Thursday 31 March 2022

Yet Another Time Travel Argument II

See Yet Another Time Travel Argument.

Let us consider another example:

(i) Recently I acquired a timecycle.

(ii) Five minutes from now, I will mount the timecycle and travel twenty years into the past.

(iii) I fully intend, on arrival, to perform an action that will prevent my present self either from existing or at least from having acquired a timecycle.

(iv) I succeed in performing such an action.

(iv) is written in the present tense. Really it should be in some other tense that would exist in Temporal although not in English. (iv) cannot be written in the past tense because (i)-(iii) describe a timeline in which I have not been prevented either from existing or from acquiring a timecycle. This timeline exists at least until I depart on the timecycle. It is logically possible that the timeline will terminate at the moment of my departure although that would contravene the conservation of energy but there is no logical reason why it should terminate then. (iv) entails the existence of a parallel or "later" (different temporal adjective needed) timeline in which (i)-(iii) do not occur.

2 comments:

S.M. Stirling said...

Poul deals with this in the first Time Patrol series; in that universe "infinite discontinuities in the world-lines" are possible -- you can prevent your parents meeting, and you'll still exist, a discontinuous product of a world-line.

S.M. Stirling said...

BTW, "infinite discontinuities" is not just bafflegab; it means something in physics, which was Poul's educational background.