Skepticwithachainsaw

Right some background; I was on a random Forum and there was a thread in which God was being discussed, and as usual it mutated into a battle between some agnostics and some Christians.
One of them posted a reply, which included in it the oh-so-often-used premises that 2nd Law thermodynamics contradicts the theory of evolution.
Now being a good Agnostic/Skeptic with a very strong interest in Physics that I am, I immediately pounced on it and pummelled him with a refutation of the idea, his next reply admitted defeat on this issue.
However I’m not totally confident about my answer (I'm only 18 and haven't started my intended Physics + Philosophy degree ) and I was hoping that someone with more Physics knowledge than me could check through it and correct any mistakes/expand on something I missed and generally make it clearer.
Thanks in advance.

His original post.
Him
Gravity is no longer a theory. It's a Law. When a theory stands up to testing it becomes a law. That means it can't be disproven. Evolution, however, is still a theory as the 'over whelming evidence' is so full of holes that it will never make it to law status. One difficulty evolution faces is that it contradicts an established law: the second LAW of thermal-dynamics. This law states that all things in a given system move from order to chaos, the entropy law as some of you may know it. Evolution suggests the opposite. Taking a chaotic system, ie the primordial soup and moving towards order ie multi-celled organisms. This fundimental flaw has caused many scientist to abandon the theory (yes, they are abandoning it). I can get you documentation on this when I get home.

And this was my reply…
Me
Umm, there is no such thing as Law in science, only a theory that has been successful.
Whose Law of Gravitation are we talking about anyway?
Newton's or Einstein's?
Newton's for example has been shown to be inaccurate when dealing with very large masses, indeed it is unsuccessful in predicting the orbit of Mercuary, let alone dealing with Black holes and the like.
Einstein's theory has appeared to be successful so far, but this does not exclude the possibility that it may be found to be in error (i.e inaccurate) in the future.
This is a core principle of the scientific method, nothing can be proven with Science, only disproved.
Laws are scientific theory's that are assumed to be right, enough so that we can build more theories based on these theory's and be fairly confident that the base of these theories won't be found to be inaccurate.


Anyway the 2nd "Law" of Thermodynamics is a principle, not a strict theory/law, it says that since systems change over time, they are far more likely to change into a state that appears to us to be disordered, this is because their are an almost infinite variety of possible states it could become and most arrangements of atoms/molecules (etc) would appear "disordered" to us. However there is a very small chance that it would form an arrangement that we would consider "ordered", this is very unlikely to happen so in general we say that in closed systems the amount of disorder increase. However it is perfectly possible for the formation of a fairly complex macromolecule (for example) to occur, even if it's "order" increases.

Saying that "Entropy" = "Disorder" is a far to simplified version, disorder is an aesthetic quality with which we describe a system. Entropy however is a physical quantity, it is defined as the measure of the unavailability of energy available for doing work. In other words the proportion of energy not available for Potential energy (i.e. in the form of heat).

In order to increase the "order" in a system energy must be put energy in (to create potential energy states and the like), and the "Laws" of thermodynamics state that the state of the waste energy released from this procedure will increase the overall entropy in the greater system. The most commonly used example is a computer storing data. The heat energy from a computer released after it stores information is greater than the energy now in an "ordered" state. Thus the total Entropy increases, even if an ordered structure is formed.

You're right, thermodynamics does say that the amount of entropy will increase in a closed system, it is concluded from the principle that the "order" of a system is almost certainly to decrease overtime (like I explained previously).
However This planet is not an enclosed system, it radiates energy into space (our planet glows…) and it receives energy from the Sun, a lot of energy.
So the entropy in the sun and the rest of the universe may increase but the "order" (or a reduction in entropy) on small areas of this planet may (temporarily at least) increase, without violating the laws of thermodynamics.

Sorry if this isn't too clear in places.

Anyone want to give it a try?

Gooch's dad

Well, I do have a degree in Physics, and I couldn't have put it better than you did. I especially like the way you explain the 2nd LoT in terms of statistical possibility, in that there are tremendously more diordered states than ordered states.

I had to chuckle at the fellow's attempt to use the 2nd law, and calling it 'thermal-dynamics'. I wonder if it is the same guy I was chatting with on Yahoo yesterday, who said the 2nd law of 'therma-dynamics' proves atheism to be wrong.
<img src="graemlins/banghead.gif" border="0" alt="[Bang Head]" />

Godless Dave

I especially liked the distinction you drew between "order", a sujective valuation, and "entropy", a measurable scientific property.

Freethinking Ferret

You should also ask him to name one reputable scientist who abandoned evolution solely because of this tired old "proof", so that we can track that scientist down and give him a good horse-whipping.

The creationist's 2LoT argument is designed to convince only the layperson, since anyone who knows anything about thermodynamics recognizes that we're hardly within a closed system. As an aside, I had assumed even ICR had dropped this one, but a quick search of their page shows that there are a ton of articles spouting this nonsense.

Good job on your reply.

Tim Thompson

It certainly seems that Mr. Chainsaw did an adequate job. But I would also say that his opponent gave up rather more easily than mine seem to do.

