I originally posted the following: "... I believe I found a solution (or a negation) to one of temporal mechanics most enduring paradox: If you travel back in time, could you kill your own grandfather, thereby altering your future, even erasing yourself from existence? The short answer is NO. You can't. This is simply because the moment (present instant) you formulate the thought to travel back in time to do anything to alter your fate as you remember in that instant (past and present), the mere act of formulating the thought means that on fact you DID NOT travel back in time and altered your fate as you remember it in the first place. This is because if you did in fact travel back in time and altered your fate (past and present), you would (in the present instant you formulate the thought) already have the memory that you did in fact travel back in time and altered your fate. Since you do not have these memories (as you formulate the thought of traveling back in time in the first place), simply asking the question, rather than remembering past actions (remembering that you already traveled back in time and altered your future) , negates the paradox... ..." I received this response: "... This is too speculative. As far as I know, there has not been a conclusive physics experiment that has tested this issue. Therefore, all answers are purely hypothetical and philosophical. Hence, this discussion is better suited on some philosophy forum instead of PF. Thread locked. Do read this (section 4, 5 and 6): http://en.wikipedia.org/wiki/Time_travel#Time_travel_to_the_past_in_physics Any question about this can be asked in our forum. Personal theories such as the OP cannot be allowed as such..." Today, the following article appeared on Popular Mechanic: http://www.popsci.com/article/science/quantum-mechanics-saves-grandfathers-time-travelers Quantum Mechanics Saves Grandfathers From Time Travelers Probability solves a great question of time travel. Well, probably.