Sunday, August 21, 2011

Physics and Philosophie

I'm looking for topics where theoretical physics has a relevance for philosophy, for no particular reason other than my curiosity and maybe yours as well. Here's the usual suspects that came to my mind:

  1. Are there limits to what we can possibly know? The human brain has a finite capacity and computing power. What limits does this set? Is it possible to extend? What is consciousness?

  2. Why is the past different from the future? What is "The Now" and why do we have an "arrow of time"? (Or several?)

  3. Is there a fundamental theory that explains everything we observe and experience? Is this theory unique and does it explain everything only in principle or also in practice?

  4. Do we have free will? And what does that question mean?

  5. Are there cases where reductionism does not work? And what does that imply for 3?

  6. What is the role of chaos and uncertainty in the evolution of culture and civilization? Is it possible to reliably model and predict the dynamics of social systems? If so, what does that mean for 4?

  7. What is reality? What does it mean to "exist" and can an entirely mathematical theory explain this? Does everything mathematical exist in the same way? Why does anything exist at all?

  8. And Stefan submits: What is the ontological status of AdS/CFT?

88 comments:

Johann said...

Hi Bee !

Those are great topics !
Some I'm very passionate about, so I'll share my thoughts :

1) We already got an answer since a long time, because sciences and math particularly exist precisely because our brain capacity is limited. I think they are our attempt at going beyond our limitations.

2) Haven't got enough insights in physics to build a pertinent case. Fascinating question though...

3)I think our limitations are here the main obstacles to such a theory. Not that it cannot exist, but I doubt we could grasp it. If it had to be logical and purely based on math, the answer is clearly no, not possible, because math themselves cannot give us a complete coherent theory, there's always some bivalent foundations, I mean like some axiom that can give us coherent theories based either on itself or its negation. It can be viewed as a problem of interpretation, as in model theory (two different models can give different meanings to the same proposition - that is to say one can be right for a model and wrong for another).

4) Too difficult a philosophical question for me to have any definite idea. All I can think of here is that it may well be tied to question 2 and the nature of time...

7) The answer to 1 makes me think that mathematical objects do not exist beyond our thoughts.

Hope my views don't seem too simplistic, but they clearly are influenced by the fact that I studied a lot of math, even though I didn't make it my profession.

Always nice to read you !

Best regards,
Johann

Plato said...

That's quite the list Bee

What is the ontological status of AdS/CFT?

See: Heretic

Use his search feature and type in, "AdS/CFT"

Best,

Varun said...

Hello, Bee. I'm a high school student from India, and am following your blog from quite some time. This post seems quite intriguing to ponder upon, so I'll just post my thoughts on it.

1. There has to be a limit. Our brain capacity is limited, although the purview is expanding day by day. But we cannot decipher everything, we cannot even verify our knowledge. Everytime we explore more, we know more, and more discrepancies come up. The Dark matter and dark energy problem is a perfect example of that.

2. Brilliant, philosophical question. But I've perhaps thought enough on it to form an opinions.

3. No there shouldn't be. Or if there is, it won't be an ordinary theory. It would have to explain how and why things evolve over time, i.e. why events occur, precisely how are particles are formed, what formed space, and then to the more complex questions, what decides the behaviour of living organisms, are their parallel universes etc. It will have to be a *something I cannot describe* and all the other theories aforementioned will have to come out of it naturally.
And it has to be more probabalistic like the quantum theory, that a physical phenomenon has a certain chance of occuring.

4. We have and we have not. That means we have the free will, but there are plethora of factors that restrict it, namely conscience, society, stereotypes, prejudices etc.

5. There might be, but I don't know if they are. I require more understanding of the topic I guess.

Arun said...

Does the problem of measurement in quantum mechanics impose an arrow of time?

Arun said...

When a concentration of talent and money unprecedented in the history of the world is directed at a problem and there is little headway, what is the cause? E.g., grand unified theories or theories of everything.

What is a fruitful approach to the problem?

a. The problem is intrinsically hard.

While this may be the most-likely-to-be true answer, it is the least interesting from the sense that there is nothing we can do about it.

b. We're trying to answer the wrong question

(e.g., trying to explain the radii of planetary orbits instead of their periods.)

c. We're trying to find an answer to suit our theoretical prejudices

(e.g., epicycles to describe planetary motion).

In particular, in QFT, we've been trying to describe the dynamics by ever-increasing use of symmetry principles. Pros: (a) it has worked so far as the Standard Model has concerned (b) the models are more "beautiful" (c) the mathematics is more tractable. Cons: (a) each not-yet-observable symmetry requires a symmetry-breaking mechanism and a mechanism to stabilize the symmetry-breaking scale (b) symmetry principles do not constrain the solution space enough - there is a landscape problem that is fatal in the absence of sufficient guidance from experimental data.

Are there additional principles of dynamics to be discovered?

Jonathan Shock said...

Have you seen this recent essay on the relation between philosophy and computational complexity: http://www.scottaaronson.com/blog/?p=735 An enjoyable read, though I have my contentions on a number of issues.

Phil Warnell said...

Hi Bee,

All good questions which deserve equally good answers, with the answer to the first having a direct impact on the rest. So from my point of view, if we confine human capacity to what we come into the world with then most if not all of the rest of the questions could remain to be unanswered. However, as we have already been demonstrated as able to extend this, both through mutual cooperation and technical means, I see no reason to find it has a limit beyond the capacity of reality itself and yet equality as important as it relates to our desire to have them answered.

As for any firm opinion regarding the rest, I must confess to having none, yet I do have a keen interest in number four. That is what I would like to have discovered is that we do actually have freedom of will to some degree and yet fully realize that if it exists at all it is greatly restricted; that is at least at present. Then again if it is ever shown that will is not something that is free (or ever can be) then another question arises, that being to what then can will be attributed to as being, as then what is to account for that which will has shown to have clearly accomplished.

