Davy_Jones

Quite so, Mr Vat,

There are certain statements that scientists make, or theoretical entities posited, which are obviously not meant to be taken literally.

Swansont mentioned red quarks or something (can't remember exactly). Or consider point masses and ideal gases, perhaps.

Anyone who takes these things literally is . . . well, missing the point . . . massively. Duh!

But it's not always so obvious how a statement or a theory is to be interpreted . . .

1 minute ago, dimreepr said:

That's the god of the gaps argument in reverse... 

Einstein's views on these matters are well documented, sir.

Would you like me to recommend some reading?

I'm not being sarcastic. Gripping stuff indeed. Or at least I thought so.

19 minutes ago, swansont said:

If your goal is to show physics describes reality, don't ignore my examples of calculational conveniences. 

No, that's not my goal.

You've been telling us (and I quote) "we know physics isn't trying to describe reality"

What I've been showing is certain of your peers, including some of the finest (Einstein, Weinberg . . ), apparently didn't receive the memo; they don't "know" what you (plural) "know".

33 minutes ago, swansont said:

Those statements are descriptions of their respective models. In Newtonian terms, gravity is a fundamental force. In GR, it's the curvature of spacetime.

Such statements should be understood in the context of physics. They are not meant to be taken out of context. One has to be willing to invest in some study of the subject matter to provide that context. If not, too bad. You get what you paid for.

The obvious problem with simplistic comments such as these is that scientists themselves disagree over how scientific theories or statements ought to be understood.

Contrast, for example, Duhem and Einstein's radically opposed understanding of scientific theories (near the bottom of page 2).

Indeed, the very same scientist may not be consistent in his interpretation of statements or theories.

If you'd asked the Mach-influenced Einstein circa 1920, perhaps, how his general theory of relativity ought to be understood, you'd likely have been told something like this:

"It's a mathematical instrument, not to be taken at face value, not to be read literally."

Twenty years later, you'd have heard something quite different. Perhaps . . .

"My theory is to be understood as a representation of reality. It should be read literally."

Our old pal Arthur Fine again . . .

Quote

In particular, following his conversion [from antirealism to realism], Einstein wanted to claim genuine reality for the central theoretical entities of his general theory, the four-dimensional space-time manifold, and associated tensor fields. This is a serious business for if we grant his claim, then not only do space and time cease to be real, but so do virtually all of the usual dynamical qualities.

Ok, thanks for explaining that.

Well, you're the scientist and I'm here to learn. Is there a universally agreed upon definition of force in science at present?

One thing we can say, I think, is that these things do tend to change, even in science.

If I'm not mistaken, Newton's action-at-a-distance concept of force was fiercely resisted for quite some time, especially on the continent.

"You call THAT a force!!??" - the French

Correct me if I'm butchering the history.

Ok. Still listening . . .

6 minutes ago, studiot said:

I offer that there is no such object as a four sided triangle.

Fine. Go on . . .

6 minutes ago, studiot said:

But some (Stokes) never believed in the aether. And yet others held an open mind.

Quite so.

I edited my previous post before seeing this.

I changed "their belief in the aether" to "their beliefs about the aether".

Not all scientists believed in it, but they all (the ones relevant to us) had beliefs about it.

20 minutes ago, studiot said:

Has that concept not affected many people for several centuries in their search for it, like your holy grail or perhaps the Physicist's TOE?

 Of course it has. But note: what affected people was their beliefs about the aether, not the aether.

On the assumption (current scientific orthodoxy, I believe) that the aether does not exist (i.e. is not real) then it never affected anyone.

1 minute ago, studiot said:

As a matter of interest can you not think of a better offering than HP to point 1, whose unreality is undisputed ?

 Ok, how about the luminiferous aether?

2 minutes ago, studiot said:

This is also why I hold that English is more versatile than either Science or Philosophy because it can allow the existence of Harry Potter as an abstract concept.

Hmm, the history of science also has no shortage of concepts which turned out to refer to nothing.

Your reasoning above is a bit like saying many people have been affected by the Fountain of Youth.

Ponce de Leon (was that his name?) squandered years searching for it. Said Fountain, as far as we can tell, does not exist; it is not real.

But Ponce de Leon believed it existed. It was his belief doing the causal work.

I'm using the term belief in the everyday sense.

15 minutes ago, studiot said:

The terms real and reality ; exist and existence can be thought of as ill defined.

1: Instead of asking if something is 'real' can you offer me something that is not 'real'.

