Entropy and evolution

>>>>>Why a textbook? Why not a book recommended by peer-reviewed journals? That's what I've got here...<<<<<<

Whose book? Do you mean the one by Atkins? He does not agree with your view on this matter, as you have admitted in some of your past posts. I deny that Atkins supports your view that there is a conflict between thermodynamics, entropy and evolution.

 

Well, put that notion aside for another day, but what about the 2lot situation? Do you see why evolutionists, thinking as we do that the picture I drew isn't imaginary, scratch our heads and wonder where people are coming from when they say 2lot prevents evolution?

 

I guess now is when we have to ask specifically what process necessary for evolution (Paul summarized it above, if needed) is forbidden by the 2nd Law of thermodynamics.

If Adkins has an opinion on that, then what he thinks is relevant. Otherwise, not.

I'd like to hear this one.

 

The 2nd Law is about entropy. Read about it here:

"Today, it is customary to use the term entropy to state the second law: Entropy in a closed system can never decrease. As long as entropy is defined as unavailable energy, the paraphrasing just given of the second law is equivalent to the earlier ones above. In a closed system, available energy can never increase, so its opposite, entropy, can never decrease."

http://www.panspermia.org/seconlaw.htm

But if you want to rephrase it, I'd sure be interested to see what process required for evolution is forbidden by entropy.

Tell us about it.

 

Entropy by itself is just a number. Kind of like the temperature. "its 90 degrees outside". Hey man, that's a lot of entropy out there!

It's only in context of a theory about entropy we can say something about some things being allowed and others not. The entropy theory that matters is the second law of thermodynamics, as Galation described above.

There is a looser way in which we speak of entropy increasing sometimes. The mess on my desk. That's a lot of entropy. I'm going to apply some intelligent design and straighten it up.

But this way of talking is not a rigourous description of what happens to entropy. But it can give one a new slant on how to perceive things in the universe.

 

Helen wrote:

And as with all expert physicists Adkins' prosaic remarks about entropy (or any other physical quantity) defined mathematically are to be understood as elucidation of the real mathematical definition. They are absolutely never to be used to undermine it. What Adkins says makes sense when read as explaining the rigirous mathematical definition of entropy; but without that mathematical context his remarks are without context. Until you know and understand the mathematical definition of entropy, your quote-mining--even of experts--will continue to miss the mark.

Again, thermodynamic entropy for a system the equation dS = DQ/T, where dS is the (infinitesimal) change in entropy for an infintesimal reversible process at temperature T causing an amount of heat DQ to flow into the system. By reversible process we mean a process in which the system's state is always well=defined (basically definite pressure, teemperature, energy, and the like.) For non-infinitesimal changes the change of entropy along a path between two well-defined states may be obtained by integration. Remarkably it can be shown that the integration between two given states is not dependent on the path between those states. Thus entropy, unlike heat or work, depends only upon the state of the system and not the system's history, or the path the system has taken to reach its state. This means that entropy is itself a state variable. (That is, up to an additive constant. We can define absolute entropies rather than just differences in entropy with recourse to the third law of thermodynamics; butfor our discussion here we are concerned only with entropy differences.)

The 2LOT sayst for an isolated system entropy, as defined aboveg function of time.

Unfortunately the definition above gives little clue what entropy is intuitively physically. At a gut level it is unsatisfying to the student. With only its definition it is not immediately clear under what physical circumstances entropy of a system is increasing or decreasing.

It is to fill that gap that Adkins writes that energy dispersion is characteristic of increasing entropy. That's not entropy's definition, though, but a usual characteristic.

To see that energy dispersion through space is not a suitable definition of entropy we provide a counterexample. Consider a cylinder containing n moles of ideal gas having a piston on top. Suppose that there is a pile of bricks on top of the piston. ligible thermal conductivity.

Now let's expand the ideal gas by removing bricks on top of the piston to decrease the gas's pressure and increase its volume. (We suppose the bricks are very small and removed one at a time so that the expansion is reversible).

