To quote the adage, I'm a solipsist, and am surprised everyone else isn't too. I think any intelligent agent should conclude that it is probably something akin to a Boltzmann brain. You could plausibly argue that I am cheating with pronoun references (other people might agree with the solipsistic logic, but centered around them). Is that what you are asking?
EDIT
Is there anything about the world that you expect would appear different to you because of this belief?
Not really. I think some of the problems with AIXI may be AIXI acting rationally where the desired behavior is irrational, but that's the only time I can think of it coming up outside of a philosophy discussion.
I often use the concept of Boltzmann brain to relax or fall asleep. Thinking that this is the only moment you will ever get to feel alive and you will die a few moments from now is a good way to put your mind "in the now". That said, if it actually were true I would expect the reality I perceive to be radically different. Almost everything I know about the outside world is really consistent and ordered and everything I've ever experienced supports the mainstream physical model of the universe. I don't think there would be an entire history of the...
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.