The paradox of grandparents is a time-travel paradox in which inconsistencies arise through past changes. The name comes from a general description of the paradox: a person travels into the past and kills their own grandparents before the conception of their father or mother, which prevents the existence of time traveler. Despite the title, grandfather's paradox does not exclusively assume the contradiction of killing his own grandfather to prevent a person's birth. Instead, the paradox considers every action that changes the past, because there is a contradiction every time the past becomes different from what it is.
Video Grandfather paradox
Contoh awal
The paradox of the grandfather is mentioned in the story written as early as 1929, and in 1931 it was described as "an ancient argument preventing your birth by killing your grandparents" in a letter to the American science fiction magazine Amazing Stories. The beginning of the science fiction story dealing with the paradox is Nathaniel Schachner's short story of Nathaniel Schachner's short, published in 1933, and 1944 of the book The Future of the Times Three by Renà © Barjavel, Other works have touched on topics in the 1930s and 1940s in varying degrees of detail.
Maps Grandfather paradox
Variant
The grandparents paradox includes every change to the past, and it is presented in many variations. Physicist John Garrison et al. provides a paradoxical variation of electronic circuits that send signals through a time machine to turn itself off, and receive a signal before sending it. The equivalent paradox is known in philosophy as an autoinfanticide, going back to the past and killing yourself as an infant.
Another variant of the grandfather paradox is the "Hitler Paradox" or "Hitler's paradox of killing", a metaphor quite often in science fiction, where the protagonist goes back to the time of assassin Adolf Hitler before he could spark World War II and the Holocaust. Instead of having to physically prevent the passage of time, it eliminates any reason for the journey, along with whatever knowledge the reason has ever existed, eliminating any point in the course of time in the first place. Moreover, the consequences of Hitler's existence are so monumental and all-encompassing to anyone born after the war, the possibility of their birth is influenced by some of its effects, and thus the lineage aspect of the paradox will apply in some way.
Some supporters of the universe approach parallel the grandparents paradox. When time travelers kill their grandfathers, they actually kill parallel universe versions of their grandfathers, and the time-traveling universe does not change; it has been argued that since travelers arrive in the history of a different universe and not their own history, this is not an "authentic" time journey. In other variants, the action of time traveler has no effect beyond their own personal experience, as depicted in Alfred Bester's short story The Man Who Murdered Mohammed .
Philosophical analysis
Even without knowing whether time travel to the past is physically possible, it is possible to demonstrate using capital logic that alters the past results in logical contradictions. If it is true that the past happened in a certain way, then it is wrong and impossible for the past to happen in another way. A time traveler will not be able to change the past from that way is , they will only act in a way that is already consistent with what always happens.
Paradox paradoxical considerations have led to some ideas that time travel is essentially paradoxical and therefore logically impossible. For example, the philosopher Bradley Dowden makes this kind of argument in the Logical Reasoning textbook, arguing that the possibility of creating the rules of the contradictions of time out into the past completely. However, some philosophers and scientists believe that the passage of time into the past does not need to be logically impossible provided there is no possibility to change the past, as suggested, for example, by Novikov's principle of self-consistency. Bradley Dowden himself revised the above view after being convinced of this in exchange with the philosopher Norman Swartz.
The consideration of the possibility of a trip backwards time in the hypothetical universe depicted by GÃÆ'¶del metrics led to the infamous logician Kurt GÃÆ'¶del to assert that time itself may be some kind of illusion. He suggests something along the line of the time display block where time is just another dimension like space, with all events at any time fixed in this 4-dimensional "block".
Loop causal
The time of retreat that does not create the paradox of the grandfather creates a causal circle. Novikov's principle of self-consistency reveals a view of how time travel backwards is possible without the generation of paradoxes. According to this hypothesis, physics within or near the near-term curve (time machine) can only be consistent with the laws of universal physics, and thus only consistent events can occur. Whatever the time traveler has done in the past must have been part of history, and time travelers will never be able to do anything to prevent the trip back in time, as it will represent inconsistency. Novikov et al. using the example given by physicist Joseph Polchinski for the grandfather paradox, from billiard balls to time machine: the older ball's self emerged from the time machine and attacked his younger self so that his younger self never entered the time machine. Novikov et al. shows how this system can be solved in a self-consistent way that avoids the paradox of grandparents, although it creates a causal circle. Some physicists state that a causal loop exists only on a quantum scale, in a fashion similar to the chronological protective estimate proposed by Stephen Hawking, so history on a larger scale is not looped. Another estimate, the cosmic sensor hypothesis, shows that every closed time curve passes through the event horizon, which prevents the causal loop from being observed.
Seth Lloyd and other researchers at MIT have proposed an expanded version of the Novikov principle, which he says is likely to bend to prevent a paradox. The result will be unfamiliar when one approaches the forbidden act, because the universe must like the impossible event to prevent the impossible.
Quantum physics
Physicist David Deutsch argues that quantum computations with negative delays - the trip backwards time - yield only a consistent solution, and the chronological-breaking area imposes an obscure constraint through classical reasoning. In 2014, researchers published a simulation that validates the Deutsch model with photons. Deutsch uses the term "some universes" in his paper in an attempt to express quantum phenomena, but notes that this terminology is unsatisfactory. Others have taken this to mean that "Deutschian time travel" involves some of the universe to resolve the paradox of the grandfather. However, it is pointed out in an article by Tolksdorf and Verch that the fixed point condition of CTC (close time curve cap) can meet random accuracy in quantum systems described by relativistic quantum field theory in spaces where CTC is excluded, raising doubts on whether Deutsch conditions are truly characteristics of quantum processes that mimic CTC in the sense of general relativity.
See also
- Causal circle
- SchrÃÆ'¶dinger Cat
- Temporal paradox
- Repetition time
- Time travel in fiction
References
Source of the article : Wikipedia
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