I do not understand - and I mean this respectfully - why anyone would care about Newcomblike problems or UDT or TDT, beyond mathematical interest. An Omega is physically impossible - and if I were ever to find myself in an apparently Newcomblike problem in real life, I'd obviously choose to take both boxes.
So as several people said, Omega is probably more within the realm of possibility than you give it credit for, but MORE IMPORTANTLY, Omega is definitely possible for non-humans. As David_Gerard said, the point of this thought exercise is for AI, not for humans. For an AI written by humans, we can know all of its code and predict the answers it will give to certain questions. This means that the AI needs to deal with us as if we are an Omega that can predict the future. For the purposes of AI, you need decision theories that can deal with entities having arbitrarily strong models of each other, recursively. And TDT is one way of trying to do that.
Previous Open Thread: http://lesswrong.com/r/discussion/lw/k9x/open_thread_may_26_june_1_2014/
(oops, we missed a day!)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
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