Does the Boltzmann brain scenario also assume that the laws of physics are presented consistently for each individual brain? In other words:
1) Why do we assume that the types of brains fluctuated into existence bear the same relation to the "external world" in order to make sense of that external world? i.e. we assume that the laws of physics are presented consistently to each individual brain.
2) Is it not more feasible that the types of brains fluctuated into existence will be brain states that are doing no more than e.g. making sense of its own brain, rather than simply responding to its environment in the way the orthodox view describes?
It seems perfectly reasonable to imagine brains to be in states in which we perceive the laws of physics to be different to what they actually are.