Thursday, December 17, 2009

What is Natural?

Our recent discussion on my post The Nature of Laws brought up a new topic that deserves a post on its own: What is Natural? I have frequently found physicists arguing something to be natural or unnatural. I usually stay clear of this for reasons that I hope to get across in the following.

First, arguably everything we observe in Nature is "natural." Thus, calling anything that we observe - may that be the Yukawa couplings or homosexuality - "unnatural" is an oxymoron. Likewise, calling something we do observe "natural" is as meaningless as calling apples "biologic."

But I'm not a linguist. Thus, leaving aside the question whether "natural" is a good nomenclature, what physicists refer to as unnatural are dimensionless parameters much smaller or larger than one. The qualifier "dimensionless" is essential since it is meaningless to talk about the value of dimensionful constants: In the right unit system they are always equal to one. (The Earth weighs exactly one Earthmass. Clearly an indication for intelligent design.) If you don't have dimensionless constants, you take ratios.

For example General Relativity. You have two parameters there. The one is the Planck mass, the other one is the cosmological constant. Take the fourth power of the Planck mass and divide it by the measured value of the cosmological constant, the ratio is 10120. That's what is commonly called unnatural. (The ratio of the cosmological constant to the present matter density on the other hand is about one. Since the density however is time-dependent, this then causes what is known as the "coincidence problem:" why are they about equal "right now." See, it's hard to satisfy a physicist.)

This notion of naturalness goes back to Paul Dirac. Sometimes used is also a refinement of naturalness offered by 't Hooft ("Naturalness, Chiral Symmetry and Spontaneous Chiral Symmetry Breaking") which takes into account that perfect symmetries too are unnatural and thus small parameters are okay if they arise from small violations of these symmetries. In his article, 't Hooft had the following to say about the cosmological constant: "Quantum Gravity is not understood anyhow so we exclude it from our naturalness requirements."

If you follow this line of thought it naturally brings you to the fine-tuning and hierarchy problems in the standard model.

Now let me tell you why I stay clear of these arguments. It doesn't matter how you turn it, in the end our notion of naturalness is based on what evolution has taught us is natural. The bears your ancestors hunted down did not differ in size more than some orders of magnitude, if you go into a forest you're unlikely to find a tree 1017 meters high, and so on. We are used to things being somehow average. In addition, our brains are constructed to look for simple, all-encompassing explanations which we find "beautiful." That's why books like "Men are from Mars, Women are from Venus" are bestsellers, that's why we look for patterns in the masses of the standard model, and that's why there are so many string theorists. (And isn't that a beautifully simple world-view?)

The naturalness arguments are eventually based on the idea that whatever a fundamental theory looks like, it does conform to this ideal: There's one or only a few parameters. They are neither fine-tuned nor appear in unreasonably large ratios. We, the stuff we are made of, and our universe, is somehow "natural," "average" or "mediocre." However, if you continue to ask "why" at this point you'll notice how the scientific basis crumbles away under your feet. Why should this be? Because very small parameters make you feel uneasy? Because you don't find many parameters a satisfactory explanation? Because it's not pretty? Because it smells like intelligent design?

It's not that I don't share the perception that a theory that unifies all the particle interactions with only a few parameters of order one and a few dimensionful ones would be "beautiful" and seems "natural." After all, my ancestors too did hunt bears. Neither do I discard the value of such considerations. They are useful guides, they show us the limitations of our current theories and point us into a direction. I however also think one should not elevate naturalness to a sacred principle. Maybe Nature is just "unnatural." Maybe the parameters in the standard model come about in a process much more complex anybody has imagined so far. Maybe they are just coincidence. Maybe Tegmark is right and we live in a level 5 multiverse or swhatever.

Bottomline: The universe just doesn't care whether you like it.

158 comments:

Arun said...

Nice essay, Bee!

Though it would be nice to have in the pocket some physics computation that yields very large or very small parameters starting from "natural" ones; just to know it is possible.

Bee said...

No problem, just put in an exponential function somewhere. A great example is the split fermion scenario: Hierarchies without Symmetries from Extra Dimensions. (Most people I've asked don't find it very "beautiful.") Best,

B.

Giotis said...

It's quite simple I think. Natural is anything that can happen. So if you want to characterize something as unnatural you must prove that it can't happen. Similarly if you want to characterize something as natural you must prove that it can happen.

It's Natural don't you think?

Bee said...

I'm afraid according to this definition nothing is ever natural or unnatural, since any such "proof" would rely on a theory that cannot be verified. But even without that, just consider that quantum mechanics tells you it's not that things happen or don't happen, it's just unlikely that something happens. That brings you full turn back to the question of how small a parameter (what probability) is acceptable. Best,

B.

Zephir said...

/*.. General Relativity. You have two parameters there. The one is the Planck mass, the other one is the cosmological constant...*/
From where we got gravity constant in Einstein's field equations, for example? How general relativity "knows" about Plack constant of quantum mechanics?

Bee said...

GR doesn't "know" about Planck's constant. The coupling constant of GR is the inverse of the square of the Planck Mass if you use a unit system in which hbar=c=1. See also The Planck Scale.

Zephir said...

So we have cosmological constant and speed of light as a constants, here.

But I still don't know, how these parameters are related to general relativity postulates. And what about gravity constant above mentioned?

Bee said...

I don't know what you mean with "gravity constant." I suspect you mean the coupling constant of GR which, as I said above, is the inverse of the square of the Planck mass in the commonly chosen units with hbar=c=1. The scales that you then have are the Cosmological Constant and the Planck mass, as I wrote in the post. Best,

B.

T. said...

Thx Bee, nice post.

"The universe just doesn't care whether you like it."

I think this is irrelevant. What is relevant is that our ancesters cared very much about what a natural theory of the bear would look like. So that over hords of generations, we have painfully evolved an efficient expectation of what is natural at our scale. So indeed it makes sense to use this (very efficient and well-deserved) expectation in order to theorize human-scale aspects of the universe.

But to extend this expectation of what is natural as a guideline for a TOE or a GUT is, of course, unfortunate to say the least.

Bee said...

Forgot: the constants do of course not follow from the axioms, they are measured data. Best,

B.

Bee said...

T: "I think this is irrelevant."

That was exactly my point...

Zephir said...

/**I don't know what you mean with "gravity constant...*/
I mean upper "G" in this strange formula..

Bee said...

G, commonly called the "graviational constant" or the "coupling constant of gravity" is the inverse of the square of the Planck mass in the commonly chosen units in which hbar=c=1. Best,

B.

Zephir said...

/*..the constants do of course not follow from the axioms, they are measured data..*/
If they cannot be computed from theory, then these constants (and their definition equations) are becoming postulates as well. Without them you cannot predict anything testable, so that theory isn't falsifiable, which means, it's not theory at all in scientific sense.

Bee said...

The value of the constants can change with improved measurements, so it's very misleading to call them postulates. Best,

B.

Zephir said...

/*..G is the inverse of the square of the Planck mass in the commonly chosen units in which hbar=c=1...*/
Nope, G is gravitational constant, c is the speed of light and pi is another constant, too.

Without these constants you cannot compute anything, so your theory isn't theory, etc..

But my question was, from where we got G in Einstein's equations?

Bee said...

Zephir, if you read my post you will find that I said arguing about the value of dimensionful constants is meaningless. Further, I already told you where the gravitational constant (and the cosmological constant) comes from: it's measured data. Best,

B.

Bee said...

Oh, yeah, and if you want to argue about the value of \pi, which is indeed dimensionless, please do so elsewhere.

Zephir said...

If I compute well, so far we have

1) pi constant
2) cosmological constant
3) speed of light
4) gravitational constant

for to have relativity theory testable... We can express G by using of hbar, but it doesn't decrease number of constants in any way...

Zephir said...

Gravity constant originates from Newton law, as you probably realized (Einstein didn't invented it, of course). Do you know, general relativity depends on Newton theory?

Bee said...

Zephir: As I wrote in the post, it is meaningless to argue about the value of dimensionful constants. The speed of light is 1. Why is it one? Because I've given it in units of the speed of light. The units commonly chosen to lead naturalness arguments are the ones with hbar=c=1, also known as Planck units.

Yes, one determines the coupling constant of GR most easily in the Newtonian limit. That doesn't mean GR "depends" on Newton's theory, but that it reduces to Newton's theory in what is called, guess what, "the Newtonian limit." Best,

B.

Peter Morgan said...

I agree (with what I think you're saying), but phenomenological models, which there is a tendency for us to gravitate to if we don't admit aesthetic or naturalness criteria, are not very explanatory. Of course "explanatory" is almost a synonym for "natural". However, there is a significant role for phenomenological rules like the Balmer series, Wien's law, and the Rayleigh-Jeans law, which enable successive abstractions to be introduced over decades or centuries, instead of trying to leap to a fully-fledged theory.

I also think the real decider over time is not necessarily beauty so much as tractability and engineering applicability, which needs a theory to be capable of being brought down to lesser mathematical abstraction (or even that grandparents can feel comfortable with it). For an engineer to be able to apply a theory routinely needs there to be a connection between a theory and the real world that can be reduced to a matter of intuition. The failure of many theories is that one can't see how to use them.

Of course a theory is typically counter-intuitive until we are immersed in it, but simplifying the process of making the counter-intuitive become intuitive is the intellectual challenge of educational exposition.

Looking back at my reaction to your post, it looks a little orthogonal to your point about the naturalness of dimensionless parameters. Making a second attempt, following on from your response to the first comment, if we can introduce a new theory in which logarithms and exponentials (or I would think Bessel or other special functions more likely) appear as a relatively immediate consequence of the mathematics, in which "natural" dimensionless constants result in "small" or "large" dimensionless constants in another theory, that would probably be thought interesting, curious, and that it would be good to keep in mind those mathematical methods when trying to construct other theories.

Zephir said...

If it depends, it cannot violate it - this is "natural"...

Zephir said...

/*..it reduces to Newton's theory in what is called, guess what, "the Newtonian limit...*/
Does it mean, GR can predict another value of gravitational constant, then the Newton theory does?

If not, what limit are you talking about?

T. said...

"that was exactly my point.."
I don't think so. I meant that your final statement was irrelevant. I don't see that you distinguished between scales in your post and I think this is essential. At one scale naturalness can and should be exploited. At another it should not. In neither case is the true statement "the universe doesn't care whether you like it" really relevant for the matter.

Bee said...

T: Yes, the final statement was irrelevant. Yes, that was the point of the statement. Or call it a joke if you prefer. Yes, as I said in my post, it is natural to expect naturalness on some scales, because that's where our ideal of what is "natural" stems from. It is not clear why we should expect such naturalness on other levels too, I agree with you. Best,

B.

Zephir said...

Could we talk about "naturalness" as about "following logics"?

Zephir said...

For example, while we know, every elastic matter spreads energy in waves and the light wave is a kind of energy - isn't it "natural" to consider vacuum as a material stuff as well?

Bee said...

Zephir: General Relativity without a CC has one free parameter that is the coupling constant. You can go and measure it. You do so most easily by employing the "Newtonian limit" which is for small curvature and small velocities. In this limit, GR reduces to Newtonian gravity, thus both constants are the same. As I said above, the value of that dimensionful constant is a measurement, it is not "prediction." Best,

B.

T. said...

argh, sorry I failed to get the joke -to my defense I'm in programming mode right now!
best,
T.

Bee said...

Hi Peter,

It is an interesting point you are raising with saying that something can appear more natural the more time you spend thinking about it.

About the dimensionless numbers, that wasn't so much my point as more a brief explanation of what is usually meant with referrals to naturalness. Bringing in functions that cover many orders of magnitude then just brings up the question how natural are these functions etc. (I guess sooner or later we'll end up with Tegmark's mathematical universe again, I can just see it coming.) Best,

B.

Zephir said...

Sorry, I can still see four constants to maintain relativity testable. We can express G by using of c by incorporating hbar from quantum mechanics, but it doesn't decrease a number of parameters in theory - it just makes GR dependent of quantum mechanics, instead of Newton's theory.

My point is, no one of these theories is listed in general relativity postulates - so we have problem with general relativity definition. In addition, cosmological constant, pi constant and speed of light doesn't occur in general relativity postulates too.

No wonder, such theory remains inconsistent with huge portion of observable reality.

Bee said...

Zephir: GR, without a Cosmological Constant, has one free parameter, that's the coupling constant. You can go and measure it. What makes this theory predictive is that this one parameter (ideally) is sufficient to explain everything else too. That you can express G as the square of the inverse of the Planck mass in units in which hbar=c=1 doesn't mean you need to measure hbar to determine the gravitational constant. It's just a choice for a unit system. I recommend you read the Wikipedia article I linked to above. Best,

B.

Thomas said...

A couple of small comments: 1) Large numbers are
not in general unnatural (as Bee pointed out). The
ratio M_planck/m_proton is large, because it is
proportional to exp(8*pi^2/g^2). The ratio of the
condensation energy (``cosmological constant'')
of a superconductor to the fourth power of the
high energy scale (the Fermi energy) is tiny
because it is proportional to exp(-N/G^2), where
G is the electron-phonon coupling.

2) Naturalness is a requirement about coupling
constants in an effective theory. It is used
successfully by many people every day. The main
problem with gravity is that we do not whether
GR is an effective field theory.

3) The other problem is that naturalness can of
course fail. In most effective field theories we
can check for fine-tuning by perturbing in the UV.
The Hoyle state is fine-tuned (and therefore,
possibly, anthropically selected) if the energy
changes dramatically in response to a small change
in the up quark mass. For a ``theory of everything''
we don't know what stability might mean.

Zephir said...

/..I recommend you read the Wikipedia article I linked to above..*/
If you haven't all four constants above listed, you cannot predict nothing testable by using of general relativity. You can still travel from place to place and take lectures and have busy life - but after then you're mathematician, not physicist.

Note that math still doesn't count as a science in Popper's sense, because it cannot be falsified by experiment.

Zephir said...

Concerning pi constant, it's true, it's dimensionless constant, but this is just because it hides another constant - a number three, i.e. dimensionality of our space-time. So you cannot avoid it as well - because general relativity wouldn't work in geometry where degrees of freedom for energy spreading doesn't reflect right angles of Cartesian system.

Ervin Goldfain said...

Bee,

How about:

1) the fine-tuning problem of the Higgs mechanism?
2) the cosmological constant problem?
3) the gauge hierarchy problem?

Can these be considered examples of how "unnaturalness" arises in field theory?

And how about the emergence divergent propagators in perturbative calculations? Can one say that "unnaturalness" is closely related, in this context, to "unphysical"?

Regards,

Ervin

joel rice said...

OK which is more 'natural' - atoms as associations of building blocks, or atoms as the result of quantum field theory ? Most likely both views are correct.
One thing we can expect is that a fundamental theory better make algebraic sense - and would be straightforward if we understood what to assume.

Bee said...

Hi Ervin,

These are examples for fine-tuning and hierarchy problems that go back to the naturalness problem but also bring in more technical assumptions (which is why I didn't discuss it in the post). But yes, that's the reason why I said such problems are pointing out to us where our theories start failing and thus are useful guides. No, unnatural is not the same as unphysical. Something that is unphysical is also unnatural, but not necessarily the other way round. There is for example nothing "unphysical" about the value of the CC. Best,

B.

Bee said...

Hi Joel,

Applying the term "natural" to concepts instead of dimensionless parameters is imho of very doubtful value. Best,

B.

Bee said...

Zephir: I already said several time, with negligible success as it seems, that what makes the theory predictive is that you measure the parameters ONCE, and then you can use them to predict EVERY OTHER experiment (in principle). The parameters are not axioms of the theory because you don't postulate them, but measure them. Further, I hate to point it out, but the occurrence of pi has nothing per se to do with the number of space-time dimensions. The factor 4\pi does indeed have something to do with the number of dimensions, but the pi itself would make an appearance in any number of dimensions. You can however absorb them into the coupling constant. What DOES have something to do with the number of space-time dimensions is the dimension of the coupling constant. Best,

B.

Uncle Al said...

G, commonly called the "gravitational constant" or the "coupling constant of gravity" is the inverse of the square of the Planck mass in the commonly chosen units in which hbar=c=1.

Ah, Bee... Do you claim the ability to ab initio calculate G to a mere five honest decimal places? Of course not. The Planck mass and G cannot be separated (to date), though hbar is good to eight decimal places and c is exact.

GR is exact in all observations, yet it cannot be complete for Planck's constant is not zero. There is a deep error in a founding postulate acoss all gravitation theory. Euclid suffered the same fate with his Fifth Postulate.

Uncle Al volunteers a novel - the parity Eotvos experiment. Think outside the toroid. Theory predicts what experiment tells it to predict. Somebody should look.

Zephir said...

/*.. the parameters are not axioms of the theory because you don't postulate them, but measure them....*/
It doesn't matter, if you believe, speed of light is constant (because you measured so), or if you believe, speed of light is 10E8 m/s (because you measured so).

Axiom: assumption of theory, accepted without logical proof.. Can you compute gravitational constant by using of another constant of your theory?

If you cannot compute it, you're forced to assume its value on background of observation - and after then the equation G = 9.81 kg/s2 becomes another postulate of your theory.

It's evident, you even don't know, formal theory doesn't recognize something like parameters: it distingushes only theorems and axioms.

I can understand your stance quite well, because it enables you to pretend, your theory requires less assumption and it appears more predicative, then it really is, which in turn enables you to ask for more grants or money.

So your stance is logical, but still transparent. Are mainstream theorists frauds? Let readers decide.

Plato said...

Without measure there are things that we do not see, yet exist.

The parameters of phenomenological order when taken down too, "specify the areas" with which you are not familiar. You never really understood that this existed until you became aware of a given space with which you'd never considered.

So is this is unnatural or just that one was never really observant before?

Best,

Plato said...

Supernova Starting Gun: Neutrinos

.....Next they independently estimated how the hypothetical neutrinos would be picked up in a detector as massive as Super-Kamiokande in Japan, which contains 50,000 tons of water. The detector would only see a small fraction of the neutrinos. So the team outlined a method for matching the observed neutrinos to the supernova's expected luminosity curve to figure out the moment in time--to within about 10 milliseconds--when the sputtering star would have begun emitting neutrinos. In their supernova model, the bounce, the time of the first gravitational waves, occurs about 5 milliseconds before neutrino emission. So looking back at their data, gravitational wave hunters should focus on that point in time.

Arun said...

Bee, that example of the split fermion, while not beautiful, is nice in the sense that coupling constants are generated from the exponential tails of wave-functions (so the exponentials are not exactly put in by hand). Or do I misunderstand?

-Arun

Ervin Goldfain said...

Bee,

You state:

" Something that is unphysical is also unnatural, but not necessarily the other way round."

I am not sure that this is always true. Take for example the Fadeev-Popov ghosts in QCD which are "unphysical" degrees of freedom. But these ghosts represent terms that are "naturally" inserted in the Lagrangian to preserve unitarity. From this standpoint, there is nothing unnatural about their utility.

It boils down to semantics, I guess.

Regards,

Ervin

eric gisse said...

I wonder how long it would take for a 10^17 meter tall tree to fall down.

Uncle Al said...

I wonder how long it would take for a 10^17 meter tall tree to fall down.

10^17 meters is 10.57 lightyears, so patience is counseled. Remember to claim your carbon credits. (Interested readers may contrast center of mass with center of gravity integral to the tree.)

Zephir said...

/*..take the fourth power of the Planck mass and divide it by the measured value of the cosmological constant, the ratio is 10E120. That's what is commonly called unnatural...*/
These two quantities are related to mass/energy density of vacuum, as predicted by quantum theory and general relativity. In Aether theory such ratio isn't inatural, because these theories are describing vacuum from dual (reciprocal) perspectives. If we compress piece of particle matter, it would appear the more void and superfluous, the more dense and brittle it would appear from outer perspective (interior and surface of neutron star as an example).

Aparently these two perspectives are of dispersive nature, being gradient driven by Kramers-Kronig relations (particle environment is always observed in tranversal and longitudinal waves).

Zephir said...

The problem of naturalness of dual perspective follows from the fact, human perspective is itself quite rare and as such broken in symmetry inside of random system. We can imagine Universe as a large blob of Perlin noise, in such blob most of energy is spreading in mixture of transversal and longitudinal waves. But very small portion of energy would propagate through it in highly broken symmetry - so we can ask, how such random system would appear from this unusual (yet expectable) perspective?

Bee said...

Eric: I doubt the tree would fall.

Bee said...

Zephir: An observation is not a postulate. Best,

B.

Bee said...

Dear Arun,

No, the exponentials are not put in by hand, but what is put in by hand are the potentials binding the particles to a particular location (to first order the potential is quadratic this is what gives the gaussian). Of course this just brings up the question where the potential comes from. But the point remains that all you need is an exponential function (if you take RS it's also an exponential function that does the trick, though not a gaussian). Best,

B.

Bee said...

Well, since Lubos could not resist commenting on the topic let me just say that he evidently didn't get the point of what I wrote. I didn't write questions of naturalness are irrelevant. I instead said that one has to be clear about how to justify them. You can turn it how you want, in the end your idea what is natural or isn't (may that be a function or a value or a measure) is just an assumption and it shouldn't be elevated to anything above that. (Wait, it's totally natural that spacetime is warped!) Basically what I'm saying is that I prefer people state their assumptions without "natural" fog around it. Best,

B.

Bee said...

Hi Ervin,

Yes, that's true. I had something else in mind with "unphysical," something that would be "really" unphysical (like: spacetime singularities). Best,

B.

Phil Warnell said...

Hi Bee,

A very interesting post addressing an aspect of physics that many theorists hold dear, which forms to be more something of a matter faith, which could in turn be said to mark the place where science isn’t scientific. However ,the way I look at it is naturalness is an axiom of science, which whether you subscribe to it demonstrates if you feel it to be a self evident truth when it comes to nature. This is also where early on Descartes and Bacon had different opinions as to how science should be conducted, with Bacon convinced science being a method incorporating inductive reason as to be done properly, while Descartes having it as largely a deductive process, with the difference being if one accepts the omission of the concept of premise.

For me what this boils down to is found in coming to realize the place where both Bacon and Decartes agreed, which Bacon did by insisting in his treatise ‘Novum Organum’ “the mathematical postulate that if two things are equal to the same thing they are equal to one another is conformable with the rule of the syllogism in logic which unites propositions agreeing in a middle term.” . This of course is to have the truths of nature to form as being an equation, which in itself holds the premise that if one side is deducted from the other it will be equal to zero. This is of course is what just about all would consider as not simply a mathematical truth but also a physical one. The fact is that there is no proof that exists as Godel pointed out that can either proof or disprove that mathematics is self consistent and thus this also in the end is simply a matter of faith (at least for now).

So for me no matter which way you slice it one always is forced to make such judgements before science can even begin. I’ve always thought Einstein expressed this best when he remarked on what indicated to be good theory when he said, "The supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience" . So this has it that as long as all the actions and phenomena can be accounted for, why should we believe that nature would find a more indirect /or convoluted method to have what is real to be real. The only concession here is one born of humility and not of conceit, as not having the scientist any more skilled at creating reality then nature itself. This of course is also a premise based on faith, yet I would argue one with all the efforts thus far it hasn’t been able to have as not to be true.

Best,

Phil

Steven Colyer said...

Has Stefan tried to defend his lady's honor or Bee to defend herself regarding this blog by Lubos at The Reference Frame?

Phil Warnell said...

Hi Steven,

I would say to defend your honour in respect to one that has no understanding of the concept is to only to throw pearls before swine. Like the flu which shares its name I would suggest the best course of action is immunization as a method of cure for something that has no purpose other than to propagate itself at the expense of others.

Best,

Phil

Bee said...

Steven: Years ago, both Stefan and I tried to discuss with Lubos at his blog, only to find that it is a waste of time since he edits and/or deletes comments. For what I have to say about his post, see my above comment. Best,

B.

Bee said...

Hi Phil,

Yes, I guess one could see it as an unwritten axiom. Problem is if people aren't aware of what assumptions they make, since the risk is that options are discarded based on believe instead of evidence. Naturalness is a guide, but how useful it is as a guide only time can tell. For me it raises the question (we discussed this here) whether we should expect the human preference for simplicity, beauty, naturalness etc to be reflected in our theories. This reminds me btw of a quotation by Einstein "“Nature hides her secrets because of her essential loftiness,” so maybe we should use "loftiness" instead of "naturalness" ;-) Best,

B.

Steven Colyer said...

Thank you Bee, you confirmed my worst suspicions that Motl "heavily moderates" his blog, as does Peter Woit at "Not Even Wrong." At least Peter doesn't "edit" as you said Lubos does, which is reprehensible to me.

Every person has to right to let through what they want on their blog, or not, but pls Lubos and in the name of all that is holy, either let the whole comment through or none at all. Sheesh.

Actually Bee, since I last posted I was aware that Scientific American responded at Lubos' blog in response to an attack by him as well, and the defense wasn't allowed, so you're in good company. Thanks to you and Stefan for being democratic.

And thank you Phil for your wonderful "pearls before swine" comment, I enjoyed that. :-)

Cheers,
Steve, who's rethinking MOdified Gravity in lieu of the Minnesota Soudan mine NON-results of yesterday. How is John Moffat doing, Bee? Ciao.

Bee said...

Haven't seen John since I moved to Stockholm. But yes, I suppose the news will give MOND a second wind. Best,

B.

Arun said...

Naturalness, a la David Gross [1996]: "Imagine that we have a unified theory whose characteristic energy scale, Λ, is very large or whose characteristic distance scale, h-bar c/ Λ is very small (say the Planck length scale of 10^-33 cm). Assume further that just below this scale the theory can be expressed in terms of local field variables. As to what happens at the unification scale itself we assume nothing, except that just below this scale the theory can be described by a local quantum field theory. (String theory does provide us with an example of such a unified theory, which includes gravity and can be expressed by local field theory at distances much larger than the Planck length.) Even in the absence of knowledge regarding the unified theory, we can determine the most general quantum field theory. In absence of knowledge as to the principles of unification this theory has an infinite number of arbitrary parameters describing all possible fields and all possible interactions. We also assume that all the dimensionless couplings that characterize the theory at energy Λ are of order one (what else could they be?). Such a theory is useless to describe the physics at high energy, but at low energies of order E, the effective dynamics, the effective Lagrangian that describes physics up to corrections of order E/Λ, will be parametrized by a finite number of couplings...." (emphasis added)

Zephir said...

/..*an observation is not a postulate...*/
If it's used as an axiom in theory, then yes (for example the constant speed of light) - it's both observed, both postulated.

Bee said...

Zephir: An observation is not a postulate, and it is not an axiom. It is not an assumption, it is a measurement.

Postulating the existence of A constant is something entirely different. But anyway, believe it or not, but you don't need to postulate the speed of light to be constant to get Special Relativity, see this post. (As I explicitly pointed out in this post that was not the way it went historically, but that's not the point.) Best,

B.

Plato said...

Hi Phil,

Just so you know that "all is not lost" in terms of deduction/induction and what is to become self evident, clarification is continued to be expounded upon so as to understand what the truth "is" of the matter.

Also in terms of an axiomatic approach what diagram best serves this exploration as to contend with, what is real or not? But to re-frame the context of the way the universe "is" not only in the context of Dirac's "i" but to see the universe in a much more dynamical way.

Gauss and Riemann saw "eye to eye?":) Einstein, was able to pick up on the simplicity and beauty of this.:)Kip Thorne too.

Best,

Giotis said...

Steven, I wouldn't be so dramatic. Lubo's attacks on Bee (among many others) are some sort of tradition; you may even say that they spice up the blogosphere a bit.

Zephir said...

/*..special Relativity assumes time is a dimension..*/
I see - I stopped read it just after this sentence. It's evident, you've very weak feeling of what belongs into realm of general relativity and what into special relativity. The fact, most of special relativity theorems can be derived by using of general relativity concepts of four dimensional space-time cannot change my opinion about you in any way. It's not surprising after then, you're mixing concepts of general relativity and quantum mechanics freely.

Zephir said...

/*..Lubo's attacks on Bee are some sort of tradition..*/
In another words, he cannot be taken seriously in anything. I'm finding somewhat ironic, just these two physmatics are in duality, despite the apparent psychic disorder and lack of sociability of the former one.

William said...

Hi Bee,

Much seems vague, and I'd be interested to know more topics which you recall of which physicists have argued whether or not something is natural.

I find it interesting that you have forbidden discussion of Pi here in this context. Wasn't the ancient Pythagorean who discovered Pi's unnatural irrationality murdered, or allegedly committed suicide, because the Pythagoreans found such a concept so disturbing? And then the unnatural irrationality of Pi was forbidden to ever be mentioned or revealed by them?

That seems to be the most dramatic of the first examples of man's confrontation with unnaturalness in science/math.

A related idea is the rather unnatural concept of "incommensurable" magnitudes. http://en.wikipedia.org/wiki/Incommensurable_magnitudes The Greeks championed the idea of discrete, atomic nature of matter, which is a parallel to modern quantum discreteness, because it seemed so logical and natural. But their confrontation with "incommensurable" lengths of a right triangle's side and hypotenuse, which was a side effect of the irrationality of the hypotenuse's length, boggled their minds and forced them to reconsider and conclude instead that space and matter must really be continuous rather than discrete and quantum in nature ... even though the concept of continuous space and matter seemed to them to be unnatural. But the irrationals and incommensurables forced them in that direction. And so today the same drama appears to being played out, as scientists try to quantize space and gravity, but are finding no natural way to do that, while their math (GR) is telling them it is unquantized and continuous.

In effect, governments have been giving grants for research into resolving that paradox of quantized vrs continuous space since 500 BC to today. 2500 years! But still, after 2500 years, the matter is unsettled; and still haunted by what seem to be unnatural mathematical formulations.

Wishes,

William

Helmut Hansen said...

To know what is natural you have to know what is fundamental in nature?
To give an example. The principle of relativity is considered as one of the most fundamental principles of nature. But this principle depends directly on the validity of the law of inertia. But no one knows the origin of this law of nature. If it would prove only as an approximate law the principle of relativity would lose its fundamental status immediately and it would lose its natural character as well.

Bee said...

Helmut: That's not what I've referred to as "natural" here. We discussed the question "What is fundamental?" here.

Bee said...

William: Gosh, I have not "forbidden" the discussion of pi, I have expressed my wish that Zephir limits the expressions of his ignorance. Yes, the question whether discreteness or a continuum is "more natural" came up before. I personally like the continuum better, but see, the point I was making is that this isn't more than an expression of liking/disliking, and thus not a scientific argument. There are better arguments than that. Best,

B.

Bee said...

Zephir:

/*..special Relativity assumes time is a dimension..*/
I see - I stopped read it just after this sentence. It's evident, you've very weak feeling of what belongs into realm of general relativity and what into special relativity. The fact, most of special relativity theorems can be derived by using of general relativity concepts of four dimensional space-time cannot change my opinion about you in any way. It's not surprising after then, you're mixing concepts of general relativity and quantum mechanics freely.


Your repeatedly stated refusal to read even introductionary text to physics is very troublesome given that you constantly try to enlighten us with your theory of whatever. In particular if one considers that you have vividly demonstrated your lacking understanding of even elementary physics.

I don't know why you are mentioning my "weak feeling of what belongs into realm of general relativity and what into special relativity," in contrast to you I know both theories pretty well, this has nothing to do with "feeling" whatsoever.

"The fact, most of special relativity theorems can be derived by using of general relativity concepts of four dimensional space-time cannot change my opinion about you in any way."

Not so surprisingly, because you have made a point out of declaring an opinion about me while simultaneously openly refusing to find out who I am or what I work on to begin with. Do you actually notice how ridiculous this is? As the name indicates, special relativity is a special case of general relativity, meaning you can actually derive the former from the latter completely, just plug in flat space. In any case, if you recall, the reason why I pointed you to this article was to correct your mistake of thinking that special relativity assumes the constancy of the speed of light. But since you're afraid of being corrected, you don't even read it. Great. At this point, Zephir, it seems it's about time you find out what you actually want to achieve. Do you really want to understand Nature? Or do you just want to close your eyes wishing Nature turns out to be how you dreamed it up? (This is a rethoric question. This means you are not obliged to answer it. I just want you to think about your own behavior, since you are simply wasting the time of your life.) Best,

B.

Phil Warnell said...

Hi Bee,

“Nature hides her secrets because of her essential loftiness,” so maybe we should use "loftiness" instead of "naturalness"

Yes I would say this to be consistent with him also saying “that although nature may be subtle, she is not malicious”. I guess perhaps this is the greatest reason why I would never be able to consider myself a true scientist even if properly trained, as I’m more concerned with nature’s reason for reason, rather then it’s methods of reason. That’s to ask questions like why would it be necessary to have random obscure a method of action or why driving things to disorder in general required in manifesting order more specific.

I’m thus reminded of a interview Lisa Randall gave to Discover magazine a few years back, where in describing the role of science she said We're not going to be able to answer the "why" questions. But when you put together all of what we know about the universe, it fits together amazingly well”.. This struck me that although science is driven to discover how all the pieces fit, yet at the same time it has little interest as to the reason behind the puzzle they struggle to put together.

Now I would never have it thought to be understood I could imagine to share the power of mind of Einstein, yet I’ve always thought I shared his greatest concern, which he expressed when he remarked "I am not interested in this or that phenomenon, in the spectrum of this or that element. I want to know His thoughts; the rest are details.” . That’s to say I’m more concerned why the pieces fit together, rather than how they do. I would then say this hidden axiom of naturalness is how many physicists hold the same thoughts while able to deny ever having them. That’s why I would call Einstein to have been a natural philosopher rather than a physicist as he found no shame in his admission of motive.

Best,

Phil

Phil Warnell said...

Hi Plato,

I am reminded of your comments regarding Aristotle’s arch as to ask if they meet to be complimentary, rather than opposed and essential I’ve often thought the same. However the question I find most intriguing is in asking if they reconcile from being equal, as the sides of an equation are thought to represent as balancing on zero, or rather is the equivalence found in that reason mandates reality to manifest itself as we find it. This replaces anthropic principle, which would have us believe that we find what we see as otherwise we wouldn’t be here to find reason, with there can be no reality absent of reason. That to say I find there to be a difference between a causal effect and a effective cause:-)

Best,

Phil

Plato said...

Hi Phil,

I am reminded of your comments regarding Aristotle’s arch as to ask if they meet to be complimentary

Phil for me this seems to a very dynamic process, that intertwines like some mobius strip, some topological turning inside/out and back. An inductive/deductive approach to it. I guess, a dance of sorts.

...rather is the equivalence found in that reason mandates reality to manifest itself as we find it.

I mean ultimately, we have arrived at a place where there can be no further reducibility other then what we have deduced "is" the the truth of it.

An equatorial "one inch equation" or the "simplicity of" as "the beauty of it," that can manifest and turn back into a explosive principal of a path like example of all particulate expressions under a model of expression from a beginning of the world. The dance is a very very intuitive one then. The "aha" is the truth of it.

That to say I find there to be a difference between a causal effect and a effective cause:-)

An example then.

In Steven's case he's moved quickly forward under a assumption of CDMs, while I know the limitations of the thoughts you have about dark matter, we still see the progression to SuperCDMs.

So in Steven's case, as to the limit of CDMs, while you stopped before that. Steven then saids, on his limit such and such should take place now, while it is insignificant to me that an model approach in terms of John Moffat pushes forward based on, while "it is okay" regardless to continue theoretically.

Does this experimental procedure kick John Moffat off the board?

So in the one sense dark matter can have reach it's limitations according to what has crystallize in perspective for any one person leaves room for the move toward the continued experimental push forward to be much clearer in our deductions. Our conclusions.

For this reason then, we seen the limitations of predictability according to the standard of, a deduction about the reality of the situation?

Is this logical? Where does "all truth manifest" and what limits us from finding that place?

Best,

Ps. I'd like to take this opportunity to wish everyone a Merry Christmas and a Happy New Year.

Neil' said...

[Somehow this first got into "To Whom it may Concern" by mistake]:

BTW, one can't say that things happen "because of laws of physics". As Hume pointed out, we see the regularities and call them "laws" - the laws aren't something that makes otherwise inert stuff do things (or are they?) We don't know why things do what they do, but in any case referring to "laws" is a circular argument.

Count Iblis said...

Typo:

t'Hooft

Should be

't Hooft

Zephir said...

/*..law of inertia. But no one knows the origin of this law of nature..*/
In AWT straight line of motion follows from diffusive character of mass/energy spreading along density gradients of aether.

Zephir said...

/*..your repeatedly stated refusal to read even introductionary text to physics */

Hi Bee, the sentence

/*..special Relativity assumes time is a dimension..*/

is simply not true, because such predicate doesn't occur between special relativity postulates. Instead of this, it belongs into general relativity postulates, ase everyone can check.

http://people.hofstra.edu/stefan_Waner/diff_geom/Sec13.html

I know it, just because I've read these "introductionary text to physics" - whereas you're not, as it seems.

Therefore everything, what you attempted to extrapolate from the above claim is simply BS, which I don't feel obliged to read anymore. It means too, you even don't know about postulates of most fundamental physical theories which you're dealing with whole your existing life - so you're always prepared to mix ideas, postulates and constants of various theories together, despite they're consistent mutually or not.

This is very common situation in contemporary physics, which contributes to general level of confusion, but it's maintained willingly by theoretical physicists, because it enables them to pile equations freely, write publications, to spent their lives by traveling around seminars, etc.

Zephir said...

/*..your mistake of thinking that special relativity assumes the constancy of the speed of light..*/

You can find postulates of special relativity here :

http://en.wikipedia.org/wiki/Postulates_of_special_relativity

"As measured in an inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body".

As you can see, no BS about four dimensional space occurs here. And it's not true, that special relativity doesn't consider constant speed of light. You're just trying to mix theorems of special and general relativity again, because of your vague & sloppy understanding of postulates and theorems meaining in formal theory.

Zephir said...

/*..as the name indicates, special relativity is a special case of general relativity, meaning you can actually derive the former from the latter completely, just plug in flat space...*/

Is the theory defined by its name or by its postulate set? If the later remains true, then the claim "you can actually derive the former from the latter completely" is not so easy to prove, because postulates of both special relativity, both general relativity are completelly different apparently.

Anonymous said...

Physicists like dimensionaless ratios of related quantities to be order 1.

There is a problem when things start diverging away from the ideal.

For instance the Hierarchy problem is simply a statement that any new physics between the electroweak scale and the Planck or GUT scale would introduce ever growing amounts of finetuning in order to fit experiment, b/c the mass of the Higgs is sensitive to radiative corrections of each new additional particle.

You ask the question, why should nature not be finetuned? My response, we don't expect miraculous cancellations to take place, particularly in light of our ignorance of relevant physics quantities.

In many ways its a problem that nature seems to be very sensitive to errors of ommission of relevant quantities that are way outside the domain of relevance of the theory, and an indication that we've goofed somewhere.

Steven Colyer said...

Bee, you wrote:

"Haven't seen John [Moffat] since I moved to Stockholm. But yes, I suppose the news will give MOND a second wind."

Thank you Bee. However, I was talking about MOG, not MOND.

However, since you brought it up, staunch MOND defender and original (in 1981) proposer Mordehai Milgrom apparently made predictions this year regarding slight variations in the path of our System's planets. Has that been confirmed as far as you know?

Regarding Moffat's MOG, I was interested in the 2004 STVG Scalar-Tensor-Vector Gravity version. Though it predicts similar results to MOND, and is not to be confused with Moffat's earlier MSTG Metric-Scalar-Tensor Gravity version, I was wondering if you knew the progress of those theories as well.

Bee said...

Anonymous:

"we don't expect miraculous cancellations to take place,"

Why?

"and an indication that we've goofed somewhere.

Is this "indication" based on a scientific argument? Best,

B.

Bee said...

Count: Thanks, I've fixed that.

Bee said...

Zephir:

"the claim "you can actually derive the former from the latter completely" is not so easy to prove, because postulates of both special relativity, both general relativity are completelly different apparently.

It is very easy to prove. As I said above: Take General Relativity, insert flat space, viola. You see this from the axioms as follows: One of the axioms of GR is that in the locally flat surrounding of every point the laws of special relativity apply. If space is globally flat, that means they apply everywhere. Can't follow? Open a textbook.

"As you can see, no BS about four dimensional space occurs here. And it's not true, that special relativity doesn't consider constant speed of light. You're just trying to mix theorems of special and general relativity again, because of your vague & sloppy understanding of postulates and theorems meaining in formal theory. "

You have two problems, Zephir. One is that you wrongly assume axiom systems are unique. In fact, there are many different axiom systems that are equivalent to each other. The second problem is that you don't read what I say but argue it must be wrong quoting Wikipedia. The point for writing the post I linked to above was exactly that it is a very common misconception that the constancy of the speed of light must be postulated to obtain special relativity. That is how it was historically, but it is not necessary. As I have shown in my post, you can uniquely define Lorentz transformations as the symmetry group of Minkowski space. If you do so, you will find these transformations have one free parameter that you can identify as the speed of massless particles. (The postulate on Wikipedia is wrong in that it is entirely irrelevant that c be the speed of light. Special Relativity has nothing to do with light in particular. It's just the speed of a massless particle.) If you want proof for that, go read my article, or at least try it. Who knows, you might learn something? Best,

B.

Bee said...

Incidentally, if you scroll down the Wikipedia article you'll find the following sentence

"In the rigorous mathematical formulation of special relativity, we suppose that the universe exists on a four-dimensional spacetime M."

There's the "BS about 4 dimensions." Best,

B.

Bee said...

Zephir:

"I know it, just because I've read these "introductionary text to physics" - whereas you're not, as it seems.

Yeah, right, I only read some dozen textbooks, wrote a couple of papers, and worked in the field for 15 years. Look, Zephir. I'm spending some of my time trying to communicate what I have learned exactly because there are people, like you, who have piled up a lot of misconceptions and ended up having a wrong picture of reality. Why don't you at least consider that what I say might not be simply wrong just because it's me who says it?

"Therefore everything, what you attempted to extrapolate from the above claim is simply BS, which I don't feel obliged to read anymore. It means too, you even don't know about postulates of most fundamental physical theories which you're dealing with whole your existing life - so you're always prepared to mix ideas, postulates and constants of various theories together, despite they're consistent mutually or not."

In essence, if I summarize your statement, it goes like this: "I read one sentence of what you were trying to explain. I didn't understand it. I couldn't find the same sentence on Wikipedia. Therefore what you say must be bullshit." Congratulations, Zephir.

Yes, 4-dimensional spacetime is an assumption of (standard) GR. (Though the number of dimensions actually doesn't matter very much, except for the dimensionality of the coupling constant as I said way above). I told you you can derive Special Relativity from General Relativity in a very simple way. If you do so, yes, space-time is also 4 dimensional in Special Relativity. Best,

B.

Giotis said...

"(Though the number of dimensions actually doesn't matter very much, except for the dimensionality of the coupling constant as I said way above)"

Well this holds for higher dimensions; in 2+1 dimensions GR is trivial, non dynamical and with no local degrees of freedom. In 1+1 dimensions the picture is very different too.

Bee, what do you mean when you say that you can derive SR from GR? As you have explained, in GR SR holds locally, that's the principle of equivalence but it's absolutely impossible to derive SR globally when gravity is considered. The hole point of GR is that space-time can never be globally flat and so it's imposible to derive SR from GR in any way. There is no limit where GR reduces to global SR. Probably you mean something else that I don't understand.

Bee said...

Giotis: Reg dimensions, I was talking about the equations. You are talking about the solutions. As to how you derive Special from General Relativity, as I said, Special Relativity is the case where space-time is globally flat. That this is in practice never perfectly fulfilled isn't the point. It's a pretty damned good approximation for many situation. Best,

B.

Zephir said...

/*..in fact, there are many different axiom systems that are equivalent to each other..*/
Maybe yes, maybe not - but where we can find rigorous proof, axiomatic system or special relativity is true subgroup of general relativity? Did you bother to give such evidence?

Anyway, concept of 4D space-time belongs into postulates of general relativity, not special one - despite the years, you've spent by studying it. Everyone can read it not just on Wikipedia.

/*..because it's me who says it..*/
Not at all - I discussed exactly the same problem with some anonymous indian guy on Orkut forum before month. Whereas this guy was complete nut concerning physics, his "arguments" were dangerously simmilar to those of yours.

Bee said...

Zephir:

but where we can find rigorous proof, axiomatic system or special relativity is true subgroup of general relativity?

You do exactly what I told you: Take GR, insert flat space. What is left is the kinematics in Minkowski space, also known as special relativity. It really isn't more than this. See Chapter 2 of Weinberg's book "Gravitation and Cosmology" if you need help, and I am very sure also Misner, Thorne and Wheeler will tell you this, or literally every other textbook on the topic.

" concept of 4D space-time belongs into postulates of general relativity, not special one - despite the years, you've spent by studying it. Everyone can read it not just on Wikipedia."

As I said already several times: You can derive special relativity from general relativity as a special case, thus the axioms of special relativity do also apply in general relativity. In particular, space-time is in both cases 4 dimensional with Lorentzian signature. Best,

B.

Zephir said...

/*..like you, who have piled up a lot of misconceptions and ended up having a wrong picture of reality..*/

??? You've complex and fuzzy theory, which is apparently not working even at the case of GRB090510 photon - whereas I've simple and clean picture of reality, which is apparently working perfectly. Can you prove, my theory isn't working well in some experimentally testable case?

Why don't you at least consider that what I say might not be simply wrong just because it's me who says it?

Bee said...

Zephir:

"You've complex and fuzzy theory,"

Meaning: you don't understand it.

"which is apparently not working even at the case of GRB090510 photon"

Huh?

"whereas I've simple and clean picture of reality, which is apparently working perfectly. Can you prove, my theory isn't working well in some experimentally testable case?"

You're kind of on the wrong track there, Zephir. If you think you have a new theory, it's your task to show that it works, not other people's task to show that it doesn't work. In addition, you need to show that it works BETTER. And then, please go and publish a paper about it, instead of dumping your "explanations" on blogs.

"Why don't you at least consider that what I say might not be simply wrong just because it's me who says it?"

I haven't. I have read and replied to every single of your misconceptions and explained why they are wrong. It's you who is either not willing or not able to understand what I am saying. Best,

B.

Zephir said...

/*.. space-time is also 4 dimensional in Special Relativity..*/

I don't think so, because general relativity can lead to different predictions, then the special one - and concept of four-dimensional space-time is universal in general relativity (it belongs into its native postulates). So it cannot remain universal for special relativity - or both these theories would become identical.

Zephir said...

/*..If you think you have a new theory, it's your task to show that it works, not other people's task to show that it doesn't work. ..*/
I'm showing it, gradually. On the other hand, until you prove the opposite, your're incompetent to claim so - so you're expected to be quiet about its true value.

You're working on quantum gravity, not special relativity. Quantum relativity was proven to lead to similar fuzzy landscape of solutions, like string theory. So I can call it a vague, despite the pile of math. Concerning the GRB090510 photon, it's indeed not inclusive evidence of special relativity, because such result could be explained just by its violation (or many other ways, independent to validity of special relativity).

Zephir said...

/*in addition, you need to show that it works BETTER..*/
I needn't to do anything, because I'm not taking money for it from anyone - and you're just expected to remain quiet concerning claims about its validity, until you have no evidence for it. Especially when you're scientist, i.e. person, who is payed for unbiased presentation of informations.

I'm not such person, as you probably realize.

Phil Warnell said...

Well one thing for certain, with all his misconceptions Zephir has had me to be convinced as not to as of yet discovered the hidden truths of nature; for if that be the case nature would be sorely in need of a fertility clinic ;-)

Bee said...

Zephir:

"you're expected to be quiet about its true value."

In case you haven't noticed, I've been very quiet indeed.

"You're working on quantum gravity, not special relativity."

You might get a clearer picture of what I'm working on if you read some of my papers. I have no clue btw what you mean with "quantum relativity."

"I don't think so, because general relativity can lead to different predictions, then the special one - and concept of four-dimensional space-time is universal in general relativity (it belongs into its native postulates). So it cannot remain universal for special relativity - or both these theories would become identical."

As I have tried to tell you several times already, special relativity is a special case of general relativity. If you approach it from that direction, it has an additional assumption (that being that spacetime is globally flat). That does not mean that both theories are identical. In General Relativity, spacetime is not in general flat. Best,

B.

Zephir said...

/*..although science is driven to discover how all the pieces fit, yet at the same time it has little interest as to the reason behind the puzzle they struggle to put together..*/
There are many reasons for this stance. To reconcile existing knowledge on background of some more general view we would be required to abandon existing paradigms, which many persons involved would perceive as the lost of meaning of their life. It's like to propose Holy Church explanation of its God or like to propose Lubos Motl, string theory isn't really TOE. In addition, scientists are simply competitive creatures, which is basically good for evolution, but it becomes a brake of it, when they lost an external enemy.

But there are deeper, not so likeable aspects of their fight against new ideas. The contemporary state of confusion helps many scientists earn their money a much easier, as it enables them to ask for another money for another research, because "there's indeed a lotta things to investigate yet". For scientists it's more comfortable to keep the rest of society in ignorance. In such way, scientists are behaving like medicinmans of ancient era, who are guarding their secrets before revealing by laymans.

And the Aether aspect of reality is particularly sensitive theme for many physicists, because their rhetoric is still based on "success of mainstream physics in refusal of ancient Aether concept", i.e. on apparent mistake. So we cannot really expect, the reconciliation of knowledge in physics would be started by some mainstream physics itself. These guys (and ladies) must be simply forced to it from outside.

Zephir said...

/*..In General Relativity, spacetime is not in general flat...*/
The point is, GR doesn't say, how curved it can be (from GR just follows nonzero value of CC) - so that it's possible to distort special relativity perspective by background noise in such a way, special relativity becomes distorted heavily. In this moment special relativity would contradict general relativity, which wouldn't indeed possible, if it would remain really "special part" of it.

Analogous situation occurs at the water surface, where capillary waves are spreading quite independently to underwater motion or Brownian noise - but when these waves would become too small, or too large, the effect of background noise would become pronounced. Special relativity is simply strictly local theory and this localeness could be limited to arbitrary value just due general relativity.

Zephir said...

Concerning the "naturalness", for me it's natural to explain abstract phenomena by these naturaly occuring ones, i.e. by our immediate real life experience with water waves and particles, instead to explain abstract phenomena by another abstract phenomena, despite it could lead to more particular predictions temporarily.

This approach has its deeper meaning, because we shouldn't explan reality by abstractness, as we have no exact knowledge of abstract concepts just because they're so abstract and our understanding of reality should be based on extrapolation, instead of interpolation.

So we should start our description of reality from particle packing geometry, because this is just what we can be perfectly sure with from its very beginning. The abstract theories like relativity and quantum mechanics could serve as a high level approximations of large particle fields behavior - but not as the introductory tool for further understanding - because we simply don't know, why and how they're exactly working.

Bee said...

Zephir: GR does tell you what the curvature of space-time is if you insert the source terms, that's the whole point. It does not "follow" from GR that the cosmological constant is nonzero, that's a measurement. The CC is a free parameter of the theory, but we already noticed earlier that you have a problem understanding what it means to measure a parameter of a theory. Regarding your comment about naturalness and abstraction, I'm afraid you totally didn't get the point of this post. Our theories should be based on what works. Whether that's "natural" according to Zephir or not is entirely irrelevant. Best,

B.

Zephir said...

To talk about GRB090510 photon in connection to whatever evidence of special relativity is particularly funny, just because special relativity prohibits any formation of photons in its consequences: it always describes light as a pure harmonic wave without any local perturbations, wave packets the less. Photon as such is the concept of quantum mechanics, which violates special relativity heavily by its very definition.

Zephir said...

/*..our theories should be based on what works...*/
Predictions of general relativity differ from those of quantum mechanics in more than one hundred of orders of magnitude. Is it what you're calling a "working theory"?

Technically speaking, even geocentric model of solar system "works" at the formal level (it enabled to predict eclipses and conjunctions) - the only problem is, it remains counterintuitive at the nonformal, qualitative level. How the hell small Earth the planet could drive the motion of many others, including of much larger Sun? It could serve as an indicia, the formal and intuitive thinking is in duality.

Therefore the abstract theories, like general relativity works well at the formal, but isolated level, but with respect to holistic, intuitive understanding of our reality are useless, they simply doesn't work "well" - just because they're based on subject of belief.

History learn us, after some period of ignorance and blind refusal even intuitive theory becomes formalized up to level, it replaces existing theories, so that Occam's razor criterion still apply: the most intuitive theory still works best even at the formal level.

Zephir said...

/*..the CC is a free parameter of the theory..*/
Of course not, because as we know from the times of Friedman, this constant must be balanced very well for Universe to remain stable. In this way, the measured value of CC or gravity constant is the only one, which keeps general relativity working in the same way, like speed of light in special relativity or like exact balance of inertial and gravitational force in equivalence principle.

There are simply no adjustable parameters of theories - only axioms and theorems. From sufficiently wide perspective every theory becomes constrained by observations up to level, no parameter could change in it at least a bit - or the theory will stop working.

Giotis said...

If you are saying that SR is derived from GR because a flat metric is a solution of the vacum field equation then ok.

Neil' said...

"this [cosmological] constant must be balanced very well for Universe to remain stable." - Zephir
No, you are confused. Back in those days "stable" meant a CC that countered gravity at the Universe's given density. That way, it was a bubble of constant size & density since Einstein et al wanted to avoid a creation-type event (see the trouble that avoiding anthropic-metaphysical-looking processes gets you?) But that turned out to be wrong: the universe is expanding anyway from an initial explosive event.

There is hence no being "stable" for the universe (what did you mean by that anyway, since it surely doesn't keep the same size.) With no CC the "uni"verse keeps expanding at the rate braked only by gravity. With a CC, it expands even faster which we find to be the case. Zephir - please don't go spewing half-formed thoughts all over, do more research and think before posting.

The real question is, why the CC we find instead of the physically "natural" value of about Planck density, which is ~ 10^120 too big compared to the actual as noted. Bee - since we'd be in deep doo-doo if that value was real, I think it means the universe *does* care whether "we" like it, in terms of being alive. What it doesn't care about is whether scientists like that way to be, versus their pet idealistic concepts based on mathematical beauty etc. It's an anthropic universe, like that or not.

Bee said...

Giotis: Yes, that's all I'm saying. Best,

B.

Bee said...

(If the CC is zero that is. But that only becomes important on large distances anyway.)

Bee said...

Zephir:

"Predictions of general relativity differ from those of quantum mechanics in more than one hundred of orders of magnitude. Is it what you're calling a "working theory"?

Bee: ..the CC is a free parameter of [General Relativity]...

Zephir: Of course not, because as we know from the times of Friedman, this constant must be balanced very well for Universe to remain stable."


I already told you above that General Relativity does not predict a value for the cosmological constant. We also know that the universe isn't "stable" in case what you mean with stable is Einstein's static universe. Some of us have learned a thing or two since Friedmann (even Wikipedia acknowledges that).

What you possibly mean is that the OBSERVED value for the cosmological constant is way off the value that quantum field theory (not to be confused with quantum mechancs) predicts for the vacuum energy. That is true. I wrote a post on that here. That this question is still under debate doesn't change the fact that both theories, GR and QFT, have made predictions that have been tested and have confirmed these theories to extremely high precision. You can stand on your head and wiggle your toes, but you're not going to change the facts. Best,

B.

Phil Warnell said...

Hi Neil,

” It's an anthropic universe, like that or not.”

Why did you have to spoil a completely valid argument by insisting it being evidence of the validity of the anthropic principle? That’s to say of course there are infinite ways that one could imagine a universe to be, yet it has always been evident that there is much more we can imagine that simply can’t be or isn’t real. So the alternative view is that it may also be necessary to have the question of why answered better then to insist simply because. That’s not that I’m certain its one way or another or for that matter particularly care, yet as has been reminded, and is the central theme of this post being it’s sciences job to limit as much as it can as to what it considers as being unassailable truth(s). Like the old saying goes, you can’t suck and blow at the same time.

Best,

Phil

Phil Warnell said...

Hi Neil,

Just to add that as far as I’m aware to have the anthropic principle to become scientifically accepted as such, would require it be supported by evidence that would have it elevated to being one. This doesn't mean it should be excluded from being a hypothesis, yet to have it considered as a principle would demote the statue of the few we currently hold as being deserving to be so.

Best,

Phil

Zephir said...

/* General Relativity does not predict a value for the cosmological constant */
I know, it considers it instead without proof, i.e. postulates it. Why are explaining me the things, which I've started to explain you?

Neil' said...

Phil, I think you're getting some different issues mixed up. I don't know what perfectly good argument you mean. It really is conceptually "weird" for a constant to be 10^120 off, yet so curious to be good for our benefit. Maybe you mean we came out of one of the rare universes with friendly constants? But you can't speak glibly of other universes if we don't know what makes things or to be the way they are. Sure, let scientists look for theories but here is a problem that the most astute of them realize: there is nothing in logic or math that has or allows the expression of "actualization" from among possible logical descriptions. The conceptual tools not only aren't there, they can't be. There is no logical (as opposed to "mystical") special property to put meat on some numbers or equations and not others. It is like the number 23 being made "real" in brass numerals and not the others.

We can't find such properties in math and logic, only more internal mathematical and logical properties. It is an anomaly to have "physics" added to "math." Indeed, modal realists are right to say we can't even define the property of "material existence" except by using some experiential trait.

People like Max Tegmark realize this, so they and modal realists say "everything" exists - the MUH, all possible universes in the omnifarious ultimate ensemble. Well, that gets rid of the problem of existential selectivity: why do some possible worlds "exist" as further material entities, and not others. But the problem then arises, that we should have a Bayesian expectation of finding ourselves in a PW *just* orderly enough to allow our existence. (IOW, sloppy variations still compatible with life being able to evolve, like slightly different particle masses, r^2.0004 force laws etc.) No, there has to be some ordering principle. If it isn't like a person, then it's got to be primordial "purpose" maybe like the alaya vijnana or the ein sof.

Sure, that's philosophy and not scientific theory. Philosophy is the best we have, and I don't think it contaminates other approaches being used best as can. Scientific theory just can't get under to the foundation, since no logical basis can be had for distinguishing it. Tegmark et al get this (versus the crowd trying to figure "why the universe is like this") even if he disagrees with my further speculation.

Note also that it is a mistake to e.g say, "the standard model explains _____". No. The SM is like saying "I think we live in a hexagonal universe" - so certain things must be consistent with that. It doesn't say why a hexagonal universe instead of a cubical or amoeba shaped universe. See also how Hume ruined the idea of laws as causes - they are descriptions of the regularities, so using them to explain is a circular argument.

Zephir said...

[q]..back in those days "stable" meant a CC that countered gravity.. With no CC the "uni"verse keeps expanding at the rate braked only by gravity. With a CC, it expands even faster which we find to be the case. [/q]
You're just confusing Friedman and static Einstein's models. Please avoid strong words, if its evident, it's just you who doesn't distinguish these two models.

[q] The conceptual tools not only aren't there, they can't be. [/q]
They're there, indeed. AWT explains cosmological constant problem easily (together with many other conceptual problems). This difference is logical: general relativity describes vacuum from perspective of transversal waves, quantum mechanics from perspective of longitudinal waves.

Neil' said...

I don't think I'm doing the confusing. Do you get the difference between being a subset, and being in a different class? Wikipedia says, consistent with my other reading:
"Einstein's universe" is one of Friedmann's solutions of Einstein's field equation, for the value of cosmological constant ΛE [Lambda sub E]. This is the only stationary solution of all Friedmann's solutions, and because it is stationary, it is thought to be non physical by majority of astronomers.
IOW, the EU is that FU for which the CC just balances the gravitational attraction. "God only know" why the hell it should do that, but poor Albert operated under militant theophobia.

As for conceptual tools, your AWT still has to take some parameters for granted among all possible models. And curiously, AWT has not found favor among the scientific community. Does it provide new predictions (such as _____), or just reinterpret the same facts?

Zephir said...

/*..AWT has not found favor among the scientific community..*/
This doesn't mean very much. No one believed Galileo, even Heim's theory or E8 theory of Lisi Garrett are way more ignored, then they deserve. And these theories are pretty formal with compare to AWT.

Concerning predictions we can consider for example superluminal speed of gravitational waves, which are just these longitudinal waves with compare to transversal light waves. Anyway, this topic is not about AWT, but about naturalness in physics and just the naturalness is very strong point of AWT: due the correspondence principle most of abstract concepts of modern theories has its own natural analogy in classical physics here - just less or more exaggerated in scale.

Zephir said...

/*..or just reinterpret the same facts?..*/
If these facts are interpreted by different theories, even the ability of certain theory to reinterpret them by using of single consistent model brings a progress into our understanding due the Occam's razor principle (two theories usually require more postulates, then the single one).

The contemporary state of physics, where various phenomena are explained by different theories may be advantageous for physicists (it creates a new jobs and grants for them) - but definitelly not for the people, who want to understand them.

Bee said...

Zephir:

/* General Relativity does not predict a value for the cosmological constant */
I know, it considers it instead without proof, i.e. postulates it. Why are explaining me the things, which I've started to explain you?


You still don't understand it, do you? General relativity does neither predict nor postulate a value for the cosmological constant. It is a free parameter, it is measured. It is determined through observation. Experiment. How can I possibly make that clearer?

Look, in this comment section you have shown an incredible amount of misconceptions. You don't know what natural units are, you think General Relativity follows from Newtonian gravity (now Einstein would have thought that was amusing), you don't want to believe that special relativity is a special case of general relativity despite my explanation of how to obtain one from the other, you don't know the difference between postulating and measuring a constant, you believe that Minkowski-spacetime is bullshit, and apparently seem to believe we live in a static universe.

I do recommend that you first clear up all of these misunderstandings before we discuss more advanced topics.

Finally, this is not the place to discuss your theory of whatever. Please omit all further comments that are not relevant to the topic of this thread (to remind you, the topic was "What is natural"). Thanks,

B.

Phil Warnell said...

Hi Neil,

I do appreciate your long attempt at justifying many worlds, yet I have to tell you I’ve heard all the arguments many times before. As far as I’m concerned it is equivalent to someone who goes to magic shows because he knows the performances are merely illusions and he enjoys figuring out how they’re done. However, one day no matter how hard he tries he can’t figure out how it’s done, so instead of giving it more thought he comes to the conclusion that there was no trick involved and therefore the illusion real.

The fact is there are alternatives to many worlds, which are equally sound and yet they also suffer the same, as not being able to pass the tests laid out by science in regards to physical evidence, so does this mean that we should believe them all. So even though I’m more of a philosopher at heart then a scientist, I still appreciate science for what it is and that being a method of discovery which doesn’t merely imagine how nature does what it does, yet able to clearly demonstrate, as to give evidence as to how.

However my greatest concern for the currents state of physics in general is in having a fear that this is changing so that as it gets more difficult it may once again surrender itself to being a collection of conjectures, instead of a coherent collection of demonstrated conclusions.

“But if there be any man who, not content to rest in and use the knowledge which has already been discovered, aspires to penetrate further; to overcome, not an adversary in argument, but nature in action; to seek, not pretty and probable conjectures, but certain and demonstrable knowledge — I invite all such to join themselves, as true sons of knowledge, with me, that passing by the outer courts of nature, which numbers have trodden, we may find a way at length into her inner chambers.”

-Francis Bacon- Novum Organum (1620)


Best,

Phil

Neil' said...

Phil, I understand you're being suspicious of philosophical arguments over the multiverse etc, and wanting to go "through" direct physical knowledge. OK... but to find why the laws are like this, we have to take a walk into the wild whatever yonder. Experiments can prove what things are like but how can they verify claims of "why"? They can't check that some other system can't exist, how could they? Nor do I don't see how easily we can directly check on other worlds one way or the other either, since it would be hard to know if apparent evidence is really evidence.

I think my argument about fundamental theory is close to air-tight. The tools for explaining and expressing preferential reification of the various mathematical possibilities aren't really there. I admit we can find consistency requirements, such as showing that certain types of laws don't conserve mass-energy. I discovered myself (yet unpublished but at my blog) that CoE runs into trouble in worlds with other than three large dimensions of space. If you believe conservation is a necessary "given" from mass-energy being an amount of stuff, then such worlds can be considered irrational or absurd I guess. But our universe is already absurd, what with wave functions, infinities and such

Phil Warnell said...

Hi Neil,

...but to find why the laws are like this, we have to take a walk into the wild whatever yonder

There’s lots I could say in response, yet as has been reminded here as of late this is neither the place or time. Just to offer an observation I would make note again that there are reasonable alternatives yet in seems either you don’t appreciate or understand that there are. As for myself,I’ve looked at many and have found none able thus far to satisfy all the problems that I have, although I do see some as being more promising than others. So I have no problem in taking a walk in the wild whatever yonder. just as I would have no problem walking to the edge of a cliff. What I do insist upon before committing to go further is I find it reasonable, as to have enough evidence I’m not likely to fall.

Best,

Phil

Zephir said...

Hi Bee, don't affraid - I can understand your problem perfectly.

1) I know, what natural units are, but you shouldn't create them by combining of constants from mutually inconsistent theories, which differ in many hundreds of magnitude by their results. Simply because you're mixing apples with oranges after then (and you're impertinent enough to pretend, it's just my mistake).

2) I know, General Relativity follows from Newtonian gravity, because it uses its gravitational constant taken from Newtonian gravity - so I've a good reason to think so. Whereas you've no reason to believe in the oposite - that's all.

