Would you cooperate in the Prisoner’s Dilemma against an almost-copy of yourself (with only trivial differences so that your experiences would be distinguishable)? It can be set up so that neither of you decide within the light-cone of the other’s decision, so there’s no way your cooperation can physically ensure the other’s cooperation.
If you’re quite convinced that the reasonable thing is to defect, then pretty obviously you’ll get (D,D).
If you’re quite convinced that the reasonable thing is to cooperate, then pretty obviously you’ll get (C,C).
(OK, you could decide randomly- but then you’re just as likely to get (C,D) as (D,C).)
This is another sort of problem that TDT and UDT get right without any need for ad-hoc add-ons. The point is that advanced decision theories can be reasonably simple (where applications of Löb’s Theorem are counted as simple), get the right answer in all the cases where CDT gets the right answer (grabbing the highest utility when you’re the only agent around, finding the Nash equilibrium in a zero-sum game, etc), and also get the right answer when other agents are basing their decisions in a knowable way off of their predictions of what you’ll do in various hypotheticals. Newcomb’s Problem may sound artificial, but that’s because we’ve made that dependence as simple and deterministic as possible in order to have a good test problem.
Would you cooperate in the Prisoner’s Dilemma against an almost-copy of yourself (with only trivial differences so that your experiences would be distinguishable)? It can be set up so that neither of you decide within the light-cone of the other’s decision, so there’s no way your cooperation can physically ensure the other’s cooperation.
If you’re quite convinced that the reasonable thing is to defect, then pretty obviously you’ll get (D,D).
If you’re quite convinced that the reasonable thing is to cooperate, then pretty obviously you’ll get (C,C).
(OK, you could decide randomly- but then you’re just as likely to get (C,D) as (D,C).)
This is another sort of problem that TDT and UDT get right without any need for ad-hoc add-ons. The point is that advanced decision theories can be reasonably simple (where applications of Löb’s Theorem are counted as simple), get the right answer in all the cases where CDT gets the right answer (grabbing the highest utility when you’re the only agent around, finding the Nash equilibrium in a zero-sum game, etc), and also get the right answer when other agents are basing their decisions in a knowable way off of their predictions of what you’ll do in various hypotheticals. Newcomb’s Problem may sound artificial, but that’s because we’ve made that dependence as simple and deterministic as possible in order to have a good test problem.