Is philosophy relevant to science?

[swansont]

("Ad hominem")

 

Ad hominem literally means referring “to the man” rather than to the substance of the argument.

It works both ways. Usually, of course it refers to “attacking an opponent's character rather than answering his argument.” (Dictionary.com)

But it works both ways, as in referring to “a man’s” credentials to support his argument, regardless of its substance.

This forum uses the above a lot.

 

But your argument included a mini-lecture on what science's job is and made reference to "any competent scientist". The fact that I am a scientist has direct relevance to that point. It looked to me that he was simply acknowledging the irony. Of course there's the further irony that you claimed ad hominem and had buttressed your argument with the credential of "any competent scientist".

[PeterJ]

Feel free to show that it's not.

 

Absent the comparison to nature, basic relativity is Lorentz transforms. Which give rise to the predictions of length contraction and time dilation. With those predictions, we can run experiments to see if they work, which they do. But that's the only area where we can get contradictions — in the comparison to nature. If the model doesn't work, we discard the model. We have had a lot of success, so we haven't reached the point where we discard the axiom: if nature didn't follow rules we would have dropped scientific inquiry long ago.

Ah. I see we mean different things by 'contradiction'. I would include logical contradictions as well as any that arise by comparison with nature. This is becasue I think philosophy is relevant to science. But there's too many topics going on at once here so I won't pursue the point.

[Cap'n Refsmmat]

That's news to me. I thought that was the meaning of "empirical science."

"Empirical" merely means that science is guided by the results of experiments. It does not mean that science's goal is to collect a Big Book of Facts which lists the absolute and accurate measurements of everything in the universe.

 

Science (well, "natural philosophy") shifted from fact-gathering to model-creation a few hundred years ago.

[owl]

....

Of course there's the further irony that you claimed ad hominem and had buttressed your argument with the credential of "any competent scientist".

I must admit that you've got me there. I could cop to its common usage here (ad hominem) and admit the influence of context. But I do not apologize for my respect for credentials as I see their merit. I refer to credentialed authorities as everyone else here does. My 178 score on the WAIS does not entitle me to any personal ad hominem credentials other than the ability to think for myself, not programmed to give the "right answers" in physics classes to earn a PhD. Nothing personal.

 

"Empirical" merely means that science is guided by the results of experiments. It does not mean that science's goal is to collect a Big Book of Facts which lists the absolute and accurate measurements of everything in the universe.

 

Science (well, "natural philosophy") shifted from fact-gathering to model-creation a few hundred years ago.

One wonders if model-creation without reference to empirical facts has been progress or regress.

"The fabric of spacetime" seems to work well as a mathematical metaphor and conceptual aid without a real world reference to what it is (excuse the existential reference) or how it is effected by mass or how it effects the paths of actual objects.

 

The same can be said of the string/M-theory model... all model and no referents in 'the world' of 'empirical science'... the apparently obsolete branch of merely verified facts in the out of date "Big Book of Facts."

How is physics different from metaphysics in the above cases?

Darn! Another demerit! How can I gain personal popularity here and therefore make my arguments more cogent?

(a little 'ad hominem' humor there.)... spelling edit.

Edited December 2, 2011 by owl

[Cap'n Refsmmat]

One wonders if model-creation without reference to empirical facts has been progress or regress.

"The fabric of spacetime" seems to work well as a mathematical metaphor and conceptual aid without a real world reference to what it is (excuse the existential reference) or how it is effected by mass or how it effects the paths of actual objects.

The "reference to empirical facts" which occurs in science goes something like this:

 

1. My math has something called a "spacetime" in it. That's interesting.
   
2. If I use my equations, I predict that this binary pulsar system will experience orbital decay at a specific rate.
   
3. The astronomers just looked with their telescopes, and I was right.

 

One tests the predictions against reality. This is quite clearly a reference to empirical facts. One does not, however, do something like this:

 

1. My math has something called a "spacetime" in it. That's interesting.
   
2. I found the spacetime. It's brown, fuzzy, and smells slightly of carrots.
   
3. Clearly, I was right.

 

Once cannot test whether there is really a "spacetime." One can, however, test whether a model using spacetime produces predictions which are experimentally verified.

 

Metaphysics, however, produces no verifiable predictions. A metaphysical question would be "What is spacetime?", since there is no experiment that could conceivably determine the answer.

