Are you an optimist or a pessimist?"
"I can't remember. Which?"
"Do you know what those words mean?"
"Not really."
"An optimist is positive and hopeful. A pessimist is negative and cynical."
"I'm an optimist."
"Well, that's good, because there’s no irrefutable evidence. There’s nothing that could convince someone who doesn’t want to be convinced. But there is an abundance of clues that would give the wanting believer something to hold on to.

Author: Jonathan Safran Foer