What does 'emergent' mean in a physics context (split from Information Paradox)

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19 hours ago, swansont said:

But I don't see how you can say that the force is not present in the parts.

(My emphasis.)

OK. So to clarify further. I said,

On 12/11/2021 at 2:13 AM, joigus said:

Pressure is not chunks of little pressure; temperature is not chunks of little temperature.

It sounded like I meant force is not present in the parts, but that's not what I meant. And, of course, that's not true. What I meant by 'pressure is not chunks of little pressure' is that it doesn't work like force, it has a qualitatively and quantitatively different law (in most cases it's not directional, it has an equation of state that relates it to other emergent variables, rather than Newton's vector or Lagrange multi-variable equations of motion.) It's related to temperature, which is clearly emergent, or highly-derived, if you wish.

It's not the same as, e.g., the macroscopic version of Maxwell's equations, which are essentially the same. If you take the properties of matter into consideration, you do have to introduce de D, H fields to complement the E, B fields, by including $$\varepsilon$$, $$\mu$$, but the equations are pretty much the same. Now, the way I understand it, the latter is definitely not emergence, but just averaging. Although some people might argue that in some sense it is.

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9 hours ago, joigus said:
15 hours ago, joigus said:

the Curie law

Sorry, that's nothing to do with pressure. Mistake.

I wondered if you meant to refer to Curie temperature as emergent ?

It is certainly a tipping point.

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14 minutes ago, studiot said:

I wondered if you meant to refer to Curie temperature as emergent ?

It is certainly a tipping point.

No, no. It was just a slip.

Certainly Curie's law I would call emergent,  and by Curie's law I mean,

But it has nothing to do with pressure. Magnetization is purely an average of microscopic fields, but how it relates to temperature (the law itself) has emergent features no doubt. But we were talking about pressure, and of course Curie's law has nothing to do with it. It was a 'Curiean slip'.

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• 4 weeks later...
Posted (edited)
On 12/11/2021 at 2:13 AM, joigus said:

I'm particularly interested in what @Eise and @Markus Hanke have to say about these matters.

Trying to challenge me?

I think we can talk about emergence when following condition applies:

The phenomena can be described without knowing or needing from what they exactly emerge.

A few examples:

• the gas laws of Boyle and Gay-Lussac: without knowing that gas is made of flying around particles these laws cna be fixed empirically (but not explained, of course, then we have to get to statistical mechanics, assuming smallest particles bouncing around)
• One of my favourite examples: traffic jams. These can be mathematically described without knowing if we are talking about horse cards, diesel or gas cars
• And yes, of course, free will. The problem of free will and determinism can be decided without reference to the brain, neurons and neurotransmitters. Just take determinism for granted, and ask if in a determined world free will is possible. That simply means that neurologists have nothing to add, if you take determinism for granted. The exact details are of no importance.

About time as an emergent phenomenon I have nothing to say: ask Carlo Rovelli, or Lee Smolin... It is of course highly speculative. But a fact is that all our established theories can work very well without knowing if time is emergent or not.

Wow, 4 weeks later. Sorry....

Edited by Eise
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Schrödinger equation describes the phenomenon of a wave function evolution without knowing or needing from what it exactly emerges. Does it make this phenomenon an emergent one?

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Schrödinger equation describes the phenomenon of a wave function evolution without knowing or needing from what it exactly emerges. Does it make this phenomenon an emergent one?

In my view no wave equation qualifies as emergent, as you have to know the wave variable to have the equation in the first place.

1 hour ago, Eise said:

Trying to challenge me?

I think we can talk about emergence when following condition applies:

The phenomena can be described without knowing or needing from what they exactly emerge.

A few examples:

• the gas laws of Boyle and Gay-Lussac: without knowing that gas is made of flying around particles these laws cna be fixed empirically (but not explained, of course, then we have to get to statistical mechanics, assuming smallest particles bouncing around)
• One of my favourite examples: traffic jams. These can be mathematically described without knowing if we are talking about horse cards, diesel or gas cars
• And yes, of course, free will. The problem of free will and determinism can be decided without reference to the brain, neurons and neurotransmitters. Just take determinism for granted, and ask if in a determined world free will is possible. That simply means that neurologists have nothing to add, if you take determinism for granted. The exact details are of no importance.

