If I contend that time travel into the past is not possible in any possible version of future reality that we can access since no time traveller from the future has yet presented themselves to rebuff this contention, can my statements be realistically defended?
This, of course, does not directly rule out future (or past) travel into the future in excess of the local passage of time, but it does preclude the discovery of time portals where we find a way to make relative reference (t-1,t,x,y,z) == (t-1,t1,x,y,z) and also follows that we cannot have (t-1,t,x,y,z) == (t-1,t,x,y,z)1 which does not alone preclude finding a way to teleport (or wormhole) where a plane or an area defined by {(t-1,t,x,y,z),(t-1,t,x,y,z)1} == {(t-1,t,x1,y1,z1),(t-1,t,x1,y1,z1)1}
I would prefer if answers must reference (t,x,y,z) that they also reference t-1 for the scale of spacetime at (t,x,y,z) in the form (t-1,t,x,y,z).
EDIT: Alright, I can see that similar statements have been made previously as shown in answers (not questions!), and by well-known names in science but, that does not explain how this question is a duplicated of another question.
I am not asking, "Is it possible to go back in time?", I am asking "Is this statement defensible?".