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Cause, effect, and programming you VCR

  1. Aug 2, 2006 #1
    A poor understanding of causality has deadlocked the discussion of a couple of video-game geeks, and so we have ventured on into the internets looking for a bit of professional help. Hope we can borow a couple moments of your brain time.
    (Please remember that this isn't really physics question, its a fantasy world, and theres magic at work, were looking at thing from the logical/philisophical side)

    Here's the deal:
    A person begins a process that will cause Time itself to "rewind" backwards through 3 day period, stopping at the begining of the the first day. As the rewind progresses, the events that would have been the "future" are lost, it is as if they had never existed in the first place.

    A problem here is that one of the first events to be lost in this way is the process that caused the rewinding in the first place. Without the cause, the rewinding (effect) would, we assume, be illogical. Apparently, we have a paradox.

    To further complicate things, the process that begun the rewinding is, in fact, a prayer. The rewinding itself is the action of a Goddess. Does her define nature allow her to contnue with her effect, even after the cause has been made as to never exist in the first place?

    One side says no, that the cause-and-effect relationship binds all events in the physical world, and that the entire concept of rewinding is incorrect. The otherside disagrees, saying the Goddess is outside the bounds of time, and needs not abide by its rules.
    Is there any ay out of this?

    Oh, and first one to guess which game we're talking about gets 3 cookies and a spring roll.
    Last edited: Aug 2, 2006
  2. jcsd
  3. Aug 3, 2006 #2

    Prince of Persia?
  4. Aug 12, 2006 #3
    Ok. First, congratulations on making me register with this site after seeing your post. Up until now I've just been voyeuristically reading threads without contributing. This time, I might have something semi-intelligent to say.

    There's one possible answer to your cause-and-effect paradox that arose when you were playing that certain game with a certain prince. I suggest you look towards David Hume who put a bullet through ideas of causality a few hundred years ago, and theorists are still struggling to come up with a decent argument against him (if anyone has, then I apologise - haven't been reading much philosophy lately, just finishing a psychology doctorate). Basically, he argued that there is no such thing as causality. Instead, we infer causality from what we observe happening in the world around us. We drop a bottle, it hits the ground and smashes. We assume that because we have let go of the bottle, it drops and smashes. But all that has happened is three separate events - letting go, droppping, smashing. We have no way of knowing that one has caused the other, it just seems to us like there has been a chain of causality. It's true that one event has happened after the other in terms of time, but it's not clear whether one actually led to another. Assumptions like this are based on a principle that Hume called the uniformity of nature. This has to do with us assuming that nature is uniform and predictable, in that chains of sequences that have happened previously will happen in much the same way again, such as the sun rising in the morning. So, if we have seen someone drop something previously or we have dropped something ourselves and it fell to the floor, we assume that it will happen again because they are linked by cause and effect. But we have no fundamental logical grounds for thinking it will do so. This may seem counter-intuitive to some people, and I certainly wouldn't want to be the one proclaiming that the sun might not rise tomorrow, but it's hard to fault the argument Hume has made.

    I hope the above paragraph was clear enough. The implications for the causality paradox in the game then are pretty straightforward - it doesn't matter if reversing time means that you remove the very cause of the reversing, because this cause is just an assumption. Rather than reversing a chain of cause and effect over the 3 days, what is really happening is that a time period containg a lot of different events is being reversed. So it's ok. That is of course if we neglect any discussion of whether it is actually possible to reverse time, but I'm too tired for that. Anyway, I'm sure the game's designers considered this paradox and Hume's argument before releasing it. Or perhaps not. I know I don't get the prize for guessing Persia first, but can I still have some ice-cream?
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