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!"