An unambiguous recipe cannot exist since it would have to give precise answers to ambiguous questions such as: if there are two identical simulations of you running on two computers, should they be counted as two copies or one?
Well this is your utility function, so you tell me! Imagine a hacker is able to get into the simulations and replace pleasant experiences by horrible torture. Does your utility function care twice as much if he hacks both simulations versus hacking just one of them? (My guess is that it does).
It wouldn't be exactly twice but you're more or less right. However, it has no direct relation to probability. To see this, imagine you're a paperclip maximizer. In this case you don't care about torture or anything of the sort: you only care about paperclips. So your utility function specifies a way of counting paperclips but no way of counting copies of you.
From another angle, imagine your two simulations are offered a bet. How should they count themselves? Obviously it depends on the rules of the bet: whether the payoff is handed out once or twice. Therefore, the counting is ambiguous.
What you're trying to do is writing the utility function as a convex linear combination of utility functions associated with different copies of you. Once you accomplish that, the coefficients of the combination can be interpreted as probabilities. However, there is no such canonical decomposition.
The 'Irrationality Game' posts in discussion came before my time here, but I had a very good time reading the bits written in the comments section. I also had a number of thoughts I would've liked to post and get feedback on, but I knew that being buried in such old threads not much would come of it. So I asked around and feedback from people has suggested that they would be open to a reboot!
I hereby again quote the original rules:
I would suggest placing *related* propositions in the same comment, but wildly different ones might deserve separate comments for keeping threads separate.
Make sure you put "Irrationality Game" as the first two words of a post containing a proposition to be voted upon in the game's format.
Here we go!
EDIT: It was pointed out in the meta-thread below that this could be done with polls rather than karma so as to discourage playing-to-win and getting around the hiding of downvoted comments. If anyone resurrects this game in the future, please do so under that system If you wish to test a poll format in this thread feel free to do so, but continue voting as normal for those that are not in poll format.