Does Accepting Einstein's Theory Mean Rejecting Newton's?

[Jimmy Snyder]

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:

From the viewpoint of this essay these two theories are fundamentally incompatible in the sense illustrated by the relation of Copernican to Ptolemaic astronomy: Einstein's theory can be accepted only with the recognition that Newton's was wrong. Today this remains a minority view.

(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.

 

[pmb_phy]

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

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.

Pete

 

[Jimmy Snyder]

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.

You seem to be taking both sides. I had hoped to polarize people more.

 

[SpaceTiger]

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.

 

[MeJennifer]

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".

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!

 

[Mickey]

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.

 

[robphy]

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).

 

[DaveC426913]

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.

 

[Jimmy Snyder]

There's no reason one should be faced with choice of simply saying Newton was either right or wrong.

I disagree with you on this point. I think the central role of science is to determine whether a theory is wrong.

 

[bernhard.rothenstein]

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.

i think a physicist is correct or wrong in the limits of the precision of the measuring devices he uses.

 

[russ_watters]

i think a physicist is correct or wrong in the limits of the precision of the measuring devices he uses.

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.

 

[yogi]

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

 

[Mickey]

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.

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...

 

[Jimmy Snyder]

Eddington made the now famous statement "Einstein right, Newton wrong"

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):

A similar argument will suffice for any theory that has ever been successfully applied to any range of phenomena at all.

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.

 

[HallsofIvy]

A similar argument will suffice for any theory that has ever been successfully applied to any range of phenomena at all.

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.

it seems that there is less support for Newton in this thread than I was lead to expect by Kuhn.

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.

 

[Jimmy Snyder]

I haven't read "Kuhn" but what did he say to make you think there would be "support for Newton"?

I quoted him on this point in my original post in this thread:

Today this remains a minority view.

 

[Jimmy Snyder]

There is no such thing as a perfectly "correct" theory- you can't prove theories, you can only disprove them.

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

 

[pmb_phy]

You seem to be taking both sides. I had hoped to polarize people more.

I see no reason to assume that a particular "side" should be more correct than what I hold to be an accurate assertion.

Pete

 

[pmb_phy]

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.

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

Pete

 

[Office_Shredder]

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.

 

[Mickey]

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.

But he didn't simply claim that his mechanics was universal. This is important because it is here that he was dramatically wrong.

To his enormous credit, he was smart enough to realize that, in order for the space and time of his mathematics to be applied to the natural world, space and time had to be well-defined "things" of a sort that had existence in the natural world. In other words, the coordinate space he was using in his mathematics had to be commensurable with the coordinate space of the natural world. But it's not!

Even at small speeds, we experience relativistic effects. There are relativistic effects in building construction and public transportation. It's just that our biology and psychology have apparently evolved to not find them relevant. So, the reason we don't care about the relativistic effects of building construction is because we don't care about precision, not because relativistic spacetime doesn't exist at that level. It does.

 

[loseyourname]

I'll admit I've never actually read Kuhn, but I'm pretty sure the relevant point of departure for him is from absolute space-time isomorphic to a Cartesian coordinate system to relativistic space-time isomorphic to n-dimensional spaces of variable curvature. Einstein chose Minkowski space-time over Newtonian space-time, and that's the relevant rejection here. It isn't that Newton's laws no longer work.

Newton made a similar choice in his own time as well. Leibniz developed a system of physics that employed the idea of space and time being relative parameters, and the scientific community chose to go with Newton's system, in which they were absolute parameters. This is the relevant sense in which Newton was "wrong."

 

[Jimmy Snyder]

There are relativistic effects in building construction and public transportation. It's just that our biology and psychology have apparently evolved to not find them relevant.

Yes, relativist effects appear at all velocities (except zero) and wherever masses appear. Our biology prevents us from finding them relevant. There is a limited resolving power to our nerve endings. I don't know this for a fact, but I expect that relativistic effects at the speeds we had knowledge of during the bulk of our evolution are dominated by that limit. I don't think there is a psychological issue since I don't think our nerve endings provide our perceptions with the necessary data for a psychological response.

Edit: This post was grossly edited to change its entire flow.

 

[Jimmy Snyder]

Einstein chose Minkowski space-time over Newtonian space-time, and that's the relevant rejection here.

Kuhn never mentions this fact. However, after convincing himself that Newton had been shown wrong, he went on to discuss whether Newton is a limiting case of Einstein. He feels that it is not. Although he did not mention the difference between Newton's space + time and Einstein's spacetime, it would have supported his argument. That is spacetime does not approach space + time in the limit as v tends toward zero. I mean, the world remains Minkowskian at all positive values of v, and discontinuously jumps away to Euclidean at zero.

 

[Kurdt]

We can only make a theory about what we know and at the time Newton's 'laws' were a very good description of what we know. They're even a very good description now. Einstein's theory is very deliberately formulated so that in the weak field limit it tends to Newtonian gravity, thus to say that GR is somehow invalidating Newton is bizarre be cause Newton's theory is a building block of GR.

Thats nothing to do with SR as I believe was originally referred to, but as for "has Newton been disproved yet?", well all I can see is that his statement that the laws are universal has been disproved but in what is now termed the classical limit he has over 300 years of success.

As a final note I echo the sentiments of many others that you can only theorise (or create laws if you will) about what you know and Newton didn't have the luxury of knowing what Einstein did.

 

[NickJ]

How's this for a reason Newton was definitely wrong: mass is a frame-dependent property of objects. Newton's mechanics treats mass as if it is a frame-independent property of objects (cf. the second law). Therefore, Newton's theory is false. I don't see the point in saying that Newton was right "within certain limits" and things like that -- everyone knows that falsehoods can contain partial truths or approximations to truths (consider the practice of lying, for example). But a falsehood is a falsehood. And since there's nothing wrong with having proposed a false theory, why bother trying to figure out some sense in which Newton was "right"?