About time as an emergent phenomenon I have nothing to say: ask Carlo Rovelli, or Lee Smolin... It is of course highly speculative. But a fact is that all our established theories can work very well without knowing if time is emergent or not.

Wow, 4 weeks later. Sorry....

I think you condition is too broad by itself, though it is an interesting approach. +1

I don't agree that the Gas Laws show any emergent features.

I do strongly agree with your second example of 'clusters'. I expect you have done a lot of simulation theory.

I am not sure about 'free will'  and like you I don't know about time as emergent phenomenon.

I look around and sometimes see light and sometimes see darkness.

I fail to class either of these as emergent, but by tour condition they would be.

I walk along the street and see a fish lying there. I can't know how it got there so that would make it an emergent phenomenon.
(This example is inspired by today's local news about a seal pup that walked into a bar in Bristol)

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Does a qualification of being 'emergent' apply to a phenomenon or to an equation describing it?

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Posted (edited)
2 hours ago, Eise said:
• And yes, of course, free will. The problem of free will and determinism can be decided without reference to the brain, neurons and neurotransmitters. Just take determinism for granted, and ask if in a determined world free will is possible. That simply means that neurologists have nothing to add, if you take determinism for granted. The exact details are of no importance.

The fact that some emergent phenomena can be formulated without referring to the more elementary level doesn't mean that we shouldn't aspire to it. I think we should aspire to it. We can't simply do away with the reductionist approach just because, oh, it can be formulated otherwise, so why bother? If the range of phenomena stubbornly resists that approach, so much the worse for our understanding --example, the weather and Navier-Stokes eq.--. But I'm sure understanding something about methane, and CO2, and conservation of energy, etc. doesn't stand in the way of understanding broadly what's going on with the weather (climate patterns).

As to time and emergence --I'm familiar with Smolin's view, not so much with Rovelli's, although they are in the same front, I think--, I think it's a distinct possibility, but I don't expect it to be anything like the picture of 'a thing made up of tiny little things' in the way thermodynamic variables are. Although this is just a hunch on my part, granted.

I'm not going down the rabbit hole of free will now.

Schrödinger equation describes the phenomenon of a wave function evolution without knowing or needing from what it exactly emerges. Does it make this phenomenon an emergent one?

The wave function picture of quantum mechanics is definitely not, in its present state, an example of emergence. That doesn't mean it's not gonna be some day.

The density-matrix picture you can consider as emergent. It's a statistical mixture of wave functions (so-called mixed state, made up of so-called pure states.)

2 minutes ago, joigus said:

The wave function picture of quantum mechanics is definitely not, in its present state, an example of emergence. That doesn't mean it's not gonna be some day.

I hadn't seen Studiot's comment, which already goes in this direction. I was editing my post. I can elaborate more, if anyone's interested.

Edited by joigus
minor correction
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Does a phenomenon become 'emergent' after we find a way to describe how it emerges?

If a condition for a phenomenon to be emergent is to "be described without knowing or needing from what they exactly emerge", and the evolution of a wave function is a phenomenon that is "described without knowing or needing from what they exactly emerge", how come that this phenomenon does not qualify as being emergent?

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A minimal criterion would be that you need:

1) Composite system

2) Parts making up that system and relations between them

The law of behaviour for the composite system is simpler (requires fewer parameters) than the laws of behaviour of the parts.

Such laws are qualitatively different. Meaning: the patterns of behaviour change too with respect to the parts.

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2 minutes ago, joigus said:

A minimal criterion would be that you need:

1) Composite system

2) Parts making up that system and relations between them

The law of behaviour for the composite system is simpler (requires fewer parameters) than the laws of behaviour of the parts.

Such laws are qualitatively different. Meaning: the patterns of behaviour change too with respect to the parts.

So, this criterion is different from:

2 hours ago, Eise said:

Trying to challenge me?

