The grandfather paradox

The grandfather paradoxcoined this for the first time in the novel"The imprudent traveller" René Barjavel)Available at La Casa del Libro), part of the assumption that a person carries out a journey through time and kill the biological father of the biological parent (grandfather of the traveler), prior to this meet the traveler's grandmother and they can conceive.

It is then when the traveler's, and by extension the traveller, parent will never been conceived, so it never will be able to travel back in time.

The grandfather paradox It has been used to argue that the travel back in time It should be impossible. Despite this, in science fiction have been suggested some solutions.

Solutions to the paradox of the grandfather

Parallel universes

This solution to the the grandfather paradox, if the the time traveler's it becomes the past, and kills his grandfather, will do it in a parallel universe in which will be never conceived. I.e., it will continue to exist in their original universe, but it will not exist in the universe that originated to kill his grandfather. Therefore, being such a true statement, never can return to their original universe, since that causes changes in each universe that exists.

Related timelines

It is possible that the universe does not have a timeline absolute, that it remains unchanged once the events occur, or from a point of view deterministic, since the beginning of time. Instead, each particle would have its own timeline and, therefore, humans would also have it. This can be considered similar to the theory of relativity, except that affects the history of a particle rather than its speed.

Quantum recoil

This solution to the the grandfather paradox", it has been postulated that some particles possess the natural quality of"back in time", which at a quantum level means that, if a particular physical process, randomly this can reverse and return (s) particle (s) involved to its previous state. Given that is not yet known when it will happen and why do it, is a process that may not recur in a controlled situation. This amounts to saying that if a paper burn for no apparent reason and then smoke and ashes will return to join to form the same role.

Restricted access

Another solution to the the grandfather paradox, which can take as an example the Novikov self-consistency principle, says that if a person travelled backwards in time, the natural laws prohibit any actions that result in their journey back in time It does not happen. This theory may lead to doubts about the existence of free will (which, in this model, may be an illusion). It also assumes that causality must be constant. That is, nothing can happen if you don't have a cause, while other theories maintain that an event can stay while their initial causes disappear. It is also possible that the action purported by the traveller to complete, but never with sufficient success as to result in a cancellation.

Another personality

Stories of science fiction has been raised that it is possible that a subject journey back in time and murder his father if that subject have taken another identity (obviously in the sense of really being different). A curious solution to the the grandfather paradox. An example cited in the game Prince of Persia: Warrior Within, where the main character travels in time to avoid that it makes a mistake in their travel time. To do this, get make a mask that transforms him into another identity, with which it is possible to alter the facts without creating any paradox.

Spectral contemplation

In science fiction books and novels also raised the idea that, if the travelers going to the pastthey are not part of it physically, they appear in the form of ghosts (ghosts). This problem-solving theory for the the grandfather paradox You can see in the game The Dig, Lucas Arts, as well as in the series Quantum Leap, when the character to the Calavicci arises in the past in holographic form. You can "see" the past, but you cannot change or participate in events that happen there. In a nutshell, travelers would be invisible to the residents of the past.

The time message

If you look at the example of the film déjà vu for the the grandfather paradox, as Doug Carlin begins to investigate the case of the murdered girl, begins to see puzzles that don't make sense: A message that is located in the fridge that says "your can save her", a towel with blood on the sink, a phone number, a call, etc. They are messages made by himself, being the condition of travel back in time true, they act as signals that he left earlier, so it will remain constant in 'their' universe. When he travels to the past and save the girl from being killed, these messages become true, because he himself devised them and carried out. This is one the grandfather paradox very peculiar, where an individual is sending messages to his "other self" of a past which, supposedly, has no certainty that exists or ever existed. If he thought in travel back in time in the near future, the desire would be on foot of her subconscious, but the journey back in time never would happen unless you happen some important fact that compel him to do so within his universe.

Origin and destination

Another statement in the public domain, it is discussed in fora science fiction on the the grandfather paradox, it is the theory of the origin and destination, which stipulates that a machine or condition is necessary to open a portal to "input" in the space-time, and other "out". Because of this, it is impossible for a human being to travel even before the creation of the first mechanism of journey back in time that he could recreate the conditions to open another portal. This theory about the the grandfather paradox It is in debate and process of improvement.

New future creation

It is possible also that from the moment in which it is achieved travel back in timeactually is is creating an AC line, where the traveller does not alter the past, but the future of a parallel universe where can not alter absolutely nothing universe where it came from. The the grandfather paradox It is the main plot of the film of Back to the future II

Overlap

There is a chance that an individual travel back in time and this play with his mother to create himself. But this case would be an impossible paradox, since to operate, the son would live another different from the one of the first future and so the story would change

Theory of a single line

This solution to the the grandfather paradoxIt expresses that there is only a timeline and there are parallel universes. If this line could be altered, from this alteration you could say "he changed his address", and the facts prior to the future of the traveller never occurred and only remain in your memory.

Theory of the multiple present

This theory that attempts to solve the the grandfather paradox, shows that if reality is altered, would create a kind of distinct timeline but without deleting the previous one, so both the memories of a reality and on the other, are real, and coming from the same individuals are aware of it to the point of confusion, not knowing to differentiate which actually living them.

How you've been able to see, there are many possible solutions to the the grandfather paradoxsome more sophisticated than others. Do you know some other, traveller described it?