”When man thinks of himself in this way, he will inevitably defend the needs of his own ‘Ego’ against those of the others; or, if he identifies with a group of people of the same kind, he will defend this group in a similar way. He cannot seriously think of mankind as the basic reality, whose claims come first. Even if he does try to consider the needs of humankind he tends to regard humanity as separate from nature, and so on. What I am proposing here is that man’s general way of thinking of the totality , i.e. his general world view, is critical for overall order of the human mind itself. If he thinks of the totality as constituted of independent fragments, then that is how his mind will tend to operate, but if he can include everything coherently and harmoniously in an overall whole that is undivided, unbroken, and without a border then his mind will tend to move in a similar way, and from this will flow an orderly action within the whole.”

-David Bohm, “Wholeness and the Implicate Order” Introduction page Xi (980)

Best,

Phil

Len Ornstein said...

All these questions of course, assume a set of 'axioms' of language.

The definitions, syntax and grammatical rules of all languages (including informal and formal logic and mathematics) are implicitly or explicitly 'agreed to' in order to make it possible to communicate to another on issues of potential cooperation (ultimately) in order to reduce uncertainties of survival.

The commitment to a set of 'axiomatics' is an article of 'faith', and is the basis of anyone's resulting 'belief' in ANYTHING – whether well-reasoned – or not.

You may be ambiguous about which axiomatics you choose to use. And this may generate conflicting 'answers' to many of the topics, as noted in Arun's:

"...some axiom that can give us coherent theories based either on itself or its negation. It can be viewed as a problem of interpretation, as in model theory (two different models can give different meanings to the same proposition - that is to say one can be right for a model and wrong for another)".

So:

1) Yes, their are limits to what we can know, because axiomatics are elements of faith – not of 'reality'.

2) No Comment.

3) Only if you're a Platonist!

4) EVERY ONE OF US implicitly acts as if an 'axiom' of free will is strongly believed. We probably can't get beyond that through non-circular argument ;-)

5) We can probably never 'know'.

6) No comment.

7) "Reality" is the input to our senses and their extensions (telescopes, microscopes, particle accelerators, etc.). We try to share models of reality through our 'languages' (including, arts and technology), but it must always remain incompletely described because we can never have experienced all of the past – let alone the future. Mathematics involves only models – most of which have NO relation at all to "reality". "Exist" has too many meanings to respond to in this context.

8) No comment.

Eric said...

On the question of 4:

I've decided free will exists when we need it. I base this opinion on the principle of asymptotic freedom and confinement. We need to have free will to differentiate ourselves. Again, this is shown in the behavior of identical twins raised together where the genetic and environmental component is pretty well removed. They self-differentiate to be able to have their own identity with their parents. If that isn't evidence for free will then I don't know what is.

I also think this principle works works for the larger universe as a whole. We attain our identity through our interaction with the universe. However, the more we are separated from our closest counterparts in the universe the more we all converge in behavior and identity to one another. Just like quarks in a nucleus.

JDM said...

If I could answer all those precisely I would be God - Literally!
But to summerize it all, I would have to say there is no such idea as free will, at all, even when speaking in terms of matter and light - the carriers of time.

Eric said...

3. Is there a fundamental theory that explains everything we observe and experience? Is this theory unique and does it explain everything only in principle or also in practice?

I actually think asymptotic freedom and confinement "may" be a more fundamental part of physics than symmetry. For instance, one could argue that symmetry breaking occurs just so the universe is allowed to self differentiate in its condensed compacted state. This is the high energy state where the forces themselves differentiate. This has to occur before particles themselves self- differentiate. But that differentiation process in the condensed state can still be put under the umbrella of differentiation through asymptotic freedom.

The confinement process can then be considered as a process where both the identities of particles and forces start to converge again as the expansion of the universe proceeds. I personally think that there is evidence of this in what is witnessed as dark matter. It seems to me as the galaxy expands it is experiencing something very similar to what happens with quarks in nuclei. The galactic cross section diameter is being confined as it expands.

So I think asymptotic freedom and confinement is very fundamental not only to physics, but also to each human beings experience of the world. Steven Weinberg alluded to this in a talk he gave a few years ago but I don't have a link to it. He didn't use the same explicit arguments I've given but his conclusion was similar.

Arun said...

I suppose free will originally was a theological question - can a human do something contrary to God's Will? Would not the performance of such an action also be in accordance with God's Plan? What kind of omnipotence would God have if it weren't so?

With physics I suppose it became a question of determinism. If the equations of physics make predictions from initial conditions, then in principle, since I am a physical system, my behavior is predictable. So do I have only the illusion of choice, as my behavior is entirely determined by the initial conditions?

If physics can successfully make such predictions then we do not have free will. If physics cannot make such predictions for practical reasons, then the question remains open.

Chaos and QM complicate the discussion.

Uncle Al said...

Are there limits to what we can possibly know? Economics - yes.

Why is the past different from the future? Causal universe. Why do we have an "arrow of time"? Feynman's sprinkler does not run backwards. Angular momentum defines the arrow of time. A chiral universe only runs in one temporal direction.

Is there a fundamental theory that explains everything we observe and experience? No. Las Vegas casinos arise from statistics, but Las Vegas winners arise from fluctuations. Gödel and Feigenbaum have strong hands.

Do we have free will? Absolutely yes. We are only bound by personal survival and cowardice. What does that question mean? You only need behave in a toxic society if you cannot buy cops, courts, and legislatures. If you do not know who the patsy is, you are the patsy. Reality, OTOH, ignores you to death. Nature does not care, we do.

Are there cases where reductionism does not work? Self-awareness. And what does that imply for 3? The future is a vicious life-sucking bitch from which there is no escape. Empirical truth is important for enjoying the ride.

What is the role of chaos and uncertainty in the evolution of culture and civilization? No determined future can work. Positive feedback demands light feet at all levels - especially in those lower levels without granted authority to bridge parts of the universe that were accidently omitted.

Is it possible to reliably model and predict the dynamics of social systems? No. Hari Seldon was wrong. Dissipative systems sometimes add.

What is reality? Absent optics, nothing is to be seen. Given optics, the view suffers aberrations. Putting your head in an opaque box still affords shot noise. The universe is about unlimited possibilities, most of them being unpleasant. The only survivable solutions are engineering solutions.

