Parallel worlds

According to the many worlds theory, 'the universe (or multiverse in this context) is composed of a quantum superposition of very many, possibly even non-denumerably infinitely many, increasingly divergent, non-communicating parallel universes or quantum worlds'.

Some people, particularly science fiction writers, like to imagine this means there are a near-infinite number of parallel versions of themselves inhabiting all sorts of exotic parallel worlds (usually featuring airships).

However, each of us is a product of a unique set of circumstances, each of which had to happen for us to have been born. The vast majority of parallel worlds, by definition, are worlds in which different things happen – that is, worlds in which you were never born. And the worlds in which parallel versions of you do exist will be substantially similar to this one, their only differences being the different possible courses your life can take.

Therefore, if you could travel between parallel worlds, the chances of meeting an alternate version of yourself would be vanishingly small, and the outcome if it did happen fairly boring.