Physics is the only real science. The rest are just stamp collecting.

arildno

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desA said:
Who thinks out & develops the equations in the first place?
Not the physicists, for the most part.
 
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Who, for instance, developed the understanding behind the conservation laws? Perhaps they weren't called Physicists, or Mathematicians in those days, but, their history would give some idea as to their general logic flow.

I've got Serway's Principles of Physics to hand, let me look a few persons of interest & we could bat that about a little. Some folks would have multiple leanings, I would expect.
 

arildno

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"Who, for instance, developed the understanding behind the conservation laws?"

Hmm..the only person I'd say qualifies to have "developed understanding behind conservation laws" is the mathematician Emmy Noether.
 
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Let's start with two:

Galileo Galilei
Isaac Newton
 
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arildno said:
"Who, for instance, developed the understanding behind the conservation laws?"

Hmm..the only person I'd say qualifies to have "developed understanding behind conservation laws" is the mathematician Emmy Noether.
A very fair comment indeed. :wink:

Perhaps the question should have read, "Who first formulated the Conservation Laws".
 

selfAdjoint

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Different conservation laws emerged at different times. Conservation of momentum was explicitly used by Daniel Bernoulli in his Hydrodynamica (1743). Newton did not use momentum; the concept occurs nowhere in the Principia, and modern interpretations of his three laws in terms of momentum conservation are just that: modern.

Conservation of energy had to wait for the insight that "energy" includes chemical and electrical energy, as well as the older mechanical KE and potential. Thus the conservation of energy belongs to Clausius and Joule in the mid nneteenth century.

Other conservation laws are twentieth century.
 
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Serway (p56) refers to Galileo Galilei (1564-1642) as follows:

"Italian physicist & astronomer Galileo formulated the laws that govern the motion of objects in free fall. He also investigated the motion of an object on an inclined plane, established the concept of relative motion,..."
 
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selfAdjoint said:
Different conservation laws emerged at different times. Conservation of momentum was explicitly used by Daniel Bernoulli in his Hydrodynamica (1743). Newton did not use momentum; the concept occurs nowhere in the Principia, and modern interpretations of his three laws in terms of momentum conservation are just that: modern.

Conservation of energy had to wait for the insight that "energy" includes chemical and electrical energy, as well as the older mechanical KE and potential. Thus the conservation of energy belongs to Clausius and Joule in the mid nneteenth century.

Other conservation laws are twentieth century.
Very interesting about Newton's not using 'momentum'.

So, Clausius & Joule are in the running. (*reaches for Serway*) What leaning did these men of stature have?

I wonder if there are thinkers from other civilisations who worked in this area - perhaps earlier than the dates above?
 

arildno

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I have always regarded as one of the fundamental shifts from classical physics to modern physics to the shift of emphasis from seeing a system described by forces, mass and velocity to seeing a system described by the conservation of momentum&energy (the concepts of mass&force receding into insignificance from the fundamental point of view), along with various requirements of symmetry/invariance.

It is a subtle shift, and it is easy to superimpose a modern view on the old-fashioned classical view.

However, if one does so, then we run the risk of not understanding what classical physical actually concerned itself with, nor how its perspective was internally consistent, but still obscured certain features that the perspective of modern physics handles better.

Take the case of the "principle of Galilean invariance":
I must confess that I haven't found this requirement stated in any pre-Einstein physicist.

Rather, to them F=ma was the fundamental law empirically verified to hold for material systems (systems that consisted of the same stuff over time).

Also, it was empirically verified that a system only could lose mass if some part left the system (mass conservation law, which I believe is the oldest conservation law)

From F=ma, it is fairly trivial to DEDUCE that there exists some sets of "equivalent observers", namely those that move with constant velocity to each other. For these groups, the force F acting on the object will be observed to be the same, since the accelerations are the same, due to the observed kinematic Galilean law that velocities are additive.

If we call one set of such observers the "true" observers, who deduce the ACTUAL forces on the object, then the other sets observe additional pseudo-forces, due to their acceleration relative to the set of "true" observers.


But at no point is this equivalent to state that classical physics REQUIRED the laws of mechanics to be Galilean invariant, they OBSERVED, or DEDUCED that they were. Nor, indeed did the idea of "absolute state of rest" lose its meaning, it was just that one couldn't deduce an absolute state of rest with the laws of mechanics!!

