A self-modifying AI is built to serve humanity. The builders know, of course, that this is much riskier than it seems, because its success would render their own observations extremely rare. To solve the problem, they direct the AI to create billions of simulated humanities in the hope that this will serve as a Schelling point to them, and make their own universe almost certainly simulated.
Plausible?
I'm not 'denying causality', I'm pointing out a way around it.
You say that one can change A by changing B, while there is no causal mechanism by which B can influence A. That's denying causality.
Well, if you don't like the term 'denying causality', feel free to replace it, but the point holds anyway.
In my prior probabilities system, finding a way around causality is somewhere near finding a way around energy conservation law. No way, unless there are tons of evidence.