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Einstein right = Newton wrong?

  1. Jul 15, 2006 #1
    This issue came up in a recent thread and I recall that it came up in another thread about a year ago. I think it deserves its own thread. If it already has one and you know of it, please direct me to it.

    Does acceptance of Einstein's theory entail rejection of Newton's?

    On page 98 of Thomas S. Kuhn's famous "The Structure of Scientific Revolutions" he writes:

    (Today means 1962, perhaps things have changed since then) Kuhn goes on to support his point of view against various objections. This takes up a good part of the next 4 pages of his book.

    While I read this a while back and remembered the part about Newton being wrong, I had forgotten the part about it being a minority view. I have agreed with Kuhn's point of view ever since I learned of SR some 30 years ago and long before I read Kuhn's book. I always take that stance in my converstations on the subject. I went back today to reread that part of the book and now I realize that I am in the lion's den and that most other posters here disagree with the idea.

    Perhaps I am attracted to the idea (that Newton is wrong) because I am not a physicist and do not calculate the numerical answers to physical problems on a day to day basis. Like Einstein, I am not interested in this or that phenomenon, but rather I wonder what the old one is thinking. (Einstein and I don't share much else in common, more's the pity for him).

    If you are interested, take a side and give a reason. If your reason is one of those handled by Kuhn, then I will paraphrase his argument against it. If it is not one handled by him, I will enjoy the chance to consider the implications of it.
  2. jcsd
  3. Jul 15, 2006 #2
    One reject's Newton in light of Einstein to the extent that Newton's equations are inaccurate in certain limits (e.g. high speed motion, strong gravitational fields, etc.). In this sense I hold that one must reject Newton and accept Einstein. However this can not be taken to mean that Newton was wrong. He just wasn't accurate and it is that sense that he is wrong. Newton's equations also do not predict certain things like gravitational redshift, the correct value for the bending of light in a g-field (Newton is off by a factor of two) and dynamics of systems of particles when the velocities are near the speed of light.

  4. Jul 15, 2006 #3
    You seem to be taking both sides. I had hoped to polarize people more.
  5. Jul 15, 2006 #4


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    The whole debate is absurd, if you ask me. Was Newtonian physics an exact description of nature? Clearly not. Was it accurate in the classical limit? Yes. Was he right or wrong? That obviously depends on what you mean by "right" and "wrong". My impression is that people who say Newton was "wrong" are usually just trying to make the scientific process look bad. In other words, political BS.

    There's no reason one should be faced with choice of simply saying Newton was either right or wrong. Do the world a favor and choose words with less ambiguity.
  6. Jul 15, 2006 #5
    Indeed, a theory stands or falls with the accuracy of the measurements not by the models it uses.

    Very likely in the future Einstein's theory will be proven inaccurate for some conditions just like Newton's did.

    Both men were pioneers and ought to be respected for their great work!
  7. Jul 15, 2006 #6
    Newton's theories depended on underlying assumptions he penned as "absolute space," an inert arena where events take place, and "absolute time," which flows at the same rate for all observers.

    Einstein blew away both of these assumptions outright. So, yes, Newton's laws must be rejected as Newton understood them.

    Thankfully, Einstein was able to make life easier for us and preserve the mathematical validity of Newtonian physics through the use of inertial reference frames.

    Einstein assumes that the speed of light is the same when measured in all inertial referenced frames. So, one day we may have to reject Einstein's laws as Einstein understood them, if we discover changes in the speed of light.
  8. Jul 15, 2006 #7


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    From the success of Quantum Mechanics, we already expect that Einstein's Theory of Gravity is not the last word on gravitational physics . Likewise, from the success of General Relativity, we may also expect that Quantum Mechanics is not the last word on quantum physics. The interesting question , IMHO, is what aspects of these theories are more fundamental..upon which newer theories will be built? and which aspects must be given up?

    Einstein did build on Newton's work... keeping some aspects (like inertia) and discarding others (like distant simultaneity).
  9. Jul 15, 2006 #8


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    Correct me if I'm wrong in this oversimplification, but:

    1] Newton didn't develop theories (i.e. models of HOW/WHY things work the way they do), what we developed were laws (a simple description of WHAT things do).

    2] Newton never suggested that the laws held all the way up to speeds that we now call relativistic.

