Frame of Reference as Subject in Subjective Idealism

[owl]

The point of departure for this thread comes from my comments in the Ontology of Time thread in the Speculations section about the insistence in relativity that there are no "preferred" frames of reference, no "correct" or "objective" measurements when comparing one frame of reference (FOR) to another.

 

From post 182, 7/2 in that thread:

I would like to return to the argument, for a moment, against relativity's claim that all measurements, as above, are equally correct.

I suggested that this claim puts relativity squarely in subscription to the subjective idealism philosophy. (See Berkeley and Hume, the most well known proponents.) I reiterated the old cliche' about the tree falling in the forest (see above recent post.)

 

The falling tree makes sound waves whether heard and measured or not. I call this real objective nature in this case, independent of perception and measurement. And, to the finer point, measuring the decibel level of that sound from further away, resulting in lower sound level, does not mean that the sound level at the falling tree diminishes. (The recorded decibel level diminishes with the square of the distance.) Again, the accurate measure of sound level is at the falling tree, and, we can adjust for further distances and quieter sound levels with the 'square of the distance' formula and not claim that the quieter measure is "equally accurate."

This is philosophy as relevant to physics.

 

So, applying the above argument to "length contraction," if there is no objective "reality" independent of various FORs, then as discussed at length in the former thread, the distance between earth and sun varies with FOR, shortening radically with high speed fly-by FORs, for instance. Likewise, earth itself, measured as above, is flattened in the direction of the motion from which it is measured.

My argument then as now is that one astronomical unit stays the same length and earth stays the same shape and size, in the objective world of what is, independent of extreme platforms (FORs) from which they are measured.

To claim otherwise, i.e., that "there is no preferred FOR... those measurements are equally correct" means that one perspective is just as accurate as another, and therefore, there is no objective universe. It all depends on how we look at (and measure) it.

 

So, accordingly the "at rest" frame with what is being measured will be the accurate FOR and yield the actual size and shape and distance between objects (measured from one of the end points.) I know this is relativity "heresy" but I believe it is sound philosophy of science. It is not an attempt to "debunk relativity" but to bring clarity to the confused subjective idealism of relativity regarding FOR as "subject."

 

I'll leave it there for now and open it up for discussion.

[owl]

pantheory:

Sounds good to me I think if length contraction did not occur it would seem to me to be illogical. Matter resists acceleration. Molecules seem like they would be more tightly compacted in the direction of accelerated motion. But as you mentioned, this is another subject.

 

Ask the physicists here, but compacting of molecules under extreme acceleration is not what the relativity measurement effect called length contraction is about... as I understand it.

I know that a bullet gets a bit shorter (and fatter) when fired from a gun. But that is not what "they" mean by length contraction.

Editing to box the quote. Better clarity.

Edited July 6, 2011 by owl

[Cap'n Refsmmat]

My argument then as now is that one astronomical unit stays the same length and earth stays the same shape and size, in the objective world of what is, independent of extreme platforms (FORs) from which they are measured.

To claim otherwise, i.e., that "there is no preferred FOR... those measurements are equally correct" means that one perspective is just as accurate as another, and therefore, there is no objective universe. It all depends on how we look at (and measure) it.

Not necessarily. A relativistic explanation would involve a four-dimensional spacetime which we view three-dimensional sections out of, and different frames of reference necessarily view different three-dimensional sections out of the four-dimensional (immutable) whole.

 

But I'm not a general relativity guy -- ajb would have to make sure I'm talking sense here.

[owl]

Not necessarily. A relativistic explanation would involve a four-dimensional spacetime which we view three-dimensional sections out of, and different frames of reference necessarily view different three-dimensional sections out of the four-dimensional (immutable) whole.

 

But I'm not a general relativity guy -- ajb would have to make sure I'm talking sense here.

First, "spacetime" is the subject of a lot of debate in the philosophy of science community. Please check out my old thread (here in the Philosophy section) on Spacetime Ontology, the Scholarly Debate, specifically the volumes of papers from the International Society for the Advanced Study of Spacetime conferences.

