A revolution in Physics needed?

Dmitry67

Well, I dont have any proof but if would be very sad.

If the number of reductions is infinite then physics is infinitely complex. In that case TOE contains infinite amount of information -> infinite enegry/mass to store it. Any system which is trying to reach some level of knowledge will inevitably become too massive and becomes a black hole. So anyone who is trying to understand everything will be veiled by the event horizon from the rest of the world... I dont believe that God is so evil. It would be a really bad joke...

nickyrtr

We are already in this predicament, even with simple Newtonian physics. To numerically represent the masses and distances between Newtonian bodies, with exact precision, would require an infinite number of digits, i.e. an infinitely large computer memory. Furthermore, an infinitely fast computer processor is required to exactly calculate the motions of these bodies, according to Newton's equations of motion.

On the other hand, this does not mean we need to give up physics. A first generation TOE, for example, could still be very useful and explain much that is today a mystery, even though some day it may be explained by an even more fundamental 2nd generation TOE, 3rd generation TOE, and so on. We do not need to understand everything, to understand more than we do now.

Dmitry67

This is correct: the size of sets different states even of 2 newtonian bodies is continium.

However, in QM matter in a finite volume can be only in the countable set of states, and even more, if energy inside that volume is limited (which is always true, otherwise it would be a black hole) matter can be in finite number of states.

nickyrtr

A single measurement will always find one of the countable states, but the volume's actual quantum state (before measurement) is some linear combination of them. Those linear coefficients are any complex numbers, so we are back to the continuum problem to completely describe the system.

Dmitry67

Agreed. However, lets take peano axiomatcs (formal arithmetics). Set of axioms is very short, but the number of numbers :) and number of their properties is infinite. So finite set of equations of TOE can govern infinite physical entities.

I can not prove that your idea with an intinite sets of TOE models is wrong, but I just dont like it. BTW Max Tegmark discusses it too.

math_04

We cannot know EVERYTHING about the universe but hopefully we can learn enough to progress our technology. My knowledge of quantum physics is still pretty limited but I think quantum mechanics is as fundamental you get and maybe, with some modifications here and there, the solutions may be interesting. But of course, that is just an ignorant student talking.

Abraham Pais once said that Einstein himself predicted that a unified field theory would churn out all the details without us having to worry about the extra particles etc.

nickyrtr

That is part of human diversity perhaps, one person is excited by an infinite field of knowledge to explore, another hopes to find a single ultimate solution. On a philosophical note, if conscious thought can go in both directions of preference, perhaps the reality is somehow a synthesis of both ways of viewing truths. In other words, perhaps the question "is there a final, ultimate theory of physics" is not an ontological question at all, but a question of how one chooses to view and discuss reality, in which case either point of view can find satisfaction :)

Fra

His response have some good points but misses some points in my objection.

I see this is what he has in mind, but it makes no sense to me. If you stick to observable ideals, then the description/image/expectation of whatever is out there is all we have.

The question is not what is, but what I can KNOW. It's the frog vs bird view again. Tegemark sees no problem with the birds view, as it seems. I do.

This defense is what you might expect from him. I disagree. The physical basis on the structures, at least exists in Tegemarks brain.

Set aside humans, the information about the enviroment exists somewhere, and it's in the microstructure of hte observer. Where else? It's the one obvious place for it.

In a sense this si a good point, but he still wants to ignore that all structures has a basis. I would like to tweak this to say thta, ok there is a kind of equivalence but my conclusion is that rather than it making everything crazy possible, physical constraits, constrains the possible mathematics! In particular when you consider elementary particles and the small. There is a limit as to what can be encoded in a small strucutre. Without this, what means to be have to constirna possible mathematical models? We would get crazy landscaps of possible models and get lost.

/Fredrik

Dmitry67

Fra, I see your main objection is that a 'pure' matematical structure can not exist without a 'basis'. It reminds me a story of either: it was so obvious for everyone that lightwaves needed some basis, some substance to propagate in, right? :)

You call it 'crazy' - yes, I agree. And, based on the history of physics, is a best sign that it could be true!

And then again, you say 'encoded'. You always assume that there is some substance needed to give life for the mathematical structures. Why?

Lets say TOE equations are published tomorrow. What do you expect to see? Do you expect to have there some purely physical axioms, which can ot be expressed in a mathematical form?

Fra

I see quite a difference from the quest for a material classical ether filling space, to a informational basis. This base I'm looking for need not "sit in space", it rather makes up space. So in a certain sene, even space requires partially a representation. But it's not a material ether ot me, it can very well sit in the matter in space, and the relation between them defining space are encoded in the microstructure of the matter concenrtrations.

I am NOT looking for a "realistic basis" like the old ether advocates wanted. It's more subtle, but a basis nevertheless.

"Life" wasn't my choice of word in this case, it sound strange.

But mathematical models are only representations, it "lables" something else as a kind of abstraction.

If I describe an atom with equations, then the state space and the action encoded in this, are just an abstract representation of what the atom itself is a manifestation of.

