"This doesn’t mean we have to go around in circles, though. Zeilinger tells me an instructive story. While a college student, he and a cousin backpacked around France on motor scooters. One night they pulled up to a youth hostel recommended by their guidebook, only to find it closed and abandoned. They decided to sneak in and sleep there anyway. As they settled in for the night, Zeilinger opened a window for air. A short while later, his cousin got up to close it. A while later, Zeilinger reopened it. And so it went all night. “I was convinced it was stuffy; he was convinced it was drafty,” Zeilinger remembers. Only in the morning did they notice that the window didn’t have any glass in it. Their nocturnal passive-aggressiveness had been pointless. For Zeilinger, the moral is that you always need to question your own assumptions."