Temporal paradox

Approaches scientific temporal paradox

A Paradoxe is a proposal which contains or seems to contain a logical contradiction, or a reasoning which, although without apparent fault, leads to a nonsense, or, a situation which contradicts the common intuition.

There exists in the scientific discipline a fundamental postulate which states that any phenomenon has a cause , and even in its weakened version, that if an event is the cause of another, the cause takes place before the effect.

By introducing the concept of temporal voyage, it results two possibilities from them of violating this principle, and thus thus of creating temporal paradoxes:

a phenomenon does not have a cause, this cause being placed in the future one disappeared because of modification from this one, and
a phenomenon is its own cause, i.e. the modification brought to time will create the causes of this same modification.

These two paradoxes offer two theories of times a priori irreconcilable: indeed, according to whether one retains the first type of paradox or the second, one can or one cannot modify the past. Certain authors did not always apprehend the existence of these two types, which brings us to a third paradox where the two types are implemented in the same account.

Temporal paradoxes and science

Although the temporal voyage is a theoretical possibility emanating of the theory of the general relativity of Einstein, it is not yet possible to implement it. It is thus currently impossible to build the least theory on the temporal paradox starting from the observation and thus of knowing which of the two types of paradox apply to our universe.

Types of paradoxes

Paradox of the grandfather and multivers of Everett

Let us take again the case of the flashback in time. If an individual Z kills a man X who is being his grandfather, the question is to know under these conditions, on the assumption of the fidelity of his/her grandmother (what in any event would have not generated Z but another individual having only half of its genome), how Z could be born. The most traditional loophole is to suppose that it can exist (at least) two lines of time , one where X is not killed and generates one of the parents of Z, another where it is killed and in which Z was not born. What does not prevent a priori Z of the first line of time to walk there. It will avoid there at least the paradox meeting itself. One enters a concept of space of possible the .

By an amusing coincidence, this possibility of multiplicity of the futures also has during in physics, which is the theory stated in 1957 by Hugh Everett and taken again since by John Wheeler, David Deutsch and some other physicists, at least as working hypothesis deserving that one examines some holding them and bordering.

Paradox of the writer

The opposite case, that of an event which would be its own cause, is also often evoked in science fiction. It is of course excluded on the assumption from the multivers.

Solutions in science fiction

The first paradox is always presented like the greatest risk of the voyage in time. There are overall two ways for of sortir :

the first consists in making rest this responsibility on the voyageur : with load for him to avoid creating any paradox. The consequences of the creation of a paradox are often fuzzy, but always alarming, being able to go until the destruction of the Universe. (for example in Return towards the future ) On the other hand, as long as one does not cause a paradox, it is perfectly authorized to modify the history radically.
the second exit is to adopt the assumption of the multivers. One finds this assumption at the X-Men. Rachel Summers sent the spirit of his/her friend Kitty Pryde in the past to prevent the events which have occurred before its birth and having led to the dictatorship of the robots sentinels. The mission succeeds, but Rachel sees its unchanged environment. It then goes itself in the past. It includes/understands whereas the past that it saved dictatorship of the sentinels is that of another universe. It can nothing make over there to modify the past of its universe. On the other hand when it turns over in its own universe, it takes along with it of the friends who help it to reverse the sentinels. But as it is turned over in its universe to a later date to that of its departure, Rachel violated the Causalité at no time.
One finds a way intermediate in which there does not exist multivers but where the travellers come from the future are not affected by what will be able to occur in the future because of their actions. It is the solution adopted for example in Terminator 2 . Terminator causes the destruction in egg of the project which gave him birth.
a last solution consists in declaring that there exists only one temporal screen. In this case, all the actions of the temporal traveller will have in fact take place in what was the past before its voyage (it can be more or less conscious about it). Of course, the paradox of the grandfather cannot occur in this case, which is also the only one to allow the paradox of the writer. The film the Army of the twelve monkeys follows not only this way, but insists particularly to make it feel with the spectator.

The solution of the multivers to the advantage of solving all the logical problems and even physics (the conservation of the mass is made on a scale multivers and causality is respected, if it is considered that the time of the multivers correpond not at very the dates in all the universes). But it is less interesting for many authors since it prohibits to modify its clean last.

The case of the Paradoxe of the writer is more étrange : on the assumption of the multivers, it is obviously excluded. What is it in the authors considering one universe? Eh well this paradox is often authorized, however doubtful is it from a logical point of view. Let us take the example of Harry Potter and the prisoner of Azkaban : Harry survives its meeting with the détraqueurs because a man launched a fate to put them in escape. It makes then a jump of a few hours in the past. During this jump, it launches the fate which saved the life to him. All seems coherent. Except that its death vis-a-vis the détraqueurs, involving the absence of temporal traveller, would be also a coherent solution.

Finally, the use of loops of causality seems a poetic license granted to the majority of the authors using the voyage in time.

Certain authors are authorized to pass from a way to the other. For example, among the solutions suggested, one observes that the first two films of the series of the Terminator employ each one a different solution.