[tar]

Like to throw the thought in here, to nobody in particular, that I think we "do" science naturally. That is we learn about the world around us, by sensing it and building an increasingly accurate model of it, and we continually test our model against reality, and adjust it accordingly.

 

Formal science is a real good way for each of us to share what we have discovered with others, and learn what others have discovered about the world. (maybe the learning part is more important and numerous than the teaching)

 

Metaphysics can pretty much be carried out in ones head, but formal science demands peer review and repeatability of the tests of the model against reality. The mere facts of precision and repeatability, tested and retested by more than one mind, make the model in the one mind more likely to "match" the model in the other.

 

And at that point, "how we know what we know" becomes less critical, and more important becomes the fact that we know the same thing. That is, I have this precise model of this thing, you have the same precise model of the thing, the model matches the thing, and we both mean the same thing that we are modeling, AND we can tell anybody else about this thing and THEY will know which thing we mean, exactly which thing we mean and be able to hold the same precise model of it that we hold. Regardless of what philosophy and metaphysics might say about our ability, individually to know the thing as it is, we at least know we are not the only intuitor that intuites the darn thing.

Edited December 2, 2011 by tar

[owl]

Very "interesting."

 

The "reference to empirical facts" which occurs in science goes something like this:

 

1. My math has something called a "spacetime" in it. That's interesting.
   
2. If I use my equations, I predict that this binary pulsar system will experience orbital decay at a specific rate.
   
3. The astronomers just looked with their telescopes, and I was right.

 

Good. Could 'it' just as well be called "whatever mass effects that then effects other masses," "whatever..." for short? Or why not just let mass attract mass without an unknown medium in between? Would the equations be different?

 

Then quantum theory of gravity could just call their "graviton" (an alternative model/theory) "whatever-G" for whatever makes gravity work in "our model."

 

One tests the predictions against reality. This is quite clearly a reference to empirical facts.

 

Quite so. No objection to that part.

One does not, however, do something like this:

 

1. My math has something called a "spacetime" in it. That's interesting.
   
2. I found the spacetime. It's brown, fuzzy, and smells slightly of carrots.
   
3. Clearly, I was right.

 

Is this another argument by ridicule? If I don't like the tie died rabbit pelt metaphor, I can have a brown, fuzzy "whatever..." that smells like carrots? Can I get that in rainbow colors and tasting like mangos?

 

But seriously folks! A paper on what spacetime IS was published by Brown and Pooley (cited many times.) They seriously charged that the whole concept was "parasitic" upon the existing observable material phenomena, asked what features of spacetime guided objects and light in curved paths, and concluded, as far as I can tell, that "it" added nothing to our understanding of gravity. (Paper title: Minkowski's spacetime, a glorious non-entity.)

(This in case anyone here thinks that "what it is" matters anymore.)

 

Once cannot test whether there is really a "spacetime." One can, however, test whether a model using spacetime produces predictions which are experimentally verified.

 

Well, science asked (something like) "what is an atom?"... and ended up with the atomic chart of elements, which added immensely to how we understand the material world and "what it is made of" in very specific detail, element by element.

 

Of course the "what" was not settled with "atoms" as little billiard balls of matter. So subatomic physics went deeper and smaller... etc.

But science is still asking what matter and energy IS at our deepest levels of understanding, even if you disdain the question as mere metaphysics.

 

A metaphysical question would be "What is spacetime?", since there is no experiment that could conceivably determine the answer.

Is, 'what is a graviton?' also an unanswerable question? Then both camps can just shout their word for (whatever.. makes gravity work) at each other.

"Spacetime!"

"No, gravitons!"

Then maybe the winner could be who shouts the loudest... or wins a worldwide "our favorite physics" popularity contest. (Just kidding.)

 

Or... each could present what the hell each buzz-word means... i.e., (grimace!) what it is in the world as a transmitter of the obvious force of gravity.

But I wax philosophical.

Good night.

[swansont]

I must admit that you've got me there. I could cop to its common usage here (ad hominem) and admit the influence of context. But I do not apologize for my respect for credentials as I see their merit. I refer to credentialed authorities as everyone else here does. My 178 score on the WAIS does not entitle me to any personal ad hominem credentials other than the ability to think for myself, not programmed to give the "right answers" in physics classes to earn a PhD. Nothing personal.