The distinction between closed & open systems is really quite important. "Advanced" creationists will try to disarm the argument by pointing out that there are no really & truly closed systems, and so the distinction should not matter. They will then argue that even in open systems, there is a "tendency" towards disorder that is violated by evolution. I tried to point out to one creationist that the word "tendency" had a certain amount of flexibility associated with it, but he would not have any of it.

When dealing with creationists, you always run into a stone wall somewhere (or at least I always do). I have tried to address the issue myself, in a new set of my own webpages, "<a href="http://www.tim-thompson.com/entropy.html" target="_blank">Adventures in Entropy</a>". It took me a long time to write just what's there, and I haven't gotten to the point of addresing creationism yet . But I think it is a pretty good introduction to entropy and the 2nd law, from which one could construct a reasonable enough anti-creationist argument, at least until I write my own.

Wizardry

I’m just going to correct one thing here.

A scientific law is not, repeat not, a theory that has withstood testing.

There is no ladder of certainty in science that goes: hypothesis-&gt;theory-&gt;law. There are fundamental differences between the concepts.

A law is a description of the way the universe works. A theory is an explanation.

Newton’s Law of Gravitation is called a law because it never tries to explain why gravity works that way, it merely describes the way it works. We know that it’s not accurate, but we still call it a law because it meets the actual definition of a scientific law. Similarly, the Laws of Thermodynamics are laws because they merely describe the behavior of thermodynamic systems, not because we are really, really sure about them.

Similarly, even though we are pretty sure about relativity, we still call it the Theory of Relativity, because it explains other phenomena. Relativity will never become a law because it is explanatory rather than descriptive. When scientists talk about Evolutionary Theory, they are referring to the mechanisms which produce common descent and speciation, which are acknowledged as facts (true statements about nature ie light is both a wave and a particle, Homo sapiens is closely related to apes) in the scientific community.

Laws don’t always trump theories. Einstein’s theory altered Newton’s Laws of Motion. It’s just that it’s what usually happens. Our description is just most often more accurate than our explanation.

Peace out.

liquid

Firstly, a small addendum to Wizardry's post. 99/100 times, a law is a mathematical description of reality. It has no explanitive value, and as such is in an entirely different sphere to theories.

Now to address your post (FYI I am an aerospace engineering student - if you really wanted to study thermodynamics (thermofluids as it is usually lumped into), physics is not the right course. Engineers actually study thermo far more in-depth than physicists - in fact, almost all macrophysics is in the realm of engineering these days, and a substantial amount of meso and micro too. But then there is so much overlap between academic engineers and physicists, and we don't touch particle, quantum and relativistic physics.)

Please note, I am being very pedantic. I will tell you now it is very good, and I'm only being 'strict' because its evident you have the curiosity to go further.


There are laws in science, but they aren't successful theories as you say. See the posts above.

All great!


It is a law. It is strictly mathematically definable. This is just semantics - I think you get the general idea. At anything even remotely above singular molecule levels, the law, statistically speaking (and that does not mean it is any less categorical a statement), does not get broken.

You should really use a more precise definition, or one of the corollaries (equivalent definitions). Specifically, you should mention entropy or irreversibilities.

'disorder' is not a defined term. Entropy is the proper mathematical and physical quantity that should be used. People use disorder, but it is not in any way synonymous. For instance, a heat-death universe would look very boring, flat and warm. On a large scale, that could be interpreted as order - no lumpy planets or humans.


Now, I am not a chemist, but this is not generally the case (although it depends on your subjective use of complex). When a complex molecule forms, although the entropy of the molecule decreases, there will be a pay-off elsewhere. For instance, the fusing of hydrocarbon chains producing water.

The point is that a macromolecule has less entropy, but:

1. If you draw the system boundary about the molecule and products, there is a net increase in entropy (and that is the important thing... net increases.

2. The system isn't closed/isolated anyway, so even if you drew the control volume around the molecule only there is a heat transfer out of the system.

All fine - but this should have come beforehand, is what I am getting at.

All correct.

perfect.

-----------------------------------------------
Now for some asides.

1. In relation to the earth emitting heat... some people don't seem to accept that the earth emits more entropy than it receives and hence agrees with the second law. In fact, this is easily provable by standard calculations and indeed, is inevitable by those same calculations. Posted here is an earlier post I made describing them in words... It is called Planck's estimation.

"It is interesting to observe that an enormous amount of entropy production is actually associated with the formation of life on earth.
According to Plank (father of quantum mechanics) the entropy flow from the sun is proportional to the reciprocal of the sun's temperature[I assume planck made the argument but I'd just like to note that this proportionality comes from the basic mathematical form of the second law for heat engines and has been around a long long time - Liquid].

More precisely it is four thirds times the heat transfer from the sun all divided by the temperature of the sun (about 6000 kelvin). By the law of conservation of energy (and ignoring global warming) the heat flow from the sun to the earth is equal to the thermal radiative heat transfer from the earth to outer-space. The entropy flow from the earth is therefore four thirds times the heat transfer from the sun all divided by the temperature of the earth as seen from outer-space (about 300 kelvin = 27 celsius). Therefore, the entropy flow from the earth is greater than the entropy flow to the earth which means that entropy has been produced on earth (via friction, etc.)."

