Paradoxes

Paradoxes are theories that could be problematic in the current understanding of Time Travel.

The most famous of these is the "Grandfather Paradox" which is the question of how a traveler could go back in the past and murder one of their biological grandfathers before he met his wife even if such would erase their existence and therefore make the murder impossible to happen.

Similar to this would be preventing a bad event in the past because this changes the timeline and therefore removes the validity of the futuristic account along with the reason for going back. The example of Michael Phillips causes a credibility issues when he describes World War 3 beginning with a nuclear exchange with North Korea but then says the conflict was avoided. He also brings up the John Titor story which despite to be widely understood to be a hoax somehow prevented a Second American Civil War in 2008 by allowing the 9/11 terror attacks to happen.

An explanation that reduces these paradoxes is that of parallel universes.