What is the Definition of Physics?

[Paulanddiw]

Physics is the study of mechanics, light, heat, electricity and radioactivity.

 

[reilly]

No, it is false.

And I have already explained why.

You haven't considered my objections.

You look like "Simplicio" from Galileo's "Dialogue", you quote and don't say.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Indeed I have examined your argument. Contrary to your assertion, I considered your objections, and rejected them. Why, you might ask?

Apparently I did not communicate why I responded as I did, and for that I apologize for faulty writing. So let's try again.

As far as I know the Physics community is a particularly reliable judge of what is and is not physics, and who is or isn't a physicist. (This the part I failed to include.)

My references simply and clearly indicate the the physics community considers Aristotle to have been a physicist. Within the world of professional physicists, my experience suggests that at least 95% of them agree with their community on Aristotle.

Subjective? Arbitrary? Incomplete? Of course. There's nothing that's wrong with your take on Aristotle; it's all a matter of opinion. On this one I go with the mainstream.
Regards,
Reilly Atkinson

 

[Critical_Pedagogy]

Today, my lecturer asked us to define physics. No one give a very obvious and correct answer to the lecturer. Can anyone here give me the best defination of the meaning of physics?? Thanks

"Physics is the science of measurement". It encompasses almost everything. I heard this at my university, and I'll never forget it.

 

[Maxos]

On this one I go with the mainstream.

So, good shipwreck.

 

[krab]

Maxos. I agree it is a bad idea to go with the mainstream in issues of morals, ethics, scientific principles. But the present topic is about language. Here, the mainstream is the final arbiter, else communication becomes dysfunctional.

 

[Maxos]

Here, the mainstream is the final arbiter

May I ask, How come?

We are not talking about language at all!
We are talking about a definition of Physics, your "democracy" is completely useless.

 

[Juan R.]

Physics is not a sinonym for science

"Physics is the science of measurement". It encompasses almost everything.

This is very incorrect, see post #55 and #60 on why, and #50 for a general definition of physics and other sciences like biology or chemistry.

 

[ZapperZ]

May I ask, How come?

We are not talking about language at all!
We are talking about a definition of Physics, your "democracy" is completely useless.

No, it isn't, because a definition, BY DEFINITION, is to be something the largest number of people agreed upon so that it can be used without ambiguity. One simply cannot define something to one's content that has already been widely defined. This will create confusion. You cannot simply define what an "electron" is according to whatever you please.

The APS, for example, has described what physics is. Who better to define what it is other than people who practice it? If you wish to define it as something else, give it a different name, unless your sole aim is to create confusion.

Zz.

 

[Juan R.]

APS, for example, has described what physics is. Who better to define what it is other than people who practice it?

Zz.

Sometimes, people who practice something is not the better to define what it is. for example physicists discover laws of nature, thus physicists would be better people for understand laws of nature are, but is not. for example the Character of physical law (Feynman) is considered trivial or even incorrect in phylosophy (epistemology).

Physics is the foundation of modern science

This is only true in a reductionist approach to the ontology of science. Since reductionist approach is highly limited for solving problems of real word, physics loses its role like "foundation" of others sciences. In fact it is well-known for non-physicists that other sciences cannot be reduced to physics. See e.g. Computers and chemistry (2001), 25, 341-348.

For example, contrary to physics' belief, chemistry is not based in physics, it is autonomous science which cannot be reduced to physics. I believe that physicists newer did heard about the concept of disunity of sciences, which is basic to modern conception of phylosophy; one which is absent in physics textbooks and peer-revieved physics journals.

But chemistry journals are also peer-reviewed

The idea of that correct approach to modelling nature cannot be based only in physics (of course physics play an important role) is a heresy for many physicists but it is real.

The quest for ontological reduction remains central to the scientific tradition, as David Lindley, astrophysicist and editor of Science notes. Despite his conclusion that the dream of a unified ‘theory of everything’ is a myth, he insists that

to abandon the notion that physics ought to reduce ultimately to a set of elementary particles and a description of the way they interact would be to
abandon an intellectual tradition going back to the very beginning
of science; it would be to abandon science.

But one does not need abandon science, simply to reinvent it on a generalized conception beyond physics. With physics reduced to a special case. That already has been done (e.g. Prigogine showed like quantum field theory is a special case of chemical reaction theory) but physicists still ignore (somewhat like they ignored law of conservation of energy during decades).

Note: particle physics (a + b = c + d) is based in S-Matrix theory, but chemical reaction theory (A + B = C + D) is more general, since in a flask molecules are not in the infinite :tongue2:

 

[ZapperZ]

Sometimes, people who practice something is not the better to define what it is. for example physicists discover laws of nature, thus physicists would be better people for understand laws of nature are, but is not. for example the Character of physical law (Feynman) is considered trivial or even incorrect in phylosophy (epistemology).