    Thus, he is not wrong, he just described the circumstances within certain limits.
  10. Jul 15, 2006 #9
    I disagree with you on this point. I think the central role of science is to determine whether a theory is wrong.
  11. Jul 15, 2006 #10
    i think a physicist is correct or wrong in the limits of the precision of the measuring devices he uses.
  12. Jul 15, 2006 #11


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    That's not a bad way to look at it, considering Newton didn't have access to any data about how things behaved at high speeds or in large gravitational fields.

    My opinion is similar to the others, but the way I would put it is that Newton's theory (or model, if you prefer) was correct within the limits of what he was able to measure and Einstein's theory more clearly defined those limits and established new rules for how things worked outside those limits.
  13. Jul 16, 2006 #12
    Eddington made the now famous statement "Einstein right, Newton wrong" after collecting data on a solar eclipse in 1919 - the data, however, wasn't really accurate enough to reach that conclusion - but it greatly enhanced Einstein's image.

    The two approaches to gravity are conceptually different - Einstein asserts that matter conditions space-time and this causes the attractive force we call gravity - Newton believed that space was a universal backdrop - and that the masses acted directly upon one another for a reason which he could not explain. So when Einstein explains the force as a conditioning of spacetime by mass he has advanced a theory which has different results and consequences than that which could be obtained using Newtonian principles. But neither theory is complete in the sense that Einstien does not tell us why matter affects space and time, nor does his theory predict the value of the gravitational constant
  14. Jul 16, 2006 #13
    Newton spent more time on theology, prophecy, and alchemy than he did on physics. So, no, I suppose it's not right to say that he developed theories in the modern sense of the word.

    As for #2, no, Newton never imposed limits on his work. He declared that they were universal and that his laws described everything that the sense organ of God saw.

    Remember, he was describing the motions of the planets! These are as relativistic speeds as any. I wonder what he would have done if he knew about the perihelion shift of Mercury...
  15. Jul 16, 2006 #14
    Thank you for this. I was aware of the role Eddington played in forming the public image of Einstein. I was unaware of the statement above.

    I haven't tallied the results yet, but it seems that there is less support for Newton in this thread than I was lead to expect by Kuhn.

    As for the argument that Newton is correct, but that it is a mistake to extrapolate his results beyond speed of which he had no direct knowledge, Kuhn argues as follows (I only supply excerpts, interested parties should obtain a copy of the book):

    He gives the example of phlogiston which even today explains the phenomena it first did. And yet for practical reasons, we must be allowed to extrapolate the implications of a theory beyond the phemomena and observational precision in hand. A restriction would put most of cosmology out of the realm of science.

    Edit: That last paragraph is a mixture of Kuhn's ideas and my own.
    Last edited: Jul 16, 2006
  16. Jul 16, 2006 #15


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    Yes, of course! So what? There is no such thing as a perfectly "correct" theory- you can't prove theories, you can only disprove them.

    I haven't read "Kuhn" but what did he say to make you think there would be "support for Newton"? As I said above, you can't "prove" Einstein is exactly correct (he almost certainly isn't) any more than you can any other theory but experimental evidence has shown that he was, at any rate, "more right" than Newton.
  17. Jul 16, 2006 #16
    I quoted him on this point in my original post in this thread:

  18. Jul 16, 2006 #17
    This is my feeling as well. However, it then becomes a valid question:

    Has Newton been disproven yet?

    As I read Kuhn, most scientists would say no. I repeat, he said that in 1962. The posts in this thread are less negative than I had been lead to expect.

    Edit: extraneous blather removed
    Last edited: Jul 16, 2006
  19. Jul 16, 2006 #18
    I see no reason to assume that a particular "side" should be more correct than what I hold to be an accurate assertion.

  20. Jul 16, 2006 #19
    The term "theory" as it is being used here does not mean "how/why things work." That is beyond the scope of science (but is within its 'desires'). The term "theory" as used here means

    theory - a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena

  21. Jul 16, 2006 #20


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    Newton was right..... yes, he claimed his mechanics laws held for all conditions, but why wouldn't he? He had no way of knowing how out of whack things get at high speeds... most people today don't even realize that.

    Besides, you cannot possibly show me how dropping an object from a height of h doesn't convert mgh potential energy into 1/2mv^2 kinetic energy. The reason being because it does, for all intents and purposes. Newtons laws and their byproducts are probably more used in engineering than Einstein's theories, because Newton's are simpler, and give more than necessary precision for the job needed.
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