Few theoretical debates are as baffling and complex as the logical and physical possibility of time travel. Numerous fiction stories explore this concept, which often results in the appearance of illogical paradoxes. However, David Lewis (1976) argues that it is possible to conceive of time travel in a manner that does not break the rule of logic. This paper will analyze three stories that employ the concept of time travel without causing paradoxes.
The first story that will be studied is a novel by Audrey Niffenegger, The Time Traveler’s Wife. It revolves around a man Henry who randomly time travels without the ability to control it. The novel is notable due to its strict physics framework, which does not allow the existence of parallel universes. The reason why Niffenegger’s depiction of time travel is coherent lies in the utilization of separate dimensions of time. A commonly stated argument is that time travel is impossible since the same person cannot be simultaneously in two different places. Lewis’s (1976) solution is to distinguish time into personal and external. External time is experienced by all people, while personal is attributed to a time traveler exclusively. In Henry’s case, his life is strictly linear since at no point does he change his own past. All transpiring interactions are entirely logical when considered from his own personal perception of time.
The second story, which utilizes a coherent time travel logic, is Game of Thrones. One of its main characters Bran obtains the ability to observe the future, past, and present. It is important to note that physically Bran does not leave his present. Instead, it is his consciousness that travels back and forth in time. On several occasions, there are actual interactions between Bran and characters in other places and even time period. For instance, the episode The Door shows Bran viewing a character in the past whom he is able to affect. An earlier scene in the same episode has another character leaving a mark on Bran while he time travels.
The reason why these interactions are logical is that they follow the rule of time loops. Lewis (1976) defines them as “closed causal chains in which some of the causal links are normal in direction and others are reversed” (p. 3). In both aforementioned cases, the transpired events are closed casual chains. The character whom Bran has affected in the past shows the consequences of that interaction before it happens in the actual story. Similarly, a mark left on Bran remains with him in the present and serves as an important plot device. No parallel universes are created; therefore, no casual paradoxes exist.
However, both The Time Traveler’s Wife and Game of Thrones have one potentially lore-breaking possibility. For instance, from a purely physical standpoint, both Henry and Bran have the ability to interact with and affect past versions of themselves, thus creating a paradox. An example of a story that avoids this possibility entirely is Star Wars: Rebels. One of its main characters, Ashoka, is presumed to be dead at an earlier point. However, the episode A World between Worlds shows that Ahsoka was saved by a time-traveling character who put her into his own time period. There is no contradiction because Ahsoka was not physically present in the universe between the moment of her departure from the past and arrival in the future. She cannot go back, affect herself or any characters in the past, and at no point do two versions of Ashoka coexist in the universe.
In conclusion, The Time Traveler’s Wife, Game of Thrones, and Star Wars: Rebels avoid paradoxes due to the use of closed casual chains. All three stories avoid the creation of alternate universes while distinguishing between personal and external time. In essence, the simplest way to make time travel coherent is to conceptualize a fixed time loop, which cannot be altered, prevented, or corrected by any influence or involvement.
Reference
Lewis, D. (1976). The paradoxes of time travel. American Philosophical Quarterly, 13(2), 145-152.