This means that when the phenomena of electro-magnetic forces began to be studied, there was NO CONCEPTUAL CONFLICT with previous physics, rather what one discovered was that since the laws of electro-magnetism were not Galilean invariant, it followed that the state of absolute rest could in principle be deduced/observed by the study of electro-magnetic phenomena. Maxwell's laws were assumed to be valid for the absolute rest frame, and hence another observer's absolute velocity could in principle be deduced from HIS observed laws of electro-magnetism under the assumption that all velocities would, indeed, follow the Galilean empirical law of velocity addition.

This perspective is internally consistent, even though we now know that several of the assumptions are wrong.

However, as I hope I have shown, it wasn't because physicists previously were dumb that they didn't question their assumptions when the non-Galilean electromagnetic phenomena appeared; it was simply accommodated easily into their system of thought as some rather weird forces.

However, with the Michelson-Morley experiment came, one of the basic observational laws hitherto known failed, that of velocity addition, then something seriously wrong were understood to be the case.

However, Einstein's revolutionary thoughts, for example his fairly unique requirements of invariance, are by no means the only, or most obvious way to try and find resolutions to the problems at hand.
Others were tried out, most of them forgotten because at one point or another, they failed.
 
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An excellent informative review... :smile:
 

selfAdjoint

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arildno said:
Very interesting about Newton's not using 'momentum'
Let me add just a little bit more.

Among the bitter controversies over the new knowledge that divided the British from the Continental European mathematicial and physicists, was one about how to model mechanics. The British, following Newton, used forces, but the Continentals used momentum and "vis viva", a pretty close concept to kinetic energy. This controversy continued until the nineteenth century, when the Continentals won the day everywhere but in anglophone engineering departments.

I believe there is a discussion of all this in Max Jammer's Concepts of Force, which I recommend.
 

arildno

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Actually, it is desA you quoted there.

Newton did, however have the corresponding concept to momentum called "quantity of motion", which incidentally, is the word that Scandinavians still use for linear momentum.
 

MathematicalPhysicist

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the philosophical approach that argues that everything can be broken down to physical theory is physicalism.

i must say that this approach has some appeal to me, but im biased, as was rutheford.
 

arildno

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It is not Rutherford's physicalism as such that there is something wrong with, it is his arrogant and unjustified dismissal of other disciplines dealing with phenomena that are too complex to deal with in the manner of maths&physics.
 

matt grime

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Right.

1. DesA, I"m worried that you think current mathematical research trends are based upon your understanding of the physical sciences from several centuries ago.


2. Gettting back to the topic at hand, arildno, Rutherford's opinoin is purely based upon those things that were science at the time, and he terms them 'stamp-collecting', not 'uncomplex' or any other term. Arguably modern chemistry and biology bear little relation to their study at the start of the 20th Century. If you're going to accuse him of arrogance then at least acknowledge that.
 

matt grime

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desA said:
Who thinks out & develops the equations in the first place?
what equations? Who thinks mathematics is the study of equations...?

Is current Mathematics research internally, or outwardly focused?

As a 'current mathematical researcher' I think I'm in a better position to judge than you are whether or not we just 'work things out for the physicists to use'. We don't. Some mathematics is motivated by the 'real world', some real world scientists are now using mathematics developed without reference to the real world.
 

arildno

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Well, at Rutherford's time, Darwin's principle of natural selection was very well known, and it is really all too dismissive of Rutherford to label Darwin's work as "stamp collecting".
 

matt grime

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desA said:
Let's start with two:

Galileo Galilei
Isaac Newton
Yes, lets start with people who have nothing to do with the modern trends in mathematical research..... You noticed the bit where I said the ideas you had about research hadn't been true since the early part of the 20th Century? So why invoke two people who weren't even alive in the 19th Century? (Newon dead before 1750, Galileo before 1650).
 
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arildno

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As for the atomic theory of matter, this was developed by chemists, and it worked excellently.

Physicists were not too eager to go along with this theory at first, not because they didn't believe in it, but that they found the theoretical framework unsatisfactory built out, in particular that one should not rule out other possibilities for the constitution of matter.
As the physicists sharpened their tools in order to do so, they could verify in their own manner what chemists had hypothesized before.


Rutherford's statement arrogantly dismisses the conceptual work done by leading chemists prior to his own time.
 