I think we can talk about emergence when following condition applies:

The phenomena can be described without knowing or needing from what they exactly emerge.

A few examples:

• the gas laws of Boyle and Gay-Lussac: without knowing that gas is made of flying around particles these laws cna be fixed empirically (but not explained, of course, then we have to get to statistical mechanics, assuming smallest particles bouncing around)
• One of my favourite examples: traffic jams. These can be mathematically described without knowing if we are talking about horse cards, diesel or gas cars
• And yes, of course, free will. The problem of free will and determinism can be decided without reference to the brain, neurons and neurotransmitters. Just take determinism for granted, and ask if in a determined world free will is possible. That simply means that neurologists have nothing to add, if you take determinism for granted. The exact details are of no importance.

About time as an emergent phenomenon I have nothing to say: ask Carlo Rovelli, or Lee Smolin... It is of course highly speculative. But a fact is that all our established theories can work very well without knowing if time is emergent or not.

Wow, 4 weeks later. Sorry....

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So, this criterion is different from:

Yes. Mine is more specific: The emergent system must be simpler to describe than the parts, and, most importantly, the criterion I proposed does not ignore that the system is made up of 'parts.' Eise, I think, prefers to place a black box around the 'simpler parts' in order to describe the laws of the composite system without referring to the simpler parts, because they are 'irrelevant.' If I understood him correctly.

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Thus, there are things which are emergent as per less specific criteria but not emergent as per the more specific one.

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Does a qualification of being 'emergent' apply to a phenomenon or to an equation describing it?

When we understand the difference... 😉

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Does a qualification of being 'emergent' apply to a phenomenon or to an equation describing it?

The quality (not qualification) or characterisitc of being emergent applies to a phenomenon, not to an equation.
However I think that since emergence only occurs in special circumstances, these special circumstances need be incorporated in any description or specification of an emergent phenomenon.

As a for instance, my earlier example of arching action.

Despite the antiquity of the arch, we do not have an 'equation' to this day that properly describes arch action, although we understand it. Furthermore arch action only occurs in particular circumstances.

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18 minutes ago, studiot said:

The quality (not qualification) or characterisitc of being emergent applies to a phenomenon, not to an equation.
However I think that since emergence only occurs in special circumstances, these special circumstances need be incorporated in any description or specification of an emergent phenomenon.

As a for instance, my earlier example of arching action.

Despite the antiquity of the arch, we do not have an 'equation' to this day that properly describes arch action, although we understand it. Furthermore arch action only occurs in particular circumstances.

First of all, thank you for the correction. I like it.

And, yes, I also think that it (something being emergent) refers to phenomenon rather than to our description of it, including all the circumstances that the said phenomenon needs in order to occur.

Then, the criteria of a phenomenon being or not being emergent should not depend on how we describe it and what we know or need to know to describe it. In other words, the criteria should be about the phenomenon and not about us.

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Posted (edited)

Schrödinger equation describes the phenomenon of a wave function evolution without knowing or needing from what it exactly emerges. Does it make this phenomenon an emergent one?

You can only see if a phenomenon is emergent, when you can explain it from simpler constituents. My hunge with the Schrödinger equation is that it is not emergent, given that physicists already do not not agree if it is just a calculation algorithm, or is ontic. The Schrödinger equation already 'lies deeper' then our direct experience. E.g. we cannot observe its phase. We can only observe that it describes our observations statistically correctly.

2 hours ago, studiot said:

I don't agree that the Gas Laws show any emergent features.

Well, since we know it we can derive the Gas Laws from statistical mechanics, we know they are emergent. (But, btw, I understand swansont's doubts that it is a good example of emergency, because the effects of more or less bouncing particles in a bottle can be linked to the macroscopic pretty directly; I like my example of the traffic jam better).

2 hours ago, studiot said:

I look around and sometimes see light and sometimes see darkness.

Do you mean 'light' and 'darkness', or your seeing of them. (Hopefully Koti is not around... )

2 hours ago, joigus said:

The fact that some emergent phenomena can be formulated without referring to the more elementary level doesn't mean that we shouldn't aspire to it.

I nowhere implied that! Of course, my expectation is that we live in 'natural world' through and through. If somebody would not accept natural explanations, he is simply enforced to introduce new metaphysical entities, like souls, or God. So yes, I am interested in neurology, to a certain level, but for certain questions we do not have to know much about it.

2 hours ago, joigus said:

I'm not going down the rabbit hole of free will now.

That's fine. It surely will pop again when some newbie starts a new thread, saying 'We are determined so we have no free will!'. Then the great free will defender will do his work again (if he is not too stressed at that moment...).

1 hour ago, joigus said:

Eise, I think, prefers to place a black box around the 'simpler parts' in order to describe the laws of the composite system without referring to the simpler parts, because they are 'irrelevant.' If I understood him correctly.

No, you did not understand me me correctly. I only said it is possible to describe phenomena at a higher level than its composite parts, not that our understanding of the phenomena incredibly increases when we know how they are rooted in more fundamental parts. The other way round: there are things we, as humans, simply cannot understand at its fundamental level. I do not need quantum physics when I write programs for my databases, but the workings of computers is only understandable from quantum theoretical technology (PNP layers, and so). (Here you see an interesting example 'the other way round'. First there were the 'quantum discoveries', then the question 'what could you do with it', build a transistor, put millions of them together, et voila, a computer!).

Edited by Eise
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I see. OK. We all've got words that kind of set off our 'philosophical alarms.' In my case it was that you seemed to imply 'irrelevant.'

Quote

That simply means that neurologists have nothing to add, if you take determinism for granted. The exact details are of no importance.

(My emphasis.)

But I understand what you mean now: Irrelevant for the business of handling the emerged laws within their domain of applicability.

Am I getting closer?

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51 minutes ago, Eise said:

I do not need quantum physics when I write programs for my databases, but the workings of computers is only understandable from quantum theoretical technology (PNP layers, and so). (Here you see an interesting example 'the other way round'. First there were the 'quantum discoveries', then the question 'what could you do with it', build a transistor, put millions of them together, et voila, a computer!).

Whilst I agree with you about the QM and programming, there are many sorts of computer whose working do not depend upon QM. Some of these are purely mechanical from astrolabes and orrerys to slide rules, some are electrical, some elctromechanical, some fluidic. De Morgan can also be demonstrated with a variety of devices.

57 minutes ago, Eise said:

Do you mean 'light' and 'darkness', or your seeing of them. (Hopefully Koti is not around... )

I shan't tell him if you don't

But no, I mean that I can tell when there is day and when there is night around me.
I don't need to see or know the source of any light but I don't consider any light I do see to be 'emergent'.

Pretty well everything in this universe had a beginning, a middle and an end but I don't consider that because everything came from something that went before it, it is therefore emergent.

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2 hours ago, studiot said:

Whilst I agree with you about the QM and programming, there are many sorts of computer whose working do not depend upon QM. Some of these are purely mechanical from astrolabes and orrerys to slide rules, some are electrical, some elctromechanical, some fluidic.

I hope you see that you exactly make my point: as I said earlier that it makes no difference if a traffic jam consists of horse cards, diesel or gas cars, for a computer it makes no functional (or logical) difference if it implemented in a completely different way. I happen to work, as most of us, with computers that are transistor based, not gear based, but to write my programs I do not need any knowledge of the computer's physical principles. So another way of seeing this, is that emergent properties have some independence of its physical substrate. No question, a physical substrate is absolutely necessary, but there are many cases where different kinds of substrates can do the job.

I do not exactly get your example of day and night. Not knowing the cause of a phenomenon does not mean it is emergent. It is essential that the emergent phenomena arise from their components, mostly many of them (molecules for the Gas Laws, neurons for mental phenomena, vehicles for traffic jams, etc).

3 hours ago, joigus said:

Am I getting closer?

Definitely.

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Posted (edited)
27 minutes ago, Eise said:

I hope you see that you exactly make my point: as I said earlier that it makes no difference if a traffic jam consists of horse cards, diesel or gas cars, for a computer it makes no functional (or logical) difference if it implemented in a completely different way. I happen to work, as most of us, with computers that are transistor based, not gear based, but to write my programs I do not need any knowledge of the computer's physical principles. So another way of seeing this, is that emergent properties have some independence of its physical substrate. No question, a physical substrate is absolutely necessary, but there are many cases where different kinds of substrates can do the job.

I agree but my point is that I don't think your definition is enough to make a phenomenon special enogh to be called emergent. I agree that you may or may not know where the phenomenon arose or came from.

8 hours ago, Eise said:

The phenomena can be described without knowing or needing from what they exactly emerge.

My example with the light is just such.

I see light.
It could have come all the way from the furtherst star in the universe or the candle by my bedside, it doesn't matter.
I don't atually need to know its source.

But I don't call it an emergent phenomenon, just light. Yet it conforms to your definition quoted above.

Please also note it is a horse and cart or a horse and carriage ( both precursors of the abbreviation car)

Sorry to hear about the covid problems in the Netherlands. We didn't make it to Leiden this season as we didn't last season either. My nephew and niece made it back there, don't know when or how they will be able to get back (to work) in the England. They did get a luxury BA flight for £20 though as no one wanted to go to Schipol before Christmas.

On another tack entirely, I can udnerstand why people think perhaps Schrodinger leads to an emergent phenomenon.

When we solve the equation we use (introduce) suitable boundary conditions and then find quantum numbers 'emerging' from the solutions in the form of values where the solution can be set to zero in a periodic fashion.

I prefer to observe that this is common with many equations and nothing special at all.

Consider the following much simpler equation

x2 -4 = 0  therefore x is 2 (yes or minus 2)

Now change this to x2 - 4 = 5

Now x is 3.

Nothing special at all.

Wouldanyone say the numbers 2 or 3 emerge from this ?

Edited by studiot
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Posted (edited)

You can't reverse engineer an emergent phenomenon and, conversely, you can't predict the outcome of an emergent phenomenon from its component parts. Ultimately, emergence has a strong unpredictable element about it.

Quote

An emergent property is a system-level property that is dependent on the organization of the system’s more basic elements or parts but cannot be reduced to them. For example, the chewiness of bread is an emergent property, because it depends on flour, water, yeast, and salt but cannot be reduced to these basic ingredients.

Emergence typically arises in a complex system, in which system-level properties are produced by the collective behavior of a large assembly of simpler elements. These system-level properties are:

Irreducible
They are distinct in existence from the basic elements that give rise to them.

Unpredictable
The starting values, context, and the interactions between basic elements produce probabilistic outcomes.
Conceptually novel

They can be described effectively only by introducing a new concept does not exist at the lower level of the basic elements. (That is the concept is ontologically new with respect to the more basic elements.)

Edited by StringJunky
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49 minutes ago, StringJunky said:

You can't reverse engineer an emergent phenomenon and, conversely, you can't predict the outcome of an emergent phenomenon from its component parts. Ultimately, emergence has a strong unpredictable element about it.

So by this definition a pile of broken egg or humpty dumpty shells or perhaps the ashes of a burnt letter are emergent phenomena.

I think that tying down the concept is really difficult and that there are as many definitions as there are definers.

Nevertheles it can be a useful concept.

Thank you again for introducing the subject +1

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Just now, studiot said:

So by this definition a pile of broken egg or humpty dumpty shells or perhaps the ashes of a burnt letter are emergent phenomena.

I think @StringJunky is implying a necessary condition for a phenomenon to be emergent, not a sufficient one.

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13 minutes ago, studiot said:

So by this definition a pile of broken egg or humpty dumpty shells or perhaps the ashes of a burnt letter are emergent phenomena.

I think that tying down the concept is really difficult and that there are as many definitions as there are definers.

Nevertheles it can be a useful concept.

Thank you again for introducing the subject +1

I dunno, this concept is a work in progress for me.   Just musing: could entropy have something to do with your examples not being emergent?

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