> a single brain to spontaneously and briefly form in a void I recall first hearing about this by being introduced to it via the "giant marshmallow hypothesis"

> a single brain to spontaneously and briefly form in a void I recall first hearing about this by being introduced to it via the "giant marshmallow hypothesis"†: it's somewhat equally likely that a giant marshmallow spontaneously and briefly form in a void. A Boltzmann brain is then merely a different arrangement of atoms and stuff. † I don't think it has a specific name.