Predestination paradox
From Memory Alpha, the free Star Trek reference
A predestination paradox, also called a causality loop, is a paradox of time travel. The idea is that when one travels back in time, one may influence events while in the past, such as causing, or undoing, the original reasons for the journey.
Suppose a man travels back in time and impregnates his great-great grandmother. The grandmother would thus give birth to one of the man's great grandparents, who would then give birth to his grandmother or father, who would then be able to give birth to one of the man's parents, and finally to the man himself. As a result, the man's very existence would be pre-determined by his time traveling adventure, and therein lies the paradox.
The Predestination paradox is very closely related to the Grandfather paradox.
One of the possible examples of this paradox is the death of Edith Keeler: if Doctor McCoy does not travel back in time accidentally and change the timeline by saving her, Captain Kirk does not follow him, does not fall in love with Keeler and does not leave her in the way of that certain truck.
- The possibility remains, however, that the vehicle originally striking Keeler was different from the one that eventually did via Kirk and McCoy's interventions.
A predestination paradox may exist in Star Trek IV: The Voyage Home when McCoy and Scotty give Dr. Nichols the formula for transparent aluminum. McCoy comments that if they do so, they may alter the future but Scotty asks how do they know he didn't invent it? McCoy seems satisfied with that.
- The Star Trek IV novelization expands on this scene and shows that Scotty indeed knew that Nichols invented transparent aluminum and that it may well be essential that they give him the formula for it, which would cause a predestination paradox.
In order to stop him making advances on her, Beverly Crusher told Berlinghoff Rasmussen that she could be his great-great-great-great grandmother. (TNG: "A Matter of Time")
The Temporal Investigations agents Dulmur and Lucsly hated predestination paradoxes. (DS9: "Trials and Tribble-ations")
[edit] References
- TOS: "The City on the Edge of Forever"
- TAS: "Yesteryear"
- DS9: "Trials and Tribble-ations"
- VOY: "Relativity"
See also:
- TNG: "Cause and Effect"
- VOY: "Future's End"