 

Since you didn't follow that path, how do you know physicists are 'programmed to give the "right answers"'? Another bald assertion.

[PeterJ]

Metaphysics, however, produces no verifiable predictions. A metaphysical question would be "What is spacetime?", since there is no experiment that could conceivably determine the answer.

That's an odd view. Metaphysics predicts that all positive metaphysical theories are false. It predicts. therefore, that all scientific theories embodying such a position are false. Not an insignificant prediction, and not irrelevant to our theories about space. It is incredible to me that physicists so often think such philosophical predictions can be ignored. They are only the result of thinking carefully.

[swansont]

Or why not just let mass attract mass without an unknown medium in between? Would the equations be different?

 

Since spacetime is not a medium, the answer would obviously be yes. To what situation are you referring? Is there a theory of gravitation with a medium in it under discussion?

But seriously folks! A paper on what spacetime IS was published by Brown and Pooley (cited many times.) They seriously charged that the whole concept was "parasitic" upon the existing observable material phenomena, asked what features of spacetime guided objects and light in curved paths, and concluded, as far as I can tell, that "it" added nothing to our understanding of gravity. (Paper title: Minkowski's spacetime, a glorious non-entity.)

(This in case anyone here thinks that "what it is" matters anymore.)

 

A philosophy paper, written by philosophers, arguing merits of whether relativity is a principle or constructive theory. As far as I can see, they do not make any claim about what spacetime IS. It's also rife with the argument from authority form of ad hominem (which I know you hate), because part of their discussion concerns Einstein's satisfaction (or lack thereof) of the two approaches.

[Cap'n Refsmmat]

Good. Could 'it' just as well be called "whatever mass effects that then effects other masses," "whatever..." for short? Or why not just let mass attract mass without an unknown medium in between? Would the equations be different?

One could call it "that thingy in my equations" and it'd work reasonably well, although it'd be a bit difficult to refer to in conversation.

 

Then quantum theory of gravity could just call their "graviton" (an alternative model/theory) "whatever-G" for whatever makes gravity work in "our model."

I think most physicists already interpret "graviton" in that way.

 

Is this another argument by ridicule? If I don't like the tie died rabbit pelt metaphor, I can have a brown, fuzzy "whatever..." that smells like carrots? Can I get that in rainbow colors and tasting like mangos?

Certainly. I prefer a nice strawberry-banana myself.

 

And no, it's not an argument by ridicule. It's a slightly ridiculous demonstration of my point: if your idea has no testable consequences, it's not part of science. Since the mathematical nature of spacetime is what gives us predictions about the universe, that is what is important to science; the ontological nature doesn't help us predict the outcome of experiements, so it is not.

 

Unless you can give an example of how the ontological nature of spacetime would help us predict an experimental result?

 

Well, science asked (something like) "what is an atom?"... and ended up with the atomic chart of elements, which added immensely to how we understand the material world and "what it is made of" in very specific detail, element by element.

Not exactly. Science said, "if things are made of atoms, we should be able to observe this result when I perform this specific experiment." So scientists did the experiment and observed the result. Then they said, "if atoms have nuclei, I should be able to scatter particles off of them and observe this specific pattern," and they did.

 

Theories are tested by the predictions they make. What observable predictions does the ontology of spacetime make?

[owl]

Cap 'n R,

I think this exchange is really getting to the essence of my ontological inquiry into 'spacetime':

Me:

Could 'it' just as well be called "whatever mass effects that then effects other masses," "whatever..." for short? Or why not just let mass attract mass without an unknown medium in between? Would the equations be different?

You:

One could call it "that thingy in my equations" and it'd work reasonably well, although it'd be a bit difficult to refer to in conversation.

 

Now, if you will just answer my bolded question above.

 

Meanwhile, back to the Brown and Pooley challenge and Swansont's reply.

Warning: The time has come to shift from generalities to specific details in this discussion, so maybe it should continue, after this, in my "Spacetime, the Scholarly Debate" thread.

He answered my bolded question as follows:

Since spacetime is not a medium, the answer would obviously be yes. To what situation are you referring? Is there a theory of gravitation with a medium in it under discussion?

"Yes," the equations would be different without a non-existent entity, spacetime mediating... er... whatever a non-medium does?

Yes. See below, but first, you also said:

A philosophy paper, written by philosophers, arguing merits of whether relativity is a principle or constructive theory. As far as I can see, they do not make any claim about what spacetime IS.