Why does anything exist at all? The universe exactly sums to zero. Art lies in keeping two sets of books.

And Stefan submits: What is the ontological status of AdS/CFT? Conformal field theory is typically explored in 2-D. In higher dimensions (e.g., Calabi-Yau, AdS/CFT correspondence, supersymmetric gauge theories, Sasaki-Einstein) it yields string theories having no empirical tests. The universe is not fundamentally mirror symmetric. Perturbation treatments do not validate Euclid drawing triangles on a 2-sphere. CFT, though rigorous, cannot bring forth a physical model.

The weak postulate's failure is demonstrable at will. It originates outside physics or it would not be valid. Opposite shoes falsify the Equivalence Principle. Somebody should look.

http://www.mazepath.com/uncleal/erotor1.jpg
Two geometric parity Eotvos experiments.

JDM said...

Correction
I will attempt to write this,
but unfortunately it is not free,
it takes energy in the form of work;it also take influence -
I am writing under the influence during a fraction of my entire life.

Christine said...

Hi Bee,

I think there is link between 1 and 7 if you think in terms of nature as a completely knowable entity (be that knowledge obtained by whatever means). If the latter is not true, then there is an intrinsic limitation and nature would have secrets that are unknowable by design (even to itself?!). But if it is 100% knowable, then it can only be understood if there is a 1-to-1 correspondence between its most pristine fundamental elements and a representation system (e.g. mathematics, computational power, whatever of the sort). Our brains might be able to achieve that or not.

Reality, otoh, would not be a definite property of nature, under the above perspective. Unknowable secrets could be real. Knowledge could be unreal. Reality seems a pre-nature thing.

Best,

Christine

Bee said...

Hi Arun,

Interesting question, as I was thinking about this recently. I think it does. Not sure though how this arrow of time corresponds to others. Best,

B.

Bee said...

Hi Jonathan,

Yes, I saw it, but didn't read it. Best,

B.

Bee said...

Hi Christine,

Yes, I agree, these two are related. So is 1 and 6. I think 1 is an important question because it might mean that there's some level of insight and also management of civilizations that we'll never get across. At present, I'm not very optimistic about the Singularity saving the day... Best,

B.

Steven Colyer said...
This comment has been removed by the author.
Steven Colyer said...

The human brain has a finite capacity and computing power. What limits does this set?

That first sentence is an assumption, possibly untrue, and having worked with philosopher-Physicist Lee Smolin, you know Philosophy's gift/use to Physics (with feedback) is to question the assumptions. If only we could get Warnell and Plato to understand AdS/CFT correspondence math we'd have more answers.

Regarding that first assumption, might it NOT be true? Macroscopically it might be true, just as macroscopically it seems that the sun revolves around the Earth. But consider we use our brains to interact with other brains, both living and dead (through their writings). There is potentially an infinite number of them.

Is it possible to extend?

Very much so. The Cojoiners in Alastair Reynold's sci-fi books produce a human hive mind, via nanotechnological nets interweaved with neurons such that all individuals can talk to each other, either directly (telepathy) or via a central superdupercompuer. This technology however, if it comes to pass, is easily 100's of years in the future.

Large, but still finite, I know, Bee. :-)

What is consciousness?

The hottest potato of them all and a question I studiously avoid. Except this: the EXPERTS in Biology who specialize in answering this question can't even agree on its definition, so we're probably 50 years away from serious experimentation.

Free Will vs what? Destiny?

I logically deduced at the tender age of 37 that Free Will does not exist, only its illusion. I'm not happy about it. Before that I would have vociferously defended Free Will. But I may be wrong. If I find time this week I shall try to reconstruct.

One interesting factoid is that the press tried to say that Quantum Mechanics proved the existence of Free Will when QM was new in the 1920's, but it does not. The Encyclopedia Britannica (Macropedia) has an interesting explanation for this, in the QM section article "Mechanics." Nor does QM refute Free Will.

Christine said...

Hi Bee,

As for #4, we only have free will if nature has free will. According to our present understanding, nature is a constrained system, so we are.

Best

Christine

Christine said...

Hi Bee,

As for #3, in connection to my previous post, it is related to whether the knowable representation of nature is "one-to-many". Then it is a question of the contigency of our representation versus an intrinsic property of the knowable nature. We might be often fooled to think we have a final theory. Or not.

Best

Christine

Plato said...

Still got to love the generalizations on AdS/CFT Steve.:) I try.

Christine said...

Hi Bee,

As for #2, I am partially with Bergson. Time is a coordinate. We must understand what *duration* is. Not simply an interval between two time coordinates.

Best

Christine

Plato said...

A Conformal Field Theory Approach. What does this mean Steve?:) Yes I agree, it is very interesting.

Bee said...

Hi Steven,

When I wrote "The human brain" I meant "The human brain" and not "the connection of all human brains". Which, I'd want to put forward, will also have finite computing power because there's arguably not infinitely many humans. The question isn't whether or not it's finite, but whether it's large enough to understand everything that can possibly be understood or, if you just consider the first step, if we'll be able to take the second step at all. The human brain has a finite amount of cells, neutrons, synapses, and it has a finite amount of time because it ages. All that prevents it from being able to process and solve, and also to understand, arbitrarily difficult problems. Best,

B.

Christine said...

Hi Bee,

As for #6, forget it, Bee. In fact that item doesn't interest me at all. It is clear the human being is unpredictable. Be one, many, or the infinite limit of them in an abstract mathematical model of mankind. Not clear? Well, I can't prove that. But, really, I wouldn't waste my time, because in the grand scheme of things it doesn't matter, except perhaps for a dictator willing to find a way to gain control over... ;)


Best,

Christine

Bee said...

ah, i meant neurons, not neutrons... Anyways, the number of neutrons in the human brain is also finite.

Christine said...

Hi Bee,

Finally, as for #8, as far as you see it as a spinoff of quantum field theory, it is just Ontic Structural Realism. But I wouldn't bet on that. :)

Best,

Christine

Steven Colyer said...
This comment has been removed by the author.
Steven Colyer said...
This comment has been removed by the author.
Steven Colyer said...

