If the mass of light (of a photon) is 0, then... can it really be considered physical? cause only things that have mass are considered part of the physical universe, right? So... is light really "physical"?...:eek::bugeye:

Originally posted by TruthSeeker
cause only things that have mass are considered part of the physical universe, right?
Apparently not. Light has no mass, yet appears to be part of this universe.

- Warren

But it is still not physical...:bugeye: It is obviously a part of this universe, but it is not physical... or it is...?:bugeye:

Please define "physical" for me, Truthseeker.

A photon has no rest mass, but it has energy. The higher the frequency the more energy and vice versa.

In a sense it has mass which can be calculated using e = mc².

I suppose that if there were some way to make it stand still, it would not exist. Since a photon always travels at light speed, you cannot even slow it down (in a vacuum), so stopping is probably not a possibility. Note that it can be slowed when traveling in some medium other than a vacuum.

BTW: The above is sloppy. I am mixing the wave and particle views of light. Photon as particle has energy. Light as wave has frequency, wave length, and amplitude. Amplitude is related to number of photons in a beam of light.

I am not an expert, so check with a guru before you bet large sums of money on the above. I would bet small sums on the above if you gave me odds.

didnt the schrodinger's cat experiment state that light is a physical object and its wave funtion collapses and becomes a particle only when observed or measured.

thus it is a theory (or wave) until you measure it (look at it to prove it is there, or some other way of observing it) then it becomes particle. oddly enough the information is only relevent to the observer.

instead of looking in a box to see if the cat is really ok in there. you can do the same to look at the light to see if is really is there.
yet what if you close the cat box? is the cat still in there?
better open it up and take a peek.

Please.

Can you see your computer monitor,

Do you nearly crash your car trying to grab a look of a hot chick.

Light is definately physical, it interacts with matter.

OPEN YOU EYES......HEHEHEHEHEHE:)

No, light has spiritual existence instead.

light is musical also. i read somewhere about light music.

Truth Hurts: The Schroedinger’s Cat experiment is a thought experiment intended to raise questions about the Copenhagen interpretation of Quantum Theory. It was not a real experiment.didnt the schrodinger's cat experiment state that light is a physical object and its wave funtion collapses and becomes a particle only when observed or measured.

thus it is a theory (or wave) until you measure it (look at it to prove it is there, or some other way of observing it) then it becomes particle. oddly enough the information is only relevent to the observer. instead of looking in a box to see if the cat is really ok in there. you can do the same to look at the light to see if is really is there. yet what if you close the cat box? is the cat still in there?
better open it up and take a peek.The cat experiment did not say anything about light or the wave/particle duality problem. Furthermore, so called “wave function collapse” does not occur only when a particle property is measured. It also occurs when a wave property is measured. The wave/particle duality problem relates to the chimerical nature of light (and other Quantum entities), sometimes acting as a wave and sometimes acting like a particle. Worse yet is the fact that the two-hole experiment works when individual photons are sent through the apparatus. A single photon can interfere with it self and act like a wave going through both holes at the same time.

I would like to have a description of what is meant by Collapse of the Wave Function. It seems to be Jargon for a Limbo state becoming a known state, but I wonder if more is implied by the phrase. In the context of wave particle duality, it means that the entity has displayed either a wave or a particle property.

I personally think the Wave Function Collapse view of Quantum Theory over emphasizes the role of an intelligent observer. There are some experts in the field who agree with me, and I am sure some who accept the view. I think this might be a part of the Copenhagen Interpretation or might be jargon for that view. The Copenhagen Interpretation essentially states that quantum entities have no properties until they are measured, and that it is illegal, immoral, unethical, and fattening to base any line of thought on the existence of such properties before they are measured.