Right.. and someone else who only has a superficial understanding of physics is better qualified to define what physics is. Does that mean that I, who only have a superficial impression of who you are, are more qualified to describe your character and who you are? Would you buy this?

This is only true in a reductionist approach to the ontology of science. Since reductionist approach is highly limited for solving problems of real word, physics loses its role like "foundation" of others sciences. In fact it is well-known for non-physicists that other sciences cannot be reduced to physics. See e.g. Computers and chemistry (2001), 25, 341-348.

And if you have followed the "history" of my postings on here, you would have realized that I am the LAST person you want to argue with regarding the "reductionist" approach. I am a condensed matter physicist, and by my training, I do NOT buy into reductionism. Vanesch can verify that we have had a long discussion on the validity of reductionism and why I argue of the idea of emergent phenomena that cannot be explained via reductionism.

It still isn't relevant to what is being discussed here UNLESS you are implying that the APS's definition somehow does not encompass those of us working in condensed matter. This would be VERY strange since the division of condensed matter physics/material science makes up the LARGEST percentage of the APS membership! That definition says nothing about "reductionism". You just imagined it.

Zz.

 

[Juan R.]

Precision please

Right.. and someone else who only has a superficial understanding of physics is better qualified to define what physics is. Does that mean that I, who only have a superficial impression of who you are, are more qualified to describe your character and who you are? Would you buy this?

There exists a failure of logic on your reasoning. The original "sometimes" has been omited in your logical sequence!

And if you have followed the "history" of my postings on here, you would have realized that I am the LAST person you want to argue with regarding the "reductionist" approach. I am a condensed matter physicist, and by my training, I do NOT buy into reductionism. Vanesch can verify that we have had a long discussion on the validity of reductionism and why I argue of the idea of emergent phenomena that cannot be explained via reductionism.

You may be confused. My

This is only true in a reductionist approach to the ontology of science. Since reductionist approach is highly limited for solving problems of real word, physics loses its role like "foundation" of others sciences. In fact it is well-known for non-physicists that other sciences cannot be reduced to physics. See e.g. Computers and chemistry (2001), 25, 341-348.

follows directly APS quote. I said nothing about you or your ideas.

It still isn't relevant to what is being discussed here UNLESS you are implying that the APS's definition somehow does not encompass those of us working in condensed matter. This would be VERY strange since the division of condensed matter physics/material science makes up the LARGEST percentage of the APS membership! That definition says nothing about "reductionism". You just imagined it.

I'm sorry but i just did comments on that people wrote. Interpretation is a suggestive issue.

APS said

Physics is the foundation of modern science

And this phrase (i did not imagine) said that moderns science relies on physics, which is not true.

The correct phrase would be

Physics is one of the foundations of modern science.

Other foundation is math.

Other foundation in chemistry is 19th century chemical theory.

Etc.

 

[Juan R.]

some logical calculus

Physics is the foundation of modern science

Since chemistry is one of modern sciences then

Physics is the foundation of chemistry

But in Foundations of Chemistry 3: 269–271, 2001 one reads

chemistry is an autonomous science, with its own foundations. To consider it in the shadow of physics [...] is boring and pointless.

That is (conclusion),

To consider physics is the foundation of chemistry is boring and pointless.

Since we desire the maximum rigor for APS, they would change its (peer-reviewed) web quote to anything like

Physics is one of the foundations of modern science

It would be remarked that none claim about ZapperZ follows in a logical maner from this calculus.

 

[ZapperZ]

There is failure of logic on your reasoning. The "sometimes" has been omited in the logical sequence!

And does it apply to THIS particular case? It should, or else why would you bring up this point? So I'm asking, is THIS the case where someone else outside physics has the SAME ability and expertise to define what physics is?

APS said



And this phrase (i did not imagine) said that moderns science relies on physics, which is not true.

The correct phrase would be

Physics is one of the foundation of modern science.

Other foundation is math.

Other foundation in chemistry is 19th century chemical theory.

Etc.

Now let's see. The energy gap between bonding and antibonding bonds in H2 molecule were discovered in chemistry eons ago without ANY idea on where it came from. We had to wait till QM was developed to actually figure out the origin of such phenomenon.

Something from biology? Sure. Linus Pauling used QM to estimate the bond angle in a protein chain. This was used by Watson and Crick in figuring out the structure of the DNA.

Even more: emergent phenomena as described in the two papers by Laughlin that I've cited a gazillion times included biological and chemical phenomena. These large scale, non-reducible properties are the essential evidence for the study of many-body phenomena.

ALL of what I've said about came out of PHYSICS. And all I've described are the "source knowledge". I haven't even started yet on how the advanced in physics allows for people in chemistry, biology, medicine, etc. to USE those knowledge to advance those individual fields. People don't use MRI, synchrotron radiation, x-rays, PET scans, etc. without the advancement in physics about those things.