I wrote:
Large, but still finite, I know, Bee. :-)

You might have missed that, I understand completely, I suppose I wasn't being clear and so: sorry.

Infinity is a concept, yet for all intents and purposes, the number of humans on Earth is so large (7,000,000,000, yes?), that it may as well BE infinite, for no one of us can get to know everyone else, not even close.

But the computer changes all. One person can move the world easier than ever. One needn't expend the energy Alexander did to take over the Greeks and march on Darius in Persia. One mind, right now (yours for example), can effect millions.

And yes while I understand you meant the capacities of each individual brain, my point was that no brain exists in a vacuum, and therefore it is our intellectual interactions that "grow" our species, not one individual at a time, but many individuals at a time, and groupthink manymerge onesupermind may come to passthink.

baghdadserai said...

1. No matter how you come to know truth, there will always be truth you do not recognize.
2. I did not know the answer to this question yesterday, I do not know the answer to this question now, but perhaps I will tomorrow.
3. Yes, with the exception of the table tennis games and jazz saxophone solos.
4. No, generally it’s pay as you go.
5. You can ride the bike or take it apart, but not both at the same time.
6. Grw vviond xplshekk, shock whskn koan.
7. This is reality. Mathematics is reality; just add 3.62 cups of water. Why not?
8. The same as that of a baby’s diaper, changing.

Kay zum Felde said...

Hi Bee,

one question you mentioned is: does knowledge has an end ? I think it is like a logarithm, that means we come closer to full knowledge, but the steps gonna be smaller day by day.

Best, Kay

Donnerstilzchen said...

Hi Bee.

Now let me try on some of the hardest problems known to mankind.
The Questions 3,5,7 and 8 belong to ontology. From a logical point of view, ontology leads into inevitable circles of arguments. You can not prove statements about first principles from inside what is given already. (This applies for realists. Idealists just insert "what is perceived already") Without a foundation, ontology can only serve pragmatic purposes. There is an implicit model which you ultimately have to use when thinking about things, consisting of you and the world as two separable things, sharing abstract similarities. One can question that.
Fortunately, as a human being, you are not limited to logical arguments. You can believe in arbitrary numbers of contradictions without getting hurt in your brain. It only becomes increasingly difficult to tell what is "you".
Regarding Question 1: No logical system can tell about it´s own limits, for this you would need a meta-system. This then leads into another circle. But again, you don´t have to argument logically.
No 4: No answer, due to problems with my understanding of the concept named "will".
Question 2: need more relevant input about "time", same with no 6: "chaos".

Best,
Donnerstilzchen

Eric said...

This kind of series of questions is more of a rorschach test of your inner prejudices than anything else. A bit silly in my view. But what do I know.

Michael F. Martin said...

Read more Wittgenstein. The questions you ask are physics questions, not philosophical questions. Philosophy is a language game.

Ulla said...

The AdS/CFT question is actual for me. What can it be compared to and how relates the different spacetime concepts?

I have understood it is rather primitive, but much science is done with this frame. Is it only because of lazyness?

The questionlist can be seen only as a frame and reminder. So complex questions cannot be answered here. You forgot the most controversial, the cognition.

The Unknowable and Gödel etc. showed there are always things we cannot know/measure. If the space is folded, as instance.

http://www.cs.auckland.ac.nz/CDMTCS/chaitin/unknowable/index.html

William said...

At 8:54 AM, August 22, 2011, baghdadserai said...
7. This is reality. Mathematics is reality; just add 3.62 cups of water. Why not?


Mathematics should not be confused with reality. But, unfortunately, by a subconscious process of reification, the brains of mathameticians are physically wired to believe in the tangibility of the purely mathematical concepts which they think about frequently.

So, in that way, things like point objects of math are unabashedly considered by them to have real physical existance. Yet the real existance of concepts such as point objects and 2 dimensional strings is totally absurd, but the process of reification has surreptitiously beguiled their minds into believing in their tangible reality. It happens on a neural level, without their even being aware of the process happening.

Sure, in math it is easy to add 3+pi cups of water .... but in reality, that is impossible.

mathematical world =/= real world

Giotis said...

"ontological status of AdS/CFT"

what does this mean?

William said...

What is the ontological status of AdS/CFT?

Holograms are fun flashy toys.

You shine a laser through a pinhole, you get a zone-plate pattern. You shine a laser through a zone-plate pattern, you get a point. So that is the crux of the game. A discrete object can be encoded as a large 2D pattern, and it can be reconstructed therefrom.

But the object is not the pattern, and the pattern is not the object. Without the laser, all you have is the object in reality and a pattern in theory.

William said...

"Is there a fundamental theory that explains everything we observe and experience? Is this theory unique and does it explain everything only in principle or also in practice?"

No there isn't one in hand, but if the universe is deterministic (which ist is and must be), then such a theory is possible. Have to have get the right model and find the hidden variables.

William said...

What is the role of chaos and uncertainty in the evolution of culture and civilization? Is it possible to reliably model and predict the dynamics of social systems? If so, what does that mean for 4?

Chaos and uncertainty are mainly important in that they lead to sex between unlikely partners. And having sex is why we exist, and why we exist is from sex being had ... so that must be important.

Chaos and uncertainty also contribute to the impovershment of the lower classes, in the form of lottery games, where it is proven that the poor are the victims of those "luck of the draw" games.

Chaos and uncertainty are used by the rich who operate the casinos of Wall Street to repeatedly beguile and scam "investors" on a regular basis ... constantly taking wealth from the working class and even upper class, and concentrating that wealth in the hands of the small elite of mega-wealthy who run the Wall Street casino. (Wealth on Wall Street defies thermodynamics, in that it always becomes more and more concentrated.) And so in that way it is critical to the structure of society.

William said...

"Are there limits to what we can possibly know? The human brain has a finite capacity and computing power. What limits does this set? Is it possible to extend? What is consciousness?"

yes.

dunno

yes ... mankind must eventually transfer to AI .. AI is a game-changer

you know: "you know"

Bee said...

Hi Giotis,

I think it means, is the world 'really' a hologram, rspt are both sides of the duality equally real. I am aware that this question doesn't make sense unless one knows what 'reality' is supposed to be. I personally don't believe that reality "is" the math that we use. I take the pov that it's just a model that describes reality more or less well. In this case one has a 'dual model' rather than a 'dual reality' and I have no problem with that. If you however believe that math is all there is to reality, and that math has a dual in some other theory, then that must be real as well. Or is it? Best,

B.

William said...

Why is the past different from the future? What is "The Now" and why do we have an "arrow of time"? (Or several?)"

We did this one a couple of years ago, in the past! The interesting theme back then was block time, as I recall. Haha ... speaking of block time in such temporal tenses.

Anyway, my thoughts on that now are the same as back then.

Plato said...

Bee:I take the pov that it's just a model that describes reality more or less well.

I think people are most definitely stuck in varying PVs.

I think that the point of asking about a ontological perspective by Stefan, is it not as to where bouts does this AdS/CFT correspndence concept/model stands?

Giving pov perspective toward how the model is developed becomes a template for assign certain attributes to understanding parts of the issue and where they can be seen in the model.

For me experimental correspondences needed to be understood where this model may be used, and this help direct my attention to the QGP.

How is one ever to describe what is happening toward such a singularity? That was my perspective but this one was even more evident.

I sometimes why Clifford used the word "Heretic" for his posting.:)

I am reading opinions and still thinking about the rest of your list.

Best,

Arun said...

Are there measurement procedures for QM systems that do not increase the entropy as a result of the measurement?

Eric said...

Terrific question Arun!

Uncle Al said...

@ Steven Colyer, What is consciousness? Consciousness is the ablity to feel sad.

Big Pharma suspends consciousness, government trivializes it. The First World oozes dependency, multiculturalism, contrafactual historical fantasies, and virulent Luddism. On 20 January 2013 we'll have snake-handling POTUS Elbert Snork. Darth Vader has been overthrown by Jar Jar Binks, and not a tear has been shed.

Giotis said...

Hi Bee,

I'm not sure I understand exactly but as I see it the two sides of the duality are just two different descriptions of the same physics but in different regimes.

In the large t'Hooft coupling λ>>1 the supergravity (geometric description in the bulk) is the appropriate language to describe (and to do) physics.

In the small t'Hooft coupling λ<<1 the field theoretic perturbative language is appropriate to describe the same physics.

Or in other words:

The strong coupling limit of the field theory is described by (or is) the week curvature limit of the of the gravitational theory.

and the strong curvature limit of the gravitational theory is described by (or is) the week coupling limit of the field theory.


So I see them as two different languages able to describe the same physics in different regimes. None of them is more real than the other; what ever that means anyway...


Which of the two sides is the fundamental one and which is emergent is a different question. The conventional wisdom is that the field theory in the UV is the fundamental one from which the gravitational side (and thus spacetime) emerges. This is because in the week coupling limit of the field theory there is no dual spacetime description, it emerges at its strong coupling.

So again both describe reality but in different regimes(this is why they are called dual). At least this is the way I understand it but anyway I didn't even know that there was a debate about this and so I'm not well informed; maybe I'm missing something.

mmfiore said...

I believe that there is a fundamental Theory. As an alternative to Quantum Theory there is a new theory that describes and explains the mysteries of physical reality. While not disrespecting the value of Quantum Mechanics as a tool to explain the role of quanta in our universe. This theory states that there is also a classical explanation for the paradoxes such as EPR and the Wave-Particle Duality. The Theory is called the Theory of Super Relativity and is located at: Super Relativity http://www.superrelativity.org
This theory is a philosophical attempt to reconnect the physical universe to realism and deterministic concepts. It explains the mysterious.

Christine said...

Arun asked:

Are there measurement procedures for QM systems that do not increase the entropy as a result of the measurement?

Classical or von Neumann entropy?

Christine

Neil Bates said...

This may not be a limit on what we can possibly know but at least on, what we can know "logically": the old idea that someday we'll find a sort of mathematical explanation of why the universe is the way it is, cannot happen. That hope was based on a fundamental category mistake, and one you can get a good inkling of why a mistake if you read Paul Davies' books or dig into modal realism. (I know, I have a hangup about all that.) Math and logic can only tell us about relations inside and among various "possible worlds" represented by models. They can't find or even express the extra "spark" of "material embodiment" that we think makes our world "really real" and not just a Platonic outline, as it were. Equations don't have extra features that express embodiment or "deservedness" of same to be manifest.

I don't think our world is the same as a model or mathematical construct, so I don't believe MUH is true. What I mean is, that idea that there is no way for math and logic to justify and explain the "picking out" of realness from all that conceptual ultimate landscape, is a valid claim. Whatever does that picking out, is "mystical", it is and must be beyond equations and logical relations.

Robert L. Oldershaw said...

Want to make some empirical and theoretical contact with nature.

On 8/24/11 watch the NOVA program on PBS entitled:

"Hunting The Hidden Dimension"

9 PM EST

(Can also be viewed at PBS website anytime)

Bee said...

Hi Giotis,

Well, using your words then it would be the question which side is fundamental and which side is emergent though the way you use the words 'fundamental' and 'emergent' here doesn't make much sense to me. Yes, in practice one uses either side in a particular limit, but that's not because only that limit exists but because that's where one can do the computation, so I don't know what one gains by constraining oneself to these limits. Best,

B.

Bee said...

Hi Arun,

If you coarse-grain probably not. Best,

B.

Giotis said...

I use it in the Wilsonian sense i.e. you don't have to integrate out any degrees of freedom since the fundamental theory is applicable at the UV and thus complete.

The extra dimension of the d+1 bulk is mapped to the energy scale of the d dimensional field theory. The field theory in d dimensions is located at the boundary and thus at the UV. That's why is fundamental in the sense that is complete and we don't have to integrate out any degrees of freedom of a more fundamental theory. The extra dimension of the bulk is a derived concept which emerges as we go to lower energy scales by integrating out degrees of freedom.

Bee said...

Hi Giotis,

I see. No, that's not what I think the question is supposed to mean. Suppose you're trying to describe a black hole in our universe. Would you say it's "really" a black hole (as in: some metric with some properties etc) or it's "really" a dual qft on the boundary (presuming that works for a realistic background), or would you say, well, both is equally real or not (which, as I said above, is my pov). Now, do the same for a strongly coupled qft in our spacetime. Is that the 'real' part now or what? Best,

B.

Phil Warnell said...

Hi Arun,

“Are there measurement procedures for QM systems that do not increase the entropy as a result of the measurement?”

Yes, there are two, the first being when no measurements can be taken at all and the second when measurement is continually constant.

That is I don’t think (orthodox) Quantum Mechanics tells us much if anything about entropy as it relates to measurement. That is if there is nothing to have things to be measured we can neither say there is any reason for things to happen or worse even exist at all. On the other hand if measurement is constant things can’t change to have them happen at all. Thus I would say in some sense it could be said entropy is a process which occurs despite Quantum Mechanics.


Best,

Phil

Phil Warnell said...

Hi Arun,

Then again the central problem is when we consider concepts such as measurement to be relevant at all; along with many of our preconceived ill defined notions.

”Here are some words which, legitimate and necessary in application, have no place in a formulation with any pretention to physical precision: system, apparatus, environment, microscopic, macroscopic, reversible, irreversible, observable, information, measurement.”

-J.S. Bell , "Against Measurement" , Physics World, page 34 (August 1990)

Best,

Phil

Bee said...

Hi Phil,

I'm not sure what Arun meant with 'measurement procedures' but the examples you mention only work for specific systems and/or specific measurements. The 'procedure' itself does generically increase entropy if you stick w/ the collapse interpretation. Best,

B.

Phil Warnell said...

Hi Bee,

”The 'procedure' itself does generically increase entropy if you stick w/ the collapse interpretation."

Yes, understood, and yet that’s why I qualified things in my second comment as it relates to Bell’s commentary regarding such matters.

“The orthodox approaches, whether the authors think they have made derivations or assumptions, are just fine FAPP — when used with the good taste and discretion picked up from exposure to good examples. At least two roads are open from there towards a precise theory, it seems to me. Both eliminate the shifty split. The de Broglie- Bohm-type theories retain, exactly, the linear wave equation, and so necessarily add complementary variables to express the non-waviness of the world on the macroscopic scale. The GRW-type theories have nothing in their kinematics but the wavefunction. It gives the density (in a multidimensional configuration space!) of stuff. To account for the narrowness of that stuff in macroscopic dimensions, the linear Schrodinger equation has to be modified, in the GRW picture by a mathematically prescribed spontaneous collapse mechanism.

The big question, in my opinion, is which, if either, of these two precise pictures can be redeveloped in a Lorentz invariant way.”



-J.S. Bell , "Against Measurement" , Physics World, page 40 (August 1990)


Best,


Phil

Giotis said...

Hi Bee,

I would agree with pov but with one objection. When the gravitational (geometric) side is well defined at small curvatures the strongly coupled field theory is not. So what's the point of talking about a theory that is equal 'real'? We can't do physics in the strong coupling limit and we can't describe anything or make predictions. In other words we don't have a theory.

Plato said...

Thank you Goitis and Bee for the exchanges on 8?:)

Clifford:The point is that de Sitter is not a nice bystander at all, so why are we sure that our most basic rules of quantum theory are complete enough for the job of understanding it? (I mentioned this near the end of the discussion. The good news was that I was not burned at the stake…)

This explains Heretic I think :)

From what I understood at Planck length there are no rules about geometry from inside the black hole, so this exchange would be appropriate from the standpoint that we do not have an explanation of what is happening in that environment yet?

So Goitis is this your final explanation on the absence of a theory?

You are essentially describing the interior of the blackhole from the boundary yes?:)

As much as one tries to distance them self from the model described as AdS/CFT it serves it's purpose as demonstrating a means of describing from that boundary?

In our current experiments at LHC then how would such values be assigned such relevance to what is happening in the collision process/ early universe, once you recognize the value of the QGP?

Best,

Plato said...

Holography encodes the information in a region of space onto a surface one dimension lower. It sees to be the property of gravity, as is shown by the fact that the area of the event horizon measures the number of internal states of a blackhole, holography would be a one-to-one correspondance between states in our four dimensional world and states in higher dimensions. From a positivist viewpoint, one cannot distinquish which discription is more fundamental.


Pg 198, The Universe in Nutshell, by Stephen Hawking


In one fell swoop, Kaluza had written down a single covariant field theory in five dimensions that yielded the four dimensional theories of general relativity and electromagnetism. Naturally, Einstein was very interested in this preprint .(sorry link now dead)

If you understand the pattern then you understand the way in which to look at the model. A 2d explanation of a 5d world?

Okay, it's not real for you because it does not make sense to you right now. Especially to those who talk about the math and all, what's real, and about this correlation with Platonism.

You just don't get it right now?:)

IT's not mystical Neil.

Clifford's post is the latest on the ontological status of that question 8.

Best,

Plato said...

Juan Maldacena:The strings move in a five-dimensional curved space-time with a boundary. The boundary corresponds to the usual four dimensions, and the fifth dimension describes the motion away from this boundary into the interior of the curved space-time. In this five-dimensional space-time, there is a strong gravitational field pulling objects away from the boundary, and as a result time flows more slowly far away from the boundary than close to it. This also implies that an object that has a fixed proper size in the interior can appear to have a different size when viewed from the boundary (Fig. 1). Strings existing in the five-dimensional space-time can even look point-like when they are close to the boundary. Polchinski and Strassler1 show that when an energetic four-dimensional particle (such as an electron) is scattered from these strings (describing protons), the main contribution comes from a string that is close to the boundary and it is therefore seen as a point-like object. So a string-like interpretation of a proton is not at odds with the observation that there are point-like objects inside it.

