Right, dissecting why that answer would be worthless is part of the fun of the thought experiment. It seems like it should be ... spectacularly interesting to somehow discover that your entire memory is a lie and the world you're in is radically different than you thought, but the fact you can't do anything with that knowledge completely neuters it. It implies that in the calculation my mind does about how much I care about a possibility, there's something like a term for "how much control (or even a vague casual connection) do I have over the world?" that everything or nearly everything else is multiplied by. Even if a deity told me I was a Boltzmann brain, I would still hang on to the minuscule chance or delusion that I was a human and still process decisions that way, because in some sense I fundamentally can't care about a situation where there's zero utility to be gained besides as a curiosity. It feels like this might be a useful intuition pump to think about concepts like motivation and learned helplessness. The fun in a thought experiment is how it gives you a new lens to view other concepts with.
