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Macroscopic vs. microscopic

  1. Nov 23, 2004 #1
    Several times I've listened to Brian Greene talk about string theory and say that General Relativity is a macroscopic theory but Quantum Mechanics is a microscopic theory. Do you think it could be otherwise?
    I know that this is an accepted "dogma" that is often repeated by others but I wonder how far it really goes and maybe it is a line of thinking that leads one away from reconciling the two theories. How is it that microscopic particles must follow special relativity but not general relativity? What is mass? What is charge?
    Dr. Mendel Sachs makes some good points in his writings such as QUANTUM MECHANICS FROM GENERAL RELATIVITY that perhaps General Relativity can be incorporated in microscopic physics once the two theories are speaking the same mathematical language. There are some similar ideas in the writings of Lasenby and Doran and others working with Geometric Algebra. Whether this unified theory should be written in the language of spinors, quaternions, clifford algebra, geometric calculus or some other dialect, (all of these are related) I don't like the tower of Babel that currently exists in Physics. Several researchers have pointed out similarities of Yang Mills theory and General Relativity in a clifford algebra form. Could the idea that General Relativity is ONLY a MACROSCOPIC theory be a red herring?
  2. jcsd
  3. Nov 23, 2004 #2


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    No one is saying that GR is only a macroscopic theory, just that on the microscopic scale quantum effects become significant and also have to be taken into account.

    Of course the macroscopic scope of GR becomes microscopic in the earliest stages of the Big Bang and so it then becomes imperative to have an integrated quantum gravity to find out what was going on, but that lies in the future.

  4. Nov 24, 2004 #3


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    With respect, laserblue, it doesn't seem that you know enough about the "Tower of Babel" to seriously question its veracity. Keep learning.

    As Garth said, gravitation still exists at the subatomic scale, but its effects are so insignificant that they cannot really be measured.

    - Warren
  5. Dec 8, 2008 #4
    well, subatomic is just OK to call the Quantum mechanics with, but you know quantum mechanics itself has a kind of macroscopic point of view not microscopic. that is because it talks about observables and thinks of what can be measured just like as any macroscopic point of view does care about but not microscopic point of views.
    be careful of what you name macroscopic or microscopic, for they do not only contain the matter of scale but it is like to say every macroscopic has a microscopic and vice versa.

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