Monday, April 13, 2009

Terminating John Connor

In one episode (“Adam raised a Cain”) of the Sarah Connor Chronicles, Derek is killed by a Terminator. In the next episode (“Born to Run”), John Connor is whisked off into the future, where he’s reunited with Derek.

This raises a number of logical and dramatic problems. A premise of the whole Terminator franchise is that you can change the future by traveling back into the past and changing the past. That’s why Skynet keeps sending Terminators into the past to kill John Connor. If, however, killing a person in the present doesn’t erase his future self, then the exercise is futile.

Indeed, the very fact that John Connor exists in the future, so that Skynet must send Terminators back into the past to kill him, already forecasts the failure of their efforts–for if they had succeeded in killing him, there would be no future John Connor whom they must eliminate by sending Terminators back into the past.

There is, to be sure, a disanalogy. Derek came from the future. So, in that sense, he already had a future existence–unlike John, whose actual life-history extends from some point in the past (the moment of conception) to the present.

Still, that distinction doesn’t solve the problem. For, by traveling back into the past, the future Derek is no longer there, in the future. Hence, if you kill him in the present, he has no future counterpart, waiting for the present to catch up with the future.

Perhaps we could try to get around this by claiming that the Derek who traveled back into the past is not the future Derek in toto, but the Derek who, on one day in the future, went back into the past. If, on May 5, 2020, Derek travels goes back, then there’s no longer a Derek on May 5, but maybe there’s a Derek on May 4 or May 6.

Assuming that this is coherent, it would make it difficult for Skynet to terminate John Connor. For there is more than one John Connor to terminate. John Connor has many past and future doubles. A John Connor for every instant along the timeline.

But one of the problems with this scenario, and, indeed, the primary problem with all time-travel scenarios, is the order of causality. If the order of time tracks the order of causality, and effects can’t precede their causes (admittedly a circular description), then it’s not possible treat temporal objects as discrete units which can be excerpt edfrom one point along the timeline, and reinserted at another point. Temporal objects are continuous for the duration of their existence.

This is what makes it difficult to construct a philosophically or scientifically coherent model of time travel. And, of course, Hollywood screenwriters have never been overly concerned with the philosophical or scientific details.

It’s striking, though, that some people insist on the principle of parsimony in science while they can’t resist the principle of plenitude in science fiction. Occam’s razor for science, but Leibnizian or Meinongian opulence for science fiction!

Some folks attempt to ground time-travel in a particular interpretation of quantum mechanics, where branching timelines constitute alternate histories. But even if we were to stipulate to all of the controversial assumptions and consequences of that interpretation, it isn’t the same thing as time travel. Except at the initial point where these alternate histories fork off in different directions, there is no point of contact.

And even if there were, that would raise issues of personal identity. Commuting from one alternate history to another is not the same thing as moving backward or forward within the same world history.

Bracketing the metaphysical quandaries for a moment, some folks think we have actual evidence of time-travel. They point to reported timeslips. The celebrated case of Annie Moberly and Eleanor Jourdain is a noteworthy example.

Assuming, for the sake of argument, that they really had the experience they describe, would this be an actual case of time-travel?

Not necessarily. An alternative explanation is telepathy. They were perceiving the past through the memories of others.

Finally, one might contend that retrocausation only generates temporal antinomies given the conventional view of causation. Suppose, though, we challenge the theory of causation which generates temporal antinomies? Then what?

For example, Jonathan Edwards was an occasionalist. He regarded spatiotemporal existents as essentially discontinuous rather than continuous. Earlier events didn’t cause later events. Rather, God was the direct cause and sole cause of all events. Geulincx was another Reformed occasionalist.

On that view, a future event would be causally insulated from an earlier event. So, in theory, it would be possible to rearrange the order of events. And that would sidestep the grandfather paradox.

However, this strategy cuts both ways. If I’m not making things happen, then I can’t change anything. Even if I traveled back into the past, I couldn’t change the future. For, on this view, I’m causally inert.

Yet you could still salvage time-travel. The time-traveler would not be the agent. Rather, God would be the agent. God would be causing the time traveler to move backward in time, or skip ahead.

But there is another problem with occasionalism. If I insert a shotgun in my mouth and pull the trigger, that seems to have an effect. I’m not in the same condition after I pull the trigger as I was before I pull the trigger.

But an occasionalist can also explain (or explain away) this phenomenon. He could say that God has arranged events to simulate causal relations.

Now, before you dismiss this as absurd, keep in mind that this is quite similar to another convention in SF literature: virtual reality.

There are many variants on this theme. For example, aliens subject abductees to virtual stimuli to study their reaction. Virtual reality simulates causal relations. And this is not ad hoc. Rather, it’s designed to simulate an environment wherein there are apparent consequences for one’s actions. Illusory, but a functional illusion.

(For a Scriptural instance in which God creates a collective illusion, cf. 2 Kgs 6:15-23.)

Offhand, occasionalism is the only mechanism I can think of to coherently model time-travel. Of course, that doesn’t make it true–or even plausible. But given the popularity of time-travel scenarios, and given the further fact that many SF buffs are ardent secularists, it’s someone ironic that only a theist has the metaphysical resources to pull this off.

I myself am not an occasionalist. And I have no concrete reason to believe in time travel.

However, I’d suggest that if a Christian novelist wants to write about time-travel, and if he wants to treat time-travel, not merely as a literary convention, but as a realistic possibility, then occasionalism might be the best way (or only way) of grounding this scenario.

5 comments:

  1. "A premise of the whole Terminator franchise is that you can change the future by traveling back into the past and changing the past."

