The theory is that after a couple of days of you short circuit the natural sleep cycle, to go into REM sleep instantly when you sleep. As we only experience about 2 hrs of REM sleep per night, you get all of the sleep you need in these 15-20 min bursts, every 4 hrs or so. Think how when you’re really tired, a little nap will fully refresh you for a few hrs., but sleep a little longer, and your fucked!
We don’t have to be special though. We can only exist at certain points in space time, under certain conditions. Those conditions are currently met, therfore we can exist, regardless of the infinite time/space conditions where we can’t.