[frotaur]

The conclusion only holds if you assume that you yourself are not a BB. Yes, in our universe, the laws of physics predict that BBs are much more likely than normal brains, given you wait long enough.

However, the moment you assume that then it must mean that you yourself are a BB, the argument breaks down. Because the huge probability of BB applies only to the laws of physics of the universe you live in; if you are a BB, the laws of physics of your universe have no reason to be the same as the laws of physics in the actual universe, where the BB exists. Thus, you can make no prediction on the likelihood of a BB arising, since you don't know the physics of the actual universe.

[jvanderbot]

I'm confused. We make predictions about things we don't fully understand all the time. And about things we cannot possibly perceive. We do so by recognizing patterns across things we can see, and probing the relationship to the things we cannot. (See could mean any perception).

It's not guaranteed we could do that, even in our universe it's not guaranteed, but it's also not ruled out.