Single Timeline
The single timeline theory suggests that time is fixed and unchangeable. There is only one timeline, and everything that happens — including time travel — is already part of it. However, there are two major interpretations: 1. Single Timeline With the Grandfather Paradox In this version, if a person goes back in time and changes something significant (like killing their grandfather), it would create a paradox. They would never be born to commit that action, creating a logical contradiction. This form of the theory suggests that time travel to the past is either impossible or leads to universe-breaking paradoxes. 2. Single Timeline Without the Grandfather Paradox This version avoids paradoxes by assuming that anything a time traveler does in the past has already happened. If you go back in time, your actions were always part of history — and you cannot change the outcome. You may try to kill your grandfather, but you’ll always fail, or somet...