I do miss stuff - shit, 30,000 mentions... I need to get out more. And there are folk I just don't read, but that does not include you. Thanks.

Well, yes, but in so far as we are concerned with what we believe - what we hold to be the case - we are in an anthropocentric position.

Hume cannot be absolutely sceptical. — JuanZu

And do you think that he is absolutely sceptical? I don't.

Is the conversation about which bedrock is preferable, or is it about about whether we can avoid bedrock altogether? If the latter, then exactly how?

I am trying to understand legitimate beliefs in Hume — JuanZu

So stuff Hume. — apokrisis

14 pages of fulmination to arrive at the blank refusal to address the topic of the thread. No one forced you to engage in a topic you have only contempt for. "It's your own time you're wasting."

But it raises a lot of questions about the details of this objective, but invisible and all-powerful, existence that laws partake of. Are the laws all omnipresent? If so, how does that fit with them being numerically distinct? Or is there really one big law that explains everything? Do laws change? Eternal god(s) without the personality? — bert1

"All powerful"? Whatever gives you that idea?

According to the theory, laws are relations between types of objects. These relations exist when and where these types exist. This removes the mystery associated with a platonic view of laws, by proposing they exist as part of the ontological structure of the world.

There's no reason to think they would change. Bare possibilities are irrelevant, because the theory is an inference to best explanation of regularities we observe in the world. The theory isn't dependent on the tentative current state of the discipline of physics; if an apparent "law of physics" were to change, it would be imply there's more to this "law of physics" than we thought.

Is there one big law? That might be the case if monism is true. But these questions are irrelevant to the theory.

No one forced you to engage in a topic you have only contempt for. — unenlightened

You are waving words around as if they were arguments. What is abduction, and how does it help? — Banno

By page 4, the subject had switched to abduction.

So stuff abduction.

Why not just say what is really bothering you? :grin:

You tell me.

A pinch and a punch and no returns, eh. :up:

"All powerful"? Whatever gives you that idea? — Relativist

Just that on that view matter always obeys laws.

According to the theory, laws are relations between types of objects. — Relativist

Oh, OK. That weakens their claim to be real, perhaps, perhaps not. Maybe they are real, but not in the sense of having an independent existence from the systems they govern. I'm not familiar with the view. Interesting though. I can think of further problems - is the generation of objects governed by laws, or do the laws only exist once the object exist? Why does the same type of law always occur with the same type of objects? Why is there consistency across space and time?

Abduction includes elements of induction and deduction, no? The issue still remains.

Also consider Goodman's new riddle because it's fun. Lets say we have a model arrived at by abduction that predicts that water boils at 100C at earth surface pressure. Now let 'roil' mean 'boils at 100C before 2030 and boils at 150C after". Now do we have two model-predictions that are equally supported by evidence:

Model 1: Water will boil at 100C at Earth surface pressure next week
Model 2: Water will roil at 100C at Earth surface pressure next week

We all presumably think Model 1 is likely to survive the year 2030 and we will abandon model 2, but why? Is there a reason to prefer model 1 over model 2?

Science doesn't need to worry about this, it gets on fine. But this is philosophy, so we do this kind of shit.

This is traditionally framed as a problem for induction. But does abduction help particularly?

(hopefully I've got Goodman roughly right, correct me if not)

Or maybe predictive model-formation does not really admit of rational analysis. If it has evolved it has done so without philosophy and intellectual reflection (perhaps), but that doesn't mean we can't apply reason to it anyway after the fact. Especially if there is a claim to truth.

Hume is deeply uninteresting. — apokrisis

Not so uninteresting as some.

So sure, take Maxwell's equations and apply gauge symmetry, and "the answer just jumps out"; but don't then claim that the theory is ex nihilo; it used Maxwell's equations and gauge symmetry.

Oh, OK. That weakens their claim to be real, perhaps, perhaps not. Maybe they are real, but not in the sense of having an independent existence from the systems they govern. I'm not familiar with the view. — bert1

It's not weak at all. It's referred to as existing "immanently". In metaphysics, an immanent property is one that exists within an object itself, as opposed to a transcendent property that would exist beyond or outside it.

The -1 electric charge of an electron exists immanently in an electron. It seems to me that immanent properties make more sense then having properties be independent things because then you'd have to account for how these properties attach, and explain what they're attaching to (are they attaching to a thing lacking any properties at all?!)

The attraction between an electron and proton is a relational property that exists imminently in an electron-proton pair. There's no evidence that their attraction is contingent on anything other than the properties of each of the objects and their proximity.

- is the generation of objects governed by laws, or do the laws only exist once the object exist? — bert1

Yes and no.

The laws exist iff the set of objects exists in the arrangement that exhibits the law. If inflation theory is correct, then there was a time in the universe in which no particles existed - so there were no electron-proton pairs, and thus no laws could be exhibited between them.

However, the fact that such a law would be exhibited when protons and electrons came about would have been baked into the physics of the quantum fields - so ultimately (and assuming reductionism is true) the electron-proton law is just exhibiting more fundamental natural law that would always have been present.

Why does the same type of law always occur with the same type of objects?

Remember that the existence of laws of nature is a hypothesis, one that best explains the empirical evidence. I argue that this hypothesis is an "inference to best explanation" for these regularities. You could counter this claim by presenting an alternative hypothesis that you can show to be a better explanation. The hypothesis seems to be consistent with what we know about the world through physics.

But GIVEN the hypothesis that there are laws of nature, it is the case that a set of objects arranged in a particular way that exhibits a law of nature will do so necessarily. That's simply what it means to be a law: it is a necessary relation that exists between types of things.

Why is there consistency across space and time?

Because the relevant objects in the past are the same sort of objects that exist in the present and future.

Not so uninteresting as some. — Banno

Yes. You measure your worth in mentions. What could be more cringe?

So sure, take Maxwell's equations and apply gauge symmetry, and "the answer just jumps out"; but don't then claim that the theory is ex nihilo; it used Maxwell's equations and gauge symmetry. — Banno

Exactly. Which was the point. :up:

There were the Bayesian priors. And they could be well chosen for a reason. The answer might have lain anywhere. But it became tightly constrained to a somewhere.

A community of inquiry exploring a new physical paradigm – quantum theory – had to reconcile it with another newish paradigm – relativity – and this combo of priors drove it rapidly to the only logically self-consistent outcome possible. Quantum field theory.

Maths – or at least algebraic geometry and matrix multiplication – was discovered to be "unreasonably effective". A level of theory so robust that even its observables were determined. Establish the symmetry and its symmetry breakings came with it. Something that seemed like Platonic magic.

A trick that folk like string theorists have been trying to repeat to reach their goal of a total symmetrification of existence in terms of quantum gravity as the final theory of everything. But something went wrong. Physics had made its extraordinary leap pursuing one uber-paradigm – the merger of two quite contradictory seeming paradigms – and then stalled.

A huge army of the best minds found themselves bashing their heads against a new wall. Symmetry had turned into the enemy when the moment came to make the last push and assimilate general relativity to quantum field theory (that being the Bayesian prior that felt right to the particle physics community, having already worked so splendidly with special relativity being assimilated to quantum mechanics.).

String theory still persists. You can't kill a bad paradigm until a better one comes along. But the lack of observables is seeing it fade out to be "just interesting maths". Not "unreasonably effective" maths.

So this is a nice little tale of how science works. Plug in the right priors and you create a context that narrows your search to its most fruitful avenues of thought. Follow the symmetries, became the collective thought. And that worked splendidly until it didn't.

This is the theory space I am now interested in. The need for a fresh IBE. But one that is a refinement on what already works. You can't junk everything. That's how crackpots think. You want to jettison the right things.

Penrose for example – a great illustration as he his very public about his creative process – argues that the error is trying to assimilate the complex number magic of the quantum to the real number realm of gravity. GR doesn't reduce to QFT. It has to be the other way around.

So at heart, a pretty simple flip in priors. The obvious logic of counterfactuality. If pushing on the door doesn't work, pull it instead. One is never working without a context of established rational habit. Abduction always starts standing on the shoulders of giants. It is never "just a lucky guess".

As I have remarked many times, my own expectation is that rather than symmetries all the way down, it is symmetry breaking all the way down. And that is the systems view first outlined by Anaximander, and brought home nicely by Peirce, to be generally confirmed by more recent scientific developments – such as not only the stories of Big Bang cosmology and the topological hierarchy of the Standard Model of particle physics, but of course, the failure to unify GR and QFT by a simple reductionist metaphysics.

The current impasse is exhibit A in the argument that it is instead dichotomies all the way down. Or at least until you strike the vagueness that Peirce defined in logic as the failure of the PNC to apply. The unity at the bottom of it all has to have the irreducible complexity of a triadic relation. And indeed, we already know this from Okun's cube of theories. The fact that the whole edifice of modern fundamental physics has been about taking the Planck triad of constants – c, G and h – and combining them to create a structure of theories.

You add c to Newtonian mechanics to get special relativity. You add h, and you instead get quantum mechanics. You add the c to h and you get quantum field theory. You add the G to the c and you get general relativity.

So you wind up with GR and QFT as both having eaten two of the three Planck constants. GR eats cG, and QFT eats ch. Naturally – it is by now bleeding obvious – one must finish the job with a theory of quantum gravity. A final theory that eats all three constants as cGh.



[Or actually I find there is this neat new website with animations devoted to the cube. Check https://cube-of-physics.org.]

The belief in quantum gravity seems a necessary truth. The wall physics has been banging its head against for longer than it took to figure out GR and QFT. Again, this is how the process of scientific reasoning actually plays out. Your priors just become so specific as you follow the trail of what has worked. Any IBE-ing has become as constrained as driving your 18-wheeler semi up a tiny country road.

But as I say, you can make a bigger inversion than Penrose suggests. Not just apply the symmetry flip of GR=>QFT into QFT=>GR, but apply the larger flip of symmetry=>symmetry-breaking. You start from the cGh of the Planck scale as itself a unity of opposites. The unit 1 description of not three disparate constants but of the one irreducible triad of relations. A collection of self-organising fundamental ratios.

The first breaking that could then keep breaking forever. Or at least until its Heat Death saw it all fizzle to effectively nothing. The biggest and coldest nothing that could ever exist in terms a dichotomisation under the complementary bounds of Nature described by GR and QFT.

So does this have anything much to do with Hume's scepticism and even Peirce's abduction by now? Well it certainly ought to inform any current Philosophy of Science in terms of what we've actually got done.

We have both success and failure to tell us about IBE in practice. Or Bayesian reasoning if you prefer. We can now see how Newton was standing on the shoulders of giants, but also why his turn towards blind faith in the maths – I feign no hypotheses – was indeed a paradigm shift that raced us all the way to QFT in particular. Just follow the damn symmetries no matter how weird its seems to start getting.

But then now, what about following the symmetry breakings instead? Or understand how the two ideas of the complementary limits of the third thing which really concerns us – the asymmetry which is the actual hierarchical order of a Cosmos born of the self-stabilising balance of symmetries and their breaking.

Again, this was essentially the IBE already framed by Anaximander in simple physicalist terms, and what Peirce came to understand as both the structure of mathematical logic and cognitive reality. So it has a rich pedigree. Scoff all you like.

You start from the cGh of the Planck scale as itself a unity of opposites. The unit 1 description of not three disparate constants but of the one irreducible triad of relations. A collection of self-organising fundamental ratios. — apokrisis

AI says:

The idea that entanglement entropy could give rise to spacetime is a frontier concept in theoretical physics, drawing connections between quantum mechanics and gravity through the holographic principle. This framework proposes that spacetime is not a fundamental entity but an emergent phenomenon arising from the collective quantum entanglement of microscopic degrees of freedom. 
The proposal can be broken down into several key ideas: 

The Ryu-Takayanagi formula 
A foundational piece of this concept comes from the AdS/CFT correspondence, a duality between a gravitational theory in a certain spacetime (Anti-de Sitter, or AdS) and a quantum field theory (Conformal Field Theory, or CFT) living on its boundary. 
The Ryu-Takayanagi (RT) formula explicitly links a geometric property in the gravitational bulk to an information-theoretic quantity in the boundary quantum field theory. It states:

(garbled)

This formula provides a precise mathematical recipe for calculating geometry from entanglement, suggesting that if we know the entanglement structure of the boundary quantum system, we can deduce the geometry of the bulk spacetime. 

Spacetime connectivity from entanglement 
Physicist Mark Van Raamsdonk built on the RT formula by considering how changes in entanglement affect spacetime geometry. 
A connected universe: If a quantum field theory is prepared in a highly entangled state, the dual bulk geometry corresponds to a smooth, connected spacetime.
Disconnecting spacetime: If the entanglement between two separate parts of the quantum system is reduced to zero, the dual spacetime breaks apart into two disconnected regions. This suggests that entanglement is the "glue" that holds spacetime together. 

Tensor networks and emergent geometry 
To model how a continuous spacetime can arise from discrete quantum degrees of freedom, physicists use mathematical tools called tensor networks. 
Microscopic network: A tensor network is a web of interconnected nodes that represents the structure of entanglement in a quantum state. The connections, or "links," of the network encode the quantum entanglement between degrees of freedom.
Macroscopic geometry: The geometry of the higher-dimensional bulk spacetime is modeled by the collective structure of this tensor network. The more entangled two regions are in the quantum network, the closer they are in the emergent spacetime geometry. 

ER=EPR: Wormholes and entanglement 
A striking conjecture by physicists Juan Maldacena and Leonard Susskind, known as "ER=EPR," proposes a deep connection between entanglement (EPR) and wormholes (ER). 
Entangled particles: In the standard picture, two maximally entangled particles (an EPR pair) can be spatially separated by any distance without losing their quantum correlation.
Spacetime geometry: The ER=EPR conjecture suggests that the link between these two entangled particles is a microscopic, non-traversable wormhole (or Einstein-Rosen bridge). In this view, entanglement itself is a bridge through spacetime. 

Emergent time 
The relationship between entanglement and spacetime also offers a new perspective on the nature of time. 
Timeless universe: Some interpretations of quantum gravity, such as the Wheeler-DeWitt equation, suggest a "frozen" or static universe at the fundamental level.
Emergent time flow: The experience of a flowing time could be an emergent property related to the constant evolution and growth of quantum entanglement throughout the universe. According to this idea, the arrow of time points in the direction of increasing entanglement. 

The big picture 
In summary, the theory that entanglement entropy gives rise to spacetime proposes a revolutionary reversal of our conventional understanding: 
From geometry to information: Instead of spacetime being a fundamental backdrop in which quantum mechanics operates, the geometry of spacetime and even its existence are determined by the patterns of quantum entanglement within a more fundamental, information-based reality.
A computational universe: The universe can be viewed as a massive, continuous quantum computation, where spacetime, time, and gravity are the emergent macroscopic consequences of how information is processed and entangled at the quantum level. 

The big picture 
In summary, the theory that entanglement entropy gives rise to spacetime proposes a revolutionary reversal of our conventional understanding: 
From geometry to information: Instead of spacetime being a fundamental backdrop in which quantum mechanics operates, the geometry of spacetime and even its existence are determined by the patterns of quantum entanglement within a more fundamental, information-based reality.
A computational universe: The universe can be viewed as a massive, continuous quantum computation, where spacetime, time, and gravity are the emergent macroscopic consequences of how information is processed and entangled at the quantum level. — PoeticUniverse

Yep. But you see how the urge to collapse the holism of holography to some new form of reductionism shows itself once again. A Bayseian prior that most can't escape.

As soon as you discover the dichotomy – as in AdS/CFT – you must collapse it to a story where one is more fundamental than the other. One is baseline and the other emerges.

But I'm saying that it is instead the complementary limits on Being that emerge. The dichotomies or symmetry breaking is what it is about all the way down.

Besides, AdS/CFT has the fatal problem that it is anti-de Sitter spacetime and not de Sitter spacetime. And the Universe is de Sitter by observation. It even has the dark energy to prove it. A rather empirical constraint on the rational speculation.

But string theory still has hopes this keeps it going. One last swing for the stands. :grin:

The dichotomies or symmetry breaking is what it is about all the way down. — apokrisis

The ordered phase of a deeper quantum system:

It seemed that its future could never be,
That its unfamed name was but written
On the water and the wind
With a feathery quill
Whose ink was the smoke and fog
Of Symmetry’s shimmering dream;

But, ere the wind that could erase it blew,
Broken rotational symmetry—
That immortalizing winter, flew
Athwart the stream—and the printless torrent grew

A scroll of crystal—geometry as the condensate,
Blazoning the name of Space-time!