(2018-05-04, 06:56 PM)Sciborg_S_Patel Wrote: Does Linear Time (tm) realy exist at the fundamental level?
Time is at least in part the measure of change, so the fundamental level of reality must have at least some timelike properties in order for it to be at all interesting, in particular for it to contain conscious beings (consciousness requires change to exist). If this timelike property of the ultimate level of reality is nonlinear, then all bets are off as to whether coherent consciousness could exist in it.
Quote:Is time travel possible? Are there time travelers among us?
Because of the many kinds of well-known untenable paradoxes it entails, time travel is probably impossible. The following would be just one of the types, an alternate form of the "grandfather paradox":
The purposeful complex ordered configurations of information constituting human invention and artistic creation must necessarily have had a definite origin in time in the creative thoughts and intuitions of an intelligent human mind.
Let's say that in the future a time machine is invented, and its inventor decides to shortcut human creative invention and change history by sending back a technological invention and a work of art to before their historical creators were born. Say the design of the light bulb and a Rembrandt portrait. A situation would then exist in the subsequent timeline that an invention and a work of art would exist in our world that had no creation by human (in this case Edison and Rembrandt) or indeed any other minds. But we know that of absolute necessity these constructs had to have somehow been created by mind(s).
Of course, this interference with past human events might easily change subsequent history so that the time traveler is never born. But he must exist. So the foregoing is just one of the paradoxes created in this thought experiment.
So it appears that at least this particular type of time travel is impossible.
The only way out of this seems to be the last resort of positing some sort of overarching hyperdimensional continuum of which our universe is just a part. If the largest scale of this continuum includes absolutely everything (including the history of the time traveler and his world), at that ultimate level of reality all timelines would exist and the invention and the work of art would indeed still have had conscious creators. At least that paradox would be avoided.
Anyway, since time travel is probably impossible, there probably are no time travelers.