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arildno said:
Well, at Rutherford's time, Darwin's principle of natural selection was very well known, and it is really all too dismissive of Rutherford to label Darwin's work as "stamp collecting".
Yes, but not everyone accepted it. I'm not saying that Rutherford didn't, but it may not have been considered as "truth" by a majority. We still have people, althogh insane, dismissing it as being "just a theory." Moreover, that's just one...you still had chemistry people labelling elements and botanists labelling plants and so on.
 

arildno

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Furthermore, it was not physicists that came up with the idea that infections did not occur due to miasmas but by living organisms, it was guys like Koch and Pasteur who developed these ideas into such a form that it could be tested out empirically.

This vast advancement in biology&medicine is not dismissable as stamp-collecting, either.
 

SF

Anatomy is still basically physics, but at a different level.

What physics can't even touch in this field is predicting models for the mechanism of "life". You simply can't take a bunch of formulas put them together in a computer and spit out a zebra.
Heck, it can't even analyse and explain the similarities between a simple bacteria colony and the psychology of a human comunity.
 
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There are, in my judgement of the issue two ways to look at this.

The first is a purely secular view of knowledge. Given the presupposition that we (humanity) are all finite then logically all sciences which are based around human behavior (psychology, economics, social sciences etc.) are all also finite and therefore irrelevant in the long run. Making the potentially eternal laws which can be learned from the natural sciences superior. So in this respect we have narrowed down the conflict by determining that natural sciences > social sciences. Next would be a comparison of the natural sciences biology, chemistry, physics, etc. Again coming from a secular viewpoint biological organisms will eventually die out therefore making biology a finite science. However, logically from this viewpoint, gravity, force, etc. are all permenent concepts. Therefore, physics>biology. I'll leave chemistry, geology etc. to be debated in comparison to physics but in this opinion physics does seem to be eternal.... at least in comparison to other fields.

However, If you have a non-secular philosophy, this means you beleive that living things have an eternal aspect. In which case those sciences which deal with how we interact with other people will have a symbiotic relationship with the natural sciences. The non-secularists need to pursue the study of the natural sciences and philosophy in order to justify their viewpoint, and the social sciences in order to efficiently put their viewpoints to work.

BTW FIRST POST!!!! hello everyone!!!!
 

loseyourname

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"Physics is the only real science. The rest are just stamp collecting."

-- Ernest Rutherford

How valid is this statement. I think it has a lot of validity considering the fact that you are learning the fundamental laws of the universe and nature. You are basically studying the "Mind Of God". Where as other sciences such as social science, geology, biology and even chemistry are more specific into detail that may be more mundane that what physics teaches. Physics seems to be the big picture of science, and thus its essence as well.
Okay, I know I'm coming to this a little late, but since nobody else seemed to mention it, this comment needs to be taken in context. Chemistry at the time was still heavily invested in the discovery and classification of elements; biology in the discovery and classification of species. The theoretical aspects of these sciences have developed heavily since Rutherford's time; back then, a lot of the work done was "stamp collecting." His comment has nothing to do with the current state of sciences other than physics.

Furthermore, the theoretical breakthroughs of biology at least have not been reducible to physics. It is neither possible to predict nor understand what mutations will take place at the molecular level, and which will take hold and why, using physics. Phenotypic expression and community ecology need to be taken into account to create any form of coherent theory on the matter.
 

arildno

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Okay, I know I'm coming to this a little late, but since nobody else seemed to mention it, this comment needs to be taken in context. Chemistry at the time was still heavily invested in the discovery and classification of elements; biology in the discovery and classification of species. The theoretical aspects of these sciences have developed heavily since Rutherford's time; back then, a lot of the work done was "stamp collecting." His comment has nothing to do with the current state of sciences other than physics.

Furthermore, the theoretical breakthroughs of biology at least have not been reducible to physics. It is neither possible to predict nor understand what mutations will take place at the molecular level, and which will take hold and why, using physics. Phenotypic expression and community ecology need to be taken into account to create any form of coherent theory on the matter.
Darwin and Mendel were PRIOR to Rutherford.
So were guys like Koch and Pasteur, who found out that it was living organisms that caused diseases, not "bad air", miasmas, which was what most others, including physicists, believed at the time.
So were the chemists who developed the highly successful atomic theory.

So, basically, Rutherford was WRONG, also in his own time, as I've said before.
 
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