3) I don't believe that special relativity is a special case of general relativity, because it uses a different postulate set, so it can predict different results, then general relativity.

4) I know, the difference between postulating and measuring a constant doesn't exist, because both is required to keep theory predictable. For example without value of speed of light special relativity isn't testable and it can predict anything - so that SR is not testable scientific theory anymore.

5) I don't believe that Minkowski-spacetime is BS (this is just an apparent lie of yours) - but I KNOW, it doesn't belong into special relativity postulates (with compare to you). You cannot change definition of existing theories, which you didn't postulate.

The fact, I disagree with You in something while having a good reasons doesn't mean, I don't understand it or even I don't know about it. Instead of it, it's just you, who doesn't know/understand subject, until you cannot refute my arguments in logical way.

Bee said...

Zephir:

1) Great.

2) Well, you believe you "know" something that is factually wrong.

3) Another believe of yours that is factually wrong.

4) Okay, Zephir. I herewith postulate that the distance to the moon is 3.5 inches.

5) You reffered in this comment to "BS about four dimensional space." I already told you above that axiom systems are not unique, and there are many that are equivalent to each other. It doesn't matter whether you write it explicitly in the axioms or not, spacetime in special relativity is 4 dimensional.

The point isn't that you disagree with me. The point is, Zephir, that you "disagree" with actual mathematical proof (which you ignore) and theories that have been tested to excellent precision during the last century (which you evidently don't understand since for you a measurement is the same as a postulate).

Best,

B.

stefan said...

Dear Zephir,

it has been since days now that you are spamming our blog with your comments that just show that, how should I say, your understanding of physics is dubious. And on top of that, you insult those who try to explain things to you. This is quite rude and uncivilised. Why not take a break, shut up, maybe learn some physics, and troll around at other blogs? Blogosphere is big enough.

Have a nice holiday season,

Stefan

Zephir said...

/*..and there are many that are equivalent to each other..*/

Nope, the invariant light speed postulate isn't equivalent to parameter of Minkowski space.

One reason you gave already: while special relativity was postulated just for light, the above extension applies it to every massless particle. But such theory isn't special relativity theory anymore, but different, a slighly bit more general theory.

After all, the very same problem like me Einstein had in 1910 with Minkowski, who derived relativity transforms independently by using of general relativity concept 4D space-time.

Einstein was confused and anoyed by this achievment: he understood Minkovski derivation, but he wasn't sure, newly derived theory is really equivalent to his original electrodynamics of moving bodies. Now we know, his intuition was right, because Minkowski approach generalizes special relativity a bit toward general relativity. And these two theories aren't equivalent, because they can lead into different predictions. You simply cannot mix postulates of different theories together despite the pile of equivalence relations between them.

After all, the very similar inconsistency in thinking lead prof. Smolin to false claim, LQG is able to predict Lorentz symmetry violation by its definition - and he was punished for it. The fact, some extension of theory can have meaning in particular theory still doesn't mean, original theory is capable to derive it in causual way.

Zephir said...

/*.. your understanding of physics is dubious. And on top of that, you insult those who try to explain things to you. This is quite rude and uncivilised..*/

My stance toward Bee is completelly symmetric. She accused me from incompetentness many times, instead of giving relevant arguments. I know very well, Bee does many things in the way, which she learned a few years before like many others, she just never had though about it.

The mixing of mutually inconsistent postulates isn't speciality of LQG theorists in any way. String theorists are doing it in much larger extent. This approach leads into fuzzy and vague theories, which is capable to predict everything and nothing at the same moment. But it still enables to pile equations and publications, which is the reason, why scientists are using it so often.

Bee said...

Zephir:

"She accused me from incompetentness many times, instead of giving relevant arguments."

As anyone can easily see, in this and other comment sections, it has in fact been you who has repeatedly insulted me, not the other way round. I have instead done my best to ignore your remarks about my alleged "incompentence." I have given you arguments that you have repeatedly failed to address. Evidently, you don't even read enough of my explanations to notice that I'm not insulting you. Apparently it doesn't matter whether I'm polite or not, because you already know what I say before you read it, right? So, thanks for the fish, Zephir, I'm feed up with you. I hope you get happy in your dream world. Und Tschüss

B.

Psychydyl said...

On the side of the planet I live in, when creatures of the M-fliud stick their heads out (of the M-fluid) and talk about something being "natural", almost always imply, when asked, that the other state is "man-made"!
When countered, they always agree that a crow's nest is "crow-made" but "crow-made" is "natural". Only "man-made" somehow isn't.
Lol!

Zephir said...

I apologize for acussations, Bee.
I hope, our fundamental antogonism based on AdS/CFT duality won't affect well-contented survival of Christmas :-)

Anonymous said...

Stress is like a truth serum.

The cowardly, the bigoted, the demagogic and the tyrannical can all seem like quite reasonable people when the going is smooth and their physical and intellectual security are not challenged.

But as you gradully increase the stress levels, you increasingly see a more comprehensive display of people's true psychological makeup.

I have enjoyed studying these phenomena lately.

Ulrich

Psychydyl said...

@Ulrich
You nailed it! They are creatures of the M-fluid and the M-fluid permeates their selves. They're happy and nice as long as they're bathed in the M-fluid but things start getting nasty the moment you make them feel that you are trying to imply that the "M" in M-fluid stands "Moronic".

Phil Warnell said...

Hello Anonymous,

” But as you gradully increase the stress levels, you increasingly see a more comprehensive display of people's true psychological makeup.”

Thanks for pointing out how insightful the methods of the Inquisition where for having been able to discern what be truth. That’s what I’ve always maintained if only we had more thumb screwing, rackings and burning at the stake we might have had an unified theory already :-)

Bee said...

According to João, M stands for masturbation. Anyway, people differ greatly in what represents "stress." It is often neglected that both over- and understimulation is a stressor. "Gradually increasing the stress-level" can thus have individually different meaning. In any case, may I kindly remind you to omit off-topic comments? Thanks and merry Christmas,

B.

Phil Warnell said...

Hi Bee,

Although off topic I would like to offer one of the more popular and modern definitions for stress:

“Stress is the state one finds themselves in when you want to choke someone deserving to be and yet reason and a sense of humanity prevents one”

Best,

Phil

Steven Colyer said...

Stress is mental weightlifting.

When combined with Morality, it is the engine of change and can be beneficial.

When combined with Greed, bad things happen.

When combined with bombs from on high falling down about your village, it can lead to cardiac arrest and death... assuming the bombs or associated shrapnel don't get you first.

Happy Christmas, everyone!

Neil' said...

Steven, I appreciate that insightful sentiment. Greed has been the undoing of humanity's progress this decade, even more than before. Merry Christmas to you too and everyone. (I grant that "Happy" is perhaps more mature than "Merry"? - but we need merriment also.)

BTW, I notice your interest in fundamental issues of quantum mechanics. Same here, and check out the post on decoherence and many worlds at http://tyrannogenius.blogspot.com/2008/11/open-forum-dish-against-or-defend-many.html , under my namelink. Seriously, the decoherence argument is fallacious and partakes of post-modernist semantic gamemanship. I would say the process is "unnatural" in the general sense, not the directly topical point about dimensionless parameters. You need a collapse mechanism to convert distributed, wave-like amplitudes into "hits" or localized measurement events. IOW, collapse - whatever it is - converts coherent wavefunctions into one type (orderly) of statistics, and it converts incoherent waves into another (disorderly) type of statistics. But it without the collapse, the decoherence would just be a less orderly feature of something that is still wave-like. Pretending that the decoherence can cause or vitiate the collapse, instead of just setting the background for what kind of results the collapse produces, is a circular argument. Can you appreciate this? tx

BTW, do a google for quoted "quantum measurement paradox" and some posts of mine are in the top five.

Zephir said...

/*..Stress is like a truth serum...*/
Most people would rather willing to die, then to admit openly, they were wrong in public - so we can force people to deny whatever apparent fact just by proper manipulating them into their stance. It's interesting, but natural aspect of human nature which is IMO related to surface tension of small droplets: the smaller these droplets are, the higher surface tension force they're impeding against fusion with the rest of environment. While large mercury droplets are merging rather willingly, these very small ones are forming black dust, which is stable for years. I presume, the stability of weak nuclear force is the stuff of the same category - without it all observable matter would collapse into singularity immediately.

Steven Colyer said...

Neil', I'm right on board with you re the inanity of the Many-Worlds Interpretation of QM by notorious savage alcoholic Hugh Everett III. How the hell John Archibald Wheeler helped him attain his PhD with THAT pile of poo is beyond me.* I rank it right up there with the Anthropic Landscape of S.T. and Tachyons as one of the three great embarrassments of Physics and its reputation amongst the general public. SyFy writers seem to like it though, plenty.

*- "If MWI is true then nothing else is true." ... John Stewart Bell

Regarding Decoherence though, are we talking about the same thing? I think Copenhagen-Plus, or the Copenhagen Interpretation with Decoherence makes all the sense in the world ... indeed it's one of the few things ABOUT QM that makes sense!

What I AM talking about can be found in the Wiki article on Decoherence, and is explained beautifully in Andrew Thomas' Quantum Mechanics Introduction website: "What Is Reality?"

I specifically call attention to his 4th chapter: "Quantum Decoherence", which can be found by clicking here.

Read that, including the replies, then reply back if you would (and as an aside, tell your Mom I liked her poem).

Phil Warnell said...

Hi Steven,

Not to side with Neil with his preference for many worlds ,since my sentiments rest with those you indicated as expressed by Bell, however Decoherence serves no better as an explanation in the resolution of the measurement problems as it still stands as being an explanation of a mechanism in denial of a component of its required action. That’s simply to say that in any physical process one should be able to have such a process shown how it works as to be completely consistent with the theory it’s meant to support.

Now I would say that if one agrees with Bell that to believe in the truth of many worlds forces one to be in disbelief in anything else being true, then I would call this a natural argument. However, if one is going to rely on Bell’s wisdom as to what relates to being natural in relation to truth you must extend him the courtesy as to what that actually represented to be which was neither MWI or the Cophenhagen Interpretation with the addition of a incoherent proviso of decoherence. The truth being after the Fifth Solvay Conference unnatural became the rule of physics and not the exception. That’s why I often questionnot only the logic of some modern physicists who make such arguments, yet also their integrity in being so insistence.


”It is widely believed by proponents of orthodox quantum theory that the measurement problem itself is somehow resolved by decoherence. It is not easy to understand this belief. In the first formulation of the measurement problem, nothing prevents us from including in the apparatus all sources of decoherence. But then there is no longer any room for decoherence to be in any way relevant to that argument. Be that as it may, one of the best descriptions of the mechanisms of decoherence, though not the word itself, was given by Bohm (Bohm 1952), who recognized its importance several decades before it became fashionable. (See also the encyclopedia entry on The Role of Decoherence in Quantum Mechanics.)”

-Dr. Sheldon Goldstein-Stanford Encylopedia of Philosophy-Bohmian Mechanics (section 7)

Best,

Phil

Neil' said...

