Temporal Paradox

We all know about the paradoxes of time travel. That includes the infamous Grandfather Paradox. However virtually all of them can be explained away with the existence of Parallel Universes within a grander Multiverse. There are also a number of other paradoxes ranging from the fields of science to philosophy. In this case we are looking for the ultimate paradoxes culminated from the most mind boggling questions humankind could never hope to comprehend!  The top three...