Now, Helen, it is clear that the original energy of the gas has dispersed through space, right? The gas occupies a larger volume than before, and by expanding against the piston it has lost some energy equal to the work it has done on the piston. We need not care where that energy is beyond that it isn't in the gas anymore.

According to the pseudodefinition of entropy as dispersal of energy throughout space, the process I have described would lead to increased entropy of gas plus bricks.

But in fact the processes I have described is an adiabatic (non-entropic) process. THERE IS NO CHANGE IN ENTROPY OF ANYTHING ASSICIATED WITH THE PROCESS!!!!! wE CAN EASILY SEE THIS FROM THE DEFINITION OF ENTROPY i GAVE ABOVE, "Ds = DQ/T..." Here we have reversible expansion of the gas cylinder, but since the walls and piston do not conduct heat, there is no heat flow. For each infinitesimal step in the process DQ = 0, and when integrated the change in entropy of the expanding gas is ZERO. Nor is there any entropy associated with the work done by the expanding gas on the piston. (One might object that there is entropy produced by removing the bricks, but while that is is strictly true that there must be some entropy increase associated with this process it can be aritrarily small.)

I cannot stress it enough that Adkins' (or any author's) verbal description of entropy must be understand to elucidate the mathematical discription with the verbal description being understood by the student in terms of the mathematical. The verbal is meant to help inexperienced students understand the mathematical.

And Adkins' statement is patently literally false; but that confuses no student of physics. As I did in my previous post here any good physics student would look for the sense in which Adkins' statement was sort of true and would take that as the likely sense of Adkins' meaning.

That the statement is literally false is obvious. First it talks of the entropy of the energy; but energy does not, as energy, have entropy. Rather, thermodynamic systems have both energy and entropy. That isn't a mistake by Adkins (although perhaps he could have been more careful). He's just trying to give you a rough approximation of what entropy is.

It is not really even true to say that a thermodynamic system having a certain energy E will have higher entropy than a corresponding system having the same energy at a lower temperature. However, it is easy for an experienced reader to see what Adkins is talking about. He is really talking about the availability of energy in the form of heat from high and low temperature bodies. This is easily seen by those who have any understanding of the mathematical definition of entropy I gave above. Suppose that the same amount of heat flows from two systems at temperatures Th and tl respectively, with Th (Thot) > Tl (Tlow). Then the entropy lost by the hot source is simply Q/Th, while that lost by the low-temperature source is Q/Tl. Obviously the magnitude of the latter is greater than that of the former, and that's all Adkins means! The simple implication is that it is possible to operate a heat engine more efficiently if its heat source is at a higher temperature because that reduces the inevitable production of entropy. In a figurative sense one might say with Adkins that the part of the entropy contained by the higher temperature source lost in heat transfer would be less than the corresponding part of the entropy of a lower-temperature source associated with a heat transfer of similar magnituede; but Adkins' statement is not literally true.

And it does little damage. Most students will soon learn to understand his misstatement as he intended it as I have indicated.

Ther is, however, no salvation for quote-miners here.

(Helen quotes Adkins continued)

Adkins is explaining the working of a heat engine. That context is crucial here, since he envisions that the energy "stored" at either high or low temperature is available to be transfered as heat. One must be very careful here. Energy, as you know, can be stored in many ways andexpended in many ways. Adkins was talking about the process of heating (or cooling, rather.)

But suppose that our system is a storage battery and that a certain amount of energy is stored in that storage battery and available to produce electric current. Would the energy stored in the high-temperature storage battery be somehow more able to do useful work, of higher quality than that in the low-temperature storage battery?

The answer might not be obvious to you; but the answer is that in this case they both have the same "quality". In principle either might be connected to wires of arbitrarily low resistance so that all of that energy is available for whatever device the battery is to power.

Remember Adkins' remarks in their narrow context. They really cannot be understood generally!
]quote]As I said, please argue with him, I just referenced him as an expert so I could make my point.[/quote]

Why would I argue with Adkins? I do not disagree with him. What I have done is to supply Adkins' context.

