Change
Change involves a relationship between a state changed from and a state changed to. That is a relationship of before and after, thus a temporal relationship. If there were no experience of change, then there would be no need to refer to time. (Also, if there were no experience of change, then there would be no experience. A durationless experience, beginning and ending simultaneously, would not happen.)
Change In Three-Dimensional Space
One three-dimensional state of the spatial universe changes into another. If there were only one state, then there would be no change. (Obviously.) Such states do not coexist in space but succeed each other in time. They succeed each other along a single temporal dimension. Each moment of time contains an entire three-dimensional (state of the) universe. Our single timeline is a four-dimensional spacetime continuum.
Change In A Four-Dimensional Continuum
Can such a continuum change? If so, then one four-dimensional state of the spatiotemporal universe changes into another. Again, the before-and-after relationship between such states is temporal. Each moment of a second temporal dimension contains an entire four-dimensional (state of the) universe.
We now need a total of five dimensions (three spatial and two temporal) to account for:
the three spatial dimensions in each moment of a single timeline;
the single temporal dimension within each timeline;
the temporal relationship between timelines.
Poul Anderson's "Delenda Est" describes three successive timelines:
(i) the Romans win the Second Punic War;
(ii) Neldorian time criminals help the Carthaginians to win the Second Punic War;
(iii) Time Patrol agents prevent Carthaginian victory in the Second Punic War.
Within timeline (ii), it is true to say that the Romans never won the Second Punic War. However, within the five-dimensional framework, it is true to say that the Romans had won that war in timeline (i) but have now lost it in timeline (ii). Dialogue between Anderson's characters confuses these two frames of reference.
25 comments:
Poul dealt with this in the first Time Patrol story: it's what he meant by 'infinite discontinuities in the world lines'.
You're making an assumption about the linearity of time and of a uniformity of temporal direction which, if time travel were possible, would not be true.
I now realize that we can all enjoy the Time Patrol and must each come to our own understanding of its theoretical basis. (That is always the case, of course, although, in this case, agreement or even mutual understanding are unusually difficult.)
It's the conditional-hypothetical of SF... 8-).
I don't know what infinite discontinuities are.
Paul: it means that causes don't have to precede effects, and the effects can negate the ultimate -cause- of the negation.
Eg., the "cause" of the Roman defeat in DELENDA EST starts in the far future.
The "effect" is in the Second Punic War -- and in that universe, the future that -produced- the effect never happens.
From the POV of the Neldorian time-bandits, that future no longer exists, though they remember it, and now exists only as a memory in their heads.
-Their- world-lines are now infinitely discontinuous. They exist, but nothing produced them.
They're causeless, in that sense. The world exists because people from a nonexistent future intervened in a battle.
And after the quantum fluctuations in THE SHIELD OF TIME, Manse and the others are in the same position as the Neldorians. Their world-lines are now infinitely discontinuous.
Well, I still think that my way of putting it covers what you are saying but there you are.
Poul was a physicist, and I think he caught the implications of the setup he'd postulated fairly well -- it's the only explanation if you accept time-travel, mutable time, and a single timeline.
I still find "mutable time" and "a single timeline" contradictory. I think that mutable time has to mean one timeline changing into another, thus successive timelines. But maybe these are different ways of saying the same thing.
I am clear on the difference between successive timelines and a single, discontinuous timeline. You seem to be saying that the Time Patrol scenario is definitely the latter.
Paul: pretty much.
That's what's said by the authoritative figures -in universe-; it's the assumption made by the author.
Given the knowledge needed to create time travel, they'd know if there were multiple (simultaneous) timelines, with new ones being created all the time.
The operating assumption of the TIME PATROl stories is that there is only -one- timeline; that if the history is changed, the new timeline is the -only- timeline.
Conversely, the CORRIDORS OF TIME assumption is that time travel is possible, but you can't change the past -or- create a new timeline -- there's only one and it's fixed. The characters work around that.
Ditto for THERE WILL BE TIME. The antagonist's perception of the future he 'creates' doesn't correspond to a timeline that then is changed (or split off); it's simply false to (an unalterable) set of facts because he's deliberately deceived about it.
If I had to -bet-, I would probably agree with your assumption that changing the past creates multiple futures. Though that's untestable/non-falsifiable at present.
But I don't think it's the TIME PATROL universe's operating code.
Kaor to Both!
Ugh! No wonder trying to make sense of time traveling hurts my head. But I like the suggestion being made that multiply split off time lines becomes alternate or parallel universes.
I have sometimes wondered what it would be like to be cast back in time 50 or more years. It would be so strange to see my parents again and my younger self. Needless to say I have no memory of that happening!
Ad astra! Sean
I know that a lot of the Time Patrol texts clearly do mean that there is a single discontinuous timeline. However, this involves the contradiction of a Time Patrolman saying, "It may turn out to be the case that this I who exists now does not in fact exist now."
With successive timelines, the deleted timelines exist not in parallel with the current timeline but in the past of a second temporal dimension. New tenses are needed but we understand that Temporal has those.
Kaor, Paul!
You would need a philologist like Tolkien working with a writer like Anderson, with an education in physics, to get a chance of those tenses getting coined.
Ad astra! Sean
The Patrol stories imply (or state) that there are differences between the duration-sense/experience of individuals and that of the universe exterior to them.
Kaor, Stirling!
I agree. I think that was first made clear in either "Brave To Be A King" or "Delenda Est."
Ad astra! Sean
OK. As far as that goes, that could mean that someone remembers events that have not happened in any sense or tense whatever in external reality. That would mean a single discontinuous timeline. However, there is still the contradiction, explicit in "Brave To Be A King," of Everard telling Dennison: (paraphrase) "The you that does exist here and now might not exist here and now."
Kaor, Paul!
And I admit to not knowing how to resolve that contradiction. It probably needs a special language like Temporal to make sense of such conundrums.
Ad astra! Sean
Sean,
But (using the only tenses we have), it does mean that there is SOME temporal dimension within which Everard is saying that the Denison of this time and place NOW exists but LATER might not. That is not compatible with a single discontinuous timeline.
Paul.
Paul: it's only a contradiction if time is unidirectional.
The "later" is in terms of Denison's personal experience, but with time travel that personal experience does not necessarily correspond to anything outside.
There is still something I am not understanding here.
If Everard travels into the past and changes the course of events, then his experience of the changed events does not necessarily correspond to any reality outside himself?
Kaor, Paul!
It seems to me the "reality" Everard REMEMBERED experiencing belongs to now split off time lines he can no longer access.
Ad astra! Sean
That much I agree with, maybe expressing it slightly differently, but I think that something else is being said.
Kaor, Paul!
Much more can be said about such things--and has been by writers with as views as different from each other as Frank Tipler (THE PHYSICS OF CHRISTIANITY) and Sean Carroll (SOMETHING DEEPLY HIDDEN). And I don't claim to understand time traveling or alternate/parallel worlds theories.
Ad astra! Sean
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