Therefor there is in some sense IMHO at least (I guess it's also part of my personal reasoning and intutition, so there is nothing I can "prove") a one-2-one correspondence between a minimal representation of observed reality and mathematics.

This is also why I have objections to the use of continuum as a fundamental starting point. In this representation mapping, the information capacity is important. I can not stretch myself to picture infinite information content, in a small region of space. It makes no sense to my brain. THAT choice of abstraction is IMHO redundant, and is only obscuring things. IT is not one bit surprising that you get infinites coming up all over the place. I have yet to see nature produce a representation of an infinity.

Ok. Good question. If we by TOE mean unification of all forces including gravity, then I think first of all that theory would still not be closed and leave no further questions. I'd expect the theory to take the form of an evolutionary relation between observations. The best possible understanding would in my imagination be implemented in a specific observer, by designing the observer along these principles.

So I expect to see a kind of learning model, where physical interactions, and emergent structure of matter are a result of intrinsic logic between interacting parts. This "logic" is what I consider to be the CORE of a new model. Particle masses etc, would be outputs following from processing experimental data in line with this principle.

To me the mathematics is just a representation. If I am going to write down a model
in a paper, it will be in the form of mathematics and algorithms. Probably some information processing algorithms along with normal dynamics equations with initial conditions. But no equation on a sheet of paper can answer everything. I think what we can write down, are the core of the logic of our understanding, the further encodes howto process the information at hand in the best way.

I see physical interactions, as communication between system. Each and every one part can consider themselves an observer, observing the rest. Each choice of observer will give a different picture, and I think the tension between these pictures is the origin of forces. Internal forces are after all a manifestation of a sort of disagreement or inconsistencies.

It's a description at this level, I am looking for, and the core I expect to be: the logic of how nature processes, acts and encodes this. IF you sense a chicken/egg case here, I like Zureks statement that "what the observer IS, and what the observer KNOWS" is inseparable.

Meaning that your knowledge does not SIT on external hardware (memory device), reather the hardwre is inseparable from the information encoded into it.

But I haven't yet seen a full implementation of these ideas, but it's what I expect to see tomorrow when You publish the TOE equations

/Fredrik

Fra

It's difficult to not notice the similary to this, and Tegemarks statement regarding mathematics :)

Indeed, I can partially see sense in what he says. But I think the main difference is that I require that all of this, is constrained into a frogs perspective.

Tegemark seems to have some strange idea that he will find a master bird view, from which he can "compute" any given frogs view. That's exactly what I think is impossible. His birds view, even if it did exists, would not fit into tegemerks own brain!! :)

That may seem both silly and obvious, but I think it does change the strategy a bit.

/Fredrik

Fra

I think the more realistic "problem", is howto GUESS the behaviour of one frog, beeing one of the other frogs. Ie. reasoning and acting based on incomplete information. In this quest, it is a desirable trait to develop an "image" of the environment, on which your decisions are made. And moreoever this image, is continously update depending on the feedback. As I see it, space is encoded in this image. And when all observers agree upon space, they agree upong the relations between them. But as I see it, this connection that restores the symmetry is emergent by an indeterministic process.

Similary, I think there are emergent bird views, between local groups of observers, that can even be seen by some "larger frogs", but the ultimate birds view is I think just an illusion. OTOH, the action of a frog, will be as if his image is a birds view. But when a third largers frog analysis this, he will (personal conjecture here) see an inconsistency in the two birds view. Therefore, calling them bird views make little sense. The actual BIRD never enters the equation, because it's an abstraction. There are only frogs, to interact, observer and compare each other. The only difference is that some frogs are smaller, and some frogs are bigger. The big frogs may feel like gods, giggling at the small frogs interacting, without realising that they are themsleves also just frogs.

/Fredrik

Dmitry67

1
Remember, non-eucledian geometry was developed for purely mathematical reasons before GR needed it. We could say: curved space is an abstraction. And oops, there we live.

We used to say "complex numbers are just a way to solve some problems in physics mathematically. All physical variables MUST be real. And oops, vawefunction is complex!

Do you see a trend here?

You say "But mathematical models are only representations - I would add, "so far".
So may be it is time to actually make this step?
mathematical models WERE only representations...

1A
You see, if we accept Max Tegmerk's point of view, we dont need to answer "what the reality is". If TOE equations are just a model of reality, what is reality? Why it does not collapse and dissapear? Why the core nature of reality can no9t dissaper, like a virtual world in my computer, when I shut it down?

2
It looks like you are worrying about the Matrix, about being asked to emulate our world. So, you see the problem of having infinite amoutn of information is a finite region of space. But wait, space is infinite. Why dont you have a problem with an infinite information for the whole universe? No matter if information in some region is finite or infinite, it does not "help" your computer...

3
Thank you for riminding me about the mass spectrum. How many "free" parameters do you expect to see in TOE?

Dmitry67

Again, it depends on if we talk about the EQUATIONS of the bird's view or all the details of all the worlds which obey these equations.