2. In relation to the above, research indicates that thermodynamic gradients set up ordered systems spontaneously in order to encourage entropy flow. This is analogous to a stream finding the quickest course downhill (indeed, as you know, all things seek low-energy states). These are called dissipative structures, and earth may just be one.

3. People think that chickens sit on eggs to warm them. They are wrong. In fact, the egg passes net heat to the chicken, as a by-product of creating an ordered chick. The hen just ensures that the escaping heat doesn't drop the temperature of the egg so low that the reactions cannot take place.

PopeInTheWoods

I'm inclined to take your word for this, as I'm neither a scientist nor an engineer, but what about the heat passed from the chicken to the egg as a by-product of keeping a much larger ordered chicken in operating condition?

Andy

Skepticwithachainsaw

Thanks for the compliments
It's always reassuring that I'm doing something vaguely right

Yeah, I have to agree with you 'Thomson, it appears that it was something he had vaguely read on some Christian Propaganda rather than seriously trying to read up on it and when I challenged this it was his (lack of) actual knowledge of the subject was shown. AndI have seen S = k*ln(Omega) (used in some versions of the Big Bang theory?) in combination that the Universe as a whole is a closed system as an argument. (?) I don't know enough about Physics to respond to this but I would still assume that this doesn't conteract the idea that Entropy can still increase even if some apparent Complexity is formed.

Thanks to Wizardry for sorting out the difference between a Law and a Theory, that was very helpful, I had never been told about that.

Special thanks goes to Liquid for giving a very detailed and full answer, extremely helpful thank you,

However I have a couple of points I want to check
1) Is the definition for entropy all ways of looking at the same thing?
For example is the statistical explanation a direct consequence of the loss of energy available to form new potential states?
If so could you explain this (or point me in the right direction), I think I've got a vauge idea of how this works but I'd like something more concrete.

2) How does this relate to irreversible reactions, is it that the Entropy involved in a reaction/interaction always increases or that it only increases for irreversible reactions?

Thanks again.

Heh Mr Arboreal Pope, I'm not sure but I would guess that although the Chicken produces more heat energy, the Temperature of the egg is slightly greater (a bit confusing I know) and so the heat passes from the egg to the chicken.
However because the Chicken is still warmer than the environment (unless the egg is in some boiling water or something&#8230 the rate of heat energy is lost from the egg to the chicken is smaller than if it was just exposed to the environment. Thus the Egg always maintains it's "operating temperature".

liquid

Thanks for the thanks! Unfortunately, I have a very severe hangover *delerium tremens - it's a beer, it's 9% and I drank a lot of it*, so forgive dodgy answers. I might have to revise or add stuff later.


"1. Is the definition for entropy all ways of looking at the same thing?
For example is the statistical explanation a direct consequence of the loss of energy available to form new potential states?
If so could you explain this or point me in the right direction, I think I've got a vauge idea of how this works but I'd like something more concrete."

Well, by and large, there are many different ways of dealing with 2LoT, and they indeed are all equivalent at the fundamental level. For instance, saying that you cannot make a 100% efficient machine implies the same as saying net entropy always rises. I'm not quite sure what you are trying to get at - I hope that answers it. If you are looking for a specific example of a 2LoT definition and how it can be changed into a corollary then I can do that for you when I recover!

<img src="graemlins/banghead.gif" border="0" alt="[Bang Head]" /> &lt;- My body right now....


"2. How does this relate to irreversible reactions, is it that the Entropy involved in a reaction/interaction always increases or that it only increases for irreversible reactions?"

Irreversibilities in an energy exchange are, as you know, things like friction that 'cause' the entropy to rise. They are inefficiencies, by another name. The reason we give them the name we do is because they prevent you from reversing the system to its previous state without additional work.

Theoretically, entropy increase does require irreversibilities. When you first study heat engines, many of the problems you solve are isentropic - no change in entropy. These are 'perfect' heat engines - reversible, but even they cannot be 100% efficient - the maximum efficiency is the carnot cycle, if memory serves. I really should go back to my notes to check all this.

As for the chicken and the egg -

1. Yes, you both are right to point out the scenario isn't quite so simple but to address your concerns... - told you people never quite feel comfortable with this!

2. Think about it if heat is flowing from chicken to egg for a moment. The egg is creating it's own heat, but as it is at the bottom of the thermal gradient, none flows out. During the meantime, even more heat is flowing down that gradient. Net effect: slow-boiled egg. Thermal equilibrium is impossible - according to the assumption of the thought experiment, and the egg will rise in temperature unstoppably. *If the chicken sits on it forever and it has an unlimited supply of yolk though!*

Now think about it if heat is flowing from egg to chicken - the chicken actually acts as a heat transfer buffer, preventing the temperature from dropping too far. Heat is generated in the egg, which rises momentarily above thermal equilibrium. The excess flows to the chicken, to the surroundings.

Hope that helps *and makes sense*

PS odd punctuation in places I know - the forum is having trouble with parentheses