2: How would I test this ?

3: Can something which is not 'real' affect some things that are 'real' in any way ?

4: Is Harry Potter Real ?

5: Harry Potter has certainly affected millions of 'real' people.

This, I would suggest, is the real reason behind why Science shies away from such terms (pun intended)

 

 

I've added numbers to your points above for convenience.

1. Ok. I hereby offer Harry Potter (Doubtless there are lots of people named Harry Potter out there. I mean the fictional character we both have in mind right now.)

2. We might conduct a search. Pretty sure we'd never find him, though.

3. I don't think so 

4. No (but see 1 above)

5. Many people have been affected by their beliefs about Harry Potter. Said belief corresponds to nothing in reality.

I throw these answers out--somewhat diffidently (lol)--to see what happens next. What do you think?

19 minutes ago, MigL said:

'True', and 'truth' are subjective, and R Dawkins would be the first to agree.

 To the contrary, I suspect Dawkins would throw a fit.

If truth is subjective then the Creationists' truth is just as good as his own. It's all relative, eh?

Bring two guns

"Gravity is not a version of the truth. It is the truth. Anyone who doubts it is invited to jump out a tenth-storey window." - R. Dawkins

(It's a very silly comment, but gives you some idea what he thinks of truth)

19 minutes ago, MigL said:

You seem to continuously want to steer the discussion in the Philosophy direction.

Well, as I hinted at in the OP, I'm not sure it's possible to examine a question of this type without delving into a li'l philosophy.

19 minutes ago, MigL said:

I am not well versed in Philosophy, but I have deluded myself into thinking I know a little Physics; and that is guiding the opinion I'm giving you.

And I'm very grateful for it, sir.

59 minutes ago, beecee said:

Abstract

Editor's Note: There is probably no modern scientist as famous as Albert Einstein. Born in Germany in 1879 and educated in physics and mathematics at the Swiss Federal Polytechnic School in Zurich, he was at first unable to find a teaching post, working instead as a technical assistant in the Swiss Patent Office from 1901 until 1908. Early in 1905, Einstein published “A New Determination of Molecular Dimensions,” a paper that earned him a Ph.D. from the University of Zurich. More papers followed, and Einstein returned to teaching, in Zurich, in Prague, and eventually in Berlin, where an appointment in 1914 to the Prussian Academy of Sciences allowed him to concentrate on research. In November of 1919, the Royal Society of London announced that a scientific expedition had photographed a solar eclipse and completed calculations that verified the predictions that Einstein had made in a paper published three years before on the general theory of relativity. Virtually overnight, Einstein was hailed as the world's greatest genius, instantly recognizable, thanks to “his great mane of crispy, frizzled and very black hair, sprinkled with gray and rising high from a lofty brow” (as Romain Rolland described in his diary). In the essay excerpted here, and first published in 1936, Einstein demonstrates his substantial interest in philosophy as well as science. He is pragmatic, in insisting that the only test of concepts is their usefulness in describing the physical world, yet also idealistic, in aiming for the minimum number of concepts to achieve that description. In 1933, Einstein renounced his German citizenship and moved to the United States, where he lived until his death in 1955. A recipient of the Nobel Prize in physics in 1921, he was elected a member of the American Academy of Arts & Sciences in 1924.

(your own emphasis)

And your point is?

Did you notice the bit about "describing the physical world"?

Read that as "describing reality".

20 minutes ago, MigL said:

Words are a tool, just like math is, and both can be used to describe ( model ) Gravity. Math is much less subjective and ambiguous, however, and usually doesn't lead to these kinds of discussions.

There are also people (known as instrumentalists) who feel that scientific theories are nothing more than a tool, or a model, or an instrument for calculation, not subject to the predicates true and false.

But if you think all scientists subscribe to instrumentalism, think again.

Try asking Richard Dawkins, say, whether he thinks the theory of evolution is merely a tool with no bearing on the way things really are.

You might wanna bring a gun.

20 minutes ago, MigL said:

If I were discussing Gravity with someone versed in GR, I would certainly use the curvature of space-time description.
If I were talking to a high-school student, I would use the force description.

We touched on this earlier in the thread.

Now, if you are treating the two theories as mere instruments (as described above), there is no problem.

On the other hand, if you are presenting the two theories realistically--as the way things really are--then, assuming that the curvature of spacetime is not a force, you would be making two inconsistent statements. You would be contradicting yourself.