The trouble is that you have referenced him to make a point outside of the scope or context of his remarks. If your point had been that entropy is "sort of" a measure of energy dispersal and you had quoted Adkins without more I'd not object. But you tried to base an argument--your point having nothing to do with heat engines on remarks Adkins made narrowly pertaining to heat engines.

Yes, Helen. entropy does go way beyond heat engines. But not everything Adkins or some other expert (including myself) says about entropy pertains to that full scope. Unfortunately you are trying to make a wide point based upon a quotation of narrow scope. If, instead of seeking experts to quote, you would study thermodynamics then you might learn to evaluate quotations' scopes such as those of Adkins.

And obviously that statement isn't literally true. It is not in any way unnatural for a ball of gas to compress and for its temperature to rise and therefore its energy to be "stored" at a higher temperature. It is not "unnatural" for isolated reactants to combine exothermically, with their temperature increasing. Does that make Adkins wrong?

No. He does not mean for his remarks to be rigorously interpreted. By the natural direction he does not mean the only direction. He means the usual direction, and the ultimate direction.

As one learns thermodynamics one learns that certain chemical and physicsl processes can be shown to be thermodynamically impossible because they would result in a global increase in entropy (as mathematically defined). One does not learn, because it is not true, that some processes are thermodynamically impossible because they violate the principle of energy dispersal or the principle that energy must be stored at ever lower temperatures. If you quote some expert on thermodynamics talking about entropy as energy dispersal or energy storage at lower and lower temperatures through time it must ina context of illustrating how mathematically-defined entropy is increasing. Outside of that context Adkins' remarks are meaningless. There is no doubt that he would agree.

And you say so based upon the level of your expertise in thermodynamics. And I say that I have no argument with him, understood in the context which he doubtless intended (the physically correct one) based upon the level of my expertise in thermodynamics. I am a Ph.D. physicist. You might have had a calculus course sometime.

I do not argue a point of physics based upon my expertise and your lack thereof. I do not think that I have done so in the past either. However, when it comes to reading the physics literature and explaining what a reasonable (or even expert) physicist meant when he wrote such and such, then you ought to defer to my credentials.

Thus I do not think you should think that evolution is not impossible because I say so. You shouldn't even believe that evolution isn't impossible because it violoates the second law of thermodynamics because I say so as a physicist. You shouldn't believ me, based upon my credentials or expertise, even when I say that evolution does not violate the second law of thermodynamics and describe what the second law of thermodynamics is. You should require demonstration to the best of your ability that evolution and the second law of thermodynamics as I would describe the second law of thermodynamics are not in conflict.

However, when I tell you that evolution is not inconsistent with the second law of thermodynamics, when I describe the second law of thermodynamics and show that evolution and the second law of thermodynbamics as I have described it are not in conflict, and when someone with no expertise in thermodynamics asserts, based upona vague formulation of the second law of thermodynamics different from mine, and perhaps based upon fragmentary quotes from some expert whom that someone doesn't understand, then you ought to tentatively go with me.

Nope. What I object to is misquoting a book, which includes, as with your quotes of Adkins, quoting him out of context, broadly when his meaning is, to one expert in thermodynamics, patently narrow.

That's the kicker. Even with that bogus notion there isn't any problem with evolution. Where energy "has to become dispersed" that refers to "net" energy dispersal. It does not mean that in some places energy may become more concentrated. AEven if one were to agree (which one does not) that evolved organisms are more ordered (in a thermodynamic sense) than their relatively unevolved predecessors, or energy had some superior "quality" in the former lacking in the latter, there would still be no incompatibility as long as more of this "quality" of energy is lost to the rest of the environment than is gained by the evolved organisms.

