I think the excerpt is getting at “maybe all possible universes exist (no claim about likelihood made, but an assumption for the post), then it is likely that there are some possible universes—with way more resources than ours—running a simulation of our universe. the behaviour of that simulated universe is the same as ours (it’s a good simulation!) and in particular, the behaviour of the simulations of us are the same as our behaviours. If that’s true, our behaviours could, through the simulation, influence a much bigger and better-resourced world. If we value outcomes in that universe the same as in ours, maybe a lot of the value of our actions comes from their effect on the big world”.
I don’t know whether that counts as the world likely could be a simulation according to how you meant that? In particular, I don’t think Wei Dai is assuming we are more likely in a simulation than not (or, as some say, just “more in a simulation than not”).
I think the excerpt is getting at “maybe all possible universes exist (no claim about likelihood made, but an assumption for the post), then it is likely that there are some possible universes—with way more resources than ours—running a simulation of our universe. the behaviour of that simulated universe is the same as ours (it’s a good simulation!) and in particular, the behaviour of the simulations of us are the same as our behaviours. If that’s true, our behaviours could, through the simulation, influence a much bigger and better-resourced world. If we value outcomes in that universe the same as in ours, maybe a lot of the value of our actions comes from their effect on the big world”.
I don’t know whether that counts as the world likely could be a simulation according to how you meant that? In particular, I don’t think Wei Dai is assuming we are more likely in a simulation than not (or, as some say, just “more in a simulation than not”).