In fact they make the case that it is irrelevant to the math.

Here are some quotes.(Btw, the focus was not just on whether relativity is a principle or constructive theory. The quotes below are from before that section of the presentation.)... my bold as usual and parenthetical interjections:

We have seen that for Einstein the inertial property of matter requires explanation in terms of the action of a real entity on the particles. It is the space-time connection that plays this role: the affine geodesics form ruts or grooves in space-time that guide the free particles along their way.

(Ed: Sounds like a "real entity", doesn't it?)

 

For both Leibniz and Newton, absolute space-time structure is

not the sort of thing that acts at all. If this is correct, and we believe it is, then neither Newtonian mechanics nor SR represent, pace' Einstein, a violation of the action-reaction principle, because the space-time structures in both cases are neither acting nor being acted upon. Indeed we go further and agree with Leibniz that they are not real entities in their own right at all.

 

Nonentities do not act, so for Leibniz space and time can play no role in explaining the mystery of inertia.

... But to appeal to the action of a background space-time connection in

which the particles are immersed—to what Weyl called the “guiding field”—is

arguably to enhance the mystery, not to remove it.... (more editing)

For the particles do not have space-time feelers either. Without postulating any background space-time scaffolding[/b], In what sense is the postulation of the 4-connection doing more explanatory work than Moliere’s famous dormative virtue in opium?

(Ed: Moliere's what? I'll need to check it out, but the sense is clear.)

....

It is of course non-trivial that inertia can be given a geometrical description, and this is associated with the fact that the behaviour of force-free bodies does not depend on their constitution: it is universal. But again what is at issue is the arrow of explanation. In our view it is simply more economical to consider the 4-connection as a codification of certain key aspects of the behaviour of

particles and fields.

The last statement would then require an analysis of the meaning of the "affine geodesics" involved.

Anyway it involves "the generalization of the notion of "a straight line to curved space" (Wiki, I think, forgot to footnote) and that already assumes space curvature.

 

The term "geodesic" comes from geodesy, the science of measuring the size of Earth; in the original sense, a geodesic was the shortest route between two points on the Earth's surface, namely as a segment of a great circle.

(Edited for run-together transcription.)

 

But, in the real world, the shortest distance is straight through the globe, not on the surface... The difference again between conceptual models and the 'real world'... more ontology.

Edited December 2, 2011 by owl

[PeterJ]

I wrote earlier that I would debate the fact that the maths underlying physics is consistent, as S claimed, and suggest that its inconsistencies are usually just buried in the foundations. I walked away from a challenge to back up this comment, thinking a reply would be way off-topic. On reflection a reply may be bang on topic. This is how I see it.

 

The problem for physics, to the extent it is a mathematical construction, is that it is prone to all the usual foundational problems that afflict almost all such system. This is not a personal theory. There is an essay online somewhere by Stephen Hawking titled 'The End of Physics' in which he explains the impact of incompleteteness on the mathematical scheme of physics, and he suggests that it represents a real problem for the ability of physics to describe the world. Then there is Russell's set-theoretic paradox, just as awkward to deal with in metaphysics as mathematics, and which has to be solved for any fundamental theory. These problems and paradoxes are caused by contradictions lying at the heart of the system. Usually in physics they are ignored or go unnoticed since physicists, these days at least, seem to be largely uninterested in foundational issues. They cannot be ignored or unnoticed in philosophy, however, for they are its meat and drink.

 

The implication of Hawking's article is that they cannot be ignored in physics, that metamathematics and metaphysics have also to be considered. Most people here will have read Paul Davies' Mind of God, where he discusses the difficulties that these underlying contradictions pose for physics. I suppose it's a matter of opinion whether this book is about physics or philosophy, it's not a distinction that serves any useful purpose in my world, but to me it seems a perfect example of the benefits that a recognition of the relevance, or even crucial importance, of philosophy would bring to physics, and it does highlight various relevant mathematical problems.

 

The mathematics of nonreductive theories need not be affected by these problems, but for a fundamental theory, of anything at all, we would have to solve them. I suppose if physics makes no claims to being fully reductive then perhaps it's underlying maths can be consistent. This is what Hawkins suggests. (And David Chalmers in a roundabout way). But this would not mean that there are no contradictions in the maths, only that physics has conceded both the problem and the limitation it places on theories, and chosen to live with it.

