Parallel reality refers to the idea that multiple, coexisting realities or universes exist simultaneously, often with variations in events, circumstances, or outcomes. This concept is popularly associated with the multiverse theory in physics, which suggests that every decision we make could create a new branch of reality.
In essence, if one decision leads to a different outcome, then in a parallel reality, that other choice is realized, leading to an entirely different set of circumstances. For instance, if you chose to take a particular job instead of another, one reality exists where you took the job, and another where you did not.
This concept is not just confined to science fiction; it also entertains philosophical discussions about fate, free will, and the nature of existence itself. Parallel realities challenge our understanding of the universe, suggesting that our perceived reality is just one of many possible experiences.