It's metaphorical. There are unwritten words implied:
  "The Entire Universe [of your Understanding of the Universe] is
  in your mind and nowhere else."

  It's not that hard. Deepak steals quotes and writes in
  metaphorical form, not literal form.

  So did my pal Carl Sagan. How disappointed was I when I tracked
  down "We are all made of stardust" and found out it WASN'T Sagan
  at all. He happily stole quotes too and attributed them to
  himself. Tyson, Krauss and Bill Nye also love stealing Sagan
  quotes... which usually turned out not to be Sagan quotes
  either, and allowing themselves to be liberally quoted as the
  sources.

  Oh well. He inspired me, so that was good. End justifies the
  means I guess. Still hate misattributed quotes 'cause dead
  people can't rise up and say, I NEVER SAID THAT! or HEY! THOSE
  WERE MY WORDS - YOU STOLE MY WORDS, JACKASS!"