Edited December 2, 2011 by PeterJ

[owl]

Editing problems... sorry.

Edited December 2, 2011 by owl

[Cap'n Refsmmat]

Now, if you will just answer my bolded question above.

Mass attracting mass can't account for light being bent around massive objects. Hence it doesn't stand up to comparison with reality.

[swansont]

"Yes," the equations would be different without a non-existent entity, spacetime mediating... er... whatever a non-medium does?

 

But GR does not have a medium. I'll ask again, what theory are you discussing that has a medium?

 

Yes. See below, but first, you also said:

 

In fact they make the case that it is irrelevant to the math.

 

But you said it was a paper that explained what spacetime IS.

 

Here:s what you said:

But seriously folks! A paper on what spacetime IS was published by Brown and Pooley (cited many times.) They seriously charged that the whole concept was "parasitic" upon the existing observable material phenomena, asked what features of spacetime guided objects and light in curved paths, and concluded, as far as I can tell, that "it" added nothing to our understanding of gravity. (Paper title: Minkowski's spacetime, a glorious non-entity.)

 

It cannot simultaneously be a paper on what spacetime IS and not be. You agree that they don't actually address this.

 

Hmm.

 

And whilke it may be that they feel that "it" added nothing to our understanding of what gravity is, that's a very different issue than the understanding of what gravity does. The latter, of course, is what physicists are interested in. And it did advance that understanding.

 

But, in the real world, the shortest distance is straight through the globe, not on the surface... The difference again between conceptual models and the 'real world'... more ontology.

 

Are you really this obtuse? (no offense, of course)

 

They're discussing a SURFACE. It's constraining the motion to TWO dimensions. The first rule is that you have to travel on the SURFACE. In case you want to go through it, REFER TO RULE NUMBER ONE.

 

———————

 

The thread as a whole was tl;dr, but I have just a couple of points. Science is a subfield of philosophy, so I'd rather say philosophy is indeed relevant to science. Where do you think the concept of falsification came from?

 

From my perspective the argument is a little more nuanced than this. Science came out of philosophy so it's been given the same meta-label of philosophy. That's semantics. The issue is the divide between what we call philosophy now and what we call science, since the divide (i.e. since the development of the scientific methods). My contention was that science uses falsification from empirical testing. Philosophy does not.

[owl]

But GR does not have a medium. I'll ask again, what theory are you discussing that has a medium?

Holy smoke! A new low in lack of communication!

 

I have always argued that regarding "the fabric of spacetime," "The emporer has no clothes"... nothing there but the word.

Brown and Pooley were discussing what spacetime is *supposed* to be, not, like myself, proposing that 'it' Is anything. That is my point. Cap'n R seems to agree..

 

But you said it was a paper that explained what spacetime IS.

As above, they argue that 'it' does not exist, not that 'it' IS something.

 

It cannot simultaneously be a paper on what spacetime IS. And now you agree that they don't actually address this.

They make the case that 'it' does not exist.

What was that about me being "obtuse?" No, certainly nothing personal!

 

Are you really this obtuse? (no offense, of course)

Of course not. If you were actually saying that I am obtuse, that would be another personal ad hominem attack, in which of course you never indulge.

 

Btw, I quoted quite a few substantive arguments above and you didn't reply to9 any of them.

 

They're discussing a SURFACE. It's constraining the motion to TWO dimensions. The first rule is that you have to travel on the SURFACE. In case you want to go through it, REFER TO RULE NUMBER ONE.

 

Ontologically, space is the empty volume between things, not counting forces as "things" for the moment. It has no surface.

When speaking of a straight line, I recognize no such rule. The shortest distance between two points on the surface of a sphere is not along its surface but straight through it from one point to the other.

[owl]

Mass attracting mass can't account for light being bent around massive objects. Hence it doesn't stand up to comparison with reality.

Are you absolutely sure that photons are absolutely zero mass? I know the difference between the “momentum" of light, as with the box of mirrors experiment and laser gun recoil, solar wind, etc.... and ‘resting mass’ as applied to light in this case, but of course photons can not be arrested to measure ‘at rest mass.”

 

In other words, the question remains, how can ‘mass-less light’ be “attracted’ by mass?

If curved space is only a concept and not an operative entity, how is light bent by mass?