Uncle Al, I know your trying.:)

Best,

Plato said...
This comment has been removed by the author.
Plato said...

Last link for Juan Maldacena did not work, pic might be more useful for people here now? Look carefully:)

Best,


http://www.sns.ias.edu/~malda/nature6-12-03.pdf

Eric said...

Plato, you have once again come through with references. But as I remember more about the talk that Steven Weinberg gave at CERN his final conclusion was string theory may not be the correct theory. That asymptotic safety and confinement may it.

Of course that is one man's opinion. But I happen to share it. Also I don't know how Ads cft fits in string theory or if it requires it. However I think it is deeply incorrect to think confinement can in any way be identified with gravity. It causes gravity to occur but is not gravity. I also happen to think that the large halo extending past the physical
diameter of galaxies is identified by it's ability to bend light. So quite rightly the halo extending well past the confined diameter of the galaxy whould be seen as the gravity produced simply from the confinement of the outer perimeter of the galaxy, not the gravity of the nucleons comprising the bulk of each galaxy.

Again, this is one man's opinion. Mine. It could be wrong. (but I don't think so). :-)

Eric said...
This comment has been removed by the author.
Eric said...

I should add that my understanding is that the geometry of the halo around galaxies is produced by subtracting the actual measurement of light being bent coming from outside each galaxy to the amount that light should be bend from the known distribution of nucleons in the galaxy.

Bee, if I'm incorrect in how they calculate the galactic halo maybe you could weigh in, or even if I'm correct.

RLO, this halo of gravity is what is already left over and unaccounted for after also including the large black hole at the center of the galaxy, and the smaller black holes distributed throughout. What say you?

Plato said...

Hello Eric,

Just curious how you wipe out a model for understanding by attaching the word string theory?:)

Historically I have demonstrated how Lee Smolin himself tried to explain "the Thing."

You see, it is a method by which to attempt to explain what is going on inside the black hole?

Consider this for a second.

I linked a "superstring theory" diagram that is very similar to Bekenstein's model.

Now in the LHC process they are trying to explain what is taking place "at the center of the collision process," and here again, the latest on the QGP has been identified and confirmed as to it's basis. At the LHC you may say?

So you have two diagrams and you have a collision process...does it exemplify the happening of what is taking place from a experimental perspective in relation to the two models described?

Of course we always have to be careful about claiming and shouting as if some Stringevangelistic, but this does not discount the correlation I making toward describing that interior? You see now?

Because people do not like "string theory" or proclaim their displeasure with not conforming to some reality based examination, this is so far from the truth of the work being done....that such talk has to be dismissed as "arrogant talk" without the supporting the framework with which to understand it's application?

I will not judge you, or Uncle Al, or anyone for that matter for their opinion....just ask that you understand the applications and how it is being used?:)

You may want to see Marcelo Gleiser on 13.7 for his explanations of the universe in context of "the heretic."

Best,

Arun said...

Hi Christine,

I mean if the universe is described by a density matrix ρ then in the usual double slit experiment or other experiment, Trace( ρ log(ρ))changes. Can we do measurements without a change?

Hi Phil,
Can you explain more why "measurement" is not part of any fundamental physical theory?

I happen to think it has to be.

-Arun

Arun said...

Christine,

So yes, I mean von Neuman entropy. (I'm very poor at remembering names associated with concepts. I guess it comes from having learned some mathematics from Soviet textbooks, where Gauss was replaced by Ostrogradsky and so on.)

-Arun

Arun said...

Phil,

How is one to relate the mathematics of a physical theory to the physical world, without "apparatus", "experiment", "measurement", etc.?

-Arun

Eric said...

Plato, you bring up many good points. I'm afraid you have me at a disadvantage when talking about the intricacies. I would really have to study string theory to carry on an intelligent conversation with you about it. That I haven't done. But we all have our centers of expertise that we know a lot about, or at least more than our close acquaintances. That is something I would never begrudge you on. And of course we all have a natural instinct to want to teach our brethren what we know. I prefer to not characterize it as arrogance but rather a basic urge to bring the world into compliance with our own view. It cannot be stopped.

The problem only lies when parts of two different world views are incompatible. That is every human beings struggle when he gets up in the morning, having to deal with others who have a different world view about something. We can choose to emphasize that difference or we look at the larger picture and weigh those differences with our commonalities. I happen to know we share a great deal in common with our world view on politics, philosophy, etc. So don't at all take my views on string theory as a judgement of you as a person. I take the whole person into consideration and you are doing very well in my view. I have not met a person yet who has agreed with me on everything and I doubt I ever will. So don't think disagreements on particulars renders me unable to see the person as a whole.

Don Foster said...

An additional question of interest, one that has an ontological aspect, would be that of identifying examples in which dynamic organizing principles at the quantum level of description are found to “percolate” upward and reveal themselves as phenomenon at the macroscopic, work-a-day world level. The example that comes to mind is that of John Scott Russell’s “solitary wave” which was first viewed on horseback.

Giotis said...

Hi Plato,

Yes AdS/CFT is not used only in QGP but also to study space-like singularities like the ones you found in the interior of a black hole or in the big bang. In this case by examining how the weakly coupled dual field theory behaves when the bulk develops the singularity they are trying to qualitatively understand the nature of the singularity. As far as I know though this kind of research is still in a very early stage.

Phil Warnell said...

Hi Arun,

I could attempt to explain why ‘measurement’ should not be part of the formulation of fundamental theory and also why other words such as “apparatus, environment, microscopic, macroscopic, reversible, irreversible, observable, and information” should also be so excluded, yet I would be just echoing a conviction grounded in logic expressed more than 21 years ago which still largely is lost to deaf ears. So rather than do that I would invite you to read John Stewart Bell’s paper “Against "Measurement" ” as he is more likely not to leave you confused as I’m more likely to do.

I apologize for leading you to a copy that needs to be printed out to be read, yet to do anything else would have me in contravention of copyright. However I’m certain if you look around a bit you can secure a copy that is more accessible. Just as a closing remark the word “experiment” was not excluded by Bell and as you read the paper you will discover as to why its continued inclusion lies at the heart of the matter.

