moderately high probability, that it will not be instrumentally rational for my future self to do so. Read on for the explanation.