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Predicting the future

  1. Mar 14, 2010 #1
    This is a bit speculative and without sources, so thats why ill chuck it here for some 'light debate'.

    Could it be that the unpredictability of the quantum world occur to negate any possibility of accurate future prediction? I'm under the assumption that there is something fundamentally wrong with the notion of predicting ones future since the process itself would destroy itself.

    Yeah don't kill me for crackpottery ;/
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  3. Mar 14, 2010 #2


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    The future is predictable to a certain degree, due to causal relationships. For example, if I drop an egg I'm fairly sure that I'll be cleaning the floor soon.
    Absolute predictability is impossible. Back when I was reading up on this kind of stuff some 35 years ago, the term used for it was 'superdeterminism'. It's a no-no by QM. One nasty effect of it would be that we have no free will whatsoever. Everything would have to follow a script like clockwork. (And even that is a bad example, since I've had more than a couple of clocks go south on me.)
  4. Mar 14, 2010 #3
    What does that mean: "the process itself would destroy itself"?
  5. Mar 14, 2010 #4
    Yes I agree that the future is predictable to a point, since the human race is one of the few animals to plan. But why are some things predictable? It seems almost as if the larger the object is, the more predicable it is (such as planetary movements).

    Is it possible that the reason why we can predict the movements of these objects is that their ability to affect our future is somehow less than those of the smallest atoms?

    I guess it is safe to say we don't have any 'free will' to an outside observer. I don't think its nasty since only those higher up have the ability to see the gears turn. (Also whats with the term 'go south'? Not quite an expression used in Australia).
  6. Mar 14, 2010 #5
    However as you are distracted by a phone call, the dog rushes over -being fond of eggs- and cleans the floor for you.

    However the sudden earthquake makes you run and eventually there is no more floor to clean.

    However when looking for a cleaning cloth, you trip over the yoke, break a leg and you'd be rushed to the hospital. Some friendly paramedic cleans the floor.
  7. Mar 14, 2010 #6
    Technically we always have free will. I can go outside right now and will myself to fly through the air like superman. It won't work, but I can will it.
  8. Mar 14, 2010 #7


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    Yeah, I guess that there isn't much 'south' from there. Does 'go sideways' work for you? As in malfunction in a large manner?

    edit: Andre, you have made the specific point that I was aiming for. That's why I said that I'd be fairly sure about cleaning the floor. Zoob, you still have that choice of whether or not to go outside. After that, it's up to gravity. (And remember next time to close your 'quote' function... :tongue:)
    Last edited: Mar 14, 2010
  9. Mar 14, 2010 #8
    I wasn't sure quite how to phrase it, knowing your own future would change that future and you'll end up dividing by zero...

    Is it a reference to American 'Southerners'? Could use the same term to describe those from South Australia :P
  10. Mar 14, 2010 #9


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    Science would hope that predicting the future (with reasonable accuracy) is possible. Of course, many of us are just interested in how the universe works. But if there's a way it consistently works, through cause and effect, then it must also be predictable to the extent to which we understand the nature of the cause/effect relationship.

    So predictability is a necessity for any scientific theory.
  11. Mar 14, 2010 #10


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    I really don't know the origin. It might be a strictly Canadian saying, although I think that I've heard it used on Yank TV shows a couple of times.
  12. Mar 14, 2010 #11
    Hm...no. Knowing the future wouldn't automatically change the future.
  13. Mar 14, 2010 #12


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    Uh oh! Now you're going to have to explain the "dividing by zero" part!

    It is an idiom used to indicate that something has lost value or reliability. Our standard conventions for direction associate 'north' with upwards and 'south' with downwards (we - sort of ironically, though perhaps not being intentionally ironic - refer to maps with South America above North America as "upside down" maps). If the value of a stock "went south", that means it's price went down (think graphically).
  14. Mar 14, 2010 #13

    Jonathan Scott

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    I don't personally agree that determinism implies no free will. Even if there is only one future, if the only way to determine its path accurately is to experience it, then that does not in any way limit the scope of free will, which describes the same future but using a different approach.

    Even if you want to bring in unscientific concepts like "mind" or "soul", if the future is deterministic but unknowable, then you haven't restricted the freedom to choose.
  15. Mar 14, 2010 #14
    So you predict that you will meet your friend john tomorrow at his house. Don't go to his house under any circumstance. I can't see any reason why you would be 'forced' into your prediction, there is no destiny BS. Its all cause and effect. If you know the effect you can change the cause...