I believe that the equations of the bird's view are simpler then the ones for the frog's view. QM is a perfect example. In MWT, bird's view is QM without collapse. Frog's view is created by the Quantum Decoherence. And it is here, in the frog's view, where all the weirdness comes in place: randomness, non-locality, collapse.

If you read his article you problbly remember that "the whole ight be simpler then each part of it"

Fra

> 1A
> You see, if we accept Max Tegmerk's point of view, we dont need to answer "what the reality is". If TOE equations are just a model of reality,
> what is reality?

The TOE equations would ideally be the _best answer_ to What's reality. That's good enough for me.

> Why it does not collapse and dissapear? Why the core nature of reality can no9t dissaper, like a virtual world in my computer,
> when I shut it down?

There is still a state of the PC when it's shut down. You just removes the forced state from PC programs and circtuis. You can't make a direct analogy. In reality one can't pull the plug between the microstate and microstructure.

The reason for the "stabiliy of the image" is IMO related to inertia of the hardware. The hardware has evolved along with the state, and NO observed event can instantaneously change this, because I think the notion of time is entangled with this. It's impossible for me to try to convince you in this thread, but I see many ways in how the origin of inertia, in the context of information processing is why a "virtual" image actually does acquire inertia and stability.

This is because the construction of the "hardware" that SUPPORTs the image has a certain inertia, and deformation of the hardware is a slowly evolving process, compared to changing the STATE of the hardware. It's analogous to the dynamics IN spacetime, and the dynamics of spacetime geoemtry itself. There is a feedback, but the inertia of spacetime is large enough to give a certain stability.

> 2
> It looks like you are worrying about the Matrix, about being asked to emulate our world. So, you see the problem of having infinite amoutn
> of information is a finite region of space. But wait, space is infinite.
> Why dont you have a problem with an infinite information for the whole universe?

Why would there be a problem with that? As long as I don't see it all at once, which I don't I'm fine :) The point is that I can not even construct a measuring device to measure this infinite size.

> No matter if information in some region is finite or infinite, it does not "help" your computer...

First I should att the "computer hardware" in this case, is the matter itself. Computations are simply physical interactions. The memory is the STATE of the hardware - the microstate of matter. But even when solving the equations of a human theory, a normal Pc may be used, and it can not handle infinite information. You can't perform a computation in finite time on infinite information. That's one very practical part.

A local computer does not NEED all information in the universe for his daily business, because I think any local observer, responds only to his local information. Therefore, information unavailable has no impact, and can be disregarded with no ill effects.

It will never be possible to deterministically predict the future. The problem at hand, is to guess the future sufficiently good to survive in your given environment. This provides a selection for algorithms. Stupid algorithms doesn't get preserved, but neither do they need to be banned. They punish themselves out of business.

> 3
> Thank you for riminding me about the mass spectrum. How many "free" parameters do you expect to see in TOE?

I think this questions reveals that you may have a different idea of what the theory is like than me. I think the answer depends on it's evolutionary state. Ideally each parameters is a result of an evolutionary history, and if you loose the information of the history, then you end up with a "free parameter", but it really isn't "free", it's just that you might have lost track of it.

If we take a more practical question, as to how many of the current parameters in the standard model I execpt to see go away, then for sure all the particle masses should be explained. I think the spectrum of particles will correspond to different evolutionary stages as you scale up the mass. And I expect that the logic here should explain the hierarchies
we see. If you start the observation at a late stage, the more free parameters do you need to "fit" to experimental data. I think this is natural, and isn't a flaw by any means.

/Fredrik

Fra

The scaling of mass is also the same as origin of inertia. The particles aquires large and larger inertia by evolving their information processing algortihms. Not all algortihms can be successful, therefore, a prediction of the algorithm spectrum that survices is expected.

If I'm right this will be the particle spectrum we see. And masses as well as the participation in the forces should hopefully come out.

/Fredrik

Dmitry67

Then there are laws of that evolution. If these laws are included in the TOE, then parameter is not free. If it is not included, then it is not TOE (by the definition of TOE)

But let me back up to the question about the model. What is a difference between model and reality, map and territory? Imagine that TOE equations look like

F(Y)=0

where F is formula. Y is some variable (complex? quaternion?). If appears that this equation can be solved only when Y is a variable in (real, complex, quaternion, something more complex) K-dimensional space. Based on the equation, the value of Y tends to compactify to something which appears to be a string. Different vibration modes manifest as different particles, etc, etc, you get the idea.

It is important that you dont need any words. You can derive anything from this formula.

Now your turn.

A. You can say "F(Y)=0 is just a formula, just a model. It is not a reality"
Then please tell me what a "reality" is and what it is made of.

B. You can say "TOE wont look like a set of formulas. We will need formulas and something extra"
Then your turn - please give any example of a physical property which can not be expressed in the mathematical terms.
So far we had no such examples (expect may be consciousness)

C. Finally you can say - there is an infinite sequence of TOE's, and no final, ultimate TOE. As I said, it would be depressing but I dont have any contre arguments.