The APS statement (it isn't a definition) is accurate.

Zz.

 

[Juan R.]

[...] someone else outside physics has the SAME ability and expertise to define what physics is?

Yes, "sometimes".

Now let's see. The energy gap between bonding and antibonding bonds in H2 molecule were discovered in chemistry eons ago without ANY idea on where it came from. We had to wait till QM was developed to actually figure out the origin of such phenomenon.

Said i contrary?

This is the reason i say that one of foundations of chemistry is physics (e.g. quantum mechanics). But physics is not the foundation of chemistry.

The same for biology, sociology, geology, economy, etc.

Moreover, QM has not changed classical foundation of chemistry. Chemistry before and after QM is practically the same. The contribution of QM is more "computational" than "theoretician". However, QM was a radical modification of pre-QM physics.

Chemistry cannot be reduced to physics, chemistry is autonomous science, with its own theories, principles, and methods.

Yes advance in physics is used in chemistry, but three precisions are needed here:

1) Advances in chemistry are also useful for physics.

2) Advances in physics may be always complemented with pure chemical research for successing on laboratories of real world.

3) Many outcomes of physics are really outcomes of chemistry. For example, fisrt formulation of superposition principle of QM was from chemistry not from physics. The first formulation of supersposition of an electron between two atoms was in Lewis theory of chemical bond, before QM.

You cite MRI as one of advances of physics. It is true, but many of work of MRI is direct outcome of chemical research. Is not a pure contribution of physics like physicists usually state. As said in other post, history of physics is usually rewritten.

Chemists also played a vital role in developing nuclear magnetic resonance spectroscopy and its medical spin-off, magnetic resonance imagin (MRI). But today, MRI is often see as an example of how physics can contribute to biomedical research.

in Nature 2001, 411, 408. But history of science is here like Nature article states.


And not, unfortunately the APS statement cannot be accurate because both the "one of" and the "s" are lacking.

 

[ZapperZ]

Yes, "sometimes".

OK, so put your definition where your mouth is. Show an accurate and accepted definition of physics made by someone else.

Said i contrary?

This is the reason i say that one of foundations of chemistry is physics (e.g. quantum mechanics). But physics is not the foundation of chemistry.

The same for biology, sociology, geology, economy, etc.

Moreover, QM has not changed classical foundation of chemistry. Chemistry before and after QM is practically the same. The contribution of QM is more "computational" than "theoretician". However, QM was a radical modification of pre-QM physics.

I could have sworn that the APS was referring to MODERN SCIENCE. The field of quantum chemistry (a MODERN science) is dominated by physicists.

This is still an argument of PREFERENCES. It will never be settled. I will choose the mainstream definition and statement by people who intimately know the field, rather than rely on somebody who doesn't. I am strange that way. If you think that in THIS particular case, a definition produced by something or someone else is more accurate, be my guest. Maybe you could write to the APS and complain to them. Who knows, something "productive" could come out of this.

Zz.

 

[Maxos]

Some missing points:

Physics is the sole foundation of modern science.

Nothing can be autonomous from Physics.

 

[Juan R.]

OK, so put your definition where your mouth is. Show an accurate and accepted definition of physics made by someone else.

I already said one.

I could have sworn that the APS was referring to MODERN SCIENCE. The field of quantum chemistry (a MODERN science) is dominated by physicists.

Yes, APS was referring to modern science. My claim continue to be correct. Physics alone is not the foundation of modern science (or MODERN SCIENCE if you prefer). APS statement is not accurate.

Regarding the last part of your comment, if already your comment on spectroscopy and MRI was misleading (those fields are, of course based in physics but are not the outcome of physics alone) then your comment on quantum chemistry may be ______.

I'm sorry but i cannot find any soft word.

 

[Juan R.]

Some missing points:

Physics is the sole foundation of modern science.

Nothing can be autonomous from Physics.

Amen!

P.S:

As explained Maxos belief is completely wrong.

chemistry is an autonomous science, with its own foundations. To consider it in the shadow of physics [...] is boring and pointless.

Foundations of Chemistry 2001 3, 269–271.

 

[Caesar_Rahil]

Physics is everything that can be studied, excluding fields of Biology and Chemistry.

 

[robousy]

I'm surprised no one has quoted a dictionary yet:

1) (used with a sing. verb) The science of matter and energy and of interactions between the two, grouped in traditional fields such as acoustics, optics, mechanics, thermodynamics, and electromagnetism, as well as in modern extensions including atomic and nuclear physics, cryogenics, solid-state physics, particle physics, and plasma physics.
2) (used with a pl. verb) Physical properties, interactions, processes, or laws: the physics of supersonic flight.
3) (used with a sing. verb) Archaic. The study of the natural or material world and phenomena; natural philosophy.

 

[Juan R.]

Physics is everything that can be studied, excluding fields of Biology and Chemistry.

And excluding economy, sociology, mathematics, geology, history, philosophy...

 

[Nomy-the wanderer]

It's the philosophy that describes natural phenomenas..

 

[Enos]

You mean, so far excluding...

 

[Juan R.]

It's the philosophy that describes natural phenomenas..

Chemistry describes chemical (i.e. natural) phenomena, but chemistry is not physics. This is the reason of different names, different schools, different universities and careers, different books (there are books on chemistry!), There is a ACS that is not APS, etc.

 

[Juan R.]

You mean, so far excluding...

See Enos how confused people that claim that physics is about almost all that from a global rational point of view physics is around almost nothing. The DW standard index contains

# 100 Philosophy and Psychology
# 200 Religion
# 300 Social Science
# 400 Language
# 500 Natural Science and Mathematics
# 600 Technology (Applied Sciences)
# 700 Arts
# 800 Literature
# 900 Geography and History

and the 500 section si divided in subsections

# 520 Astronomy
# 530 Physics
# 540 Chemistry
# 550 Earth Sciences
# 560 Paleontology
# 570 Life Sciences
# 580 Botanical Sciences
# 590 Zoological Sciences

Even ignoring division of other non-500 index, Physics is around 1/15!

It is difficult that can explain everything . :rofl:

 

[Maxos]

What on Earth is this index, you have always on your mouth?

Anyway, I do not care.

Physics cannot be explained within other subjects, else this subject would be Philosophy, which has no longer means to understand Physics.

You know, God is dead.

 

[Enos]

Sure, If one takes it at an educational level. What I meant is if there is a theory in physics that explains everything. Wouldn't it be able to explain everything, if not, is it a theory of everything?

 

[Juan R.]

What on Earth is this index, you have always on your mouth?

Anyway, I do not care.

Physics cannot be explained within other subjects, else this subject would be Philosophy, which has no longer means to understand Physics.

You know, God is dead.

The question is that physics is a science like others, with its own postulates, theories, and field of application.

The others sciences also are sciences.

 

[Juan R.]

Sure, If one takes it at an educational level. What I meant is if there is a theory in physics that explains everything. Wouldn't it be able to explain everything, if not, is it a theory of everything?

Since physics is the science of basic laws of nature, the search of a realistic TOE is impossible. At the best, physicists could obtain (i doubt) a basic framework of the basic laws of the basic items of the Universe but other sciences develop special laws for concrete systems.

Since reductionism fails, there is not posibility for deriving special laws from physics laws. Therefore, others sciences are autonomous sciences. Already cited above the article on Foundations of Chemistry.

 

[cscott]

Since reductionism fails, there is not posibility for deriving special laws from physics laws. Therefore, others sciences are autonomous sciences. Already cited above the article on Foundations of Chemistry.

Generaly, is it the accepted view that reductionism fails?

 

[Juan R.]

Generaly, is it the accepted view that reductionism fails?

I do not undesrand your question very well, can you explain?

 

[inha]

Generaly, is it the accepted view that reductionism fails?

Amoung condensed matter physicsts is it a common view. And CM physicists are the majority.

 

[cscott]

I do not undesrand your question very well, can you explain?

I meant that if I were to poll practicing physicsts, what would be the majority view on reductionism.

 

[Juan R.]

I meant that if I were to poll practicing physicsts, what would be the majority view on reductionism.

Aha!

Well, inha already explained the topic on condensed matter. Their favourite phrase is More is different launched by Nobel laureate P. W. Anderson. The phrase means that condensed matter is not trivially reduced to applied particle physics.

Physicists working in thermodynamics and statistical mechanics, almost all of the comunity of complexity and chaos and other are antirreductionist.

Particle physics and string theorists (the same) are reducttionists, but is easily explained particle physicists or string theorists newer have solved complex problems. Moreover, that is usually said by people like Ed Witten, B. Greene, or S. Weinberg on chemistry and reductionism is incorrect. E.g. last article on the topic by Weinberg is completely wrong and just reflects a complete misunderstanding of Weinberg in chemistry and other stuff. Weinberg is a pure reductionist.

Gell-Mann was a pure reductionist when was particle physicist but when begin shis research in complex systems in the Santa Fe institute changed his mind and now admits that research in others disciplines is so fundamental like pure particle physics. Still Gell-Mann is wrong in some important details.

In other disciplines Reductionism does not work. It does not work in chemistry, for example Nobel laureate Jean Marie Lehn already explained why. In biology or medicine reductionism does not work according to D. C. Mikulecky.

Etc.

 

[cscott]

Thanks for summing that up nicely, and sorry for derailing this thread a bit