32 minutes ago, MigL said:

What does the ideology of scientists, and the purpose of Science, which is being discussed at some length, have to do with the nature of Gravity ???

Because whether or not physicists purport to describe reality is relevant to how we should read a statement such as "Gravity is a fundamental force" or "Gravity is the curvature of spacetime".

Should such pronouncements be understood as a mere façon de parler, not to be taken at face value, or are we being told this the way things really are.

25 minutes ago, beecee said:

It can, as I said, but that isn't the primary goal of physics and scientific theories . . .

And who has the final word on these things again?

11 hours ago, swansont said:

One other aspect of the problems with thinking physics is telling us what reality is is that over its history we've found better and better descriptions of how nature behaves. So it's ludicrous to think that Newtonian physics described reality, when we know that it was supplanted by relativity and quantum mechanics, and we know that these models are incomplete, and it's likely we will have a better model at some point down the line.

Oh, I agree it's ludicrous nowadays to think that Newtonian physics describes reality. Times have moved on.

But this is to miss the point that for two centuries or more, Newtonian physics might as well have been carved in stone. I daresay it was almost universally taken to be a faithful description of reality.

In other words, a great many physicists (I'm tempted to say the vast majority) did not find it remotely ludicrous that physics--at least sometimes, at least physics at its very best--can describe reality.

And I daresay many still do.

Looking forward to hearing what @TheVat's pal Don Lincoln has to say on all this.

Edit:

What you seem to be saying, swansont, if I'm understanding you right (please correct me if I'm wrong), is that we should not believe anything physicists have to say about unobservable reality (quarks, bosons, and all the rest). After all, it's all--on your account-- just models, and "making up stuff", and "we know physics isn't trying to describe reality".

Is this a fair representation of your position?

If it's any consolation, it's a position I'm not unsympathetic to myself.

I'm just afraid a riot might break out at any time.

19 minutes ago, beecee said:

In reality, and as others have explained, it is not an opinion, and it is not anti-realist, whatever slur that's supposed to project.

Dude, antirealist is not a synonym for anti-science. Sigh!

Many of the finest scientists have held antirealist views.

Try this:

https://plato.stanford.edu/entries/scientific-realism/

19 minutes ago, beecee said:

I read Steven's book, "The First Three Minutes" and he also expressed his views that in time we may find a final theory of everything, but as yet that has not happened. Again physics models what we see and its success is in making successful predictions...eg: GR.  Physicists/scientists are not searching for reality and/or truth, whatever that is, but if it should accidently be found, then all well and good...no problems at all!

"All this [i.e. Kuhn's ideas] is wormwood to scientists like myself, who think the task of science is to bring us closer and closer to objective truth."

- S Weinberg

Physicists are not searching for truth, you say? Evidently, at least one is.

You think he's the only one?

9 hours ago, swansont said:

 

One other aspect of the problems with thinking physics is telling us what reality is is that over its history we've found better and better descriptions of how nature behaves. So it's ludicrous to think that Newtonian physics described reality, when we know that it was supplanted by relativity and quantum mechanics, and we know that these models are incomplete, and it's likely we will have a better model at some point down the line.

I repeat once more, you are perfectly entitled to your opinion that physics is not about describing reality. That is what you're saying, right?

Indeed, in your antirealist corner stand some of the very finest physicists, including Niels Bohr whom you quoted earlier.

My only animadversion is that every time you say such things, they are never qualified by a humble "in my opinion" or "of course not all physicists feel as I do".

Rather, what we see instead is invariably an unqualified "Physics is not about describing reality" as if a statement of undisputed fact is being presented, as if there is an unspoken "and that's all there is to it!", as if to say "ask any sensible physicist and they'll tell you the same thing". (at least that's how your peremptory pronouncements strike my ears)

This is what I find objectionable. Why, some of our more naive, wet-behind-the-ears members (if there are any) might even be beguiled into thinking that's the end of the story, there's nothing more to discuss.

That, of course, is not the end of the story. It is not a fact that all physicists feel as you do, that physics has no business describing, or at least trying to describe, reality.

Surely no one here needs reminding of Einstein's heroic realist stance against (what he saw as) the prevailing antirealist tyranny of Bohr, Heisenberg et al.

But he's six feet (depending on your frame of reference) under, you might well retort.

Among contemporary physicists, I can think of no more staunch realist than Steven Weinberg. One can barely turn the page of one of his popular expositions without tripping over antirealist bogeymen such as truth and reality. Here's a tantalizing teaser . . .

