Here's some background on Boltzmann brains for those unfamiliar with the term:
https://en.wikipedia.org/wiki/Boltzmann_brain
"The
Boltzmann brain thought experiment suggests that it might be more likely for a single brain to spontaneously form in a void (complete with a memory of having existed in our universe) rather than for the entire universe to come about in the manner cosmologists think it actually did. Physicists use the Boltzmann brain thought experiment as a
reductio ad absurdum argument for evaluating competing scientific theories.
In contrast to
brain in a vat thought experiments which are about perception and thought, Boltzmann brains are used in
cosmology to test our assumptions about
thermodynamics and the development of the universe. Over a sufficiently long time, random fluctuations could cause
particles to spontaneously form literally any structure of any degree of complexity, including a functioning human brain. In this
thought experiment, a Boltzmann brain is a fully formed brain, complete with memories of a full human life, that arises out of
thermodynamic equilibrium. The scenario initially involved only a single brain with false memories, but physicist
Sean Carroll pointed out that entire bodies, even entire worlds and solar systems are more likely to be Boltzmann entities in a randomly fluctuating universe..."