There are several other interpretations. An actual state occurs when a quantum process affects the classical world. This seems to be a rewording of the Wave Function Collapse view. I like this view. The intelligent observer is not necessary. The cat can be dead before anybody looks in the box, and the Schrodinger thought experiment is merely a statement about a lack of knowledge about the cat. The hidden variables view, which essentially claims that if we knew more about quantum processes, we would understand what goes on in the quantum world and it would not be so damn weird. Von Neumann published a proof that there could be no “hidden variables,” and Bell (or somebody) claimed that his proof was nonsense, believed only due to faith in the author. Whether the proof is valid or not, there just do not seem to be any hidden variables. At least there seems to be no way to escape the probabilistic nature of quantum processes and what seems to be a breakdown of causality. Hidden variables or not, quantum entities seem to have neither continuous paths nor continuous properties. Energy and other properties seem to be quantized. No matter what we learn, the Quantum world will always seem capricious and weird. The Everett/Wheeler Many Worlds view, which assumes that extra universes are created for each possible outcome of a quantum process. In this view, there is one universe with a live cat and one with a dead cat. This view seems crazy. I wonder if the believers in this view ever heard of Occam’s razor, conservation of matter/energy laws, or just plain common sense. Some laws of logic are not applicable to Quantum processes. Without logic to tell us that the Quantum World acts strangely, what is the problem? I do not like to give up basic laws of logic in any context, so I do not like this view. I do not remember any of several other views I have encountered in various books and articles.It is not a view or interpretation, but I like the following.Quantum entities, like photons, travel as waves, but depart and arrive as particles.

as i understand it, this is not what everett s interpretation says at all, although it seems that most people interpret it that way. people who know everett s work eschew the term "many worlds" entirely.

Quote from Dinosaur******In this view, there is one universe with a live cat and one with a dead cat. This view seems crazy.

To entertain a crazy idea for discussion I submit the following:

If I remeber the thought experiment correctly, if I do open the box, the cat has a 50% chance of living. (due to the box being booby trapped)

If I open the box and the cat dies, then I have removed any chances for the cat to live. conversly if I remove any chances of the cat dying, wouldn't any way I open the box make the cat live?
(aside from calling in the bomb squad to de-booby trap the box, I guess I'm asking if there is a way to shift the odds in the cats favor, or to find a way to completly remove one of only two possible outcomes.)

(if i had 50 cats in 50 boxes I guess i could save half by simply opening them)

What do I believe?

You believe you are right.;)

The Schrodinger cat thought experiment was the following.A cat is put into an opaque box with an apparatus. The apparatus can detect a quantum event with a 50% probability of occurring some finite time after the cat is put into the box. For instance a radioactive decay event with a 50% chance of happening in one minute.

If the event occurs, poison gas is released, killing the cat and the apparatus is shut down. If the event does not occur, the apparatus is shut down without releasing the poison.The argument is that if the quantum event is in a limbo state until a measurement is made, then the cat is also in a limbo state until a measurement (such as looking in the box) is made.

Schrodinger intended the thought experiment to debunk Quantum theory because he claimed that a cat is not a quantum entity and must be either dead or alive. If the cat must be dead or alive, the quantum entity cannot be in a limbo state even though no measurement was made.

Schrodinger did not like or believe in Quantum Theory. He developed his wave equations in an attempt to provide a classical set of equations underlying quantum theory. When the equations turned out to merely provide probabilities, he was disappointed. He once said something like the following.If I knew how it was going to turn out, I would have been a plumber instead of a physicist.

Originally posted by Dinosaur

Schrodinger intended the thought experiment to debunk Quantum theory
......
Schrodinger did not like or believe in Quantum Theory.
let s be precise here: it is not quantum theory he wanted to debunk, but rather the copenhagen interpretation.

Lethe: You are correct. Schrodinger was trying to develop classical equations for Quantum Theory and explain away some of the weirdness. He was not trying to debunk the entire theory.

Can I go back to the first theme. James R asked Truthseeker the key question (in regard to whether light is physical or not), which was how we should define the term 'physical'. I was kinda interested in the answer, since it would settle the question of whether light is physical. Interestingly neither my science or philosophy disctionary has an entry. Any one want to attempt it?

Originally posted by Canute
Can I go back to the first theme. James R asked Truthseeker the key question (in regard to whether light is physical or not), which was how we should define the term 'physical'. I was kinda interested in the answer, since it would settle the question of whether light is physical. Interestingly neither my science or philosophy disctionary has an entry. Any one want to attempt it?

i think the only person who can tell us what in the world truthseeker meant when he said "physical" is truthseeker himself. on the whole, i can t even imagine what that is supposed to mean.

James R,

"Physical" means "made of matter"...:bugeye::p:eek:

Originally posted by TruthSeeker
James R,

"Physical" means "made of matter"...:bugeye::p:eek:

usually the word matter means baryonic matter. in which case, no, light is not matter.

so, using your definition, light is not physical.

most people will not recognize this usage of the word physical however, so be careful.

Is there a generally accepted definition?

Originally posted by lethe
usually the word matter means baryonic matter. in which case, no, light is not matter.

so, using your definition, light is not physical.

most people will not recognize this usage of the word physical however, so be careful.

I'd disagree with you, for example no-one would say that electrons aren't part of normal matter, also 'dark matter' for the most part is defintely non-baryonic. There is a definite link between the terms 'matter' and 'mass' (e.g. conservation of matter is conservation of mass).

Physical is such a vague termand I would usually take it to mean "relating to physics".

Yeah, physics deals with the physical world. That would qualify everything as physical, including matter, light, space and time.

Word.

By this view physics deals with what physics decides to deal with, and so detirmines what is physical and what is not.

I know that there are always problems reaching very precise definitions of terms but this seems a bit of an extreme case. I can't believe that consciousness is deemed to be non-physical only because studying it is not physics.

this thread is now debating semantics. maybe we should take this over to the semantics forum, eh? oh wait, we don t have one of those.

It is certainly true that defining the word 'physical' is a matter of semantics. But what's your point? Are you suggesting that it is not also a matter of physics, or that it doesn't matter how it is defined? It's damn confusing to a layman to be told that what is or is not included in the domain of physics is a just matter of semantics.

Originally posted by Canute
It is certainly true that defining the word 'physical' is a matter of semantics.

yep

But what's your point?

my point is that it s boring. what difference does it make what we call physical? what we call things is not important, it s how the models describe things that is interesting.

Are you suggesting that it is not also a matter of physics, or that it doesn't matter how it is defined?
absolutely not.

It's damn confusing to a layman to be told that what is or is not included in the domain of physics is a just matter of semantics.
i never said that. make no mistake, physics has a model that describes light. that model says that photons have no rest mass, which is a source of constant confusion to the layman, leading to questions like "is light physical?" but it should be obvious that physics has a model to describe light, confusing though it might be.

Not that it matters much - no pun intended. Since light always travels at v = c and is never at rest, the issue of "rest mass" is a non-starter. Light is light moving at c and at c I tend to view it as physical since it has momentum.

Originally posted by MacM
Not that it matters much - no pun intended. Since light always travels at v = c and is never at rest, the issue of "rest mass" is a non-starter. LIght is light moving at c and at c I tend to view it as physical since it has momentum.

this is exactly correct. saying light has zero rest mass doesn t mean much, since light can never be at rest. it s just a parameter.

Originally posted by lethe
yep my point is that it s boring. what difference does it make what we call physical? what we call things is not important, its how the models describe things that is interesting.
It matters a lot when in some other contexts here it is argued that non-physical things do not exist. People tend to use the word as if it means something. Many people argue that freewill cannot exist because something non-physical cannot act on the physical - what do they mean by that?

[i never said that. make no mistake, physics has a model that describes light. that model says that photons have no rest mass, which is a source of constant confusion to the layman, leading to questions like "is light physical?" but it should be obvious that physics has a model to describe light, confusing though it might be. [/B]
Asking how light is physical is more or less equivalent to asking how 'physical' should be defined. I completely accept your comments on light, but I'm surprised (rather than confused) to learn that calling something physical means no more than that physics has a model that describes it. Presumably new things are becoming physical all the time as science develops its models.

It's just that 'physical', unlike so many other words doesn't have a precise meaning within the context of physics. If you look in a physics or a scientific dictionary you would probably find the entry 'physical chemistry', but you wouldn't find an entry for 'physical'.

icsd,

Webster:

Physical:

1 - of nature and all matter;natural; material.

2 - of natural science or natural philosophy.

3 - of or according to the laws of nature.

4 - of or produced by the force of physics.

5 a - of the body as opposed to the mind

b - preoccupied with bodily or sexual pleasure; carnal.

c - of or marked by aggressive or rough play, activity, etc.

general - medical examination.

Well of course I didn't mean a normal dictionary, if your normal dictionary doesn't contain an entry for "physical" then I'd advise you to get a new one.

What I said was a scientific or physics dictionary.

According to webster, light is then definately physical as it falls under definitions 1,2,3,4 & 5

1/Light is definately part of nature which also means it fulfils defintion 2

3/It follows the laws of nature i.e. nature seems to obey maxwells laws, so does light

4/Can be produced by accelerating charges (such as bremssrahlung) among other things

5/It definately exists without mind. Rocks get hot in the desert.

I wouldn't argue that light is not physical. But I don't quite agree with this proof.

1. Concepts are part of nature but are not physical (although some would argue their causes are).
2. OK because a tautology.
3. By definition everything follows the laws of nature, if anything doesn't then the laws are not laws.
4. OK. Although we can't yet be sure whether the 'forces of physics' are caused by the forces of physics.
5. An idealist would argue that it is all mind. A panpsychist would argue that the rock and the desert were in some sense conscious. Both views are widespread amongst philosophers and scientists (as well as other folk).

Not really arguing - just saying that nothing is ever simple.

I don't think light is physical, you can't hold light.

I don't think light is physical, you can't hold light.
I agree.

If that is your definition of physical, then conciousness is not real as you cannot hold it in your hand. But then hey this is philosophy not physics right.

Originally posted by ryans
If that is your definition of physical, then conciousness is not real as you cannot hold it in your hand. But then hey this is philosophy not physics right.

yes, ryans is right, this has nothing to do with physics. take your semantic debates to the free thoughts forum.

Ryans is not right. And it was not suggested by fahq that light was not real, it was said (incorectly IMO) that it was not physical. As we have no definition for 'physical' this is a meaningless assertion.

It is not possible to practice science without simultaneously practicing philosphy, although of course it is possible to pretend that you're not doing it.

I won't keep flogging a dead horse but it's disturbing that this topic is not considered to be of any scientific interest. It's a discussion of what science is about. No matter - as you say it can be discussed in some other artificial compartment of thinking under some other arbitrary label.

Originally posted by Canute
Ryans is not right. And it was not suggested by fahq that light was not real, it was said (incorectly IMO) that it was not physical. As we have no definition for 'physical' this is a meaningless assertion.

It is not possible to practice science without simultaneously practicing philosphy, although of course it is possible to pretend that you're not doing it.

I won't keep flogging a dead horse but it's disturbing that this topic is not considered to be of any scientific interest. It's a discussion of what science is about. No matter - as you say it can be discussed in some other artificial compartment of thinking under some other arbitrary label.

you re missing the point. no one is claiming that we are unwilling to talk about what is and what is not physics. of course we are willing to do this. there was a time when physics was unable to answer questions like: how did the universe start?

now physics answers these questions very well. what is in the domain of physics is something we are willing to discuss.

what is simply not interesting is the question: "what does truthseeker mean when he says physical?" "is light physical?" it s a meaningless question, insofar as light is obviously something that physics talks about, and who cares what you call it?

Light is physical. You can see it. You can, in some cases, feel it too. If it can be seen and felt, it must be physical, right?

I would say that any phenomena studied in physics are undoubtedly physical, under the broadest definition of the word.

This is a semantic debate. And one that doesn't particularly advance the science of physics very much, nor one that advances one's understanding of physics. I can't say that it relates much to the philosophy of science, either. More of a general-philosophical question. I'd say it belonged in the philisophy forum, they might like this kind of stuff over there.

Is light tangible? A semantic question again.

And it was not suggested by fahq that light was not real, it was said (incorectly IMO) that it was not physical. As we have no definition for 'physical' this is a meaningless assertion.

I'd agree that Fahq's assertion was both incorrect and meaningless. However, we undoubtedly have many definitions of physical (although none of which, as far as I know, stipulate being able to hold whatever it is that you describe as physical).

...it's disturbing that this topic is not considered to be of any scientific interest.

I would say it is of very limited scientific interest beyond pointing out to people that this kind of debate is of very limited scientific interest.

There is considerable overlap between science and philosophy, but I can't see that this particular brand of semantic debate is of much interest to physicists, at least within the scope of this forum.

This might be characterised as an epistemological debate. It's kind of like the question of "if a tree falls in a forest with no-one around to hear it, does it make a sound?" It's an issue of semantics over what you consider sound to be. Whether a human's perception of acoustical shockwaves in the air, or merely the shockwaves themselves.

If we do not know what is physical we do not know what is physics. Of course we can define them in terms of each other - which is what I'm told here that we do at present - and perhaps there is little else that can we do.

But we can't then go about pretending we have defined it. That leads us into defining physics according to our hidden assumptions. Assumptions are fine - but they shouldn't be hidden.

Most people, scientists included, think some things are physical and some not. When they say this they mean something. One would imagine that a common understanding of this meaning would aid communication a bit, and that clear communication, based on the meaning of words as derived from semantics and philosophy, is important to the practice of physics.

Please don't imagine I'm trying to prove anything about what is physical or what is not. I have no opinion on it. In fact I have no working definition for the term 'physical', a problem for which I had hoped that some expert might provide an answer. I hadn't realised that it hadn't yet been decided.

In view of which I'll drop it.

A photon has no rest mass, but it has energy. The higher the frequency the more energy and vice versa.

In a sense it has mass which can be calculated using e = mc2.

I suppose that if there were some way to make it stand still, it would not exist. Since a photon always travels at light speed, you cannot even slow it down (in a vacuum), so stopping is probably not a possibility. Note that it can be slowed when traveling in some medium other than a vacuum.
I don't think this is sloppy, looks likes the simple answer to me.
Photons will push a solar sail (physical matter? Energy transfer?), photon ceases to exist if you stop it for a look (not physical matter). It would seem a photon only has one state, so it depends on how you look at it? Relativity?

canute,

can you tell something which is not physical but could be measured..?

can you tell something which is not physical but could be measured..?

Measured, No, infered, Yes.

Take for example entropy. We cannot measure entropy directly, only by first measuring energy and frequency of occurence. However systems will always evolve to a state of higher entropy, ALWAYS.

I suppose in quantum mechanics you could replace observable with physical observable. Any operator of some "observable" which has non-real eigenvalues, is not physically observable.

Originally posted by everneo
canute,can you tell something which is not physical but could be measured..?
Afraid not. As I say I don't have a definition.

Are you suggesting that 'physical' means measurable? That seems to make some sense. The trouble is the measurement is not the thing itself.

I suppose I could say that the feeling of anger is measurable, and the feeling of anger is not generally considered to be physical. But I think you meant scientifically measurable, which a feeling of anger is not, in which case I don't know how to decide.

Originally posted by ryans
Take for example entropy. We cannot measure entropy directly, only by first measuring energy and frequency of occurence. However systems will always evolve to a state of higher entropy, ALWAYS.

If the universe (cosmos, multiverse, whatever) is a closed system does this remain true?

This is what happens when musicians read Hawking.

Oooooh, look at that ad hominem argument...

- Warren

Do we really need a definition for the word physical?

If ten of the people posting here made a list of 5-20 items he/she considered physical, I would be surprised if there was much disagreement about the items listed. Most of the objections (if any) would relate to items not on some list.

Agreement about the formal definition of some word is not necessary, and is often a problem. If there is agreement about lists of items conforming to the notion implied by a word, that is sufficient for meaningful discussion.

BTW: For many complex concepts, dictionary definitions are often not usable. A dictionary assumes certain knowledge on the part of the reader and defines words in terms of other words.

While nitpicking is always possible, a definition for the word physical cannot be that difficult.

For a start, all the particles that physicists deal with can be referred to as physical, and any object composed of such particles should be considered physical.

Next, any process which can have some effect on a particle or an object composed of particles can be referred to as a physical process. Processes involving particles and objects should be included.

Perhaps somebody can add something else to the above, but it includes include most (?all) of what I consider physical.

There are some concepts which are likely to cause disagreement with any definition of physical, but this is not a problem if the context being discussed does not include the problem concepts. The following are examples of problems concepts.

I can talk about my knowledge increasing. This concept relates to physical objects and physical processes in my brain, but is knowledge physical? Perhaps there are those who would consider knowledge physical, and others who would not.

Thoughts do not seem to be physical, although they seem to be due to physical processes in my brain. Objects which I imagine are not physical, although some of them correspond to physical objects.

Entropy seems to be a problem concept here. It relates to the unavailability of energy for purposes of doing work. It also relates to the probability of certain configurations of physical objects. Some statements using the term entropy do not seem difficult to understand, and the concept belongs to the discipline we call physics. I am not sure if entropy can be called something physical.

Originally posted by chroot
This is what happens when musicians read Hawking. Oooooh, look at that ad hominem argument...
- Warren
I asked a question. I thought that was safe enough.

