1.Grandfather paradox

The grandfather paradox is a hypothetical situation in which a time traveler goes back in time and attempts to kill his paternal grandfather at a time before his grandfather met his grandmother. If he did that, then his father never would have been born, and neither would the time traveler himself, in which case the time traveler never would have gone back in time to kill his grandfather.


2.Self-Visitation Paradox

Suppose that, on sunday at noon, Jack was sitting. The next Friday, jack time travels back to sunday at noon and stands while his younger self is sitting. Can Jack be both sitting and standing ? Time traveling seems to have provided us a way in which he can, though it also seems obvious that a person cannot be both sitting and standing at the same time. What is going on?


.