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!"