Quote

I know enough about science to know that there is no such thing as a clear and universal "scientific method". All attempts to formulate one since the time of Francis Bacon have failed to capture the way that science and scientists actually work. Still, under the general heading of scientific method, we can understand that there is meant a commitment to reason, often though not necessarily crystalized as mathematics, and a deference to observation and experiment. Above all, it includes a respect for reality as something outside ourselves, that we explore but do not create.

- Steven Weinberg (from "Facing Up", essay 4, "Confronting O'Brien")

Quote

All this [i.e. Kuhn's ideas] is wormwood to scientists like myself, who think the task of science is to bring us closer and closer to objective truth.

- Steven Weinberg (from "Facing Up", essay 17, "The Non-Revolution of Thomas Kuhn")
 

Clearly, not everyone shares your view that "we know physics isn't trying to describe reality".

7 hours ago, TheVat said:

Mr. Jones suggested I'm a name dropper - I can only add that I have carefully not mentioned my long-ago acquaintance with Isaac Asimov, which I humbly offer as evidence to the contrary. 

Pfft! That's nothing. I once met (while in your beautiful country) the keyboard player from Sparks. Remember? The dude that looks like Hitler.

Edit P.S. 

Whoops! I just googled Steven Weinberg. Turns out he's six feet under too, as of a few weeks ago. RIP!

18 minutes ago, MigL said:

Davy_Jones has brought up the Ptolomaic vs Copernican systems and how they can both be used for navigation, but only one is 'true'.

A slight correction. What I actually said was:

"Given, however, that the two theories make logically incompatible claims, it is not possible that both are true"

Of course, neither is believed to be true nowadays.

1 minute ago, dimreepr said:

It maybe fair to say, we have a different understanding; but more complete is a question for tomorrow. 

"Discover" is what they call a "success verb". If the top quark has indeed been discovered, then our understanding of reality just increased by one ontological unit.

It's in the bank, so to speak.

2 minutes ago, TheVat said:

I have Don's email -- he was the resident physics expert at my erstwhile science forum for a decade.    Would you like me to invite him here to comment?   

What a name-dropper!

I mean yes pleeeeeeaaaaaase!!!!!

@swansont

Re above

You did say on the previous page . . .

"I argue that would be physics, and the reason that we know physics isn't trying to describe reality is because physics itself admits that it's making stuff up to make good models. Nobody claims that electric field lines physically exist. Phonons are quantized vibrational modes of a structure - not physical particles that exist independent of that structure. Electron holes are the absence of electrons, not some particle that exists on its own. These things aren't real, physical entities. They are calculational and conceptual aids to modeling behavior."

Given that--on your account-- "we know physics isn't trying to describe reality" and that physics "makes stuff up", how exactly are we to understand an announcement such as, say, "The top quark was discovered in 1995"?

Something unreal was discovered? The top quark has been discovered by physicists dabbling in metaphysics on their day off?

(I asked on the previous page. You didn't answer.)

Now, if the top quark has indeed been discovered, and it is real, would it not be fair to say that physics has added to our knowledge of reality, we have a better understanding of reality now thanks to physics, our description of reality is more complete than it hitherto was, or some such locution?

3 minutes ago, swansont said:

No, of course not. How do you get from what we said to this?

Because on the previous page, while speaking generically about scientific theories. I said:

 

Edit P.S. Other fairly standard realist responses would look something like the following:

"If a theory is empirically adequate (i.e. saves the phenomena), moreover, yields new and surprising predictions then we have good reason to believe that it is true"

William Whewell, meanwhile, would speak of a "consilience of inductions" conferring epistemic warrant on a theory, i.e., good reason to believe that it is true.

 

To which you replied

"True" here means valid. i.e. we have confidence that the theory can be applied and give god answers. But it's still all about behavior and observation, and not about any underlying reality.

So, just to be clear, what you're saying is that in your opinion scientific theories are not about any underlying reality, that's not the business/aim of science . . . though other scientists may have different ideas?

Given that the final clause (in red) was presented as an unqualified blanket assertion (and not a personal opinion), I took it to be just that.

@studiot above

Well, swansont and myself were talking about the aims of science. Swansont is telling us, it seems, that science does not try to get at underlying reality. Is that right, sir?

Are you (or swansont) seriously suggesting that all scientists in all times and all places have exactly the same view about the aims of science?

I've an idea: why don't we just ask them!

