The possible universes I am considering already come packed into a future light cone (I don't consider large universes directly).
I was a bit surprised by this... if your possible models only include one light-cone (essentially just the observable universe) then they don't look too different from those of my stated hypothesis (at the start of the thread). What is your opinion then on other civilisations in the light-cone? How likely are these alternatives?
..it will encourage betting on really dense universes (packed full of people or simulations of people).
Not really. Additive terms in the utility don't "encourage" anything, multiplicative factors do.
Here's how it works. Imagine the "mugger" offers all observers a bet (e.g. at your 1000:1 on odds) on whether they believe they are in a simulation, within a dense "computronium" universe packed full of computers simulating observers. Suppose only a tiny fraction (less than 1 in a trillion) universe models are like that, and the observers all know this (so this is equivalent to a very heavily weighted coin landing against its weight). But still, by your proposed utility function, UDT observers should accept the bet, since in the freak universes where they win, huge numbers of observers win $1 each, adding a colossal amount of total utility to the light-cone. Whereas in the more regular universes where they lose the bet, relatively fewer observers will lose $1000 each. Hence accepting the bet creates more expected utility than rejecting it.
Another issue you might have concerns the time-discounting. Suppose 1 million observers live early on in the light-cone, and 1 trillion live late in the light-cone (and again all observers know this). The mugger approaches all observers before they know whether they are "early" or "late" and offers them a 50:50 bet on whether they are "early" rather than "late". The observers all decide to accept the bet, knowing that 1 million will win and 1 trillion will lose: however the utility of the losers is heavily discounted, relative to the winners, so the total expected time-discounted utility is increased by accepting the bet.
I was a bit surprised by this... if your possible models only include one light-cone (essentially just the observable universe) then they don't look too different from those of my stated hypothesis (at the start of the thread).
My disagreement is that the anthropic reasoning you use is not a good argument for non-existence of large civilizations.
How likely are these alternatives? ...
I am using a future light cone whereas your alternatives seem to be formulated in terms of a past light cone. Let me say that I think the probability to ever encounter an...
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.