 

I understand 3-D space plus the time factor, as things move around in space, which "takes time." But it seems to me that you move from the "objective" ("immutable") universe into the "subjective" realm of mental concepts without objective referents when you start slicing up a debatable 4-D "spacetime" and viewing "different three-dimensional sections out of the four-dimensional (immutable) whole."

 

In what I am calling the objective world we can focus on a specific volume ("section?") of 3-D space and observe whatever is moving around in that space and measure the elapsed time as an object moves from A to B, and that looks to me like solid empirical science. But once you speak of "spacetime" and sliced up sections of it, you have introduced a debatable element and entered the conceptual, mental, metaphorical realm of "slicing" 4-D spacetime (like your loaf of raisin bread in the other thread.) It seems like a thought experiment without objective referents "in the real world" to me (ontologically speaking, of course.)

Ps: I'm gone 'til Mon.

Edited July 7, 2011 by owl

[Cap'n Refsmmat]

If I am correct that the 4D spacetime-slicing model represents general relativity accurately, than it is not a conceptual, metaphorical thought experiment; it has testable predictions -- namely, every effect that general relativity predicts -- and has been subjected to rigorous experiment.

[owl]

If I am correct that the 4D spacetime-slicing model represents general relativity accurately, than it is not a conceptual, metaphorical thought experiment; it has testable predictions -- namely, every effect that general relativity predicts -- and has been subjected to rigorous experiment.

I am very interested in your perspective on the ontology of spacetime as referenced in my thread on the subject.

I am also very interested in your relies to the specific points made in my opening post on frames of reference as "subject" in subjective idealism. For instance, don't we we all know that earth does not actually flatten out (in the direction of motion) as seen/measured from a near 'C' fly-by frame of reference?

Gotta go.

[Cap'n Refsmmat]

I am very interested in your perspective on the ontology of spacetime as referenced in my thread on the subject.

My perspective depends on your frame of reference.

 

Har. No, I don't have a perspective on ontology, because I do physics, not ontology.

 

I am also very interested in your relies to the specific points made in my opening post on frames of reference as "subject" in subjective idealism. For instance, don't we we all know that earth does not actually flatten out (in the direction of motion) as seen/measured from a near 'C' fly-by frame of reference?

No, we don't. How could we? All of our measurements occur within Earth's frame of reference, and under the relativistic model we'd expect all measurements within one frame to be consistent. Hence our measurements are consistent with relativity and with whatever objective-reality model you might propose. Excluding, of course, a number of more advanced experiments (i.e. experiments beyond measuring the distance to the Sun) which test specific relativistic predictions.

 

"There is no objective universe" does not follow from "different frames of reference see different things" if there is an objective universe, but we see different portions of it depending on our frame of reference.

[Marat]

Since this problem is stated in the philosophy forum, I think it is important to distinguish the subjective idealism of Berkeley and other 18th century thinkers from the positivism which Einstein was using. Positivism holds that the fact that we can know things only by measuring them, so the reality of everything is relative to our capacity for discerning and measuring it, and everything 'real' in the world is thus always essentially a physical relation between the observer and the signal observed, is a physical fact within a world accepted as objective. Philosophical idealism holds that the entire physical world is relatively unreal compared to our minds, which we know by a kind of superior, immediate experience, while we only know the external world as an appearance of something which underlies it, analogous to our own minds, but which we can never know. In this sense idealism is profoundly anti-positivistic, since it posits the existence of things which are somehow significant for the mind (the underlying ontology of the outside world which makes it distinct from us but which we cannot directly know, since we know the world only as an appearance dependent on our own minds) without being knowable by the mind by any specifiable experient, but just as a philosophical assertion. Idealism assumes distinct subjective and objective realms where positivism just assumes that everything known is on the same level and part of the same, single experience. True, what is known within the world is scientifically measured only according to each observer with no privileged reference systems (what experiment could show them privileged?), but it is still all part of the same universally shared, objective world of experience, and for ordinary, non-scientific purposes we all experience it alike, since our common experience is informal, linguistic, and social, and need not concern itself with exact measurements.

[moth]

If there were 4 dimensions the answer would be simple. Just like walking around a white room with a black square on the wall, depending on where you stand in the room you may see a square, rectangle, or even diamond shape.

