Does instantaneous communication implies a preferrred Lorentz frame?

In summary: Michelson-Morley experiment. So as a matter of logic, I think that's the most economical theory, to hold onto everything that is consistent with the experiments.
  • #71
zonde said:
I gave my argument previously you just dismissed it.
I said that time can be measured directly with clock while entropy do not have means of direct measurement.
So if the events A and B are causally connected, and all the clocks agree that A is earlier, how does that give us a reason to say that A caused B instead of B caused A? Ah, I see you answered that too:
zonde said:
- the reason is that we do not care about changing the past but we care about changing the future (we care about our survival in the future).
We feel that way because we feel that it's possible to change the future and impossible to change the past. Why do we feel this way? Because we have memories of the past and none of the future. Why is that? Because storing a memory is a process that increases entropy, and entropy is increasing towards the future. Why is entropy increasing? Because the universe started out in a low entropy state. Why did it do that? No one knows.
 
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  • #72
zonde said:
Demystifier,
before you make conclusion I propose to consider another scenario.
Take Frederik's example with two computers communicating "1" and "0". But modify it so that it becomes non contradicting i.e. computers are just storing the value they get and then transmit it back to the past of other computer.
As I understand you allow possibility of such scenario.
In that case we can have this causality loop in two states:
1. first computer have stored "0"; it transmits "0" to second computer; second computer have stored "0"; it transmits "0" back to first computer.
2. first computer have stored "1"; it transmits "1" to second computer; second computer have stored "1"; it transmits "1" back to first computer.
Separately each of two computer do not have free will but the whole causality loop has free will to be in one of two states. The state at any point is not random and is not caused by any physical law outside this causality loop.

What you can say about this scenario? Do you see any inconsistency in my reasoning?
I think it is consistent. And it can be called "free will" if you like. However, unlike the ordinary free will, this free will acts in a nonlocal manner. That's why I do not prefer to call it "free will".

Or let me be more clear. In order to avoid inconsistencies, I need an absence of local free will. Since by "free will" one usually means "local free will", it is simpler to say a simpler statement that "there is no free will", rather than a more precise statement that "there is no local free will".
 
  • #73
Fredrik said:
We feel that way because we feel that it's possible to change the future and impossible to change the past. Why do we feel this way? Because we have memories of the past and none of the future. Why is that? Because storing a memory is a process that increases entropy, and entropy is increasing towards the future. Why is entropy increasing? Because the universe started out in a low entropy state. Why did it do that? No one knows.
The most elegant explanation of this stuff I ever seen. :approve:
 
  • #74
Fredrik said:
I don't think entanglement has a lot to do with what we've been dicussing, since entanglement can't be used to send superluminal messages.
It seems that you have not understood the whole motivation for this thread. As said in the first post, it is quantum nonlocality that suggests the existence of superluminal messages. (I guess I don't need to explain that quantum nonlocality is a consequence of entanglement.) Of course, such messages, if exist, cannot be CONTROLLED by humans (which is what you probably meant when you said the above), but the idea is that these messages are exchanged between the microscopic particles anyway. In this context, my requirement that "there is no free will" actually means that microscopic particles do not have free will, i.e., that these particles cannot CONTROL the messages. But the inability to control does not mean that they do not exist.

Concerning the relation between human free will and microscopic-particle free will, there is a "free will theorem" discussed several times on this forum.
 
  • #75
Fredrik said:
It seems to me that the only thing that can be a problem for the illusion of free will is the existence of easily detectable tachyons.
With that I agree. And decoherence explains why the effect of tachyons responsible for superluminal communication among entangled particles, if they exist, cannot be easily detected.

Fredrik said:
On the other hand, that assumption strongly suggests that there's an underlying theory that does describe what actually happens, and that the variables of that theory aren't observables. (If they were, I think we'd have problems with Bell inequalities and that sort of stuff). Since we have no idea what that theory is, it's hard to speculate about it, but I'll offer two thoughts about it anyway.
Well, Bohmians do have an idea what that theory might be. I have given a link to a concrete theory in the first post.

