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Question about the Limitations of Physics

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  1. Jan 23, 2015 #1
    Here is a question about the possible limitations of physics, specifically about whether a theory of everything can actually explain everything.

    Assume we have a theory of everything. Now, consider an electron e with all the relevant properties. Now, our theory of everything, being mathematical in form, can capture perfectly everything about the electron ex hypothesi.

    But it cannot tell whether this electron actually exists. What is the difference within the TOE between electron e that I am observing now in my lab and electron e* that is exactly the same in all mathematical respects but is just theoretical?

    It seems to me that the theory, whatever it turns out to be, cannot tell the difference between the two and thus cannot really be said to explain or even describe everything physical. This is precisely due to its purely mathematical form. With an existing physical objection there seems to be something more than just a math. description. But that "something more" no TOE can really have anything to say about.

    What are some objections to this argument? Is there anything it simply overlooks? And, if it is sound, what does it imply for a TOE?
     
  2. jcsd
  3. Jan 23, 2015 #2

    Drakkith

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    Staff: Mentor

    Theories don't 'tell' whether something exists or not. They describe the properties of an electron and give the rules used to predict what will happen when the electron interacts with something. That is all. If your hypothetical electron and your real electron are subject to the same conditions for an interaction, then the predicted outcome for both interactions will be the same if the theory is accurate. This applies to all theories, not just a theory of everything.
     
  4. Jan 23, 2015 #3

    Dale

    Staff: Mentor

    Whether or not something "actually exists" is not a scientific question. It is a philosophical question. Specifically, that is the primary question of ontology which is one of the main branches of metaphysics.

    Scientific theories are not expected to answer philosophical questions, just scientific questions.
     
  5. Jan 23, 2015 #4
    Who gets to decide if a question is philosophical or not? In the hunt for the Higgs Boson, were we not trying to see if the HB actually exists?
     
  6. Jan 23, 2015 #5

    Nugatory

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    Around here.... If it makes a testable prediction, it counts as science. Thus, a theory that predicts that there is a Higgs boson and suggests a way to find it counts as science.

    If I understand the original poster properly, he was pointing out that a theory that makes the testable prediction "if I have an electron, it will behave in <this way> under <these conditions>" can only be known to be true for real electrons for which we can test the prediction. That's true enough, and it's always going to be an assumption not a proven fact that the hypothetical next electron that comes along will behave like the ones we've already observed. Because this question is not testable, it counts as philosophy.

    If there's any gray area... Around here, the mentors decide. This thread is closed.
     
  7. Jan 23, 2015 #6

    Drakkith

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    That's a good question. I think the answer is that science looks at outcomes in experiments and observations and then tries to explain them in the best and simplest way possible. The outcome of over a trillion collisions events at the LHC tell us that according to standard particle physics theories, the existence of another particle would better explain our observations than anything else we've thought of so far. Every digital camera sensor on the planet operates exactly as it should if EM waves are quantized into photons. All of chemistry is explained by having electrons in orbitals around atoms and molecules. Whether Higgs bosons, photons, or electrons 'really' exist is a matter of philosophy. According to science, they are the simplest, most accurate way of explaining observed phenomena and therefore they are used. It is always possible that there is a better way of explaining of our observations, but we won't know that until someone develops the theory.

    Sorry Nugatory, I clicked 'post' just seconds after you closed the thread.
     
  8. Jan 23, 2015 #7

    Nugatory

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    As long as we're saying the same thing :)
     
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