He closed by outlining “M-theory,” which is based partly on ideas put forward years ago by another famed physicist, Caltech’s Richard Feynman. Hawking sees that theory as the only big idea that really explains what he has observed.

M-theory posits that multiple universes are created out of nothing, Hawking explained, with many possible histories and many possible states of existence. In only a few of these states would life be possible, and in fewer still could something like humanity exist. Hawking mentioned that he felt fortunate to be living in this state of existence.