Fredrik said:
I don't see a reason to think that superluminal influences between unobservables would force us to behave in a certain way to avoid a violation of "global consistency" like the paradox described in #24. So such influences wouldn't necessarily be a problem for the illusion of free will, like easily detectable tachyons would.
If you think so, then we actually agree. It is possible that superluminal influences exist without a preferred frame, without affecting the illusion of free will.

Fredrik said:
Decoherence can cause correlations in spacelike separated measurements, but does it make sense to describe those as "superluminal influences"? I don't know. I don't understand the MWI and decoherence well enough.
Well, decoherence actually DESTROYS correlations.
 
  • #76
Fredrik said:
So if the events A and B are causally connected, and all the clocks agree that A is earlier, how does that give us a reason to say that A caused B instead of B caused A?
Well maybe it was a mistake to talk about reasons for time asymmetry.
Maybe the reasons does not matter so much as long as we agree that time is asymmetric. We just extend this asymmetry to causally connected events. You can call all the effects the causes and all the causes the effects as long as you treat them asymmetrically.
The clock just gives us easy way to track this asymmetry.
Maybe we have disagreement because I am more interested about operational definition but you about theoretical definition.

Anyways I looked back at the start of our discussion and it occurred to me that there is certain difference between the past and the future. We take present as evidence about our past but we do not take present as evidence about our future. And that is basic fact of our existence that should be taken as is.
 
  • #77
Fredrik said:
We feel that way because we feel that it's possible to change the future and impossible to change the past. Why do we feel this way? Because we have memories of the past and none of the future. Why is that? Because storing a memory is a process that increases entropy, and entropy is increasing towards the future. Why is entropy increasing? Because the universe started out in a low entropy state. Why did it do that? No one knows.
Since your understanding of this stuff is so clear, I hope the following argument will look convincing to you.

There are two types of messages: those the receiving of which increases entropy, and those the receiving of which does not increase entropy (*). The former type cannot be received from the future (because it would contradict the fact that entropy is larger in the future), but the latter type can. In fact, messages the receiving of which does not increases entropy are not detected by humans. I mean, they may influence microscopic degrees of freedom of our bodies, but they are not perceived by consciousness. Since the illusion of free will is one of the manifestations of consciousness, it follows that messages from the future cannot influence the illusion of free will.

(*) One may doubt that messages which do not increase entropy can exist. But they can, provided that they occur at the microscopic level, at which the nature is symmetric under time inversions (up to irrelevant effects of weak interactions). Indeed, instantaneous messages betwen distant entangled particles in Bohmian mechanics are of this sort.
 
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  • #78
zonde said:
We take present as evidence about our past but we do not take present as evidence about our future. And that is basic fact of our existence that should be taken as is.
The question is: Is it only our subjective experience of time, or is it an objective property of the time itself?

Fredrik and me are proponents of the idea that it is only our subjective experience, an illusion. You seem to think that it is an objective property. But you know that an objective (i.e., observer independent) distinction between future and past is not compatible with relativity (viewed as a fundamental law). That's probably the main reason why many physicists prefer the idea that the distinction between "future" and "past" is only an illusion and does not make any sense in the absence of increasing entropy. Just like the distinction between "up" and "down" is only an illusion, and does not make any sense in the absence of gravity.
 
  • #79
dmtr said:
AFAIK all these causality-loop paradoxes simply go away under the MWI interpretation. In the example above 'Alice sending 0' would be from a different subjective history from the 'Alice sending 1'.
This is actually not true. According to MWI, the universe splits ONLY when decoherence takes place. On the other hand, causality-loop paradoxes may also appear in cases in which decoherence does not take place.
 
  • #80
As time goes by the level of organization and complexity in the universe is increasing.
I see Life ( and US with our increased capacity to work on knowledge) as the ultimate organization, the last creation of the Universe.
In the beginning of the universe there are no organization at all.
How can we say that entropy increases?

The universe is not closed as required by 2nd law. Also it is not open because ...
the relation open/close involves more than one entity nor we can not find frontiers, nor any other 'object' surrounding the universe.

At least in the scale of the universe we can not say 'the entropy increases'
-----------------------
The whole story about 'arrow of time' is misleading.
We construct equations that describe events, in an observed order. It gives us even some capacity to preview how events will be.
But the 'arrow of time' of our equations are a mental construction, not a real object and we can not manipulate it, reverse it, etc. It is an index we assign to events.

-------------------------
Does a system like the universe could survive if instantaneous communication were possible ? I think not.
Instantaneous communication can not be faster then light. I can live with this.

--------------------------
Entanglement ?
I see it this way :
particle pair A, B created at the same time. Latter we find and measure A. Latter if we find B don't we measure it as B? The properties of A and B are determined from the beginning on the moment of their creation.
 
  • #81
Fredrik said:
Consider the following scenario: (You probably have the spacetime diagram in your head already, so I won't describe everything in detail).

A computer that's hooked up to a tachyon transmitter is running a program that tells it to send a 1-bit message at t=1 that contains the NOT of the 1-bit message it received at t=0. (If we receive 1, send 0. If we receive 0, send 1). The computer at the other end is set up the same way, except that it's running a program that tells it to send the same 1-bit message that it has received, immediately after it has received it. This scenario contains a paradox:

Receive 1 → send 0 → receive 0
Receive 0 → send 1 → receive 1

You're suggesting that a way out of this is to say that free will exists only as an illusion. How does that help? Do you mean that computers running these two programs can't be built? Do you think they can't be hooked up to tachyon emitters or tachyon detectors? What do you think happens if I try? Do I get hit by a meteor? What if we all try? More meteors?

Do you think we would be unable to choose to try? I have two problems with that option. First of all, that doesn't just eliminate free will, but also the illusion of free will. How can we resolve a paradox by assuming that something we know is true (that we have the illusion of free will) is false? Second, if our brains are just physical systems that gather and utilize information, then we're not very different from the computers mentioned above. So why would it be more likely that the event that prevents the paradox happens in my brain than in the computer?

Such a paradox may also be resolved in a slightly different way, any scenarios which are not consistent may simply interfere destructively with each other. So in the above example the tachyons won't reach the detector, they will probably slightly miss, just enough to not register, because the actual path between the sender and the receiver will have 0 probability of being realized.

This would mean that future is naturally restricted by interference to scenarios which do not lead to paradoxes and it does not say anything about free will as the actual selection happens on the level of physics.

Quantum interference in time has been demonstrated which I think gives some support to this hypothesis: http://arxiv.org/abs/quant-ph/0507044
 
  • #82
heldervelez said:
Instantaneous communication can not be faster then light. I can live with this.
So you can live with
infinity < 300.000 ?
Good for you, but I can't. :smile:
 
  • #83
PTM19 said:
Quantum interference in time has been demonstrated which I think gives some support to this hypothesis: http://arxiv.org/abs/quant-ph/0507044
The work of Horwitz (though not this particular paper) has been also influential on the paper mentioned in the first post in this thread.

If you like the work of Horwitz, you may like this paper as well. In fact, this paper also solves some problems of the Horwitz approach.
 
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  • #84
Fredrik said:
My pairs are of the form (t,x). That's seems to be the most common way (by far) to write them.

Can't say I've ever seen them written that way, but I don't do much with SR. I do teach, publish and referee in GR and you're right, we (almost) always put time first in the four vector so it seems odd that we switch them in the SR graph. But, as I said, I've only seen it (x,t) there.

Fredrik said:
I hope that clears it up.

Crystal clear, thanks. I will use this simple example when showing SR to the non-science students in my general education courses.
 
  • #85
Demystifier said:
So you can live with
infinity < 300.000 ?
Good for you, but I can't. :smile:

Demystifier :
A obvious nonsence I've written and you did spot. I'm not imune to errors. This one is a a comunicational 'lapsus linguae' and, for sure, I will add some errors about spelling.:blushing:

Why should the entropy be increasing, as you said, and against all evidence as I said?

All errors are not at same level. I do not know yet what "smile" to choose to your error.
 
  • #86
Fredrik said:
We feel that way because we feel that it's possible to change the future and impossible to change the past. Why do we feel this way? Because we have memories of the past and none of the future. Why is that? Because storing a memory is a process that increases entropy, and entropy is increasing towards the future. Why is entropy increasing? Because the universe started out in a low entropy state. Why did it do that? No one knows.

That's a common misconception. Only erasing a memory is a process that increases entropy (look-up Landauer and Bennett).
 
  • #87
Fredrik said:
That may be true, but I suspect that it's not that simple. If it's true, then it should be easy enough to write down a QM description of the sequence of events I described in #24 that makes it obvious that what you said is correct. I expect that the result would be the opposite, i.e. that if we tried to prove this, we would end up proving that the same paradox is present in the MWI too. I haven't tried to do this yet. Maybe I'll give it a shot later.

Just skim over a relevant chapter of 'the Fabric of Reality' by David Deutsch (one of the MWI proponents).
 
  • #88
Demystifier said:
The work of Horwitz (though not this particular paper) has been also influential on the paper mentioned in the first post in this thread.

If you like the work of Horwitz, you may like this paper as well. In fact, this paper also solves some problems of the Horwitz approach.

Thanks, I'll check it out.


dmtr said:
That's a common misconception. Only erasing a memory is a process that increases entropy (look-up Landauer and Bennett).

I think what you refer to is only true in information theory, it certainly does not hold for biology. Human brain increases entropy when storing memories - neurotransmitters are being released into synapses, neurons change connections, genes are switched on and off and plenty of of ATP is hydrolyzed.
 
  • #89
PTM19 said:
I think what you refer to is only true in information theory, it certainly does not hold for biology. Human brain increases entropy when storing memories - neurotransmitters are being released into synapses, neurons change connections, genes are switched on and off and plenty of of ATP is hydrolyzed.

I prefer to be very careful with the entropy. As Landauer and Bennett have shown our intuitions can easily be wrong. For instance new entanglements in between the biological system and the environment are continuously generated (decoherence). So you have to consider the contribution of the entanglement entropy. This contribution is negative (entropy of the entangled systems is less).

So my answer to your 'certainly' would be: not necessarily.
 
  • #90
heldervelez said:
Why should the entropy be increasing, as you said, and against all evidence as I said?
You have argued that the evolution of life is an evidence against increasing entropy. Even if you are right that this is AN evidence, you still cannot claim that ALL evidence is against it. I think that it is safe to say that MOST phenomena in nature confirm increasing entropy, even if the evolution of life is an exception.

Now, how the evolution of life may be compatible with increasing entropy? To be honest, I don't know. But that's because I don't have a good understanding of the evolution of life. After all, I am a physicist, not a biologist.
Nevertheless, I do know that total THERMODYNAMIC entropy in the Universe is increasing with time, despite the fact that life becomes more and more ordered.

Even though I don't know the answer to the question above, I think I can still say something nontrivial about it.
There are two possibilities:
Either life is a quite improbable and rare event in the Universe, or a very probable and frequent phenomena happening on a large number of planets with appropriate physical conditions (liquid water, atmosphere, etc.).
If it is quite improbable, then life is a statistical fluctuation. As the law of increasing entropy is a statistical law, not the exact law, a rare fluctuation is not in contradiction with that law.
If it is very probable, then it is in fact a consequence of increasing entropy, even though we do not understand in detail why exactly is that so.
 
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  • #91
https://www.physicsforums.com/showpost.php?p=2439230&postcount=31" I' mentioned a cold start for the universe
I can defend that position, but I was not allowed to say how is it possible (because the post was closed).

In this scenario of cold start universe the 2nd law does not hold.
It appears to be valid only with a 'hot start'.

But instead of contend on the start of the universe let's look to the evolution of the universe:

back think 'homogeneous- no structure'
but a star has more structure than a cloud of..
a galaxy has more structure than a single star..
a cluser of galaxys has more structure than a single star..
a planet has more than...
life has more strucrure than anything else...
our brains has more ...
life was the last creation of the universe ...
all this happenings of crescent organization are aganst 2dn law..
 
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  • #92
Life does not violate 2nd law...
 
  • #93
dmtr said:
I prefer to be very careful with the entropy. As Landauer and Bennett have shown our intuitions can easily be wrong. For instance new entanglements in between the biological system and the environment are continuously generated (decoherence). So you have to consider the contribution of the entanglement entropy. This contribution is negative (entropy of the entangled systems is less).

So my answer to your 'certainly' would be: not necessarily.

Hydrolysis of ATP generates work and releases energy rising the temperature I don't think it's possible for entanglement to offset the associated increase in entropy. For that to work it would have to provide a substantial amount of negative entropy and the amount of entanglement would have to keep accumulating over time while I would say it roughly stays the same over time - as new entanglement is being generated it overwrites the old one.
 
  • #94
The evolution is not the evidence against the 2nd law - every biological process which produces order generates even more disorder in it's environment so life actually speeds up thermalization. In other words the exact same Universe as our own but one in which evolution and life never happened would have a *lower* entropy.
 
  • #95
Dmitry67 and PTM19, it is not the question whether life itself is consistent with the second law. As you say, it is consistent.
The question is whether the EVOLUTION of life (in the Darwinian sense) is consistent with the second law. How evolution helps to increase the total entropy of the ecological system?
 
  • #96
heldervelez said:
But instead of contend on the start of the universe let's look to the evolution of the universe:

back think 'homogeneous- no structure'
but a star has more structure than a cloud of..
a galaxy has more structure than a single star..
a cluser of galaxys has more structure than a single star..
a planet has more than...
life has more strucrure than anything else...
our brains has more ...
life was the last creation of the universe ...
all this happenings of crescent organization are aganst 2dn law..
You're saying that gravity pulling things together decreases entropy. That's not true. I don't know how to prove it, and I'm not going to discuss it any more than to say this, but there are other threads here on that topic. I suspect that you can find an explanation in one of them. If not, consider asking about it in a new thread.
 
  • #97
heldervelez said:
https://www.physicsforums.com/showpost.php?p=2439230&postcount=31" I' mentioned a cold start for the universe
I can defend that position, but I was not allowed to say how is it possible (because the post was closed).

In this scenario of cold start universe the 2nd law does not hold.
It appears to be valid only with a 'hot start'.

But instead of contend on the start of the universe let's look to the evolution of the universe:

back think 'homogeneous- no structure'
but a star has more structure than a cloud of..
a galaxy has more structure than a single star..
a cluser of galaxys has more structure than a single star..
a planet has more than...
life has more strucrure than anything else...
our brains has more ...
life was the last creation of the universe ...
all this happenings of crescent organization are aganst 2dn law..

Isn't this fairly off topic?
 
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  • #98
Fredrik said:
That may be true, but I suspect that it's not that simple. If it's true, then it should be easy enough to write down a QM description of the sequence of events I described in #24 that makes it obvious that what you said is correct. I expect that the result would be the opposite, i.e. that if we tried to prove this, we would end up proving that the same paradox is present in the MWI too. I haven't tried to do this yet. Maybe I'll give it a shot later.

I believe that MWI would eliminate the possibility of superluminal communication before the experiment ever gets underway. Remember, the theory that superluminal communication exists is derived from entanglement in the first place, and MWI would argue that there were always multiple sets of entangled particles, and that by measuring one particle, no 'message' is sent to the second particle at all, but the observer (who is local to the observation, and bound by lightspeed in receiving the results of the measurement) is instantaneously 'split' from the 'multiple' worlds where the measurement of both particles could be one of several values into a 'single' world where both entangled particles 'have always had' the measured value. So without the entanglement argument to suggest superluminal communication, you'd either have to abandon the experiment or carry it through with lightspeed as the maximum velocity for both the communication and any other actions...
 
  • #99
dmtr said:
I prefer to be very careful with the entropy. As Landauer and Bennett have shown our intuitions can easily be wrong. For instance new entanglements in between the biological system and the environment are continuously generated (decoherence). So you have to consider the contribution of the entanglement entropy. This contribution is negative (entropy of the entangled systems is less).

So my answer to your 'certainly' would be: not necessarily.

PTM19 said:
Hydrolysis of ATP generates work and releases energy rising the temperature I don't think it's possible for entanglement to offset the associated increase in entropy. For that to work it would have to provide a substantial amount of negative entropy and the amount of entanglement would have to keep accumulating over time while I would say it roughly stays the same over time - as new entanglement is being generated it overwrites the old one.

I would think it do accumulate over time. New entanglements are generated (i.e. ATP generates work and releases energy -> coupling with the environment -> decoherence = new entanglements with the environment). Old entanglements don't go away, they get more and more diluted in the environment, but the entanglement of the system with the environment is not being reversed.

Considering that decoherence involves a lot of entanglements, and the environment is continuously increasing in size (light cone) I wouldn't be surprised if the corresponding entanglement entropy contribution is substantial and keep accumulating over time.
 
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  • #100
DougW said:
I believe that MWI would eliminate the possibility of superluminal communication before the experiment ever gets underway. Remember, the theory that superluminal communication exists is derived from entanglement in the first place,...

Welcome to PhysicsForums!

The Bohmian class of theories started as early as the late 1920's with some work by de Broglie, so I don't think that you could really say that superluminal concepts were derived from entanglement per se. Everett started his work on MWI well before Bell's Theorem, as did Bohm.

You will find a lot of threads here about MWI and other interpretations of Quantum Mechanics. Generally, we distinguish orthodox QM (oQM), Many Worlds (MWI), Bohmian Mechanics (BM or dBB) as interpretations which are isomorphic in their physical predictions. (Obviously, if they could be tested they would.) So you shouldn't feel the need to defend your favorite interpretation at every turn - although all of us tend to do that from time to time anyway! :smile:
 
  • #101
DrChinese said:
So you shouldn't feel the need to defend your favorite interpretation at every turn - although all of us tend to do that from time to time anyway! :smile:

Yeah and I know some even take the stance that the whole argument is irrelevant, so long as the predictions are accurate. To me this whole issue, and even the wave-particle duality issue etc, boils down to making careful assumptions and applications of what we know. To me it never was a great mystery about Schroedinger's Cat, or in this case "instantaneous communication". The reality is, the entire universe is one giant closed system, meaning its only ever an approximation to treat any two things as "separate". In the case of the entangled particles, we have our minds twisted because we want to think of them as two separate particles, living separate lives. But, the reality is, they are interconnected. No "communication" is actually even happening here. No photons are exchanged. We are just a few scientists looking at the state of the system. Like the guy who opens the box to see if Schroedinger's cat is dead or alive.

The wave form collapses because it only ever was a mathematical construct from the get go. Something built by us to represent the state of the system, and what we knew about the system. Once we open the box, what we know changes, and hence the wave form collapses. Nothing mystical. We don't need to "exchange particles" with the cat's waveform to collapse it, we just have to "know". It collapses because "what we know" is built into what it is by definition.
 
  • #102
DougW said:
Remember, the theory that superluminal communication exists is derived from entanglement in the first place,
Post #1 in this thread mentioned entanglement as a reason to suspect the existence of superluminal influences, but those "influences" would only directly affect unobservables, so they can't be used to send superluminal messages. Therefore, entanglement doesn't really have any relevance to the paradox I've been talking about. This paradox arises when we consider the possibility of easily detectable tachyons. By "easily detectable" I mean that the time to detect a particle doesn't grow at least linearly with the distance they've traveled. (If it did, the paradox would be avoided. See my posts earlier in this thread). By "tachyons", I mean particles corresponding to [itex]m^2<0[/itex] irreducible representations of the proper orthochronous Poincaré group. (In special relativistic QM, the particle species correspond to different irreducible representations (see chapter 2 of Weinberg's QFT book). The ones with [itex]m^2<0[/itex] are tachyons).

DougW said:
and MWI would argue that there were always multiple sets of entangled particles, and that by measuring one particle, no 'message' is sent to the second particle at all,
I agree with this.
 
  • #103
Demystifier said:
Dmitry67 and PTM19, it is not the question whether life itself is consistent with the second law. As you say, it is consistent.
The question is whether the EVOLUTION of life (in the Darwinian sense) is consistent with the second law. How evolution helps to increase the total entropy of the ecological system?

Well, to me this way of stating the problem does not make much sense, it's a bit like asking whether by parking cars in an orderly fashion we can break the 2nd law of thermodynamics. The law is only concerned with molecular motions and if the law holds on this level then it holds no matter what happens higher in the hierarchy of complexity. When a car's engine is running it keeps increasing entropy and how it is driven or parked doesn't matter.

I would say the same holds for evolution which is a high level process to which physical entropy has no direct application. Life obeys the 2nd law on the molecular level and evolution is just a complex activity of life forms. Yes, it makes those life forms more complex over time but that doesn't mean it somehow decreases entropy on the molecular level. A particular protein operates in the exact same way whether it is part of a bacteria or a human so here the fact that humans are "more evolved" doesn't matter. The only meaningful difference on the molecular level is that humans contain more complex biomolecules but when those biomolecules are being constructed the additional decrease in entropy associated with this extra molecular order is offset by extra energy being released during their construction. So from the point of view of entropy the only effect of evolution is that the cost of life in terms of entropy keeps rising.
 
  • #104
I agree.
2nd law does not say that EVERYTHING EVERYWHERE becomes more and more chaotic. Life just breaks the symmetry creating less chaotic systems by the cost of more chaotic environment.

In any case, our planet is receiving huge amount of negentropy from Sun, as we see 1 hot spot in one place and dark sky around. Earth returns thermal radiations, spread almost evenly in all directions. Life just uses that flux of negentropy. That negentropy is what we get from Sun! Not the *energy* - because Earth emits excatly the same amount of energy into space as it receives from Sun. So there is no surprise that the life started from the plants, not from animals: plants could absord the negentropy directly, while animals - only indirectly.

Think about the Photosynthesis: contrary to C + 02 -> C02 (burning), photosynthes *consumes* energy, not releases it. Why did Nature used it? because of negentropy from Sun.
 
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  • #105
PTM19 said:
Well, to me this way of stating the problem does not make much sense, it's a bit like asking whether by parking cars in an orderly fashion we can break the 2nd law of thermodynamics. The law is only concerned with molecular motions and if the law holds on this level then it holds no matter what happens higher in the hierarchy of complexity. When a car's engine is running it keeps increasing entropy and how it is driven or parked doesn't matter.
From the phenomenological point of view, you are absolutely right.
However, I am not satisfied with this explanation from the theoretical point of view. Namely, the second law valid on the thermodynamical level is DERIVED from the ASSUMPTION that system allways evolves towards a more probable state. But if this assumption is valid at ALL levels, not only on the molecular level, then cars should also obey this law. But they apparently don't. The question is - why? Why the assumption above is valid on the molecular level, but not on the macroscopic (car) level?
 

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