The Open Thread posted at the beginning of the month has gotten really, really big, so I've gone ahead and made another one. Post your new discussions here!
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.
The reason I think it can just be a one-time shock is that we can extend our preferences to cover all possible mathematical structures. (I talked about this in Towards a New Decision Theory.) Then, no matter what kind of universe we turn out to live in, whichever theory of quantum gravity turns out to be correct, the structure of the universe will correspond to some mathematical structure which we will have well-defined preferences over.
I addressed this issue a bit in that post as well. Are you not convinced that rational decision-making is possible in Tegmark's Level IV Multiverse?
I define the following structure: if you take action a, all possible logically possible consequences will follow, i.e. all computable sensory I/O functions, generated by all possible computable changes in the objective physical universe. This holds for all a. This is facilitated by the universe creating infinitely many copies of you every time you take an action, and there being literally no fact of the matter about which one is you.
Now if you have already extended your prefere... (read more)