 

Helen wrote:

The second law and entropy are closely connected -and there is no "larger rule of entropy" as you claim. It is a figment of your imagination.</font>[/QUOTE]Mine and Atkins' and the people at the journals who recommended his book....</font>[/QUOTE]No. It is not Adkins' view that there is some generalized entropy principle beyond the second law of thermodynamics. It is based upon your misreading of some passages of Adkins, as I have explained in my previous posts here. If Adkins had thought that there was some generalization of the second law of thermodynamics he would have said so clearly and explicitly. He did not. And not only that, The "generalized role of entropy" is unknown to physicists. At the very least, if it is known at all, it isn't well known! Had Adkins discovered such a law he would have published it in the ordinary physics literature. Had he been referring to some obscure generalization known only to some physicists he would have provided a reference to a Journal article describing the additional role of entropy. Adkins did neither.

It's not Helen and Adkins urging a wider wole for entropy. It's just Helen.

 

So, what process, required for evolution, is prohibited by entropy?

A specific physical process, with your evidence that it cannot happen.

 

Helen wrote:

Thank you. I stand corrected.

Helen quotes Atkins:

"Natural" and "natural change" are terms foreign to the ordinary lexicon of thermodynamics. Atkins must have defined those terms as he intended them to be used.

It's not hard to understand what he means, though. By "natural" process he means one that is not thermodynamically forbidden to occur in an isolated tmermodynamic system. Such processeses will also TEND to occur in the same direction in nonisolated systems unless something outside the system causes the process to go in the opposite direction. This use of "natural" is not the same as "according to nature", since Atkins-"unnatural" processes occur all the time in nature.

The well-known example of freezing water is an example; an isolated system of liquid water will not evolve so that the water in one part of the system freezes while on the other side it boils. On the other hand, if such a system is not isolated from its environment and the system of water near, say, an active lava flow in an arctic climate, then it is easy to see that tparts of the system of water may freeze while others boil. Although such a process could quite easy occur in nature, it is, according to Atkins' clumsy nomenclature, not natural. One must use Atkins' nomenclature only with greatest care. A more usual term for Atkins' "natural process" is "thermodynamically spontaneous process,", but that's a mouthful. A

No. It's his use of "natural" that is much narrower than is conventional. It's not hard to see how you might be confusedx by his nuse of "natural."

No. Again, Atkins' use of "natural" is eccentric. Even if "more evolved" organisms have less entropy/disorder/non-quality than their less-evolved predecessors (a dubious proposition), the law of nondecreasing entropy would forbid the evolution only if the organisms were isolated systems, which they are not. As long as the total entropy of organism population plus environment does not decrease there is no violation of the law of nondecreasing entropy.

 

Helen wrote:

I suggest you learn to understand the book and its subject matter. The purpose of books is to convey their subject matter. I am expert in thermodynamics, Atkins' subject matter. What I have done is to explain to you the meaning behind what might have been some difficult or obscure passages in Atkins' book which you quoted, evidently without understanding.

Unlike you I have a knowledge of thermodynamics independent of any particular book. I understand the underlying principles of thermodynamics. I can solve thermodynamic problems. If I assume an author to be competent (as I do Atkins) I am able to use my knowledge of thermodynamics to understand and explain what would or might be confusing to someone like you without thermodynamics expertise.

My doing so is no disrespect to Atkins. Doubtless some of my explanations are obscure and would benefit from his expert translation. You, however, are at best a novice student of thermodynamics. You have demonstrated no grasp of the subject, no ability to articulate it apart from quotations of authority.

In the sciences we admire the facile quotation for expressing more exactly, more elegantly, or suggestive of insight which we might not ourselves have had. But when we find such a quotation we absolutely never take it as authority, but rather as something to be tested against the rigorous findings of whatever field of science to which it might pertain. It is absolutely never the quotation itself that is authoritative, but rather the arguments underlying the quotation, or the arguments that competent readers may reconstruct to underly the quotation. Atkins' quotation is written to enable you to understand the thermodynbamic principles undderlying it. Independently of those it is without meaning. To rightly read it you must seek to interpret it in terms of the rigorous thermodynamic principles, and not thermodynamic principles in terms of any facile quotation.

 

&gt;&gt;&gt;&gt;&gt;&gt;And if you don't like the term 'entropy', let me just say that in our experience, what we see is that everything becomes disorganized with time, and runs down.

