Ontological paradox

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An ontological paradox is a paradox of time travel that is often used as a convention in science fiction. It is very closely related to the predestination paradox and usually occurs at the same time.

Because of the possibility of influencing the past while time travelling, one way of explaining why history does not change is by saying that whatever has happened was meant to happen. A time traveller attempting to alter the past in this model, intentionally or not, would only be fulfilling his 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.

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."

It is sometimes called the Bootstrap paradox, in reference to its appearance in Robert A. Heinlein's story By His Bootstraps.

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[edit] Examples

On his 30th birthday, a man who wishes to build a time machine is visited by a future version of himself. This future self explains to him that he should not worry about designing the time machine, as he has done it in the future. The man receives the schematics from his future self and starts building the time machine. Time passes until he finally completes the time machine. He then uses it to travel back in time to his 30th birthday, where he gives the schematics to his past self, closing the loop.

Another example, involving more than one person:

A professor travels forward in time, and reads in a physics journal about a new equation that was recently derived. He travels back to his own time, and relates it to one of his students who writes it up, and the article is published in the same journal which the professor reads in the future.

[edit] Examples from fiction

Spoiler warning: Plot and/or ending details follow.

[edit] Literature

  • Robert A. Heinlein's stories By His Bootstraps and "—All You Zombies—" involve the predestination paradox, but also play with the ontological paradox. (indeed, the ontological paradox is sometimes called the "bootstrap paradox" in that story's honor). In By His Bootstraps, the protagonist is asked to go through a time portal by a mysterious stranger, a second stranger tries to stop him, and all three get into a fight which results in the protagonist being pushed through anyway. Ultimately, it is revealed that all three are the same person: the first visitor being his future self and the second an even older future self trying to prevent the loop from occurring. The ontological paradox here is in where and how the loop started in the first place. "—All You Zombies—" involves an even more convoluted time loop involving kidnapping, seduction, child abandonment and gender reassignment surgery, resulting in the protagonist creating the circumstances where he becomes his own mother and father.
  • In a storyline in the daily comic strip Calvin and Hobbes, Calvin attempted to create an ontological paradox by travelling two hours into the future to retrieve a story he had to write for homework and did not want to do. He reasoned that by that time it would be done and he could then bring it back to the past and spend the time goofing off instead of working. Of course, the future Calvin didn't have the homework either, having decided two hours previously to time-travel instead of doing it. Calvin eventually ended up fighting with two of his future selves, while Hobbes and his future self wrote a story based on the whole predicament. The story (which was about Hobbes saving the day) received an A+.
  • In Jasper Fforde's novel The Eyre Affair, a time-travelling character goes to Elizabethan times to discover who wrote Shakespeare's works. After discovering that neither Shakespeare, Marlowe, Bacon or anyone else seems to have written them, the character must give Shakespeare a copy of his own Complete Works and a rough timeline to ensure their existence in the future. (Confusing things further, however, the sequel revealed that the plays given to Shakespeare only included three comedies. The characters speculate that they proved so popular he wrote new ones himself. Fforde rather makes a point of not having his time travel follow any particular set of rules.)
  • Similarly, in Tim Powers' novel The Anubis Gates a time traveller attempts to visit the enigmatic 19th century poet William Ashbless, of whom he is a fan. The time traveller is unable to locate him and eventually realizes that he himself is destined to become Ashbless, "writing" Ashbless' works from memory.
  • The ontological paradox is mentioned in the Doctor Who Virgin New Adventures novel Happy Endings, in which, after taking the Isley Brothers to the 21st century, the Doctor warns them not to listen to any of their songs they haven't written yet, explaining that such information is "written by Time herself, and they contain messages".
  • In Harry Harrison's novel The Technicolor Time Machine, Barney Hendrickson travels back in time to present his earlier self with a note explaining how to resolve a seemingly insurmountable difficulty. The younger Barney carefully folds the note and puts it in his wallet, expressing his intention to leave it there until he reaches the point in his life where he travels back in time to hand it to his younger self. This prompts some discussion of how the note actually got written, and by whom, which the older Hendrickson dismisses by saying that the note was written by "time" because it needed to exist to allow the predestination paradox to play out. At the close of the novel, Hendrickson also discovers that by travelling back in time to film the Viking settling of America, he actually caused it to occur.
  • In the climax of J.K. Rowling's Harry Potter and the Prisoner of Azkaban, a series of events leading up to the apparent execution of Buckbeak and Sirius Black's imprisonment are revealed to be the doing of Harry and Hermione, who travel back in time to prevent the deaths of both. A true paradox is created when Harry realizes that the mysterious wizard who saved his life (and who Harry mistook to be his father) was actually his future self. He is able to create the life-saving Patronus because he knew he'd "already done it."