If you were referring to my previous general point you might like to consider whether you actually grasped it. However I accept that it may have had philosophical rather than scientific implications, Heaven forbid. I'm afraid I find it difficult to draw lines between different bits of knowledge - they tend not to join up properly if I try.

And please don't bloody patronise me. If I'm saying something incorrect take the trouble to explain what it is.

I believe the best definition of physical would be "anything that interacts with at least one other thing in the universe, which itself interacts with at least one other thing"

While this is partly circular, it is also raises the important point that if something is "non-interacting" then there is no way in hell any measurement apparatus could ever pick it up. Even if we have only "indirect" effects, effects proceed from a cause, and a cause can only exist if there is interaction of some kind; thus, anything that "interacts" is considered "physical"


... to make my point clear... yeah, i'm quite sure light is a "physical" thing in this sense. :m:

ryans,

If that is your definition of physical, then conciousness is not real as you cannot hold it in your hand. But then hey this is philosophy not physics right.
Can you hold an atom in your hand?:bugeye:
And why you say "real"? "Real" and "physical" are two different things...:bugeye:

Just to get the pot boiling...

What is REAL???? :m: :eek:

GundamWing,

hehe
Just to get the pot boiling...

What is REAL????


ANS: Apparently whatever we think is at any given moment.

lethe,

Re."there was a time when physics was unable to answer questions
like: how did the universe start?"

Have I been doing a Rip Van Winkle?

:m: :cool: :m:

Lets compare light to sound shall we?
Sound does not exist in a physical form, it exists in the form of a disturbance in the molecules of a given substance, however it is still real, you and i hear it all the time.
Both sound and light travel in waves, which leads me to believing that the above is also true for light.:cool:

Both sound and light travel in waves, which leads me to believing that the above is also true for light.
Oh and I muist add that light travels in some form of a really tiny substance ether or whatever its called.

Aether?? I think you need to update your physics books:)

Light is waves in electromagnetic fields and doesn't travel through any medium.

jcsd,

Light is waves in electromagnetic fields and doesn't travel through any medium.

I disagree. If you assume that light uses gravitational fields as its medium, then the near-null results of the various aether-detection experiments that have been done over the years can be explained without having to use length contraction or time dilation.

Tom

Well I can't comment on results I haven't seen, but it's hardly physics orthodoxy.




I should rephrase that first sentence of my last post as it seems contradictory:

Light is oscillations in electromagnetic fields that do not propgate through any physical medium.

Actually, I think the aether theory is being considered again. I remember I read in a scientific magazine. I think it is being considered again to explain quantum gravity...

From what I have read, light acts like waves or particles depending on the type of experiment you perform.

There is a good possibility that it is neither a wave nor a particle phenomenon. There is an interesting story about Neils Bohr. He had a conversation something like the following.Dr. Bohr, I know that light sometimes acts like a wave and sometimes like a particle, but what is really there?

There is an interesting optical illusion, which can look like a black vase or two white profiles facing each other. Analogous to the wave particle duality, you can focus your attention on either the vase or the profiles. You can never see both at the same time.

If somebody asked me what was really there, the vase or the profiles, I would say that neither is really there. What is really there is black ink on white paper.

I can tell you that light is neither a wave nor a particle. Unfortunately, I cannot tell you what it really is. I can only tell you the results of certain experiments.The above gave me a better understanding of the wave/particle duality problem than anything else I ever read.

When light is viewed as waves, there is a need for a medium and calling it the aether is as good a name as any. However, there may be no need for a medium, making discussion of the aether pointless.

Light waves do not need a medium to travel through, the idea of the aether was abandoned about 100 years ago (though as mentioned by TruthSeeker it has been mentioned as a possibilty to solve other problems).

It isn't just light that is subject to wave-particle duality, all particles are subject to this and the wave nature of electrons and even neutrons has been shown.

Originally posted by jcsd
Light waves do not need a medium to travel through, the idea of the aether was abandoned about 100 years ago (though as mentioned by TruthSeeker it has been mentioned as a possibilty to solve other problems).

It isn't just light that is subject to wave-particle duality, all particles are subject to this and the wave nature of electrons and even neutrons has been shown.

good, jcsd. this is correct. i want to say though, despite what truthseeker says, noone is considering aether for quantum gravity. it is nothing more than an historical nicety

I'm sure heard it proposed again to solve problems in physics but of course using it creates more problems that it solves.