Wouldn't we expect to see a 4-d system work in a similar way? Depending on your kinetic energy relative to another system you have a different perspective on that system (length contraction) and if that 4th dimensional motion were through the "time dimension" (one direction is faster time passage the other direction is slower time passage) a different rate of time (time dilation) would seem natural.

[tar]

Marat,

 

It seems to me that the reciprocal nature of objectivity and subjectivity, argues against one taking either to be more important than the other. It’s the both of them together that is real, that is true. Either by themselves has little meaning or value.

 

For instance, we experience time and space because we occupy only one place and moment in it. From this position, we notice the rest.

 

We can not refer to something, without something to refer to.

We can not model reality, if there is not reality to model.

 

The object gives the subject something to predicate.

 

Regards, TAR2

[md65536]

I'm replying to a post in another thread that I think this thread is based on? My reply seems more applicable here.

Yes. More like the impossibility of "visualizing" a fourth spatial dimension, since three axes fully describe "space" as a 3-D matrix. (What direction is signified by a fourth axis?... not "time" as a fourth spatial dimension.))

This will make little sense until you understand the ontological debate about space and time.

I have provided links (many times) to the ontology of the spacetime debate. Little response. The International Society for the Advanced Study of Spacetime has presented many scientific/philosophical papers on the subject over the last decade of conferences on the subject. Mostly ignored as I have presented links in this forum.

 

I suggested that you read my favorite author on this Euclidean/ non-Euclidean debate, (as pertains to relativity) but you have not commented on the paper linked above. Too busy to read new information? I don't know. Just guessing. You must be busy as a science website administrator.

Please put this thread in the philosophy section where it can be formally ignored by physicists who don't care about the ontology of time.. or space.. or "spacetime."

Thanks.

I couldn't find any actual links that you're referring to. Can you repost the links, or a link to the post containing the links? Links to specific papers and even references to sections within them would be appreciated... no one wants to wade through the ISASS site trying to find writings that back up your views.

 

Is the author you're referring to Dennis Dieks?

Have you read any of Hans Reichenbach's work? I myself haven't, but I see references to him in stuff that makes sense to me.

I don't get Dieks, personally. For example, in the first section of http://www.phys.uu.nl/~wwwgrnsl/dieks/becoming.pdf, he references Reichenbach and an idea (Conventionalism) that makes sense, but then concludes from it an idea that I can't make sense of (a "global shifting Now").

 

 

Conventionalism (http://en.wikipedia.org/wiki/Philosophy_of_time#Conventionalism) seems like a useful idea for your "ontology of time", because it seems to provide a means to sidestep GR, perhaps treating it as an arbitrary interpretation of time that is agreed on by convention. However, defining an authoritative distance (a fixed diameter of the Earth, etc) seems to be aiming in the exact opposite direction (Asbolutism or something).

 

[tar]

MD65536,

 

Only read about half of Dieks' article and none of Reichenbach's work, but I was thinking, in reading Dieks' article, that the rotation in a system is a crucial component to our recognition of time.

 

Our particular local state is a record of what happened before to our particular "location", what happens next, well, has not happened yet. That is our now. Once anything changes, one photon comes in or goes out, one particle changes it position or momentum, the history of happenings at our location is new, a different state, that has not occurred before.

 

But in a rotating system, some things happen again in the same way they happened before. The memory of all the previous events is contained in the system already, and for us humans, conscious of the comparison, we can "predict" what will happen next. The sun will rise tommorrow. Hence a period of time that exists both in our consiousness and in that which we are conscious of.

 

Without the rotation, we might not have the periods to consider.

 

Regards, TAR2

[owl]

My perspective depends on your frame of reference.

 

Har. No, I don't have a perspective on ontology, because I do physics, not ontology.

 

 

No, we don't. How could we? All of our measurements occur within Earth's frame of reference, and under the relativistic model we'd expect all measurements within one frame to be consistent. Hence our measurements are consistent with relativity and with whatever objective-reality model you might propose. Excluding, of course, a number of more advanced experiments (i.e. experiments beyond measuring the distance to the Sun) which test specific relativistic predictions.

 

"There is no objective universe" does not follow from "different frames of reference see different things" if there is an objective universe, but we see different portions of it depending on our frame of reference.

 

So you use the word spacetime like it was an established reality and comfortably ignore all the debate on what the heck it actually is. Ok, there can be no conversation on it in that case. If you look at my near-last entry in the spacetime ontology thread you will see some discussion of the possibility of "grooves or ruts" in spacetime which guide objects in their movements. Do you ever wonder what kind of 'whatever'... substance, entity, ether, medium... this "fabric of spacetime" actually is, as something (?) which guides moving objects? This is the focus of the International Society for the Advanced Study of Spacetime (ISASS), and it is a legitimate sub-field of the philosophy of science as relevant to relativity.

 

To my :

For instance, don't we we all know that earth does not actually flatten out (in the direction of motion) as seen/measured from a near 'C' fly-by frame of reference?

... you answered, "No, we don't. How could we?"

 

We "know" through earth science that earth is not like malleable silly-putty; rather that it is a relatively rigid, near spherical object,... that earth never actually flattens out as the above extreme frame of reference "sees" it. Do you deny that we know the above about earth?

 

Since this problem is stated in the philosophy forum, I think it is important to distinguish the subjective idealism of Berkeley and other 18th century thinkers from the positivism which Einstein was using. Positivism holds that the fact that we can know things only by measuring them, so the reality of everything is relative to our capacity for discerning and measuring it, and everything 'real' in the world is thus always essentially a physical relation between the observer and the signal observed, is a physical fact within a world accepted as objective. Philosophical idealism holds that the entire physical world is relatively unreal compared to our minds, which we know by a kind of superior, immediate experience, while we only know the external world as an appearance of something which underlies it, analogous to our own minds, but which we can never know. In this sense idealism is profoundly anti-positivistic, since it posits the existence of things which are somehow significant for the mind (the underlying ontology of the outside world which makes it distinct from us but which we cannot directly know, since we know the world only as an appearance dependent on our own minds) without being knowable by the mind by any specifiable experient, but just as a philosophical assertion. Idealism assumes distinct subjective and objective realms where positivism just assumes that everything known is on the same level and part of the same, single experience. True, what is known within the world is scientifically measured only according to each observer with no privileged reference systems (what experiment could show them privileged?), but it is still all part of the same universally shared, objective world of experience, and for ordinary, non-scientific purposes we all experience it alike, since our common experience is informal, linguistic, and social, and need not concern itself with exact measurements.

I know the difference between classical subjective idealism and positivism which you have distinguished above. My argument is that frame of reference is like

the subjective perspective in idealism in that relativity claims that high speed fly-by frames are equally as accurate as frames at rest with what is measured; which yield the absurdities of a flattened earth and an extremely short astronomical unit as "just as real" as the actual shape of earth and actual distance to the sun (as measured from at rest frames.)

 

Relativity theorists here have said that "for a photon" there is no distance and no travel time between sun and earth. Yet we know that 'C' is constant in space and that it takes 8+ minutes for sunlight to reach earth. But no intelligent person will say that there is no distance between earth and sun, just because the "photon's perspective" is just as real as actual travel time and distance traveled by sunlight.

 

You defined positivism above as:

Positivism holds that the fact that we can know things only by measuring them, so the reality of everything is relative to our capacity for discerning and measuring it, and everything 'real' in the world is thus always essentially a physical relation between the observer and the signal observed, is a physical fact within a world accepted as objective.

 

We can know from earth science that earth is not malleable enough to squish or flatten, so we can know that such "length contracted" measurement is due a distortion effect of the near light speed frame using light as the medium carrying the image.

And philosophically, as in a-priori epistemology, we know that the tree falling in the forest makes "real" sound waves in the air whether we hear and measure them or not.

 

I'm replying to a post in another thread that I think this thread is based on? My reply seems more applicable here.

I couldn't find any actual links that you're referring to. Can you repost the links, or a link to the post containing the links? Links to specific papers and even references to sections within them would be appreciated... no one wants to wade through the ISASS site trying to find writings that back up your views.

 

Is the author you're referring to Dennis Dieks?

Have you read any of Hans Reichenbach's work? I myself haven't, but I see references to him in stuff that makes sense to me.

I don't get Dieks, personally. For example, in the first section of http://www.phys.uu.nl/~wwwgrnsl/dieks/becoming.pdf, he references Reichenbach and an idea (Conventionalism) that makes sense, but then concludes from it an idea that I can't make sense of (a "global shifting Now").

 

 

Conventionalism (http://en.wikipedia.org/wiki/Philosophy_of_time#Conventionalism) seems like a useful idea for your "ontology of time", because it seems to provide a means to sidestep GR, perhaps treating it as an arbitrary interpretation of time that is agreed on by convention. However, defining an authoritative distance (a fixed diameter of the Earth, etc) seems to be aiming in the exact opposite direction (Asbolutism or something).

I'm on the run again, but...

I've read a lot of Deiks' edited volumes of papers from the ISASS without taking notes to support my argument. The last reference to spacetime as a medium with "ruts and grooves" for guiding objects (in my spacetime ontology thread) was, I think, from the paper on Minkowski's spacetime; a glorious non-entity. (Brown and Pooley)

 

You mentioned the jump to non-Euclidean geometry in another post.

Here is my often posted link to Kelley Ross's paper, The Ontology and Cosmology of Non-Euclidean Geometry:

http://www.friesian.com/curved-1.htm

 

Thanks for your Wikipedia link on conventionalism. I just have time for a brief comment on the following:

 

Conventionalism

 

The position of conventionalism states that there is no fact of the matter as to the geometry of space and time, but that it is decided by convention.

 

All attempts to measure any speed relative to this ether failed, which can be seen as a confirmation of Einstein's postulate that light propagates at the same speed in all reference frames. Special relativity is a formalization of the principle of relativity which does not contain a privileged inertial frame of reference such as the luminiferous ether or absolute space, from which Einstein inferred that no such frame exists.

 

If the universe is “objective” in the sense that reality is as it is, independent of local frames of reference from which distances are measured, then it doesn’t matter what you call the actual space (distance) between objects (through which light travels at constant velocity)... “absolute space” or whatever..., and whatever label for that space/distance like “luminiferous ether” is irrelevant . It stays the same no matter how or from where or at what velocity it is measured. Relativity takes into account these SR effects and yields useful and very well documented results... none of which make actual distances between objects, or sizes or shapes of objects vary with extremes of frames of reference from which they are measured.

 

If extreme frames of reference in measurement were equal and "just as real" criteria for describing the universe as at rest frames of reference, then relativity would be very similar to subjective idealism in that one subject's perspective would be just as accurate as another's... like how loud was the sound of the falling tree, from miles away as contrasted with right under it... the last sound the person with "accurate perception" heard! But we have a formula, as does relativity, for knowing the actual decibel level at the tree, even from far away, if we know exactly how far.

 

I'll find specific ontology links if you want, as requested, but first, please read those cited in my "Spacetime Onbtology: the Scholarly Debate" thread. I had barely begun to cite references for discussion there when it went off on a specific tangent.

Edited July 13, 2011 by owl

[Cap'n Refsmmat]

So you use the word spacetime like it was an established reality and comfortably ignore all the debate on what the heck it actually is. Ok, there can be no conversation on it in that case. If you look at my near-last entry in the spacetime ontology thread you will see some discussion of the possibility of "grooves or ruts" in spacetime which guide objects in their movements. Do you ever wonder what kind of 'whatever'... substance, entity, ether, medium... this "fabric of spacetime" actually is, as something (?) which guides moving objects? This is the focus of the International Society for the Advanced Study of Spacetime (ISASS), and it is a legitimate sub-field of the philosophy of science as relevant to relativity.

But is it a legitimate study of physics? Is it a subject which can be tested empirically?

 

We "know" through earth science that earth is not like malleable silly-putty; rather that it is a relatively rigid, near spherical object,... that earth never actually flattens out as the above extreme frame of reference "sees" it. Do you deny that we know the above about earth?

No, I do not; however, I do not see its relevance, as I have explained repeatedly that length contraction does not involve a physical force applied to Earth, and so Earth's rigidity is entirely irrelevant.

[tar]

Well, I would like to point out, that the "universe as it is" is a highly subjective statement, about objective reality. This, because, the word "is" implies a current state, which the universe "objectively" is never in. We would not experience it, at all, if we did not do it, from one place and time. This, in a way, allows us to know "how it is" , consisting of very many places like "this", and very many periods of time like "this". We even know that "this" place and time can be divided down to a Planck length and the period of time it would take a photon to go the distance. Or multiply "this" out to spacetime. But by definition, all of spacetime cannot be witnessed from any one place and time. So it must be only a subjective speculation.

 

If we can imagine it, it is subjective. If we can sense it, it is objective.

 

Any of our theories, attempt to fit objective reality.

 

Objective reality is under no pressure to fit our theories.

 

Scientific method allows us to compare our subjective models of the world with each other, and codify that which we, in common, find true about the world. This we can reasonably agree on, as "objective" reality. But it remains a collective, subjective model, built on those objective things that we, and our instruments sense.

 

That we know many of the ways and rules by which the objective world fits together, and works, there is no doubt. That most everybody here knows more of these things than I do, there is no doubt. That there is more for us all to discover about objective reality, there is no doubt.

 

Objective reality is that which we strive to model. Subjective reality is those pieces of it that we have managed to.

 

That is my subjective take, on what is objective.

 

Regards, TAR2

[owl]

?????? Clarification needed.

me:

We "know" through earth science that earth is not like malleable silly-putty; rather that it is a relatively rigid, near spherical object,... that earth never actually flattens out as the above extreme frame of reference "sees" it. Do you deny that we know the above about earth?

Cap ‘n R:

No, I do not; however, I do not see its relevance, as I have explained repeatedly that length contraction does not involve a physical force applied to Earth, and so Earth's rigidity is entirely irrelevant.

me:

For instance, don't we we all know that earth does not actually flatten out (in the direction of motion) as seen/measured from a near 'C' fly-by frame of reference?

Cap 'n R:

No, we don't. How could we?

 

I get your repeated statements that the flattening (length contraction) as seen/measured from a near 'C' fly-by frame of reference does not involve any mysterious force crushing earth out of its nearly spherical shape... but...

 

Are you saying that we do or do not know that earth does not actually flatten out? In your first quote above you "do not" deny the common knowledge "that earth never actually flattens out." Then, immediately above, you do deny the same. Very confusing.

 

On spacetime ontology;

me:

Do you ever wonder what kind of 'whatever'... substance, entity, ether, medium... this "fabric of spacetime" actually is, as something (?) which guides moving objects? It is a legitimate sub-field of the philosophy of science as relevant to relativity.

Cap ‘n R:

But is it a legitimate study of physics? Is it a subject which can be tested empirically?

 

Knowing the nature of what it is that physics claims as something(?) that guides moving objects is not a subject of relevance to physics??

If "it" has "grooves or ruts," what is it that has grooves or ruts? How can this not be relevant? If "it" is not that substantial, what is it anyway?... a return of the "luminiferous aether" or what... a metaphysical concept without being any kind of entity in the "real world?"

Why does gravity require "spacetime" as a medium by which objects are guided, like into orbits around stars or whatever?

[Cap'n Refsmmat]

Knowing the nature of what it is that physics claims as something(?) that guides moving objects is not a subject of relevance to physics??

If "it" has "grooves or ruts," what is it that has grooves or ruts? How can this not be relevant? If "it" is not that substantial, what is it anyway?... a return of the "luminiferous aether" or what... a metaphysical concept without being any kind of entity in the "real world?"

Why does gravity require "spacetime" as a medium by which objects are guided, like into orbits around stars or whatever?

Is it a subject that can be tested empirically? Can I experimentally determine why gravity requires spacetime?

[owl]

Is it a subject that can be tested empirically? Can I experimentally determine why gravity requires spacetime?

 

Shall we have a dialogue consisting of questions in reply to questions?

 

With “it” as spacetime ontology, how could we test to verify spacetime as an existing entity without which gravity would not work?

 

Can we experimentally verify that gravity does not work without spacetime?

 

Or is the “fabric of spacetime” that material of which the Emporer’s New Clothes are made? If only physicists fluent in math can "see" spacetime, does that make the rest of us stupid and unsophisticated, or simply childlike and in need of higher education in math/physics?

[Cap'n Refsmmat]

Shall we have a dialogue consisting of questions in reply to questions?

The answer to my question (yes or no) is the same as the answer to the question "is this a legitimate study of physics?"

 

Or is the “fabric of spacetime” that material of which the Emporer’s New Clothes are made? If only physicists fluent in math can "see" spacetime, does that make the rest of us stupid and unsophisticated, or simply childlike and in need of higher education in math/physics?

The universe is complicated. Mathematics provides levels of abstraction which make the details much easier to work with. It is a tool.

[owl]

The answer to my question (yes or no) is the same as the answer to the question "is this a legitimate study of physics?"

 

 

The universe is complicated. Mathematics provides levels of abstraction which make the details much easier to work with. It is a tool.

First, You did not clarify the apparent contradiction detailed in my post 16 above.

 

Is it not a legitimate concern of physics to have a consensual understanding of such a core and fundamental element of relativity as spacetime, since the claim is that gravity morphs "it" without any clarity on what "it" is? What do you think all the fuss is about (conferences, papers, hot debate) over the last decade on spacetime ontology? You can continue to ignore it but it is not about to go away.

 

From the conclusion of the Ross paper linked above:

Just because the math works doesn't mean that we understand what is happening in nature. Every physical theory has a mathematical component and a conceptual component, but these two are often confused. Many speak as though the mathematical component confers understanding, this even after decades of the beautiful mathematics of quantum mechanics obviously conferring little understanding. The mathematics of Newton's theory of gravity were beautiful and successful for two centuries, but it conferred no understanding about what gravity was. Now we actually have two competing ways of understanding gravity, either through Einstein's geometrical method or through the interaction of virtual particles in quantum mechanics.

 

Back to the length contraction issue as it pertains to subjective vs objective, again from md's Wikipedia link on conventionalism above:

 

Even supposing that two rods, whenever brought near to one another are seen to be equal in length, we are not justified in stating that they are always equal in length. This impossibility undermines our ability to decide the equality of length of two distant objects. Sameness of length, to the contrary, must be set by definition.

 

The above denies an “objective universe” in which things and the relationships between them exist independently of observation/measurement. Rather it asserts that everything is relative to to the frame of reference from which it is observed, length contraction being the immediate case in point. So, when the two rods of equal length ( as observed side by side) are separated and one appears shorter than the other (length contracted), the philosophy of subjective idealism (substituting frame of reference for subject) prevails. This philosophy claims that one rod magically actually gets shorter when so observed/measured, and then, when both are brought back together again, the “shorter” one is magically restored to its previous longer length, now the same length as the other rod. This makes length contraction no different in principle than a stage magic trick (illusion) of perception.

Same for the perception of earth as flattened in the direction of movement of the often belabored high speed frame of reference. If we agree (big "if," it seems) that earth does not actually deform from spherical, then that leaves the length contracted perspective/measurement in error, one would assume due to the relativistic effect.

[Cap'n Refsmmat]

Is it not a legitimate concern of physics to have a consensual understanding of such a core and fundamental element of relativity as spacetime, since the claim is that gravity morphs "it" without any clarity on what "it" is? What do you think all the fuss is about (conferences, papers, hot debate) over the last decade on spacetime ontology? You can continue to ignore it but it is not about to go away.

I'm talking about the concerns of physicists, not the concerns of ontologists. The issue of, say, feminist interpretation of literature is not about to go away, but it has nothing to do with physics.

 

If what spacetime "is" is not experimentally testable, but only the behavior of the gravity which morphs "it", then what spacetime "is" is not of concern to scientists.

 

In science, understanding "what is happening in nature" means being able to predict what will happen when you manipulate something or perform an experiment.

 

Same for the perception of earth as flattened in the direction of movement of the often belabored high speed frame of reference. If we agree (big "if," it seems) that earth does not actually deform from spherical, then that leaves the length contracted perspective/measurement in error, one would assume due to the relativistic effect.

This is a false dichotomy, as I've explained previously. The Earth does not deform. When viewed from another reference frame, it is a different shape. It has always been that shape and it always will be, in that reference frame. That is why Earth's rigidity does not enter into it.

[swansont]

The above denies an “objective universe” in which things and the relationships between them exist independently of observation/measurement. Rather it asserts that everything is relative to to the frame of reference from which it is observed, length contraction being the immediate case in point. So, when the two rods of equal length ( as observed side by side) are separated and one appears shorter than the other (length contracted), the philosophy of subjective idealism (substituting frame of reference for subject) prevails. This philosophy claims that one rod magically actually gets shorter when so observed/measured, and then, when both are brought back together again, the “shorter” one is magically restored to its previous longer length, now the same length as the other rod. This makes length contraction no different in principle than a stage magic trick (illusion) of perception.

Same for the perception of earth as flattened in the direction of movement of the often belabored high speed frame of reference. If we agree (big "if," it seems) that earth does not actually deform from spherical, then that leaves the length contracted perspective/measurement in error, one would assume due to the relativistic effect.

 

Straw man, appeal to ridicule, straw man. (In case you're scoring at home: equating science with philosophy, using "magically" and "actually" to describe length contraction and equating it with an illusion, describing the earth as "deforming")

 

If what spacetime "is" is not experimentally testable, but only the behavior of the gravity which morphs "it", then what spacetime "is" is not of concern to scientists.

Indeed. Relativity has been around for a century with the "ontological question" unanswered, and it doesn't seem to have been an obstacle at all.

[owl]

swansont:

Indeed. Relativity has been around for a century with the "ontological question" unanswered, and it doesn't seem to have been an obstacle at all.

 

As I asked yesterday, "Can we experimentally verify that gravity does not work without spacetime"... whatever that is supposed to be?

 

Yet another question even without the last one answered:

Is the quantum theory of gravity not an alternative to relativity's insistence that gravity curves "spacetime," which might as well be a metaphysical invention for all the debate over what it is (or not) in the "real world."

 

Cap ‘n R:

If what spacetime "is" is not experimentally testable, but only the behavior of the gravity which morphs "it", then what spacetime "is" is not of concern to scientists.

 

In science, understanding "what is happening in nature" means being able to predict what will happen when you manipulate something or perform an experiment.

 

This is a false dichotomy, as I've explained previously. The Earth does not deform. When viewed from another reference frame, it is a different shape. It has always been that shape and it always will be, in that reference frame. That is why Earth's rigidity does not enter into it.

 

So this totally avoids the obvious reality check that earth is in fact a near spherical body (in the "objective cosmos"... my term here), not an oblate or prolate spheroid, even though it would be seen as such from various directions of very high speed frame of reference. Your insistence otherwise rejects my "objective world" argument of this thread as contrasted with the subjective perspective that all frames of reference are equally valid.

[owl]

View PostCap, on 14 July 2011 - 12:12 PM, said:

If what spacetime "is" is not experimentally testable, but only the behavior of the gravity which morphs "it", then what spacetime "is" is not of concern to scientists.

 

As I keep asking (most recently in post 23,) here phrased a bit differently, what does “spacetime” add to the observed behavior of objects under the influence of gravity? Planets orbit stars as mutually attracted by their masses. Why introduce the elusive medium spacetime and insist that gravity curves it and then planets are guided around in their orbits by spacetime rather than by the pull of gravity without an unidentified medium.

Why doesn’t the principle of Occam’s razor cut spacetime out and let gravity be the attractive force of mass without the unnecessary medium/concept/whatever, spacetime?

Edited July 15, 2011 by owl

[swansont]

swansont:

 

 

As I asked yesterday, "Can we experimentally verify that gravity does not work without spacetime"... whatever that is supposed to be?

 

I doubt it. I don't see how you would "eliminate" spacetime.

 

Yet another question even without the last one answered:

Is the quantum theory of gravity not an alternative to relativity's insistence that gravity curves "spacetime," which might as well be a metaphysical invention for all the debate over what it is (or not) in the "real world."

 

There is no quantum theory of gravity. Whether it would be an alternative depends how you are using alternative. It would not replace GR where GR works, only where GR fails.