Editing Time travel (section)

=== Presentism vs. eternalism ===
Many philosophers have argued that relativity implies [[Eternalism (philosophy of time)|eternalism]], the idea that the past and future exist in a real sense, not only as changes that occurred or will occur to the present.<ref name="Crisp">{{citation|chapter=Presentism, Eternalism, and Relativity Physics|title=Einstein, Relativity and Absolute Simultaneity|author=Thomas M. Crisp|editor1=William Lane Craig|editor2=Quentin Smith|page=footnote 1|chapter-url=https://thomasmcrisp.files.wordpress.com/2017/07/presentism-eternalism-and-relativity-physics.pdf|year=2007|access-date=2018-02-01|archive-date=2018-02-02|archive-url=https://web.archive.org/web/20180202012816/https://thomasmcrisp.files.wordpress.com/2017/07/presentism-eternalism-and-relativity-physics.pdf|url-status=live}}</ref> Philosopher of science [[Dean Rickles]] disagrees with some qualifications, but notes that "the consensus among philosophers seems to be that special and general relativity are incompatible with presentism".<ref>{{citation|author=Dean Rickles|year=2007|title=Symmetry, Structure, and Spacetime|url=https://books.google.com/books?id=gDwJYtfoCh8C&pg=PA158|page=158|publisher=Elsevier |access-date=July 9, 2016|isbn=9780444531162|archive-date=March 24, 2023|archive-url=https://web.archive.org/web/20230324181809/https://books.google.com/books?id=gDwJYtfoCh8C&pg=PA158|url-status=live}}</ref> Some philosophers view time as a dimension equal to spatial dimensions, that future events are "already there" in the same sense different places exist, and that there is no objective flow of time; however, this view is disputed.<ref>{{citation|author=Tim Maudlin|title=The Metaphysics Within Physics|isbn=9780199575374|year=2010|chapter=On the Passing of Time|publisher=Oxford University Press |chapter-url=https://philocosmology.rutgers.edu/images/uploads/TimDavidClass/05-maudlin-chap04.pdf|author-link=Tim Maudlin|access-date=2018-02-01|archive-date=2021-03-08|archive-url=https://web.archive.org/web/20210308030324/https://philocosmology.rutgers.edu/images/uploads/TimDavidClass/05-maudlin-chap04.pdf|url-status=live}}</ref>

[[Presentism (philosophy of time)|Presentism]] is a school of philosophy that holds that the future and the past exist only as changes that occurred or will occur to the present, and they have no real existence of their own. In this view, time travel is impossible because there is no future or past to travel to.<ref name="Crisp" /> Keller and Nelson have argued that even if past and future objects do not exist, there can still be definite truths about past and future events, and thus it is possible that a future truth about a time traveler deciding to travel back to the present date could explain the time traveler's actual appearance in the present;<ref name="Presentism">{{cite journal|first=Simon|last=Keller|author2=Michael Nelson|title=Presentists should believe in time-travel|url=http://people.bu.edu/stk/Papers/Timetravel.pdf|journal= Australasian Journal of Philosophy|volume=79|issue=3|pages=333–345|date=September 2001|doi=10.1080/713931204|s2cid=170920718|url-status=dead|archive-url=https://web.archive.org/web/20081028211537/http://people.bu.edu/stk/Papers/Timetravel.pdf|archive-date=October 28, 2008}}</ref> these views are contested by some authors.<ref name="Bourne">{{cite book|author=Craig Bourne|title=A Future for Presentism|url=https://books.google.com/books?id=DJMSDAAAQBAJ|date=7 December 2006|publisher=Clarendon Press|isbn=978-0-19-921280-4}}</ref>