“It’s not that they “perceive” a universe more chaotic than ours — it’s that they would dominate the total number of observers if the universe really were more chaotic than ours. (Which it isn’t!) Also, they would tend to dissolve back into the chaos from which they came…”

If we set aside the empirical fact that BBs do not dominate over normal observers, then from the standpoint of our present understanding, whether BBs dominate or not can be posed simply as a question of measure — the universe need not be any “more chaotic” than ours. [For instance, if our universe is all there is, the dark energy is cosmological constant, and the correct measure respects FRW symmetry, then BBs dominate; but I wouldn't think one would call such a possibility "more chaotic" than those that fix the BB problem.]

There will be BBs who perceive the universe as it is, chaotic or not. But, *typical* BBs will experience the minimal delusion necessary to qualify as a member of the reference class of observers in question — presumably this permits “perceptions” (really delusions) much more chaotic than ours. [That is, there are BBs who resemble Sean Carroll insofar as to have the same DNA and experiences, having evolved from more primitive life etc in a solar system like ours, only the solar system arose via quantum fluctuation and these Sean Carrolls looks into space and sees emptiness. But, among a reference class of observers defined by the memory of some set of experiences of Sean Carroll, the dominant BBs will be those who have false memories that by chance coincide with those of "normal" Sean Carrolls', insofar as such correspondence is demanded. Insofar as it is not specified (for instance, if one does not demand all Sean Carrolls always have a white whiteboard in their office), then the BBs will have more chaotic perceptions (like writing-boards that change color from time to time). But again these "perceptions" are more chaotic because they are really delusions.]

Also, while thermal fluctuation BBs will “dissolve back into the chaos,” quantum fluctuation BBs (in dS, for instance) would not. They persist as long as their life support permits, and indeed an entire solar system may fluctuate in this way and allow for evolution and “real” experiences etc.

Telling people who have wacky theories about things that contradict science and reason that they must have Boltzmann Brains has been more rewarding (and less detrimental to my own safety) than telling them that they are full of crap.

They would perceive nothing unless they have sensory organs.

I’m pretty sure Amadeus (the character pictured) is just showing off his knowledge in an attempt to make the girl think he knows what’s going on, rather than actually thinking they’re Boltzmann brains…