[edit] Film

  • In Star Trek II: The Wrath of Khan, Admiral Kirk receives a pair of antique eyeglasses from Doctor McCoy in the 23rd Century. Kirk subsequently leaves them in the 20th Century in Star Trek IV: The Voyage Home, implying that they would be a gift again. Although presumably the screenwriter's intent in Star Trek IV was to suggest a causal loop involving the glasses, the additional problem of the glasses aging by three centuries with each loop is never addressed.
  • Also in Star Trek IV, Scotty and McCoy also trade the formula for transparent aluminum to an engineer for materials needed to build a whale tank. Scotty eases McCoy's concerns about changing history by asking, "How do we know he didn't invent the thing?" In neither case presented in the movie is there actual evidence seen of the loop, however; the characters merely assume it. It is possible, of course, that no such causal loops are formed: the eyeglasses may not be destined to be the exact same pair McCoy gifts to Kirk, and the engineer might fail in his attempt to invent transparent aluminum. It is worth noting, however, that in the novelization of the film, Scotty recognizes the engineer's name as that of the inventor.
  • In the film Somewhere in Time, an elderly Elise McKenna gives Richard Collier a pocket watch which he then takes in time to hand it to her younger self, who will then, decades later, return it to him. As in Star Trek IV, in addition to the paradox, the problem of the watch aging with each loop is not addressed.
  • In Back to the Future, Marty McFly steps in for the guitarist at his parent's school dance and plays Chuck Berry's "Johnny B. Goode". Marvin Berry, the band's guitarist, calls his cousin Chuck and tells him that he found the "new sound" Chuck was looking for. (Chuck Berry was the one who originally performed Johnny B. Goode.)
  • Also in The Terminator, Kyle Reese, having traveled forty-five years into the past, gives Sarah a message from his commander John Connor, subsequently fathering John with Sarah. In Terminator 2: Judgment Day, John says that his mother made him memorize the message — which, ironically, says that the future can be changed — in order to give it to his father, so that his father might then pass it on to her. At no point do we learn when or how the message was originally composed. Similarly, Kyle shows Sarah how to fight Terminators. Sarah teaches the same methods to John, who trains Kyle in the future.
  • In A Chinese Odyssey, Stephen Chow's character, Joker, is abducted by demons who have taken him to a place called "Spiderweb Cave". At one point, he discovers a relic called the "Pandora's Box" which allows him to travel through time. He uses it several times in the movie until he accidentally sends himself back further. Joker then spots a woman passing by and he warns her not to go further because it's the Spiderweb Cave. The woman replies "Do you think I'm blind? The sign says Waterfall Cave". Which shocks Joker. The woman continues "Although, Spiderweb Cave does sound fitting". The woman is a demon who uses her magic and changes the sign to read Spiderweb Cave.

