If anyone out there has ever read “Pastwatch: The Christopher Columbus Project” by Orson Scott Card, can one of you tell me exactly if/how that would be possible? If people from the future in fact did send three people back in time to stop slavery from contaminating the Americas, could they do it? Or would there be a paradox in space-time and some kind of universal melt-down? And if they succeeded just how would the world look?
I think there are four basic possibilities here (and most of them get explored if you read enough Science Fiction).
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No it can’t. (Relying on the principle, the name of which I can’t remember, propounded by Fritz Leiber
The space-time continuum has an elastic memory that forces history to remain constant, so that a change to an historic event (e.g., assasinate some key figure) would be overcome by other events (his lieutenants would carry out his policies anyway or his opponents would overreact to his absence and his supporters would rebel and force the situation to match his original goal). -
Yes, it could. ('nuff said)
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It can except that it can’t. I.e., any event that has occurred is real. Any attempt to go back to that event and change it results in a split in the space-time continuum so that an alternate reality occurs, giving us multiple co-existing realities or infinite alternative universes. (You get infinite universes because every decision has more than one possible outcome and every outcome is potentially real. The man who stops to pick up a penny and doesn’t step into the street to be creamed by a bus is matched by the same man not choosing to pick up the penny, thus being killed. Multiplied across every event for every sapient creature’s life, we wind up with an overabundance of possible/potential universes (which are then real, somewhere).
(In this scenario, the group going back to stop the slave trade may, indeed, succeed. However, the world they left will be unchanged and they will return to a world that they did change in a new universe.) -
It can’t happen because time is truly unidirectional and time travel is impossible.
The answer (providing #4 is not the answer): we don’t know. Read more S-F and pick the answer with which you’re comfortable.
Tom~
damned smilies–that was just a colon inside the parenthesis
If I’m reading you correctly, Tom, there’s a fifth possibility put forward by Connie Willis in The Doomsday Book, and that is that:
a) time travel is possible
b) the traveler’s actions can affect events
but
c) if anything paradoxical could/is/will happen(ing), the technology that makes time travel possible prohibits the trip. (The book makes it much more elegant than I’ve explained it here.)
And Heinlein was right. We need a whole new grammatical structure to discuss events in a time-travel scenario.
Time travel events (paraphrasing Niven, and Pournelle) either make it more likely that time travel technology will occur or they make it less likely. This inescapable fact makes time travel technology a positive reinforcement feedback loop leading to its own elimination in any universe in which it can occur. For each type of technology that could result in time travel a potential sheaf of events is propagated which results in increasing numbers of time travel events until one occurs which makes that technology unavailable.
The argument ignores the evidence that time travel is probably impossible without temporal intervention.
Tris
Imagine my signature begins five spaces to the right of center.
Alternate time-flows? Pretty deep…But if The time-continuum was split (or is, or will be, or whatever) Would we know? Would our “soul”, our self, our being know, and would we live out all possible times? That would definitely be cool and prove some type (if not the best type) of reincarnation is possible…sicne you’d be yourself, only not yourself.
You’re a twisted soul, Tris.
Tom~