Steven -

OK, I will take some time to appreciate the presumably "quality" argument about decoherence. Meanwhile, so you know the context I was coming from: my complaint was based on specific and explicit metaphors and models (albeit Sci-Am level and not the hardest math) from for example Chad Orzel at Uncertain Principles. I am just basing on what they actually said. Chad and others have used e.g. the example of the MZ interferometer in which the phase difference changes from one photon 'shot' to another. Presto, collapse is either explained or avoided or transcended or is only apparent etc., because the statistics (again, taken for granted themselves - from what?) now resemble classical statistics. - !? Never mind, how scrambling waves could lead to "statistics" anyway - waves are determined quantities spread over space and time, with deterministic rules for their evolution. You can't get "statistics" or sudden events without a break in the system, as Phil implies as well - but I'll look at your material.

Uh, No. Like I told him and/or others at various places: you don't even have to right to say a given WF construct would have one part just chucked or tossed off into another universe, and the rest localized - just because later (independent!) - shots through the same device have a difference phase between the new WFs in the new cases. The best argument may be better, but that is what I actually heard. Either it's that bad, or they can't explain it right.

Phil - I was using multiple worlds (and the separate kind with different laws, not the QM multi-worlds) more as a reductio than my being sure they really exist. I say, *if* you assume everything must exist in accordance with pure logical requirements of no special privileges for some possible worlds, then you have trouble.

BTW thanks Steven for liking my mother's poem, and she appreciated that! It is her second Internet clap (earlier, from Facebook personality and my FBF William Hodge who reposted it.) I will try to have more, and more variety, at my blog. (I want it to be worth "following.")

Neil' said...

(Like I told Chad, if ambiguous...)

Phil Warnell said...

Hi Neil,

Without going through all the details, whether it relates to many worlds parallel or not Bell’s argument would hold the same as being true, since actually only in parallel does the MWI have any semblance of decoherency at all, as one can’t have things to be decoherent unless they originally where coherent.

Best

Phil

Neil' said...

Phil,

I may be talking at cross purposes but as I understand it the coherence argument has to do with the phase between components of the WF in an actual case, in "our universe." Indeed, I don't even know what an "incoherent superposition" would be since that implies that the phase angle itself is uncertain between actual, concurrent states right here and now. In an ensemble it might make sense to imagine (pretend?) it is that way because of variations between instances, or due to our not knowing the "actual" phase.

Yet still, let's say we have a superposition of e.g. up and down spin, and nothing to take one of the them away except an intrusion into the deterministic formalism. Multi-worlds are mostly just a rug to sweep the "lost" state component under when the measurement reveals a selection. They aren't fundamental IMHO to the principle of the thing.

Phil Warnell said...

Hi Neil,

Like I’ve said many times I have no wish to turn any thread of Bee’s into a long discussion regarding the foundations, primarily out of respect for the intent and focus of this blog that serves a much wider interest and which I’m also grateful for. Yet to be completely forthright if you ever had the occasion to look at my blog you it might lend a hint as to why this single issue is no longer what captures my attention and that being I carried out such an investigation over the course of almost ten years, whereby I ended up not only exhausting myself in the process, yet also the patients of some which I never would wanted have strained. However equally important is that I found in conclusion there will never be any chance of making such distinctions before someone(s) purposes an experiment that could make such decision and it is actually successfully conducted with it in turn having its results assessed to exhaustive satisfaction.

With all that said I will shortly address your point in saying I believe you have the gist of the argument where it applies to a theory of a singular ontology, which any orthodox view of the actions of the quanta essentially are. With other models including MWI and things like the pilot wave model there are two things to be real and true to accommodate how what we observe is the way it is. With MWI its the action of particles resultant of an observers singular choice taken as the consequencial end result of infinite results of many world, while with the pilot wave picture it’s the actions observed of a real particle under the influence of a equally real guiding wave with all the permutations and possibilities it allows for in terms of configuration space. The fact is I can’t say for certain which of either be true if any at all. So until experiment find a way to make a choice I use the wisdom I find in two statements to guide my own preference which are as follows {

“But immediately upon this I observed that, whilst I thus wished to think that all was false, it was absolutely necessary that I, who thus thought, should be somewhat; and as I observed that this truth, I think, therefore I am (COGITO ERGO SUM), was so certain and of such evidence that no ground of doubt, however extravagant, could be alleged by the sceptics capable of shaking it, I concluded that I might, without scruple, accept it as the first principle of the philosophy of which I was in search.”

- René Descartes - Discourse on The Method: of Rightly Conducting The Reason, and Seeking Truth in the Sciences (1637)

Combined With

“ I yam what I yam and that’s all that I yam”

E. C. Segar-(As expressed through his fictional character Popeye the sailor)

This is not intended as a joke as I consider both statements to represent the truth as being for me self evident.

Best,

Phil

Steven Colyer said...

This discussion re Decoherence is getting confusing. I think part of the confusion is the 500-lb gorilla in the room that no one wants to talk about - Consistent Histories (as proposed my Gell-Mann, Hartle, Omnes, et. al.), as Andrew Thomas mentions in the replies to his webpage.

My personal opinion (which may well turn out to be be wrong), and Andrew's if I read correctly, is that Copenhagen + Decoherence is enough (if not complete), and CH isn't needed. But in any event ...

Sorry to see you spent 10 years on Q-Interpretation before coming to your rational conclusion, Phil, a conclusion I share. It took me about six months to reach that same place.

I could have continued as you did, but I felt there's simply too much work to be done based on what we are SURE of - I've found discussions of QI to be a bottomless pit which as you said, awaits better future experimental results to flesh out. Until then - all is speculation.

Phil Warnell said...

Hi Steven,

First let me say I’m glad you moved on to find what was out there that perhaps had a better chance of being resolved. In many ways you could say the whole point behind theoretical physics’ current attempt to find resolution to the problem from the point of view that when QM and GR are brought into harmony these questions will in some way simply be one of the fringe benefits. I’m not saying that won’t be the case, yet I would insist that before you know you have the right answer, not just the question asked should be clear, yet also what forms to be what the question actually is to begin with for the answer to be considered as correct. So in respect to QM and its interpretations as to how what we see is the way it is, for me would be for such a theory to go beyond what Richard Fenyman’s proviso of considered completeness was when he said:

One might ask: “How does it work? What is the machinery behind the law?” No one has found any machinery behind the law. No one can “explain” any more than what we have just “explained” . No one will give you any deeper representation of the situation. We have no idea about a more basic mechanism from which the results can be deduced.

-The Feynman Lectures on Physics- Volume 3- Chapete 1

I realize there are many that say to insist in having to find such a mechanism is simply irrelevant from the point of view that science only requires that we discover ways of making predictions by way of our theories that are consistent with experiment. In truth if this is the limit which science places on itself, who then am I to differ, yet would dispute it has the ability to explain the world in terms of substance and actions to the satisfaction of many who thought it might be able offer more.

Therefore my sole contention is I’m convinced that it can and to accept such a limitation can do nothing other than prohibit it from being able to. So I still wait for an explanation which can have this be known as supported by experiment. That is I find nothing wrong with insisting having the question be the right one, yet do have problems with those that insist they have them without having what’s required as proof that they do. That’s to say what can be said to be a natural quality of nature if we refuse to ask why and then to prove how that is necessarily so.

Best,

Phil

Plato said...

The Book: A Chapter Still to be Read

Since we all understand that this forum does not make allowances for the diversity and implementation of opinion in all it's regalia of bloggery design :), I thought to link since the thoughts prevailing do have me thinking in correlation to the opinions here.

Best

Neil' said...

Plato, Bee is actually rather generous and tolerant about this blog and what we can post as comments (maybe too much sometimes!) That's good, since some cross-pollination and seques can be relevant and instructive to the host post. However, readers surely do appreciate using links AMAP instead of text in comments, for anything not as much on-topic. After digesting some more QM arguments I plan to link to more posts to my own blog about decoherence etc. rather than letting it all hang it here. BTW I will present some really IMHO compelling challenges to the decoherence argument. Note also that much of my complaint is about the models and metaphors being used, not just the formal theory such as it is.

Phil Warnell said...

Hi Neil

In agreement with the intentions of this post, one could say that Bee is naturally generous and tolerant:-) In respect to the foundations however they are the search for what it is that has things to be natural. I find it then interesting such misunderstanding was what prevented Einstein to discover as to accept being possibly natural what later was proven as surely true and yet indeed still a mysterious aspect of nature.

“This makes the reality of P and Q depend on the process of measurement carried out on the first system, which does not disturb the sevond system in any way. No reasonable definition of reality could be expected to permit this.”

-Can Quantum-Mechanical Description of Physical Reality Be Considered to be Complete?-Einstein, Podolsky & Rosen (Physical Review, May 15, 1935, Vol.47)

What becomes evident for me with this, is that despite such lessons of history many theorists still make the same mistake, that is failing to realize their job is not to insist how nature should be, yet rather through the method(s) of science have it demonstrated for what they are. That’s to remind the most important aspect of science is doubt, yet not on what nature presents, but rather what one believes.

Best,

Phil

Neil' said...

Thanks Phil. Note: I am not critiquing e.g. decoherence argument because I don't think nature could be like that. Indeed, it is the other way around. The old school of QM accepted that it "didn't make sense" for a wave function to be spread around and then, somehow, a localization and collapse occurs via measurement. They accepted that nature is just weird. It was the decoherence thinkers that couldn't imagine or accept such a thing being true, and tried to "explain" it (away) via fallacious, circular arguments involving such as changing phases between different cases (not even just in the particular instance at hand, evidenced by their slight-of-mind misuse of the density matrix!) But I will look at the "better" arguments noted above. As for experimental evidence, I have a proposal out shortly that might make the point.

Phil Warnell said...

Hi Neil,

I understand you point, yet as far as I’ve been able to fathom decoherence does not logically (rather that naturally) present itself as being the resolution of the measurement problem in connection with any theory founded on a singular ontology. That however is also only a belief which still requires able to be made falsifiable as to be supported by way of experiment. That’s why I find it so unfortunate for science that J.S. Bell had such a brief existence, not because he may have solved more, yet rather if there was anyone that represented the conscious of science it was surely him; for which currently I see no replacement.

Best,

Phil

P.s. If you do ever come up with a falsifiable experiment I wish you luck or rather should I say that it become the most probable outcome:-)

Plato said...

Hi Neil,

I wrote:Since we all understand that this forum does not make allowances for the diversity and implementation of opinion in all it's regalia of bloggery design :)

I meant this literally.:) Has no other connotations.

I cannot post all that I do here to show that I am thinking about all the opinions as I said before.

Acoustic Blackholes?

Sometimes once you understand "a story and own it" it can change the way you look at things?:)

Sort of like, consuming it.

"Actually detecting the sound waves produced by the hole is really tough. But this is an exciting first step," says Bill Unruh of the University of British Columbia in Vancouver, Canada, who first proposed the idea of using quantum fluids to create artificial event horizons.See:Physicists create 'black hole for sound'

Metaphorically correlations can help extend our understanding.

Best,

DaveS said...

A beautiful and natural post. Parts of what you said call into question as to whether the universe is alive, and by that I mean whether it may respond to advances in human knowledge