Time Travel: Probability and Impossibility

October 31, 2020
Time Travel: Probability and Impossibility

There are various arguments for the metaphysical impossibilityof time travel. Is it impossible because objects could then be intwo places at once?Or is it impossible because some objects could bring about theirown existence?In this book, Nikk Effingham contends that no such argument issound and that time travel is metaphysically possible.His main focus is on the Grandfather Paradox: the position thattime travel is impossible because someone could not go back in timeand kill their own grandfather before he met their grandmother.In such a case, Effingham argues that the time traveller wouldhave the ability to do the impossible (so they could kill theirgrandfather) even though those impossibilities will never comeabout (so they won't kill their grandfather). He then explores theramifications of this view, discussing issues in probability anddecision theory.The book ends by laying out the dangers of time travel and why,even though no time machines currently exist, we should pay extraspecial care ensuring that nothing, no matter how small ormicroscopic, ever travels in time.