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Liebnez vs. Newton

  1. Dec 6, 2004 #1
    I recently read some of Liebnez's work and have become interested in a very important fact.

    I became very interested by one of his arguments and wondered if this has been dealt with recently. Its fundamental to emperical methods, let me explain the basic process in a simple way:

    We are doing an experiment to test the size of the explosion created when mixing a fixed amount of chemical A with a variable amount of chemical B. We are going to do the experiment with 3 test tubes, each has the same amount of A, and we are going to add a small, medium and large amount of B.
    This means that we (according to newtonian thinking) are only changing 1 property per case, i.e. the amount of B.

    That is known as a controlled experiment, it is the basis of emperical methods.

    Liebnez pointed out that if we look a little closer, 2 properties actually change:

    1. The amount of chemical B
    2. The location of the test tube, i.e. they are all in different locations.

    On a quick side note, you can theoretically do them all in the same location (test tube) but that means you cant do them all the same time. What am trying to say is that in any test case 2 properties always change, the common property (amount of chemical B in above example) plus either the time or location you do the test case.

    The reasoning behind this is that if you do 2 experiments in the same place and at the same time they are by definition the same experiment.

    Another example is the abstraction of a TV screen, with Newtonian thinking each pixel is defined as being the same, same size, same shape, can display colours from a range but only one colour at one time.

    Leibnez would disagree and tell you that each pixel is in fact unique by virtue of its location, i.e. no to pixels share the same space.

    The location thing is very important, I mean think about how you distinguish between things, think of two twins that from a distance look exactly the same. How do we tell them apart? The fact they are in different locations....

    Can some tell me if this has been factored out through creative thinking or is it just not been taken seriously?
  2. jcsd
  3. Dec 6, 2004 #2
    Philosophers and scientists mostly agree that natural laws operate independant of time, so generally apples ALWAYS fall to the ground and the sun rises EVERY day....and the SAME experiment at different times always give the same result ?!

    Of course this can be doubted, and there are areas with natural laws involving eg evolution over time though they also are considered independant of time mainly ?!
  4. Dec 6, 2004 #3


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    Yes, GrimDad is basically correct, but for a more accurate answer you can ask about the first postulate of Special Relativity (The laws of physics are the same in all inertial frames of reference) in the Relativity forum https://www.physicsforums.com/forumdisplay.php?f=70. They can explain it better than I can.
    Note that your question should focus on the relevance of position to the experiment. I doubt any sane person will argue that two different events can take place at the same position. You should focus on whether or not position can effect the experiment.

    You can also ask about general relativity and accelerating frames of reference. In this case, position can effect experiments. Actually your frame of reference can effect experiments. But I'm getting ahead of myself :biggrin: Ask the experts about time dilation and length contraction.
  5. Dec 6, 2004 #4


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    Here's a suggestion for questions to ask (you can cut and paste if you like them):
    According to Relativity, when can two experimenters conduct the same experiment and be assured of getting the same results? When can two experimenters conduct the same experiment and get different results? What assumptions does Relativity make in answering these questions?
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