Temporal paradox

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This article is about logical problems involved in the concept of time travel. For the controversy over the origin of birds, see temporal paradox (paleontology).

A temporal paradox, time paradox, or time travel paradox is a paradox, an apparent contradiction, or a logical contradiction that is associated with the idea of time and time travel. Temporal paradoxes fall into two broad groups: consistency paradoxes exemplified by the grandfather paradox; and causal loops.[1]

Causal loop[edit]

Main article: Causal loop

A causal loop is a paradox of time travel that occurs when a future event is the cause of a past event, which in turn is the cause of the future event. Both events then exist in spacetime, but their origin cannot be determined. A causal loop may involve an event, a person or object, or information.[1][2] A causal loop is also known as a boot-strap paradox, predestination paradox or ontological paradox in fiction.[3][4]

Grandfather paradox[edit]

Main article: Grandfather paradox

The consistency paradox or grandfather paradox occurs when a future event prevents the occurrence of a past event that was partly or entirely the cause of the future event, thereby preventing the future event from occurring, thus creating a contradiction.[2] Consistency paradoxes occur whenever changing the past is possible.[1]

References[edit]

  1. ^ a b c Francisco Lobo (2002). "Time, Closed Timelike Curves and Causality" (PDF). p. 2. Retrieved November 2, 2015. 
  2. ^ a b Nicholas J.J. Smith (2013). "Time Travel". Stanford Encyclopedia of Philosophy. Retrieved November 2, 2015. 
  3. ^ Leora Morgenstern (2010), Foundations of a Formal Theory of Time Travel (PDF), p. 6, retrieved November 2, 2015 
  4. ^ Klosterman, Chuck (2009). Eating the Dinosaur (1st Scribner hardcover ed.). New York: Scribner. p. 60. ISBN 9781439168486. Retrieved 2 February 2013. 

See also[edit]