UDT is provably optimal if it has correct priors over possible universes and the universe can read its mind only through determining its behavior in hypothetical situations (because UDT basically is just find the behavior pattern that optimizes expected utility and implement that).
On the other hand, SMCDT is provably optimal in situations where it has an accurate posterior probability distribution, and where the universe can read its mind but not its initial state (because it just instantly self-modifies to the optimally performing program).
I don’t see why the former set of restrictions is any more reasonable than the latter, and at least for SMCDT you can figure out what it would do in a given situation without first specifying a prior over possible universes.
I’m also not convinced that it is even worth spending so much effort trying to decide the optimal decision theory in situations where the universe can read your mind. This is not a realistic model to begin with.
Actually, I take it back. Depending on how you define things, UDT can still lose. Consider the following game:
I will clone you. One of the clones I paint red and the other I paint blue. The red clone I give $1000000 and the blue clone I fine $1000000. UDT clearly gets expectation 0 out of this. SMCDT however can replace its code with the following:
If you are painted blue: wipe your hard drive
If you are painted red: change your code back to standard SMCDT
Thus, SMCDT never actually has to play blue in this game, while UDT does.
You seem to be comparing SMCDT to a UDT agent that can’t self-modify (or commit suicide). The self-modifying part is the only reason SMCDT wins here.
The ability to self-modify is clearly beneficial (if you have correct beliefs and act first), but it seems separate from the question of which decision theory to use.
OK. Fine. I will grant you this:
UDT is provably optimal if it has correct priors over possible universes and the universe can read its mind only through determining its behavior in hypothetical situations (because UDT basically is just find the behavior pattern that optimizes expected utility and implement that).
On the other hand, SMCDT is provably optimal in situations where it has an accurate posterior probability distribution, and where the universe can read its mind but not its initial state (because it just instantly self-modifies to the optimally performing program).
I don’t see why the former set of restrictions is any more reasonable than the latter, and at least for SMCDT you can figure out what it would do in a given situation without first specifying a prior over possible universes.
I’m also not convinced that it is even worth spending so much effort trying to decide the optimal decision theory in situations where the universe can read your mind. This is not a realistic model to begin with.
Actually, I take it back. Depending on how you define things, UDT can still lose. Consider the following game:
I will clone you. One of the clones I paint red and the other I paint blue. The red clone I give $1000000 and the blue clone I fine $1000000. UDT clearly gets expectation 0 out of this. SMCDT however can replace its code with the following: If you are painted blue: wipe your hard drive If you are painted red: change your code back to standard SMCDT
Thus, SMCDT never actually has to play blue in this game, while UDT does.
You seem to be comparing SMCDT to a UDT agent that can’t self-modify (or commit suicide). The self-modifying part is the only reason SMCDT wins here.
The ability to self-modify is clearly beneficial (if you have correct beliefs and act first), but it seems separate from the question of which decision theory to use.