Bootstrap paradox
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The bootstrap paradox, or ontological paradox, is a paradox of time travel that refers to scenarios whereby items or information are passed from the future to the past, which in turn become the same items or information that are subsequently passed from the past to the future - this creates a circularity of cause-effect such that the items or information have no discernible origin. Thus, the paradox raises the ontological questions of where, when and by whom the items were created or the information derived.
After information or an object is sent back in time, it is recovered in the present and becomes the very object or information that was initially brought back in time in the first place. Numerous science fiction stories are based on this paradox, which has also been the subject of serious physics articles.[1]
The term "bootstrap paradox" refers to the expression "pulling yourself up by your bootstraps"; the use of the term for the time-travel paradox was popularized by Robert A. Heinlein's story By His Bootstraps.
Definition
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Because of the possibility of influencing the past while time travelling, one way of explaining why history does not change is to posit that these changes already are contained self-consistently in the past timeline. A time traveller attempting to alter the past in this model, intentionally or not, would only be fulfilling his or her role in creating history, not changing it. The Novikov self-consistency principle proposes that contradictory causal loops cannot form, but that consistent ones can.
However, a scenario can occur where items or information are passed from the future to the past, which then become the same items or information that are subsequently passed back. This not only creates a loop, but a situation where these items have no discernible origin. Physical items are even more problematic than pieces of information, since they should ordinarily age and increase in entropy according to the Second law of thermodynamics. But if they age by any nonzero amount at each cycle, they cannot be the same item to be sent back in time, creating a contradiction.
Another problem is the "reverse grandfather paradox", where whatever is sent to the past allows the time travel in the first place (such as saving your past self's life, or sending vital information about the time travel mechanism).
The paradox raises the ontological questions of where, when and by whom the items were created or the information derived. Time loop logic operates on similar principles, sending the solutions to computation problems back in time to be checked for correctness without ever being computed "originally".
Whether or not a scenario described in this paradox would actually be possible, even if time travel itself were possible, is not presently known.
The bootstrap paradox is incorrectly thought of as different than the predestination paradox, in which individuals or information travel back in time and ultimately trigger events they already experienced in their own present, but is actually just another form of the same paradox. The difference being that in the latter case, the events are consistent with what happened the first time. In the former, events ultimately go in a new direction.
In fiction
The bootstrap paradox has been used in fictional stories and films.[2] In the 1980 romance film Somewhere in Time, based on Richard Matheson's 1975 novel Bid Time Return, an elderly woman gives a young man a pocket watch in 1972. He travels back in time to 1912 and gives the pocket watch to her, which she carries with her until 1972 when she meets the young man and gives the watch to him.[3] The concept is named from the Robert Heinlein story "By His Bootstraps",[2] which is considered the "ultimate time travel paradox tale" of its time.[4] Don D'Amassa states that "The greatest difficulty in creating a story of this type is not so much the plotting of the various times loops, but to render them in such a way that the reader can follow the logic."[4]
The movie Time Lapse is built entirely around the concept of bootstrap paradox.[5]
See also
- Grandfather paradox
- Newcomb's paradox
- Predestination paradox
- Self-fulfilling prophecy
- Strange loop
- Temporal paradox
- The chicken or the egg
- Time travel in fiction
- Schrödinger's Cat
References
- ^ Matt Visser (1995). Lorentzian wormholes.
Bootstrap paradoxes A second class of logical paradoxes ...
{{cite book}}: Cite has empty unknown parameter:|coauthors=(help) - ^ a b Klosterman, Chuck (2009-10-20). Eating the Dinosaur. Simon and Schuster. p. 60. ISBN 9781439168486. Retrieved 2 February 2013.
- ^ Everett, Allen; Roman, Thomas (2011-12-15). Time Travel and Warp Drives: A Scientific Guide to Shortcuts through Time and Space. University of Chicago Press. p. 138. ISBN 9780226224985. Retrieved 3 February 2013.
- ^ a b D'Ammassa, Don (2005). Encyclopedia Of Science Fiction. Infobase Publishing. p. 67. ISBN 9780816059249. Retrieved 3 February 2013.
- ^ http://www.astronomytrek.com/time-lapse-2014-explained/