Imagine that on learning of an impending disaster – perhaps a catastrophic asteroid strike on its planet – the machine resets its memory. Now, an observer sat next to the machine can verify that the “same machine” will still face disaster after the reset. But from the perspective of the machine’s reset memory, the state of the universe in the many-worlds scenario becomes “undetermined”. After all, for all the machine knows, the reset probably occurred for a mundane reason, such as a crash of its operating system.

The next part defies our natural instincts: according to the many-worlds interpretation, all of these undetermined possibilities actually exist and open up to the machine. Even though it followed one particular history up to its resetting, it can be dealt a new card, says Mitra.