Also Keith's reference to Boltzmann brains- it seemed clever in 19-oh-whatever,

New Scientist May 2013
"Physicists have dreamed up some bizarre ideas over the years, but a decade or so ago they outdid themselves with the concept of Boltzmann brains – fully formed, conscious entities that form spontaneously in outer space.

It may seem impossible for a brain to blink into existence, but the laws of physics don't rule it out entirely. All it requires is a vast amount of time. Eventually, a random chunk of matter and energy will happen to come together in the form of a working mind. It's the same logic that says a million monkeys working on a million typewriters will replicate the complete works of Shakespeare, if you leave them long enough.

Most models of the future predict that the universe will expand exponentially forever. That will eventually spawn inconceivable numbers of Boltzmann brains, far outnumbering every human who has ever, or will ever, live."