[edit] Television

  • In the Red Dwarf episode "Stasis Leak", Rimmer encounters the future holographic version of himself who tells him that the future crew had traveled back in time through a stasis leak found on one of the lower levels of the ship. He writes this in his diary. In the future, Lister reads Rimmer's diary and looks for the leak, which the crew finds and uses to travel back in time, where future Rimmer tells past Rimmer about the leak. The paradox not only involves the knowledge of the leak, but also the fact that the phenomenon itself is called a "stasis leak".
  • In the 1973 Doctor Who serial Day of the Daleks, a group of guerillas from the future are caught in a predestination paradox, doomed to create the very future they are trying to prevent. The Third Doctor breaks the loop, averting the future, because his existence is not dependent on the loop itself. However, he creates an ontological paradox in the process, because if the events that alerted him to the loop no longer exist, where did his knowledge of the loop come from?
  • In the 2002 Doctor Who webcast Real Time, Dr. Reese Goddard, a Cyberman from an alternate 1927 where the Earth had been infected by a virus that turned people into Cybermen, came to the planet Chronos to stop the Doctor from giving the Cybermen the virus in the first place. Goddard brought a modified version of the virus deadly to Cybermen, which the Cybercontroller captured and reverse engineered to create the virus which infected Earth. It also transpired that the Cybercontroller infected the Doctor's companion Evelyn Smythe with the virus, so that when she travelled into the past she would begin the infection and eventually become the Cybercontroller herself.
  • In the 2006 Doctor Who episode "New Earth", the Doctor sends Lady Cassandra (her consciousness in her dying clone servant Chip's body) back in time to meet her younger self. "Chip" tells the younger Cassandra she is beautiful and dies in her arms. Earlier in the episode, Cassandra had stated that she cloned Chip after her favorite "pattern", implying that she got it from the man who died in her arms so many years before and leaving the origin of Chip's pattern open.
  • In the anime series Generator Gawl, the genetic code that led to the creation of the generators is taken from Gawl, a generator who had traveled back in time to change the past.
  • In the Heroes episode "Hiros", the future Hiro gives Peter a message: "Save the cheerleader, save the world". In the next episode, Peter passes the message on to present Hiro, and tells him about the encounter with his future self.
  • In the Stargate SG-1 episode "1969", SG-1 accidentally travels back in time to the year 1969, where they are aided by Lt. Hammond because of a note his future self gave to Carter before they left, spurred by a familiar cut on Carter's hand. Recalling the memory of the future SG-1 visiting him early in his career, Gen. Hammond had ordered research into using the Stargate for time-travel and was subsequently able to provide them with the information they needed to get home—before they left. Also, the present-day Stargate program was presumably started after the airmen guarding it in 1969 saw the gate activated by SG-1.
  • In the Stargate SG-1 episode "Moebius", SG-1 travels back in time to Egypt around 3000 BC in an attempt to retrieve a piece of alien technology, and end up inciting the very rebellion that originally drove Ra away and freed Earth, allowing it to progess to the point where Stargate was recovered and the Stargate Program was founded. However, this may not be a true ontological paradox, since there are subtle differences between the world "before" SG-1 went back and time, and "afterward": most notably, after the adventure, Jack's pond now contains fish.

[edit] Video games

  • In a section of The Legend of Zelda: Ocarina of Time, the player character, Link, enters a windmill where he meets an organ grinder who tells him that seven years ago, a child came to the windmill and played a song, causing the windmill to go out of control (and opening a gameplay area). He teaches Link the Song of Storms, after which Link goes back in time and becomes his younger self, who goes to the windmill and plays the song, causing the effects and planting the melody in the organ grinder's mind.
  • In The Legend of Zelda: Oracle of Ages, the player befriends a goron who gives the player a vase, his family heirloom. Then the player travels back a few hundred years, finds the goron's ancestor, and gives him the vase, to be used as a family heirloom.
  • In the computer game TimeSplitters: Future Perfect, there are many examples of an Ontological paradox, and they all involve the main character of Cortez. On one occasion, Cortez is walking along and sees another version of himself who gives him a key. Later on, the present version of Cortez finds the same grate where he saw the last version of Cortez, only to see another version who he passes the key to.
  • In the computer game Escape from Monkey Island, Guybrush travels through a marsh where time flows differently and encounters his future self on the other side of a gate, who gives him the gate's key and several other items. Unconvinced, the present Guybrush asks what number he's thinking of, and opens the gate when his future self gives the correct answer. Later in the marsh, Guybrush must go through the gate from the other side, and so has to give his past self the key and the miscellaneous items, then pass the number-guessing test by recalling what his future self told him. The question of where the key and items originally came from is thus never resolved. True to the game's humor, failure to repeat everything precisely will cause a "temporal anomaly" that sends Threepwood back to the start.

[edit] See also

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