    Hmm... I disagree. That's a premise of the TV series, but it wasn't a premise of the original movie. (It was a hope of Skynet, but it was not a premise of the fictional universe.)

    "Indeed, the very fact that John Connor exists in the future, so that Skynet must send Terminators back into the past to kill him, already forecasts the failure of their efforts–for if they had succeeded in killing him, there would be no future John Connor whom they must eliminate by sending Terminators back into the past."

    That objection seems to apply to the original Terminator movie. In that movie, John Connor's very conception was a result of Skynet's attempt to kill him through time-travel. It seemed to portray time-travel as a closed loop: Implying that you can't change anything, and your attempts to do so turn out to be part of the original cause of the thing you're trying to prevent. (Leaving it a mystery how the time-loop got started.)

    A different model is Back to the Future, where Marty was able to change things--in a way that caused him to disappear, all the way in the past. His actions caused himself never to exist. The effects seem to propagate at some non-instantaneous velocity forward into the "present", so that his brother starts disappearing in his family photo, followed by his sister, followed by him. (Though the internal logic of this model was confused and inconsistent--Present-Marty-in-the-Past starts to disappear, but his actions in the past still remain, with all the effects of those actions.)

    In the Sarah Conner Chronicles, they've established a model closer to Back to the Future than to the original Terminator. Actions by time-travelers do change the future, so that Jesse and Derek came from different futures. But unlike Back to the Future, time-travelers don't start disappearing. They (and their memories) are "safe" from the changing timeline.

    In other words, in Sarah Conner Chronicles, you can kill your grandfather, and you don't disappear. You remember the timeline as it used to be--but you will never be born in the new timeline.

    "If, however, killing a person in the present doesn’t erase his future self, then the exercise is futile."

    Killing a person in the present changes the timeline to be a different timeline, erasing the future self of the new timeline. If his future self from the old timeline already traveled to the past, then the "original" future self still exists.

    "Still, that distinction doesn’t solve the problem. For, by traveling back into the past, the future Derek is no longer there, in the future. Hence, if you kill him in the present, he has no future counterpart, waiting for the present to catch up with the future."

    I think it helps if you make the distinction between the general timeline (which apparently can be changed), and the personal timelines of time-travelers. Then visualize the way that the personal timeline loops back.

    "If, on May 5, 2020, Derek travels goes back, then there’s no longer a Derek on May 5, but maybe there’s a Derek on May 4 or May 6."

    Yeah. But with a difference between May-4-Derek and May-6-Derek. May-4-Derek is an earlier part of May-5-Derek's personal timeline. May-6-Derek only exists if May-5-Derek comes back from the past.

    OR, maybe May-5-Derek changed the past. So that in the new timeline, Derek doesn't travel back in time. So May-5-Derek#2's personal timeline doesn't loop back at all. May-5-Derek#1 is "orphaned" in time.

    ---

    Actually, that seems to have happened. Jesse and Derek came from different futures. In Jesse's future, if her Derek had traveled, then we would have two different Dereks in the present. One from each future, with different memories. Derek #1 (who's been hanging out with John Connor), and Derek #2 (who knew the Jesse that we met.)

    Either Derek #2 didn't travel, or he's still around somewhere in the present. We might meet him. (Then there's Derek #3, who John Connor just met on Friday.)

    ---

    If my description is accurate, it introduces a new problem. We should probably tend to see a proliferation of alternate Dereks from alternate futures. The only alternatives are:
    1.) Derek travels back in time, and changes things so that the "new" future Derek doesn't travel. We only have 1 Derek.
    2.) Derek travels back in time, and changes things, and "new" future Derek also travels back in time. We have 2 Dereks. (Repeat this process for second Derek, which may leave us with a third.)

    OR

    3.) Derek travels back in time, and doesn't change anything. The general timeline does not branch, so we only have 1 Derek in the present.

    Option #3 doesn't seem feasible. The number of Dereks will keep growing until some iteration results in option #1. (Of course, if anyone else travels back in time, the # of Dereks may start increasing again.)

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  2. There's also the metaphysical problem of multiple copies of oneself (from different timelines) coexisting simultaneously as they travel backward (or forward) to the same timeframe–be it past or future.

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  3. Jugulum said...

    "Hmm... I disagree. That's a premise of the TV series, but it wasn't a premise of the original movie. (It was a hope of Skynet, but it was not a premise of the fictional universe.)"

    Well, it's a good thing you're not working for Skynet, helping to correct its faulty knowledge of temporal mechanics.

    On second thought, you might be working for Skynet without knowing it since the cyborgs pass for human beings.

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  4. So long as all the cyborgs look like cute chicks, who cares?

    :-)

    More seriously, we lack enough information on this subject to discuss it. We abandoned learning by logic-chopping with the scholastics. As Francis Bacon showed, experiment is the way.

    (Which brings us back to cute chicks...)

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  5. "There's also the metaphysical problem of multiple copies of oneself (from different timelines) coexisting simultaneously as they travel backward (or forward) to the same timeframe–be it past or future."

    Hmm... Not sure it has to be a metaphysical problem, but good point. The writers could introduce a new plot convenience, and be consistent with what they've already established: If a different Future Version of you already exists in your destination time period, then you can't jump into that destination. (Would you just disappear, if you tried?) That would explain why the proliferations of time-travelers hasn't occurred.

    "On second thought, you might be working for Skynet without knowing it since the cyborgs pass for human beings."

    **Jugulum whistles nonchalantly, covers his Blogger profile with his foot.**

    ReplyDelete