On self-defining laws of physics

[ConradDJ]

Baywax, thanks for encouragement...!

I spent 12 years as an archaeologist and through most of those years I thought there was a hierarchy to the evolution of cultures and of species etc...

Well though, there is hierarchy in these evolutionary histories, if only in a very limited sense... in that complex structures do require simpler ones as precursors. Otherwise you're certainly right -- evolution has no predestined path "forward", it's just -- whatever happens to happen.

How would one go about excavating and organizing any of the evidence of these developments?

Good question. But I'm thinking that the evolutionary picture in physics may be a lot simpler than in biology or human culture, so if there are distinct structural layers, they should be fairly evident. My basic assumption is that the measurement of distances in space and time is a "late" development that requires complex structure for its definition -- so I'm looking for aspects of physical law that don't seem to depend on this.

Electromagnetism is the outstanding example -- it seems very basic, in that essentially all communication and all physical structure (at least from the atomic level) depends on it. It has several distinct, interdependent aspects, with e-static and magnetic fields, connected with charge-conservation and spin-angular momentum.

All this structure has to do with changes in direction in 3-space. And there's an intriguing kind of "self-measurement" going on here -- this business of a moving charge generating an orthogonal magnetic field, which in turn affects the motion of a charge, for example. So I'm trying to see what aspects of this structure might be definable without the measurement of distances or velocities... just focusing on how a network of directed vectors might define itself, "selecting itself" out of an underlying network of interaction-events that had no predefined spacetime structure.

My guess is that if we could get one or two relatively simple structural layers to come into focus, the "methodology" for untangling the deep complexity of particle physics might also begin to be clear. And if it were possible to sort this out into a series of stages, where we could see how each stage might define itself on the basis of the prior ones, that in itself would be compelling evidence for an evolutionary approach.

-- Conrad

 

[baywax]

Baywax, thanks for encouragement...!



Well though, there is hierarchy in these evolutionary histories, if only in a very limited sense... in that complex structures do require simpler ones as precursors. Otherwise you're certainly right -- evolution has no predestined path "forward", it's just -- whatever happens to happen.



Good question. But I'm thinking that the evolutionary picture in physics may be a lot simpler than in biology or human culture, so if there are distinct structural layers, they should be fairly evident. My basic assumption is that the measurement of distances in space and time is a "late" development that requires complex structure for its definition -- so I'm looking for aspects of physical law that don't seem to depend on this.

Electromagnetism is the outstanding example -- it seems very basic, in that essentially all communication and all physical structure (at least from the atomic level) depends on it. It has several distinct, interdependent aspects, with e-static and magnetic fields, connected with charge-conservation and spin-angular momentum.

All this structure has to do with changes in direction in 3-space. And there's an intriguing kind of "self-measurement" going on here -- this business of a moving charge generating an orthogonal magnetic field, which in turn affects the motion of a charge, for example. So I'm trying to see what aspects of this structure might be definable without the measurement of distances or velocities... just focusing on how a network of directed vectors might define itself, "selecting itself" out of an underlying network of interaction-events that had no predefined spacetime structure.

My guess is that if we could get one or two relatively simple structural layers to come into focus, the "methodology" for untangling the deep complexity of particle physics might also begin to be clear. And if it were possible to sort this out into a series of stages, where we could see how each stage might define itself on the basis of the prior ones, that in itself would be compelling evidence for an evolutionary approach.

-- Conrad

That's a great approach!

I just want to add that you can see the lack of resistance offered by distance, velocity, and all things that have to do with space when you see lightning taking place on Earth from space.

Of course we are amazed that there are simultaneous discharges of lightning over huge distances... sometimes half or three quarters of the way around the globe... but, these could almost be compared... (without using metaphor!) to quantum simultaneous location. (if that's the correct term)

 

[Naty1]

I think Aperion posted:

The question was about how a universe (or even multiverse) might emerge through some sort of self-organisation out of pure possibility, a chaos of geometry of some kind, a quantum foaminess of some infinite description.

I personally liked the post "Order is a particular form of Chaos."

James Hartle discussed some of these features in his talk in Cambridge, England commemorating Stephen's Hawking 60th birthday. The following is from his talk "Theories of everything and Hawking wave function of the universe" published in THE FUTURE OF THEORETICAL PHYSICS AND COSMOLOGY,2003.

My colleague Murray Gel-Mann used to ask me "If you know the wavefunction of the universe, why aren't you rich?". A quantuum mechanical theory of the Hamiltonian and the initial state does predict probabilities for everything that might happen in the universe. However only a few things are predicted with near certainty. The vast majority of alternatives are predicted with approximately 505-50% probabilities giving no useful information. That's the sense in which a 'theory of everything' is not a theory of everything...It is only because so little of the complexity of the present universe is predicted byt the fundamental universal laws that we can discover them...the regularities of of interest in (many) subjects are not predicted by the universal laws with near certainty even in principle. They are frozen quantum accidents that produce emergent regularities.

"Frozen accidents" is terminology attributed to Murray Gel-Mann.

And Roger Penrose also had some interesting comments in his talk, "The problem of spacetime singularities:implications for quantum gravity"

There is a very different structure...at the Big Bang from the kind of structure we find in a black hole's singularity. (The Weyl curvature at later times diverge to infinity; at the Big Bang the Weyl curvature is essentially zero.) This initial constraint is actually enormous. Calculations show that the chance of it having arisen purely by chance is less than about 1 in 10¹⁰¹²³+ . If one takes the the view that the sought for "quantum gravity theory" is just the imposition of standard quantum field theory on standard relativity, each being time-symmetric, one finds it very hard to see how to get this extraordinary time -asymmetry. Yet this time-asymmetry is an actual feature of our universe. How do we find the appropriate asymmetric theory?

+ The power published and shown above may have a typographical error...

 

[baywax]

ConradDJ there's another way to objectify and solidify whether or not there is an evolution of the laws of nature taking place and that would be by measuring changes within the laws themselves between say 1900 and 2000. If there is an evolution taking place and the changes that would come with it, the law of gravity, conservation laws etc... would show change over that 100 years. Mind you, the evolution of a natural law is probably measured in millions if not billions of years so the increments of change will be miniscule and would require pain staking observation and research. I only mention this idea because someone once said that all the theorems they learned in science, 30 years ago, have been proven to be wrong today. I wondered if this was not an indication that the natural laws had been evolving over that period of time rather than humans just getting it wrong all the time.

 

[ConradDJ]

ConradDJ there's another way to objectify and solidify whether or not there is an evolution of the laws of nature taking place and that would be by measuring changes within the laws themselves between say 1900 and 2000.

Hi baywax... I just want to point out that the evolution of laws of physics doesn't necessarily mean that they have changed over time, in the sense you mean. I just posted a long note about this in another thread, you may be interested --

https://www.physicsforums.com/showthread.php?p=2368754#post2368754"

Thanks -- Conrad