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Philosophy homework - need to support predefined future

  1. Oct 2, 2007 #1


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    To a lot of us it sounds evident that the future is predefined, that we know the future will only be one way, even through we cannot really predict how it would be (infinitely long equations, ect, an infinity of variables).

    Ok, its logic , but i need to find clear arguments to support that idea

    i was thinking of :

    - example : we can predict with enough precision what will happen in a chemical reaction, and theres chemical reactions in our brains too (and other reactions) , and since we obey to the laws of physics and chemistry, our thoughts are predefined : we may think we are acting on our own , and that we did not do what fate expected us to do, but it was already predefined that we would think that;ect)

    Ok that was just an example , how do i make a theory out of this ?

    No very complicated philosophy language, ect please, im in 12th grade in french school , scientific section (yes , in france you have to do philosophy in scientific section)
    Last edited: Oct 2, 2007
  2. jcsd
  3. Oct 3, 2007 #2

  4. Oct 5, 2007 #3


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    yes but which arguments can i put ?
  5. Oct 6, 2007 #4
    Modus Ponens
    If P, then Q
    Therefore, Q

    If the argument is modus ponens and its premises are true, then it is sound.
    The premises are true.
    Therefore, it is a sound argument.

    If modus ponens is a sound argument, then it has been tested valid.
    If valid, then it works to define future events.
    Modus ponens is a sound argument.
    Therfore it works to define future events.

    That was a multiple modus ponens. I think you can add to this if necessary if it is deemed worthy.

    Of course in the areas described best in quantum terms forget about ponens.

    Modus ponens works in the everyday world.
  6. Oct 7, 2007 #5


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    never heard of this

    it sounds logic, but whats the proof ?
  7. Oct 7, 2007 #6
    Proof is sometimes a fuzzy thing. What do you mean by "proof?" I can use modus ponens and say:
    If I can draw a circle that a match falls within when dropped from certain place 1 inch above the center of the circle, then I have demonstrated that the future is fixed.
    I've dropped that match and it always has fallen in the 30 foot diameter circle.
    Therefore the future is fixed.
  8. Oct 7, 2007 #7
    One could argue this -- let the following line A->B be some time line of events, with X, Y and Z being specific points in the time line:


    If you are at X, then Y is in the future and cannot be predicted. However, for any "Y" it is possible to argue that the events from X to Y are perfectly defined, since they are in the past and actually happened, leading to Y. Therefore once you reach Y, you can argue that events leading up to and causing it are predefined, since they obviously already happened.

    Any point on the time line can be viewed as either past or future, depending on which point you pick to observe it from.

    One can argue that the time line could be split into infinite futures. The reply to this could be that while this may be true, any future you pick to examine would then be (pre) defined by the time line that leads to it.

    Your teacher may or may not buy this.
  9. Oct 7, 2007 #8
    There isn't going to be any one answer to this.

    With regards to philosophy, you'll find all sorts of stuff on determinism, check on wikipedia for instance.
    Where you're probably going to come to a road block is with the 'problem of induction'.
    And I'm thinking thats the real point of this homework.
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