”SURELY, after 62 years, we should have an exact formulation of some serious part of quantum mechanics? By 'exact' I do not of course mean 'exactly t r u e '. I mean only that the theory should be fully formulated in mathematical terms, with nothing left to the discretion of the theoretical physicist . . . until workable approximations are needed in applications. By 'serious' I mean that some substantial fragment of physics should be covered. Nonrelativistic 'particle' quantum mechanics, perhaps with the inclusion of the electromagnetic field and a cut-off interaction, is serious enough. For it covers 'a large part of physics and the whole of chemistry' (P A M Dirac 1929 Proc. R. Soc. A 123 714). I mean too, by 'serious', that 'apparatus' should not be separated off from the rest of the world into black boxes, as if it were not made of atoms and not ruled by quantum mechanics.
T he question, '. . . should we not have an exact formulation . . . ? ' , is often answered by one or both of two others. I will try to reply to them: Why bother? Why not look it up in a good book?”


-John Stewart Bell, Against "Measurement", Physics World, page 33, (August 1990)

Best,

Phil

Plato said...

Thank you Eric for your kind words.

As a layman I have been following those who know what string theory is about so as to get a better understanding, yet, I am far from understanding the full scope of the subject myself.

Goitis, I want to thank you as well.


String theorists describe the physics of black holes in five-dimensional spacetime. They found that these five-dimensional objects provide a good approximation of the quark-gluon plasma in one fewer dimension, a relationship similar to the one between a three-dimensional object and its two-dimensional shadow. Image: SLAC National Accelerator Laboratory See: String theory may hold answers about quark-gluon plasma

I wrote: Last link for Juan Maldacena did not work, pic might be more useful for people here now?

CFT was an approach from on the surface, "so as to describe the bulk" as well as, understanding the inside of the black hole as a 5d world which includes gravity as a model inclusive with the standard model? At a point in the early universe the question of this relation is pointed out as question mark by Ramond.

Best,

Plato said...

Ramond should read John M. Pierre

Michael Gogins said...

If there were true, fundamental limits to what we could know, we would not be able to know what they are.

That means, we cannot know whether there is or is not a fundamental theory. However, scientists must of course bet that there is, and that they can learn what it is.

Goedel's dilemma, MacKay's logical indeterminacy of a free choice, Bringsjord's appeal to the busy beaver, and Kripke's critique of functionalism imply that we are not Turing machines and, indirectly, that Nature is not a Turing machine. In that sense at least we have free will. It is not clear what this really means.

What does it mean to exist? First that consciousness exists. Beyond that it gets murky. Certainly as Wittgenstein pointed out there are facts that it is simply absurd to doubt, such as that you are reading this when you are reading it. So at that point you indubitably exist and are reading this. I think that this sense of "exist" is the truly fundamental one, for it is this to which we appeal in conducting experiments to test physical theories, and so on.

All of the above arguments for free will boil down to the same thing, namely that the work of science in trying to learn exactly which Turing machine nature is, must be conducted using "existant" (I use the word advisedly) means of thought, which are informal, which do not assume some Turing machine, and which, we must also assume, are ultimately equal to whatever task we face. It's worked spectacularly well so far.

Physicalism, mechanism, computationalism all assume that underlying this unreasonably effective program of human thought is some Turing machine. If there were, we would not be able to identify it. If there were not, we would not be able to prove it.

If the above is true, then there is a dilemma: either Nature and ourselves hypercompute, or something like dualism is the case.

Regards,
Michael Gogins

Zephir said...

1. The human knowledge limit is given with stability of the part of Universe, where we are living in.
2. Because the time is defined so. We are livin in random Universe, the direction in which it doesn't change is considered a space, the direction in which it changes in most pronounced way it's called a time.
3. AWT considers Universe is random gas and everything else can be derived from particle simulations of it. The general theories suffer with fact, they're not very specific and vice-versa. It's tic-for-tac situation: a sort of generalized uncertainty principle applies here.
4. Every large system of interacting particles or neural wave solitons is complex enough to become effectively unpredictable.
5. The random particle system is driven with energy wave spreading and these waves are of both transverse, both longitudinal nature. Reductionism is based of deterministic simplification of this reality - it doesn't work in situation, when the indeterministic part of reality manifests and vice-versa. It leads into fragmentization of our understanding of reality.
6. With increasing scope the behavior of human civilization becomes more close to behavior of random particle gas, because the individialistic motivations of intelligent human creatures compensate mutually ("what is good for you isn't good for me")
7. In AWT the reality is probabilistic distribution of aether gradients - we cannot see an aether/vacuum in the same way, like we cannot see the gas, we can see only density fluctuations of that gas.
8. AdS/CFT is the duality of extrinsic/insintric perspectives of particle environment, mediated with transverse (relativity) and longitudinal waves (quantum mechanics)

Plato said...

Michael Gogins,

Physicalism, mechanism, computationalism all assume that underlying this unreasonably effective program of human thought is some Turing machine. If there were, we would not be able to identify it. If there were not, we would not be able to prove it.

A foundational basis of knowledge can exemplify how one may look a the world?

Any thoughts with regard too,

Weber Bars Ring True?

Best,

Arun said...

Phil,

Thanks for Bell's "Against Measurement". Merits a discussion but later.

One thing struck me: "Landau-Lifshitz emphasize, following Bohr, that quantum mechanics requires for its formulation "classical concepts"...."

Well, space is the first of these. In the context of non-relativistic quantum mechanics, I don't think we can measure space, distances, set up coordinates using purely quantum mechanical concepts.

-Arun

Plato said...

Hmmmmm...

A quantum view of a Classical world?

Plato said...

It is always interesting to me how complexity arises out of simplicity? :)

Investigation of quantum entanglement is currently a very active area. Research is being done on measures for quantifying entanglement precisely, on entanglement of many-particle systems, and on manipulations of entanglement and its relation to thermodynamics. See:Quantum Entanglement