 

I suspect that the answer lies in a not-quite-zero photon mass... which would, of course , violate the assumed “light speed limit” for “mass”, however infinitesimal.

 

(Follow-up)

Swansont; post 133;

 

Since you didn't follow that path, how do you know physicists are 'programmed to give the "right answers"'? Another bald assertion.

 

It was not a formal survey but a philosophical perspective; that a PhD in physics requires a lot of “right answers*” to pass all the tests. *(Textbook physics.) I was never burdened with those requirements. Just a difference in backgrounds here... relevant to ”credentials” as positive ad hominem support for arguments... i.e., not relevant at all.

[Cap'n Refsmmat]

Are you absolutely sure that photons are absolutely zero mass? I know the difference between the “momentum" of light, as with the box of mirrors experiment and laser gun recoil, solar wind, etc.... and ‘resting mass’ as applied to light in this case, but of course photons can not be arrested to measure ‘at rest mass.”

There is an experimental upper limit on the photon mass, and it can't account for their behavior in gravitational fields.

 

The point is moot. Other experiments and observations, such as the precession of Mercury's orbit, frame-dragging, and so on have produced results which cannot be explained through "mass attracted by mass" models of gravity.

 

You should familiarized yourself with general relativity before you criticize it or propose alternate explanations. It would make the conversation significantly easier.

[Iggy]

There is an experimental upper limit on the photon mass, and it can't account for their behavior in gravitational fields.

And since heavier things don't fall faster, there is an upper limit on the amount of deflection a corpuscular theory of light can give.

 

[latex]\delta \theta \approx \frac12(1+ \gamma)1. " 7505[/latex]

 

It is interesting to note that the classic derivations of the deflection of light that use only the corpuscular theory of light (Cavendish 1784, von Soldner 1803 [277]), or the principle of equivalence (Einstein 1911), yield only the “1/2” part of the coefficient in front of the expression in Equation (46). But the result of these calculations is the deflection of light relative to local straight lines, as established for example by rigid rods; however, because of space curvature around the Sun, determined by the PPN parameter γ, local straight lines are bent relative to asymptotic straight lines far from the Sun by just enough to yield the remaining factor “γ/2”. The first factor “1/2” holds in any metric theory, the second “γ/2” varies from theory to theory. Thus, calculations that purport to derive the full deflection using the equivalence principle alone are incorrect.

 

The prediction of the full bending of light by the Sun was one of the great successes of Einstein’s GR

 

page 39

[swansont]

It was not a formal survey but a philosophical perspective; that a PhD in physics requires a lot of “right answers*” to pass all the tests. *(Textbook physics.) I was never burdened with those requirements. Just a difference in backgrounds here... relevant to ”credentials” as positive ad hominem support for arguments... i.e., not relevant at all.

 

Gee, if there is no requirement for right answers in philosophy, it must be pretty easy to pass the tests.

 

 

Holy smoke! A new low in lack of communication!

 

I have always argued that regarding "the fabric of spacetime," "The emporer has no clothes"... nothing there but the word.

Brown and Pooley were discussing what spacetime is *supposed* to be, not, like myself, proposing that 'it' Is anything. That is my point. Cap'n R seems to agree..

 

 

As above, they argue that 'it' does not exist, not that 'it' IS something.

 

 

They make the case that 'it' does not exist.

What was that about me being "obtuse?" No, certainly nothing personal!

 

"It" obviously exists, in so far as "it" is part of general relativity. I thought the argument was about whether it was a physical entity (from the description of being "malleable") and you were citing them in support of your position. From what I could tell, Brown and Pooley are arguing about principle vs constructive theories, i.e what drives what — does spacetime cause things to move in a certain way, or does the motion cause spacetime to be that way.

 

Of course not. If you were actually saying that I am obtuse, that would be another personal ad hominem attack, in which of course you never indulge.

 

No, that was personal. A response in kind. If you are going to engage in similar behavior and try and hide behind "no offense" or "nothing personal" it's rather hypocritical to complain about such comments, no?

 

Ontologically, space is the empty volume between things, not counting forces as "things" for the moment. It has no surface.

When speaking of a straight line, I recognize no such rule. The shortest distance between two points on the surface of a sphere is not along its surface but straight through it from one point to the other.

 

I recognize no such rule. Seriously? I guess this is the crux of the problem. You can't both ask what physicists mean by a theory, and then turn around and tell us what we mean by it. You can't make up your own definitions — that IS obtuse. It's beyond idiotic. There's absolutely no point in a discussion of you are going to do that.

