Yet we know from observation, rainbows, and other refractions, that light must consist of waves, therefore there must be a substance there which is waving. — Metaphysician Undercover

M-M explicitly disproved that notion. If there was a substance, then M-M would have detected it. That's what eventually led to relativity. If I'm misunderstanding it then please explain.

I've studied enough physics to know that a wave is an activity of a substance. That's simply what a wave is, and all waves are understood through modeling the movement of the particles within that substance. That's what a wave is, a specific type of activity of a substance which involves an interaction of its particles. Therefore a wave in empty space is simply impossible because there would be no particles there to make the wave. Yet we know from observation, rainbows, and other refractions, that light must consist of waves, therefore there must be a substance there which is waving. — Metaphysician Undercover

Ok, suppose space is the "substance there which is waving". After all, the gravitational wave observations in recent years, (combined with electromagnetic observations of the source of detected gravitational wave observations) provide some pretty good evidence for space waving.

M-M explicitly disproved that notion. If there was a substance, then M-M would have detected it. That's what eventually led to relativity. If I'm misunderstanding it then please explain. — EricH

What M-M disproved is that the relationship between massive objects, bodies, and the ether, is not as was hypothesized. That does not prove that there is no substance which is waving, it just proves that the relationship between massive objects and the substance which is waving, is not as they thought it ought to have been. I think you can read this on Wikipedia, or other online explanations of M-M.

Then, instead of trying to determine the proper relation between massive objects and the ether, the physics community decided just to dispense with the ether altogether, because that facilitated the application of Einsteinian relativity.

Ok, suppose space is the "substance there which is waving". After all, the gravitational wave observations (combined with electromagnetic observations of the source of detected gravitational wave observations) provide some pretty good evidence for space waving. — wonderer1

All right then, do you understand that a "wave" consists of an interaction of the particles which make up the substance which is the medium? So if "space" is the substance within which the waves exist, then space must be made up of particles.

I've studied enough physics to know that a wave is an activity of a substance. That's simply what a wave is, and all waves are understood through modeling the movement of the particles within that substance. That's what a wave is, a specific type of activity of a substance which involves an interaction of its particles. Therefore a wave in empty space is simply impossible because there would be no particles there to make the wave. Yet we know from observation, rainbows, and other refractions, that light must consist of waves, therefore there must be a substance there which is waving.
— Metaphysician Undercover

Ok, suppose space is the "substance there which is waving". After all, the gravitational wave observations in recent years, (combined with electromagnetic observations of the source of detected gravitational wave observations) provide some pretty good evidence for space waving. — wonderer1

What M-M disproved is that the relationship between massive objects, bodies, and the ether, is not as was hypothesized. That does not prove that there is no substance which is waving, it just proves that the relationship between massive objects and the substance which is waving, is not as they thought it ought to have been. — Metaphysician Undercover

This is completely at odds with the fundamental basis of modern physics. There's no legitimate physicist in the world who believes it. Light propagates without a medium. If you post this on a physics forum, it will be removed immediately. It's pseudoscience.

All right then, do you understand that a "wave" consists of an interaction of the particles which make up the substance which is the medium? — Metaphysician Undercover

I've already said that I have a broader perspective on using "wave" than you seem to. So no. I don't see any value in restricting the usage of "wave" to such a narrow definition.

Do you disagree that space waves in the case of gravitational waves?

The Michelson–Morley experiment was an attempt to measure the relative motion of the Earth and the luminiferous aether, a supposed medium permeating space that was thought to be the carrier of light waves. The experiment was performed between April and July 1887 by American physicists Albert A. Michelson and Edward W. Morley...

The experiment compared the speed of light in perpendicular directions in an attempt to detect the relative motion of matter through the luminiferous aether ("aether wind"). The result was negative, in that Michelson and Morley found no significant difference between the speed of light in the direction of movement through the presumed aether, and the speed at right angles. This result is generally considered to be the first strong evidence against some aether theories, as well as initiating a line of research that eventually led to special relativity, which rules out motion against an aether."  — Wikipedia - The Michaelson-Morley Experiment

I think you can read this on Wikipedia, — Metaphysician Undercover

I did and it refutes what you are saying.
Per Wikipedia:

"Physics theories of the 19th century assumed that just as surface water waves must have a supporting substance, i.e., a "medium", to move across (in this case water), and audible sound requires a medium to transmit its wave motions (such as air or water), so light must also require a medium, the "luminiferous aether", to transmit its wave motions. Because light can travel through a vacuum, it was assumed that even a vacuum must be filled with aether."

The experiment compared the speed of light in perpendicular directions in an attempt to detect the relative motion of matter through the luminiferous aether ("aether wind"). The result was negative, in that Michelson and Morley found no significant difference between the speed of light in the direction of movement through the presumed aether, and the speed at right angles. This result is generally considered to be the first strong evidenceagainst some aether theories, as well as initiating a line of research that eventually led to special relativity, which rules out motion against an aether.

These results have been repeatedly confirmed.

Ha - you beat me to it!

Ha - you beat me to it! — EricH

I don't think they're paying attention to me. Perhaps they'll listen to you.

I don't think they're paying attention to me. — T Clark

Am I among "they"?

This is completely at odds with the fundamental basis of modern physics. There's no legitimate physicist in the world who believes it. Light propagates without a medium. If you post this on a physics forum, it will be removed immediately. It's pseudoscience. — T Clark

The idea he's presenting here is that of quantum field theory if I understand him correctly - he did bring that up before. Quantum field theory is, by my understanding, far from pseudo science, though the comparison between quantum field theory and the aether *might* be - it seems like at least a fair comparison to think of, but I don't know enough to say why it's not.

I have read, though, that the fields of quantum field theory are supposed to be "relativistic", which I guess implies that they wouldn't conflict with the Michelson–Morley experiment anyway. Whether these fields could be consider an aether or not, and why not, might be an interesting question.

Or maybe you're right and it's pseudo science, but I guess I don't know enough to say it is at this point

Edit. https://physics.stackexchange.com/questions/308413/ether-vs-quantum-field-theory#:~:text=The%20quantum%20fields%20though%20by,identified%20with%20the%20luminiferous%20aether.&text=The%20aether%20or%20luminiferous%20aether,that%20which%20light%20travelled%20through.

The comparison is an understandable one to bring up, I think, but this answer illuminates what I was saying above: the quantum field(s) being Lorenz invariant makes it fundamentally different from the aether

Edit 2.

Answer here is interesting as well: https://physics.stackexchange.com/questions/518806/do-qft-fields-constitute-an-ether

This is completely at odds with the fundamental basis of modern physics. There's no legitimate physicist in the world who believes it. Light propagates without a medium. If you post this on a physics forum, it will be removed immediately. It's pseudoscience. — T Clark

It's not pseudoscience which I am engaged in, because I do not pretend to be doing science. I am speculating in metaphysics and not at all pretending to be doing physics. The larger problem though is with the way that many people regard physicists. If a physicist speculates in metaphysics, many individuals will believe that such speculations are actually science because the speculations are carried out by a scientist.

Clearly such speculations, even if carried out by a scientist, are not science. And in reality, unless the physicist is properly educated in metaphysics, this physicist is just an undisciplined metaphysician, practising pseudo-metaphysics. Steven Hawking is a prime example of a pseudo-metaphysician. He clearly had very little if any training in metaphysics, yet in books like "The Grand Design" he pretended to be well-versed in it.

The experiment compared the speed of light in perpendicular directions in an attempt to detect the relative motion of matter through the luminiferous aether ("aether wind"). — Wikipedia - The Michaelson-Morley Experiment

This is the key point, the attempt to detect "relative motion" of matter through the ether. If it is the case that matter as well as the waves are both properties of the ether, then there would be no such relative motion, what we perceive as matter would just be a moving part of the ether. And, this is supported by quantum field theory. Particles of matter are understood as properties of the field, not distinct from (so as to move relative to) the field.

The comparison is an understandable one to bring up, I think, but this answer illuminates what I was saying above: the quantum field(s) being Lorenz invariant makes it fundamentally different from the aether — flannel jesus

It's fundamentally different from the aether, because the aether was always understood as an independent, separate substance from the bodies which exist within it. This was the premise of the M-M experiment. Now, respecting the results of M-M, we can either say that this was a misunderstanding of the aether, and produce a new model of the aether which does not have that requirement, or we can insist that "separate substance" is essential to the conception named "aether", and therefore dismiss "aether" as inadequate, and come up with a new word to refer to the medium for light.

Clearly, "field" is inadequate because it represents the medium with random locations, arbitrary points, instead of identifying the true particles which must exist within the medium, comprising the medium, as is required to support the observed wave motion of electromagnetism. Only through identification and modeling of the true particles of the medium can an adequate understanding of it be produced. And according to what M-M indicates (no aether wind), along with what the experiments of quantum field theory indicate, all massive objects must be composed of this same medium.

I am speculating in metaphysics and not at all pretending to be doing physics. — Metaphysician Undercover

I don't speculate in metaphysics so I can't help you with this. I suggest you take your speculations to a physics forum - they will help you understand this much better than I.

The idea he's presenting here is that of quantum field theory if I understand him correctly - he did bring that up before. Quantum field theory is, by my understanding, far from pseudo science, though the comparison between quantum field theory and the aether *might* be - it seems like at least a fair comparison to think of, but I don't know enough to say why it's not. — flannel jesus

This from Wikipedia:

In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics. QFT is used in particle physics to construct physical models of subatomic particles and in condensed matter physics to construct models of quasiparticles. — Wikipedia - Quantum Field Theory

QFT has nothing to do with the propagation of light. Propagation of light does not involve movement of particles within a substance. Saying that it does is wrong. It's not only merely wrong, it's really most sincerely wrong. How wrong does something have to be before it becomes pseudoscience?

It's not pseudoscience which I am engaged in, because I do not pretend to be doing science. I am speculating in metaphysics and not at all pretending to be doing physics. — Metaphysician Undercover

You wrote:

I've studied enough physics to know that a wave is an activity of a substance. That's simply what a wave is, and all waves are understood through modeling the movement of the particles within that substance. — Metaphysician Undercover

This is not a metaphysical statement. In this context it's a statement about optics, the physics of light, and it's wrong.

This is the key point, the attempt to detect "relative motion" of matter through the ether. If it is the case that matter as well as the waves are both properties of the ether, then there would be no such relative motion, what we perceive as matter would just be a moving part of the ether. And, this is supported by quantum field theory. Particles of matter are understood as properties of the field, not distinct from (so as to move relative to) the field. — Metaphysician Undercover

Again - this statement is at odds with the fundamental basis of modern physics.

quantum field theory has EVERYTHING to do with the propagation of light.

quantum field theory has EVERYTHING to do with the propagation of light. — flannel jesus

Do you believe that light must have a medium in order to propagate as a wave? It doesn't.

my beliefs aren't relevant. I'm just exploring the topic.

Even though my beliefs aren't relevant here, I'll answer the question honestly: I'm completely agnostic. I would defer to the experts. If the experts of quantum mechanics think that quantum field theory is true, then I might further ask if that field could reasonable be called an aether (even if it's not the same as the original aether concept the MM experiment tested for), and/or ask them if they would describe the field as a "medium through which light propagates".

If quantum field theory is correct, then that would mean light does in fact propagate via a quantum field. Right? That's the idea. It seems to be the idea to me, anyway.

Based on my readings, it seems the consensus is that while these fields perhaps have some conceptual overlappings with the aether theory tested in MM, a quantum field is *fundamentally different* in some important ways that make people justifiably reluctant to call it "aether".

It's not clear to me what degree of ontological "existence" these fields are taken to have by the proponents of qft, or if instead they're considered an abstract mathematical model. Is it a "thing" that occupies all of space? I really don't know.

This is not a metaphysical statement. In this context it's a statement about optics, the physics of light, and it's wrong. — T Clark

You're displaying very poor reading skills T Clark. Please reread the statement you quoted. It's not at all a statement about the physics of light. I never mentioned "light" or "electromagnetism". It's a statement about what it means to be a "wave", how the concept indicated by that word is understood through normal human conventions, especially as it is used in the more specific physics of waves.

So, if light exists as a wave, which much evidence indicates, then it exists according to the principles understood by the concept signified by "wave", which i was talking about in the statement. It is a simple conclusion of deductive logic. P1, Waves have x essential properties. P2 Light exists as waves. C Therefore light has X properties.

Again - this statement is at odds with the fundamental basis of modern physics. — T Clark

It might be "at odds with the fundamental basis of modern physics" but it's a true statement about the logical conclusion we can draw from the M-M experiments, if we adhere to the premise that light exists as a wave. As the article you quoted stated, the experiment was an attempt to detect the relative motion of matter through the aether. The experiments could not determine any such relative motion, and strongly indicate that there is no such relative motion. From here we can either conclude that there is no aether therefore light does not exist as waves, but for some unknown reason appears to be spookily similar to waves, or we can maintain the premise that light exists as a wave, therefore there is an aether: and from the results of those experiments we can conclude that matter moves with the aether, so that there is no such relative motion. If modern physicists have failed to draw the latter conclusion, and cannot understand why light spookily appears to exist as a wave, then that is a problem with modern physics, not a problem with my statement, which is at odds with modern physics.

It's a statement about what it means to be a "wave", how the concept indicated by that word is understood through normal human conventions, especially as it is used in the more specific physics of waves.

So, if light exists as a wave, which much evidence indicates, then it exists according to the principles understood by the concept signified by "wave", which i was talking about in the statement. It is a simple conclusion of deductive logic. P1, Waves have x essential properties. P2 Light exists as waves. C Therefore light has X properties. — Metaphysician Undercover

Phenomena in the world are not constrained to behave in accordance with our definitions. Before Michelson-Morley, people did believe that a medium was required for a wave to propagate. It took them a while to be convinced otherwise. Your definition is 150 years out of date.

:100: :party:

So, if light exists as a wave, which much evidence indicates — Metaphysician Undercover

The behavior of particles at the atomic & sub-atomic levels does not correspond to anything in the macro world (AKA classical physics) - and analogies to the behavior of matter at the macro level (what we can see/fell) fall apart if taken literally.

Light does not "exist as a wave". Light "exists" (and I put exists in quotes) as photons. Photons exhibit the behavior of particles when we measure their "particle" behavior. While photons have no rest mass (since they travel at the speed of light) they have momentum which can be measured and under some situations actually used (think of outer space light sails).

Photons also exhibit properties of a wave - but only when we try to measure their wave properties (wavelength, etc).

We cannot simultaneously measure both the particle & wave behavior of photons at the same time.

So the best analogy I can come up with is that photons are particles which also exhibit wave-like behavior. And particles do not need a medium in which to move.

[edit] Just to emphasize - that is an analogy. The math describes reality.

I hope this helps.

Phenomena in the world are not constrained to behave in accordance with our definitions. Before Michelson-Morley, people did believe that a medium was required for a wave to propagate. It took them a while to be convinced otherwise. Your definition is 150 years out of date. — T Clark

This is not at all true. The physics of waves is very definite. Waves require a medium. All physicists know this, it is taught in basic high school level physics. This is why light is understood by physicists to exist as particles, photons, not as waves, and the movement of photons is understood by "wave functions", not waves

So the best analogy I can come up with is that photons are particles which also exhibit wave-like behavior. — EricH

That's right, the principles of physics force us to treat this as "wave-like behaviour". This will be the case until we determine and identify the medium, at which time we will be able to treat it as true waves, which the empirical evidence indicates that it obviously is. Consider, that thousands of years ago people understood sound to be vibrations in the air. They knew, by its behaviour, wind and sound vibrations, that "air" had to be a medium, but they could not see it, nor identify the particles which air is comprised of. Having no capacity to see or identify any particles of air did not prevent them from developing an understanding of "air" as a substance. This is the same way that we should look at the aether. The evidence, wave-like behaviour, indicates that it is there, we just have not yet been able to understand its existence.

This is not at all true. The physics of waves is very definite. Waves require a medium. All physicists know this, it is taught in basic high school level physics. This is why light is understood by physicists to exist as particles, photons, not as waves, and the movement of photons is understood by "wave functions", not waves — Metaphysician Undercover

Clearly there's no reason for you and me to continue this discussion.

I do have this to say to anyone else reading this post - The fact that light can propagate as a wave through a vacuum with no medium is an established scientific fact. It's part of the foundation of modern physics. In order to reject that, you will have to reject the findings of physics for the past 150 years.

So the best analogy I can come up with is that photons are particles which also exhibit wave-like behavior. And particles do not need a medium in which to move. — EricH

:up:

The fact that light can propagate as a wave through a vacuum with no medium is an established scientific fact — T Clark

I think you've been corrected on this, the proper scientific description is "wave-like behaviour".
So, I'm going to throw your line right back at you, and please, quit with this assertion of "established scientific fact".

It's pseudoscience. — T Clark

As I indicated, I'm all done.

It's not pseudoscience which I am engaged in, because I do not pretend to be doing science. I am speculating in metaphysics and not at all pretending to be doing physics. — Metaphysician Undercover

Congratulations, MU, it appears that not for the first time you have shut down a discussion with a Trumpian, even nos4ian, display of arrogant ignorance and stupidity. Ante about 1885, there existed a belief in luminiferous aether - lots of online references for exactly what that was supposed to be. Starting with MIckleson-Morley in 1887, and successive experiments, it has become understood and accepted by anyone with at least a high school, or even junior high school, science class that the aether simply does not exist. And this is the science of the thing. You, however, insist that it does, and your best reply when challenged on the science is just above. You're in a science discussion, which you are determined to derail, and your account is just that you're "doing" no science at all, but metaphysical speculation. Like insisting on playing baseball in the middle of a soccer game. Which ultimately I find disgusting.

But we'll give you an opportunity for a last word, if you will answer three questions. Up above I suggested you might tell us exactly what a cause is, which you ignored. So that's question one: in terms of modern, up-to-date science, what exactly is a cause?

Two, you appear to be willing to interject and interpose metaphysics into a science discussion. What exactly is metaphysics? Most of us have at least a pretty good idea what science is; educate us on metaphysics.

The concept of the aether has long since been discredited and discarded. Do you believe in it? Yes or no. Please note I do not ask for any defense of your view - unless you have some hard scientific evidence!

The concept of the aether has long since been discredited and discarded — tim wood

The classical notion, yes, but perhaps not quite that simple. From Wikipedia:

Physicist Robert B. Laughlin wrote:

It is ironic that Einstein's most creative work, the general theory of relativity, should boil down to conceptualizing space as a medium when his original premise [in special relativity] was that no such medium existed [..] The word 'ether' has extremely negative connotations in theoretical physics because of its past association with opposition to relativity. This is unfortunate because, stripped of these connotations, it rather nicely captures the way most physicists actually think about the vacuum. . . . Relativity actually says nothing about the existence or nonexistence of matter pervading the universe, only that any such matter must have relativistic symmetry. [..] It turns out that such matter exists. About the time relativity was becoming accepted, studies of radioactivity began showing that the empty vacuum of space had spectroscopic structure similar to that of ordinary quantum solids and fluids. Subsequent studies with large particle accelerators have now led us to understand that space is more like a piece of window glass than ideal Newtonian emptiness. It is filled with 'stuff' that is normally transparent but can be made visible by hitting it sufficiently hard to knock out a part. The modern concept of the vacuum of space, confirmed every day by experiment, is a relativistic ether. But we do not call it this because it is not accepted (taboo).