The show proposes that Dr. Samuel Beckett, a scientist of the near future, uses a quantum accelerator to “leap” into the past (although only within his own life span), exchanging places with other people, and setting things right that have gone wrong.
This show has an interesting, although flawed, way of dealing with the Bucket Factor. The traveller switches places with a person in past, sending that person to the “present”, and leaving the traveller in the past until it is time to “leap” again. The flaw in the theory is that the traveller and the person he switches places with will never be of exactly the same mass and size. This also left a large plot hole in the show, as Dr. Beckett, the time traveller, was expected to impersonate the person he switched places with. Ignoring the fact that he looked nothing like the persons he switched places with (a fact which was addressed in the show), he was still expected to wear the person’s clothes, stand as tall or short as the person, etc. A difficult task when he “replaced” a woman, or an infant, or an amputee.
By limiting time travel to within Dr. Beckett’s own life span, the show also addressed the Universal Time Factor. When travelling only within your own life span, time, theoretically, can be calculated by the age of the traveller, all the way back to “point zero” (conception). For this kind of time travel you don’t use a calender to control your travels. Rather, you use the person’s DNA.
Quantum Leap commonly alternated between Theory A and Theory C of time travel, at times brushing dangerously close to Theory D. The writers of the show proposed that by tampering only with “little people” who did not have any effect on the grander scheme of the universe, they could change the future of those people without affecting the entire universe, totally disregarding Chaos Theory and quantum mechanics, thus Theory C. Other times, the time traveller would be put in more relevant positions, such as the JFK assassination. Dr. Beckett succeeds in saving Jackie Kennedy from the bullet of the assassin, which is how Dr. Beckett remembers his history anyway, therefore it was meant to be, thus Theory A. On one occasion, though, Dr. Beckett “leaps” into his own past, embodying himself as a youth, and attempts to save his brother from dying in Vietnam, tinkering precariously with his own past, and brushing upon Theory D.
This television show, based on the 1994 film, which itself is based on a comic book, has a complete disregard for the nuances of intricacies of time travel. Timecop is the story of an agency which polices timelines in search of persons bent on altering history, and their attempts to stop them. According to this show, anyone can go back in time, change history, then return to the present and remember not only the “new” history, but the “old” history as well, making excessive and abusive use of the C Theory of time travel. The show is laughable and implausible in the extreme. Only the existence of Theory D of time travel saves the show some credulity. The malicious time traveller can therefore travel back in time, tamper with the past ad naseum, and return to find his present totally altered, yet himself entirely unaffected.
In the future a great war has devastated the earth. Robots, controlled by a central computer, Skynet, have taken over; But human insurgents are about to overthrow the tyrannical machine. In a desperate attempt to save itself, Skynet sends one of its robots, a Terminator, into the past to kill Sarah Connor, the mother of the rebel leader before he can be born. One lone rebel soldier, Kyle Reese, follows the Terminator into the past to try to stop it. By sending the Terminator into the past, Skynet has sealed its own fate, as Kyle Reese meets up with Sarah Connor and together they conceive their child John Connor, who will grow up to be the rebel leader who destroys Skynet. This places the film firmly with Theory A of time travel. It was meant to be, and will happen again, time and again.
Unlike its predecessor, Terminator 2 leans more toward Theory B or Theory C of time travel. A second Terminator has come from the future to kill young John Connor, future rebel leader. Old John Connor, in the future, sends a reprogrammed and “friendly” Terminator into the past to save his young self. For John Connor to be alive in the future, Theory A of time travel must take precedence – the friendly Terminator of course defeats the evil Terminator and saves young John Connor so that he can grow up to do it all over again. But this falls to the wayside as Sarah Connor, mother of John, recruits the friendly Terminator to destroy the carcass of an earlier Terminator (see the Terminator), to prevent a technology company (Cyberdyne) from using the parts to develop Skynet, the evil computer from the future. So far we are still on track with Theory A. Skynet sent the original Terminator from the future into the past to kill Sarah Connor. By doing so, Skynet inadvertently produces the means of its own destruction. But Skynet also produces the means of its own birth… by sending the Terminator into the past, what remains of the ruined robot is used by Cyberdyne to give birth to Skynet. The wrench in the works is when Sarah Connor and the friendly Terminator actually succeed in keeping Cyberdyne from creating Skynet, which begs the question: Has an alternate universe been created where Skynet never exists (Theory B), or has the future of this reality been changed (Theory C), so that there is no Skynet, therefore no Terminator, therefore no one comes into the past to try to kill Sarah Connor, therefore John Connor is never conceived, therefore everything that just happened just didn’t happen. Theory B seems to be the more acceptable, as Theory C sends us into an infinite paradox.
Other references to time travel in television and film can be found in the following sources: