[geordief (OP)]

Are there any classical behaviours that cannot be said  to be quantum to some degree?

Are there any theoretically possible tweaks to quantum behaviour  that would change the way the macroscopic  world would behave?

[Halc]

Are there any classical behaviours that cannot be said  to be quantum to some degree?

Don't understand this question. Classical physics follows from quantum physics, so an automobile can in theory be described by interactions of protons and electrons and such. There's nothing at the high level that isn't a function of the low level, even if it is beyond our capability to model at that level. No human device is capable of simulating an automobile by computing the evolution of its wave function.

Are there any theoretically possible tweaks to quantum behaviour  that would change the way the macroscopic  would behave?world

A unified field theory would be nice.

If there are such tweaks, it just means our current understanding of quantum behavior is incomplete. It doesn't mean that classical behavior of anything is not a function of quantum physics.
This is not true in the other direction. It has been demonstrated that quantum mechanics cannot be described by any classical theory, which has shot down a number of attempts to do so (with hidden variables and such).

[geordief (OP)]

Don't understand this question

Think you answered it well enough.Maybe some questions or statements can also be understood in ways that the author didn't intend .

Sometimes I don't even understand myself what I am asking .

I could try to rephrase  though.

viz "Are all supposedly classic behaviours the result ,even if indirect of more fundamental,even remotely connected quantum behaviours?"

I was happy,though  with you ranswer ,perhaps because it seems to agree with my present opinion.

[Eternal Student]

Hi.

"Are all supposedly classic behaviours the result ,even if indirect of more fundamental,even remotely connected quantum behaviours?"

    This would seem to be the case.   
It's the usual reductionist view of physics:   It should be possible to reduce a large scale system to it's smallest parts and then things that happen in the large scale system should be explained by things that are happening to these smallest parts.

Best Wishes.

[geordief (OP)]

Hi.

"Are all supposedly classic behaviours the result ,even if indirect of more fundamental,even remotely connected quantum behaviours?"

    This would seem to be the case.   
It's the usual reductionist view of physics:   It should be possible to reduce a large scale system to it's smallest parts and then things that happen in the large scale system should be explained by things that are happening to these smallest parts.

Best Wishes.

Does chaos theory put a spoke in that wheel?

[Black hole]

Are there any classical behaviours that cannot be said  to be quantum to some degree?

Are there any theoretically possible tweaks to quantum behaviour  that would change the way the macroscopic  world would behave?

I find it spooky that a rock does not grow but the human fetus grows !
I find it spooky because most visual matter suppose to be formed out of atoms !
Are we to believe that atoms can grow ?

[Kryptid]

Are we to believe that atoms can grow ?

No, but you'd know that's not what's happening when a fetus grows if you actually had the professor-level education you claim to have...

[Black hole]

Are we to believe that atoms can grow ?

No, .

The only answer required without adding personal opinion .

No we are not suppose to believe atoms can grow because the cellular growth of humans for example is nothing like a Rock ! A Rock has a specific mass while human mass can change .  How  many atoms is there in a strand of hair is like asking how long is a piece of string .
Human form is not determined by natural quantum physics and this thread asks,  ''is everything fundamental quantum'' ?
Everything includes ourselves which are not fundamentally quantum in consideration of the differences .
 

[Colin2B]

Does chaos theory put a spoke in that wheel?

No, chaos theory is a deterministic theory.

[geordief (OP)]

Does chaos theory put a spoke in that wheel?

No, chaos theory is a deterministic theory.

OK.I always found it a little hard to get my head around that.(pretty pictures,though    )

[evan_au]

Are there any classical behaviours that cannot be said  to be quantum to some degree?

The ideal gas law (classical theory) does not require matter to be quantised into atoms.
- However, when you make the gas law more realistic to take into account the limits to compressibility of a gas, that is compatible with (or is explained by) the concept of atoms with a finite volume.
- So the Ideal Gas Law is a low-density asymptotic approximation...

Relativity is a non-quantized theory. It needs a quantized theory, but we don't have one (yet).

chaos theory is a deterministic theory.

Maybe so, but defining the current state depends on measurements of finite accuracy, and small measurement errors grow exponentially. So while in principle some chaotic systems may be deterministic, in practice they are not predictable very far into the future.

[Colin2B]

chaos theory is a deterministic theory.

Maybe so, but defining the current state depends on measurements of finite accuracy, and small measurement errors grow exponentially. So while in principle some chaotic systems may be deterministic, in practice they are not predictable very far into the future.

Ah, I should have included the quote from ES that @geordief was responding to: “It should be possible to reduce a large scale system to it's smallest parts and then things that happen in the large scale system should be explained by things that are happening to these smallest parts.”
@geordief “Does chaos theory put a spoke in that wheel?”

Chaos theory doesn’t change that as it only deals with deterministic systems, but as you say, nonlinear systems do become unstable very quickly.

[evan_au]

Are there any classical behaviours that cannot be said  to be quantum to some degree?

There are some chaotic systems that are "scale invariant", so the behavior of the macroscopic system is governed by smaller components, all the way down to the smallest of components (some of which are governed by quantum theory). Examples are:
- Magnetic material whose temperature drops below the Curie temperature (smallest component: magnetic spin of 1 atom)
- Viscous fluid flow in a pipe (smallest component: 1 molecule)
- Neuronal networks in the brain (smallest component: 1 neuron)
- Ecosystems (smallest component: 1 breeding pair)
- And these systems have patterns in common

While atomic physicists look at the interactions of a small number of interacting particles, the emergent behaviour of these macroscopic systems would not be predicted by the behaviour of the smallest unit in isolation.

Listen (90 minutes): https://www.preposterousuniverse.com/podcast/2021/10/11/168-anil-seth-on-emergence-information-and-consciousness/

[yor_on]

" Are there any classical behaviours that cannot be said  to be quantum to some degree? "

Depends on definitions I would guess. Quantum physics is very much about statistics and probabilities. To formalize it into a classical picture it uses '(re)normalization' and decoherence. Those are both 'educated guesses'.


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