This process, whatever you want to call it, denies evolution could have happened.&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;&lt;

Everything does not always and without exception become disorganized and run down with time. And there is nothing involving entropy, thermodynamics or the 2nd law that conflicts with evolution. Atkins does not agree with you on this, and I don't think you can find a single textbook author on thermodynamics that will agree with you. Mark is correct in saying that you don't understand the remarks by Atkins.

 

So, what process, required for evolution, is prohibited by entropy?

A specific physical process, with your evidence that it cannot happen.

 

Yes, Helen, we all await the particulars. Just where in the working out of evolution theory does entropy raise up the stop sign and say it cannot happen?

 

Here is something I found on the Internet. Three authors of thermodynamics textbooks contradict Helen's and other creationist's arguments about there being a conflict between evolution and thermodynamics:

Dr. Ken Dill provided the following comments on the claims of Thompson and Harrub. Dr. Dill is the coauthor of the book; "Molecular Driving Forces, Statistical Thermodynamics in Chemistry and Biology". He has also has more than 160 peer reviewed publications to his credit. He is Professor of Pharmaceutical Chemistry at the University of California at San Francisco. His comments are as follows:

In their item (9), Thompson and Harrub (T&H) state that "the second law of thermodynamics strictly prohibits organic evolution". I disagree. The Second Law does not prohibit evolution. The Second Law has very little bearing at all on evolution. The premises behind item (9) of T&H are that: (1) according to the Second Law, closed systems tend toward increased entropy, (2) living systems are more "ordered" than nonliving systems, and (3) entropy is a measure of "disorder". Therefore, according to T&H: (4) living systems must have lower entropy than nonliving systems. T&H conclude that biological evolution toward increasing complexity would violate the Second Law.

But there's a simple way to disprove their conclusion (4). You can measure the entropy using a standard device called a calorimeter. You will find no difference in the entropy of a living organism and a lump of coal or a rock of the right size. A small rock has less entropy than a cow and a big rock has more entropy than a cow. Entropy does not distinguish living from nonliving systems.

Here's why. There are two kinds of entropy. One is very different from the other. They don't even have the same physical units. One kind of entropy has units of energy/temperature and has to do with the Second Law. We will call this the "thermal" entropy. The thermal entropy describes the type of "ordering" and "disordering" that occur when the temperature or pressure are changed. The other kind of entropy, a mathematical measure of the flatness of probability distribution functions, has nothing to do with the Second Law, so it is not relevant for the present argument.

The Second Law has little to do with the chemical origins of life. The reason is that the sort of order and disorder that is described by the thermal entropy is not related to the sort of "complexity" that distinguishes living from nonliving systems. Why not? The term "complexity" refers to a distinction that would undoubtedly rank humans higher than earthworms, and earthworms higher than rocks. But, as noted above, the thermal entropy has no ability to make this distinction. In short, heating or pressurizing a rock cannot convert it to an earthworm. And heating or cooling an earthworm does not convert it into a human being. If temperature did interconvert these species, then the thermal entropy would predict the relative amounts of earthworm and human at a given temperature. But, of course, it does not.

Thompson and Harrub also draw attention to the distinction between closed systems and open systems. While closed systems tend toward states of maximum entropy, open systems tend toward states that are at the minimum of a quantity called the "free energy". Is this distinction important? No. You can't distinguish a rock from an earthworm on the basis of its free energy either. In short, the Second Law only tells us about how materials respond to temperature and pressure. Survival of the Fittest is the law that describes how systems evolve complexity. The Second Law gives no basis for understanding the Survival of the Fittest law. You can neither derive nor disprove chemical evolution from the Second Law of Thermodynamics. They are unrelated concepts.


End of comments by textbook authors

I think that one could have 20 experts with many years of experience in thermodynamics telling Helen that she is wrong, and poor Helen, with no experience or training in thermodynamics, would still maintain that she is right.

[ June 06, 2003, 03:47 PM: Message edited by: Peter101 ]