Because imaginary time behaves like another direction in space, histories in imaginary time can be closed surfaces, like the surface of the Earth, with no [existential] beginning or end.
The life we have on Earth must have spontaneously generated itself. It must therefore be possible for life to generate spontaneously elsewhere in the universe.
![Because imaginary time behaves like another direction in space, histories in imaginary time can be closed surfaces, like the surface of the Earth, with no [existential] beginning or end.](http://cdn.quoteddaily.com/images/stephen-hawking/because-imaginary-time-behaves-like-another-direction-in-space-histories-in-imaginary-time-can-be-closed-surfaces-like-the-surface.jpg)