Temporal paradoxes and literature

the imprudent traveller of Rene Barjavel

The temporal paradox most known is the Paradoxe of the grandfather according to whom the intervention kills the grandfather of the speaker empéchant his birth thus… and thus its intervention. Here, we are opposite the paradox of the first type, but the author advances the assumption of an autocorrection of time. Indeed, the traveller is close to an architect; inopportunely, it prevents the birth of this neighbor, but the houses carried out by this neighbor, are not drawn of it by another architect.

While wanting to check this autocorrection of time, the traveller tries to kill Bonaparte with Toulon in 1793; he supposes that the autocorrection of time must bring to the catch to be able by another emperor. But the temporal traveller is constrained to kill a guard before being caught some to lieutenant Bonaparte. However, this guard being the ancestor of the temporal traveller (and not having had yet of child), the traveller cannot exist while having killed keeps it. Finally Napoleon is not killed, and one can conclude that time was autocorrigé to prevent an important modification of the history, but not in the manner which the traveller expected.

Jean Pierre Andrevon

An alternative is the temporal traveller who meets his mother whereas it is young girl and becomes thus her own father. Jean-Pierre Andrevon seems to be the first author to have formulated it. However Poul Anderson opposes a genetic argument to it: no man can be his own father since the sexuée reproduction transmits only half of the chromosomes of each relative.

Here, we are in front of a paradox of the second type.

patrol of the Time of Poul Anderson

The temporal paradox was extensively used in the literature of Science-fiction. So much so that the idea of governmental services or deprived in responsibility appeared of protect the human history from the harmful paradoxes.

On the same idea, there are also TIME BODY of Robert A. Heinlein and the space-time service of Christin and Mézière.

Poul Anderson develops the idea of autocorrection of time and Miss in her accounts both type of paradoxes: one can modify time, but this one will generally end up being corrected, sometimes by using the actions of the temponautes, and the effects of the changes will have grown blurred at the end of a few decades. Only interventions over a few key moments can modify the history irremediably ( the other World , news of the Patrol of time )

Valérian and Laureline by Pierre Christin, Jean-Claude Mézières and Evelyne Tran-Lê

As of the 2nd board of the 2nd adventure of the series published in 1968 the City of moving water , the authors invent a situation which will pose later a true problem of coherence to them: a deposit of hydrogen bombs explodes, in 1986, close to the north pole transforming the aspect radically and the organization of the ground and it is on these ruins, during the black age, which will be born the Earth from Galaxity after the invention of the space-time machine into 2314. The authors did not think to make live the series for 18 years more. But in 1980/1981, for the publication of the diptych Subway Châtelet direction Cassiopée and Brooklyn station terminus cosmos , it is necessary well to go obviously, Valérian space-time agent has a success such, which it is not question of continuing the series in the inconsistency and even less to put an end to it. Pierre Christin , fine expert of Science fiction, then will stick in the following diptych, published into 1983/1985, the Spectra of Inverloch and the Lightnings of Hypsis , to overcome the inconsistency. He is not unaware of that it is unfortunately at the price of another well-known problem in SF, the Paradoxe of the grandfather. So while going up in the past you kill your grandfather before he had procreated, you thus do not have a father, if you do not have a father you cannot thus exist and if you do not exist you cannot kill your grandfather. In other words, if you change the past, you destroy the present and make impossible the future, it is the law of causality of the temporal paradox.

In the Lightnings of Hypsis , coming from 3152, Superintendant of the helped Space-time Service of Valérian and Laureline while preventing in 1985 the nuclear explosion which was to disorganize the ground in 1986, will destroy the future of this one, therefore to make impossible the constitution of Galaxity which was built on the ruins of the black period of the ground. If Galaxity could not be built during the black age, the space-time machine could not be invented into 2314 and Galaxity does not exist into 3152, Valérian can exist in this century nor in no other besides, unlike Laureline which it comes from Xe century, and if Valérian can exist in no century, how to justify the series. Fortunately the Shingouz negotiate with the Son of the Trinité of Hypsis the return of Valérian and Laureline to the XXe century with their spacecraft, thus authorizing the continuation of the space-time voyages also allowing the continuation of the saga.

But the paradox of the large father is not solved. It is what the authors will endeavor to make, with the will of Jal , another space-time agent survivor of Galaxity, to retort in 1988 the catastrophe avoided in 1985, but Valérian and Laureline , with the assistance of Mr Albert, ruin this attempt On the borders . Pierre Christin thus does not adopt the theory of the autocorrection which wants that time repairs time. In 2001 in By dubious times , a new negotiation brings the answer to two question: there exist two parallel stories of the Earth post XXe century and the ground of Galaxity of XXXIIe century would be some share in a black hole. Thus Schroeder and Sun Rae does not have the memory of their adventure in the City of moving water and in the Grounds in flames. Christin makes the choice of the theory multivers parallel universes. It is the topic of the last albums At the edge of Large Nothing in 2004, the Order of the Stones in 2006 and OuvreTemps , can be in 2008.

Thorgal by Jean Van Hamme and Grzegorz Rosinski

the Master of the mountains tells the history of a slave escaping a war leader and falling in love with a woman. Partly uncontrolled temporal translations will see it becoming retroactively the war leader then victim of his partner become in her turn the war leader by dislike of the preceding situation.

Other albums will use the spring scenaristic of the adult returned in the past to help itself.

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