 

(And since you freely admit to engaging in intellectually dishonest behavior like this, spare me the "you've injured me, sir!" routine)

 

This merely confirms that you are presenting a circular argument: you do not recognize anything other than one particular geometry and are trying to use that as proof that only one geometry exists. I had hoped this thread would not simply turn into a repeat of the others. I've had enough of this nonsense.

[owl]

Cap 'n R:

You should familiarized yourself with general relativity before you criticize it or propose alternate explanations. It would make the conversation significantly easier.

 

I have studied general relativity *theory* minus the math for many years. Your assumption that I have not is false. There are other *theories* for how gravity works than GR’s “curvature of spacetime" (including quantum theory of “gravitons," recently discussed), so please do not continue to present it as a proven fact that I simply don’t understand.

Thanks.

 

Swansont,

The rule you cite is based on non-Euclidean geometry which is not above criticism.

It has replaced 3-D space (plus time) with various mental, conceptual models (manifolds) which still require ontological verification as to what they represent in the real world... which makes it part of this thread’s focus.

 

For openers, Euclids’ fifth postulate has not been disproven, only sidestepped by claiming that, in a math model, parallel lines will intersect “in infinity.” In the real world, if lines intersect, they are not parallel lines.

 

Second, the shortest distance between two points is still a straight line.* You can project a straight line onto a curved surface, and that projection becomes a curved line on that surface. But, as I said, ontology questions whether or not space it is anything that can have the property of curvature. It is not an established fact, i.e., that space is curved and has form (flat, parabolic or spherical,) though the *stuff in space* is distributed in whatever debatable form. These are fundamental questions asked by ontology, a division of the philosophy of science in which you have no interest, yet you claim expertise.

 

Btw, the shortest distance between two points on a sphere is still a straight line through the sphere, point to point. The “rule” that the line must stay on the surface is only in the non-Euclidean, “space is curved” *model*.

 

Finally, you challenged me to show who is claiming that spacetime is a medium. I quoted a few examples (and criticisms of them) in my focus on specifics in the Brown and Pooley paper, which you dismissed as a couple of philosophers expounding on varieties of theoretical categories (edit: principle vs constructive.) You never responded to those examples, which you had demanded.

(Edit: “

As far as I can see, they do not make any claim about what spacetime IS.”

 

Exactly. In fact they criticize those examples quoted which assert that it IS a medium of some sort. I agree.)

 

Gee, if there are no wrong answers in philosophy, it must be pretty easy to pass the

tests.

I never said that there are no wrong answers in philosophy. Idealism... that reality depends on observation is wrong. And the conclusion, based on idealism, that Earth’s shape and the distance between (and length of) objects in the natural world depends on observation is also wrong.

 

I've had enough of this nonsense.

 

Glad to hear it. You will be happier sticking to the physics section and the axioms that you have learned as facts than trying to debate philosophy of science in this section.

I in turn intend to stay out of the physics section.

 

(

And since you freely admit to engaging in intellectually dishonest behavior...

Cite the instance or retract.

Edited December 3, 2011 by owl

[Cap'n Refsmmat]

I have studied general relativity *theory* minus the math for many years. Your assumption that I have not is false.

These two sentences are mutually contradictory.

 

Your questions about the theory indicated that you do not know how it has been tested or what its implications are.

[owl]

These two sentences are mutually contradictory.

 

Your questions about the theory indicated that you do not know how it has been tested or what its implications are.

My challenge to the theory is based on its reference to curved spacetime as the agent (medium, 'whatever...') which transfers the force of gravity from one mass to another... (and I challenge "length contraction" on world/cosmic scale.)

 

My post 137 cited quotes from those maintaining that it is such a medium and Brown & Pooley's criticism of that assumption. This is an example of ontology's relevance to science.

Btw, before I take off for the weekend (or while I am gone) will you please answer the following, now posed for the third time... very relevant to the "length contraction" part of relativity theory:

“Do you really, truly deny that "...the distance to the Sun (remains) around 93 million miles, regardless of who is flying by at whatever speed measuring it?"...

or that a squished nearly flat shape of Earth is equally valid with the well established nearly spherical shape?

[PeterJ]

Owl, my friend, you have a damn strange way of trying to get people to agree with you.