20 minutes ago, swansont said:

Believing a theory is not the normal description; in this case its because you have a non-scientific alternative that relies solely on belief. Notice that your quote does not actually cite belief.

First quote I could find . . .

[...] That phenomenon is conversion. Max Planck is often quoted to the effect that 'new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it'. A similar sentiment was expressed a half-century earlier Harvard's Professor Joseph Lovering, when he told his students that there are two theories of light, the wave and the corpuscular. Today, he is said to have remarked, everyone believes in the wave theory; the reason is that all those who believed in the corpuscular theory are dead. There is a measure of truth in such statements, as we all know, and yet a new scientific idea does win adherents, and even convinces some opponents, as has been seen in many examples throughout this book.

- Revolution in Science, J. Bernard Cohen, pp 467-468

Don't make me go searching through the forums for members believing such-and-such a theory. Pleeeeeaaaase!!

20 minutes ago, swansont said:

Nothing about that lays claim to revealing realty. But the models and mechanisms of evolution aren't the examples that are most relevant. I argue that would be physics, and the reason that we know physics isn't trying to describe reality is because physics itself admits that it's making stuff up to make good models. Nobody claims that electric field lines physically exist. Phonons are quantized vibrational modes of a structure - not physical particles that exist independent of that structure. Electron holes are the absence of electrons, not some particle that exists on its own. These things aren't real, physical entities. They are calculational and conceptual aids to modeling behavior.  

If no one believes these things are real, as you claim, why do I keep hearing--every few months or so it seems--that some new subatomic particle has been discovered?

How can that which is not real be discovered?

Prof. Lincoln again (our friend from above):

Quote

Dr. Lincoln’s research has been divided between Fermilab’s Tevatron Collider, until its close in 2011, and the CERN Large Hadron Collider, located outside Geneva, Switzerland. The author of more than 1,000 scientific publications, his most noteworthy accomplishments include serving on the teams that discovered the top quark in 1995 and confirmed the Higgs boson in 2012. 

@swansont

(Pardon my clumsiness with the quote function)

"How do you empirically determine the "best" explanation without invoking philosophy or other assumptions?" - swansont

You don't. The explanatory power (along with simplicity, etc.) of a theory is what's known as a non-empirical epistemic virtue. As I said earlier, strict empiricists will have no truck with this; the only epistemic virtue, on their account, is fit with the facts. (sounds a lot like you, sir)

Now, you may or not like it yourself, but many scientists routinely invoke explanatory goodness as a reason for believing some theory or other. Try asking Richard Dawkins, say, why we should believe the theory of evolution. You're likely to hear something like this (and I paraphrase):

"The theory of evolution provides the best explanation for all the empirical data we have. It provides a far better explanation than the theory of special creation."

(and the tacit inference is: explanatory power confers epistemic warrant; explanatory goodness is a reason to believe a theory. Otherwise why mention it at all?)

" "True" here means valid. i.e. we have confidence that the theory can be applied and give god answers. But it's still all about behavior and observation, and not about any underlying reality." -  swansont

Again, you continue to speak as if "Ask any scientist and they'll tell you the same thing". I repeat, scientists are a heterogeneous bunch; they say all manner of things about the aims of science.

There are, of course, scientists who believe as you apparently do: science is not in the business of getting at an underlying reality; the job of science is to "save the appearances" and stop right there! E.g.

Quote

Thus a true theory is not a theory which gives an explanation of physical appearances in conformity with reality; it is a theory which represents in a satisfactory manner a group of experimental laws. A false theory is not an attempt at an explanation based on assumptions contrary to reality; it is a group of propositions which do not agree with the experimental laws. Agreement with experiment is the sole criterion of truth for a physical theory.

- Pierre Duhem 

Meanwhile, in the red corner, here's another scientist who feels otherwise. The job of science, difficult though it may be, is to to go beyond mere appearances (the outside of the watch) and try to get at that underlying reality (the inner mechanism).

Quote

Physical concepts are free creations of the human mind, and are not, however they may seem, uniquely determined by the external world. In our endeavor to understand reality we are somewhat like a man trying to understand the mechanism of a closed watch. He sees the face and the moving hands, even hears its ticking, but he has no way to open the case. If he is ingenious he may form some picture of a mechanism which could be responsible for all of the things he observes, but he may never be quite sure his picture is the only one which could explain his observations. He will never be able to compare his picture with the real mechanism and he cannot even imagine the possibility or the meaning of such a comparison.

- Albert Einstein