Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Uncertainty Principal and calculating the future :p (Question)

  1. Jan 7, 2005 #1
    Wouldn't it be neat if you could build a computer good enough (ignore this current day impossiblity) to hold and calculate everything you need to be able to tell the future? Obviously (um... right?), there's also more physics we need to figure out before we could actually be able to do somthing like that (again, ignoring that the computer couldn't be made).

    Well, I think that idea's pretty neato. But the other day a friend of mine mentioned something called the Heisenberg Uncertainty Principal. Somthing about not being able to tell the exact location and momentum of an election at any given moment or somthing like that. And I guess that pretty much screws that theory up if you wanted to be really uber-precise with it.

    Anyways, I was wondering about that and If it does in fact screw somthing like that up and if there are any theories on how to um... get around it or somthing?

    I'm just a senior in hichschool (AP Physics... ) so I'm sorta hoping for general concepts sorta explination.

    Can anyone do that? Or maybe just point me in the direction of an 'advanced physics for dummies' website/book or somthing? Or just a good place to start? :tongue:
  2. jcsd
  3. Jan 7, 2005 #2
    Yes, you are right. Quantum mechanics prevents you to built such a computer. Imagine every thing you can principally create a super-computer like that. That implies your future is determined. Not only your future, your mind and your thought also determined. That means you have no control of yourself, which obviously not true.
  4. Jan 7, 2005 #3


    User Avatar
    Gold Member

    You have very accurately hit the nail on the head with QM.

    Classical scientists - Einstein being the most notable and most vocal - believed fundamentally in a deterministic universe. A universe where, in theory at least, if you knew exactly where every molecule in a system was and where it was going, you could, again, in theory, predict both the past and the future states of the system.

    The revelation that QM brought to the universe - that it is impossible in principle (let alone in practice) to determine the exact state of a system to an arbitrary level of precision - was one that shook Einstein's world, troubling him deeply til his dying day.
  5. Jan 7, 2005 #4


    User Avatar
    Gold Member

    "That means you have no control of yourself, which obviously not true."

    Alas, this is not obvious at all, though it's certainly an undesirable concept to accept.

    Just because you think you are reading this of your own free will doesn't mean it hasn't been the culmination of a set of deterministic chemical/atomic events.
  6. Jan 8, 2005 #5

    I deffinatly appears that way. But then again we don't completly understand time, which I think is key to being able to say that for sure (there could be more).
    I don't think it's clear that things arn't pre-determined. If it were that wouldn't be such a philosophical topic with so many theories.

    So part of the question is answered, how about the other part? Any theories - accepted or not about how to get around this or why it might not be true?
    And it seems like it's just a problem as far as DETERMINING the state of things, so it seems like it doesn't actually discount the possiblity of a certain future... This isn't exactly a philosophy forum so maybe we should skip the second part of what I just said.
    Last edited: Jan 8, 2005
  7. Jan 9, 2005 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    No, there's no way of "getting around this". This is how the universe is. It is probabilistic and non-deterministic. In short, there is no way to pre-determine stuff to an arbitrary level of accuracy, and this is not because of some technical inability.
  8. Jan 9, 2005 #7
    Yes of course, QM is the nemesis of every political scientist.

    Whoever said elections were predictable?
  9. Jan 9, 2005 #8
    and QM is the love of all open minded scientists
  10. Jan 9, 2005 #9
    [color=#black]Darned word limits[/color]
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook