Paradoxes of Time Travel
by Ryan Wasserman
Ryan Wasserman’s philosophical book is one of two books* that need to live on your
nonfiction shelf. One by one and with complete reference to the past literature, he
presents all the major paradoxes of time travel along with different models of time
travel and arguments against time travel even being possible. Just get it and read it
cover-to-cover. As a bonus, Professor Wasserman, who is on the Philosophy faculty at
Western Washington State University, will cheerfully have discussions about time travel
issues via e-mail with those of us up in the nearby ITTDB Citadel.
* The other, of course, is Paul J. Nahin’s Time Machines: Time Travel in Physics, Metaphysics and Science Fiction, Second Edition.
— Michael Main
Each of the foregoing cases involves a self-defeating act—an act
such that, if it were performed, it wold not be. Self-defeating acts are obviously
impossible, since the performance of such an act would imply a contradiction. Yet time
travel seems to make such acts possible. This suggests the following line of argument
against backward time travel:
(P1) If backward time travel were possible, it would be possible to perform a self-defeating act.
(P2) It is impossible to perform a self-defeating act.
(C) Backward time travel is impossible.
Paradoxes of Time Travel by Ryan Wasserman (Oxford
University Press, 2018).