    Just like Morpheus said "Theres a difference between knowing the path and walking it"

    Was just using dividing by zero as one of those end of the world expressions (Since looking into ones future would be the same as going back in time and killing yourself - who knows what would happen if it were possible).
  16. Mar 14, 2010 #15
    Our ability to predict the future depends largely on how little detail is involved. Predicting what you'll actually have for breakfast is easy compaired to predicting where every ship in the harbor will be. I suppose that future prediction is a skill and like any skill you can probably get better at it with practice. So that means that by the time im 90 I will already know what my life is going to be like when im 115.
  17. Mar 14, 2010 #16
    As I understand it, according to the rules of quantum physics, you can set up two systems in the same state, but you can't be sure that they will both be in the same state at a later time. I don't know the standard definition of determinism. But by the way I use that word, either determinism is out, or quantum physics is the limiting case of a deeper theory. I would like to predict the latter, but this may not be a good time to do it.
  18. Mar 14, 2010 #17
    It is possible to predict future but that is time intensive task such that predicting future in 1 year would take exactly 1 year/

    But realistically, if you know what's in the mind of each individual, you can turn future to some degree (you make future not observe) in your favor by taking actions advantageous to yourself. But it is psychology but not quantum.
    Last edited: Mar 14, 2010
  19. Mar 14, 2010 #18
    We can't even predict the outcome of simplest cellular automata, in which cells grow according to extremely simple rules. The only way to find the outcome of cellular automata is to run the program.

    And since behavior that behaves exactly like automata is found in nature everywhere, the only way to know the future is run its course and see what happens.
  20. Mar 14, 2010 #19
  21. Mar 14, 2010 #20
    The possibility of deliberately trying to change the predicted outcome is different than the proposition that knowing the outcome automatically changes it. The latter is a kind of Heisenberg effect: measuring the phenomenon automatically changes the phenomenon. The former proposes that unless you do something to change the outcome, it will happen exactly as predicted.

    The third possibility is that the future is written in stone and will happen whether you know the outcome or not. In this scenario, your knowing the future was part of the script all along. Any effort you make to change the outcome only serves to ensure its happening, and those efforts to change it were always part of the scenario anyway.
  22. Mar 15, 2010 #21
    Hmm Ive briefly thought about this, that perhaps a computer could simulate faster than reality runs at. I don't know what to make of it, computers are still bound by the physical laws that they are trying to 'speed up'.
  23. Mar 15, 2010 #22
    If MWI is correct, any prediction of the future has to be probabilistic. For many questions, the answer will be essentially unique (all alternatives adding up to <1%), for others, there may be variance. There is no absolute certainty. If you drop an egg, there's a 99% chance that you'll have to clean it up, and there's a 1% chance that something else will happen that will keep you from cleaning it (maybe you have a heart attack?). And there's always a 10^-30% chance that the egg will quantum tunnel through the floor and end up in your basement, and a number of possible outcomes (also adding up to an astronomically tiny number) where the question no longer makes sense, because a series of quantum fluctuations mean that the entity called "you" is no longer uniquely identifiable.

    In addition to predicting the future, there's an issue of predicting the past. If you haven't heard anything about your 80 year old great-aunt for the last five years, there's maybe a 25% probability that she's already dead but no one bothered to tell you, and a 75% probability that she's still alive. You can't know which until you do the experiment. At that point, the "aunt-unknowing you" will branch into two you's with different amplitudes and different memories. This is not substantially different from the situation "you" were in 5 years ago. The only difference is that 5 years ago answering the question "is my great-aunt still alive on 3/14/2010" would've meant predicting the future, but today it means predicting the past.

    The question can be posited even wider than that. If you possess enough computational power and you have enough initial data to compute the probability for your 75-year-old great-aunt to live to the age of 80, you can compute probabilities of different outcomes for yourself, starting with your birth as the initial branching point. It would be extremely educational for you to learn, for example, that, in 10% of universes, you're dead along with your whole family and everyone you knew because of a nuclear war, or that there is a sizable probability for you to having died or having been paralyzed from the waist down in a motorcycle accident (if you ride a motorcycle).
    Last edited: Mar 15, 2010
  24. Mar 15, 2010 #23
    Where do you get the 25-75% odds, and what exactly is the experiment that determines if she's still alive or not?
  25. Mar 15, 2010 #24
    25-75 is just an estimate. 2005 SSA death tables put overall 5-year survival rates for 75-year-old females in the United States at 83%.

    The experiment that determines if she's still alive involves calling her or someone who'd know that, and asking. It's essentially an inverted version of Schrodinger's cat.
  26. Mar 15, 2010 #25
    OK, that's more or less what I figured, and in your saying a prediction has to be probabilistic I would say, then, it is no longer really a prediction, merely an estimate of probability, which is a lot softer. A semantic quibble.
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