A post on Metafilter reveals that Caltech physicist Sean Carroll recently tweeted that he was meeting up with Lost producers Damon Lindelof and Carlton Cuse. This was posted to the forums at Lostpedia, prompting immediate spoiler complaints … so Carroll signs up and drops in to the thread to clear up the confusion, also offering some of his thoughts on the use of time travel in the show and referencing a longer blog post he wrote shortly before the start of the final season.
Qvantamon in a reply to the thread on Metafilter gives a rather homicidal theory of time-travel which addresses the notion of paradoxes.
Painquale, depends on how much you want to split hairs. You cannot alter your past (in the broadest sense – all the history of the universe as it played to cause your current state). Or, alternately, you cannot alter your past (same broad sense).
For example, let’s say 50-years-in-the future Painquale is just about to enter a machine that will, in fact, just disintegrate him at the sub-atomic level into pure entropy (his existence is not really a necessary condition). There’s a non-null chance (never mind the amount of decimal places) of, right now, 2010, zillions of sub-atomic particles just tunneling all at the same time into the exact same configuration as 50-years-in-the-future Painquale (supposing memory/thought process/sentience is a physical phenomenon). With a strong many-worlds interpretation, since that’s possible (no matter how infinitesimally improbable), that’s necessarily one component of the universe’s wave function (that is, one “parallel universe”), so, there’s definitely one branch where it just happened. If you ask that particular “time-traveling” Painquale, he’ll tell you that he sure is a time traveller, he disappeared from the future and appeared here. Never mind that there’s no causal relation between new-Painquale showing up and old Painquale disappearing, in his mind it’s solid. He can of course, go ahead and kill present day Painquale, and it won’t do shit, as there is no actual causal relation (as I said, that future where he thinks he came from may even have absolute zero chance of existing). Of course, he can decide to disintegrate himself again, and THIS pretericide-Painquale configuration can again also just show up randomly 50 years later, in another infinitesimally improbable branch of this same branch of the universe (again, no causality violation here). Again, no time travel, just particles tunneling around. But 2060 pretericide-Painquale of course has the whole causal relation in his mind. And no one around him will have any idea who he is (aside from being the guy who said he came from the future and killed Painquale), which is exactly his expected outcome of a time travel. Success, for all he cares, and no actual causality laws broken.
This is pretty much how I believe time travel would work if it were more than merely theoretically possible.
I was never happy with the solution for the grandfather paradox that some physicist put forth (I want to say Stephen Hawking because I’m surely I’m vaguely recalling a passage from A Brief History of Time) that somehow the Universe would conspire to prevent you from killing your own grandfather so as to maintain causality.
The discovery of the theory of parallel worlds suggested to me a better solution that you could indeed kill your grandfather (if that was your bag) because the man you’d be taking the life of would be from an alternate reality to the one you’d left.
I think that the notion of ‘whatever happened, happened’ can be preserved at the same time as that of being able to change one’s past like Back to the Future’s Marty McFly.
