# The 2nd Law fallacy

#1

I believe I’m qualified by training and experience to speak as an expert on this topic. I hold a Bachelor of Science Degree in Mechanical Engineering (Cum Laude) from a respected university, I got a 98+ in Thermodynamics (similar grades in physics, calculus and statistics), I have 12 years experience in the automotive industry, and I’ve thought about this a lot.

We’ve all heard the argument that the Second Law says that the disorder of a system increases with time, so evolution can’t be true because it would require a violation of physics. This argument is based on a basic misunderstanding, both of what entropy is, and of what the Second Law says and what it means.

Entropy is a state property of matter that describes the availability of heat to do work. Its value is dependent solely on the temperature and pressure of the substance, and it is expressed in units of Joules per degree Kelvin. At absolute zero, a perfect crystal has an entropy of zero. As temperature rises, so does the entropy of the substance. When the substance changes phase (such as when ice melts) its entropy changes even though its temperature does not.

The Second Law is a mathematical description of the ability of the energy of a system to do work. It states: “In a closed system, entropy increases for irreversible processes and remains constant for reversible processes”. Another way it can be stated is “There can be no machine whose only effect is to cause heat to flow from a cold body to a warm body.” And yet again, “There can be no machine that converts heat energy into an equal amount of work”. In other words, no machine is 100% efficient.

Entropy is related to “order” only insofar as “order” describes the state of the energy in the system. If all of the heat energy is contained in one body and the other body is at absolute zero, then the entropy of the system is at a minimum. When the two bodies are brought into contact and heat flows from one to the other, the entropy of the hot body decreases, while that of the cold body and the system increase. So one can say that entropy is related to how well segregated (ordered) the energy of the system is, but it is not true to then say that entropy is, in general, a measure of order or disorder. The spacial arrangement of the objects in the system, in and of itself, has no bearing on entropy.

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#2

For example, if you take a box of white and black marbles that have been segregated by color, then shake the box up well, the only change in entropy is that due to the energy you expended in shaking the box. The change in entropy due to the fact that the marbles are now mixed is exactly zero. That you never manage to shake the box until the marbles are re-segregated is due to the fact that the number of arrangements in which the marbles are mixed vastly outnumber those in which they are segregated. If you shake the box long enough, you’ll eventually get lucky - it’ll just take a very, very, very long time.

In the same way, the state of clutter in your bedroom impacts entropy only insofar as it reflects the way energy is distributed. Anything sitting on a shelf stores potential energy because you had to do work to it to pick it up, and if you shake the room hard enough it will fall down, but if you seal the room and come back a thousand years later nothing will have moved. If you lay down a mosaic of loose floor tiles they will remain in place forever, provided no one disturbs them and they don’t rot away. Rooms do not spontaneously clutter themselves up.

Let’s assume that I’m wrong, and that entropy is indeed dependent on spacial arrangement. Frozen water at 32 degrees F, being arranged in a very ordered crystal structure, would then have a higher entropy than liquid water at the same temperature. If this were true, then heat would flow out of the ice into the water and your drink would boil away! We could create an engine that has no effect but to make heat flow from a cold object to a warmer object, which is a Second Law violation.

The assertion “order cannot arise from disorder” is typically used in creation/evolution debates to describe the low probability of a particular spacial order occurring out of the quadrillions of alternative states. For example, we would take a mosaic of floor tiles as the work of a talented artist, because it would be extraordinarily unlikely for the mosaic to exist if the tiles were just thrown onto the floor. This is not, however, a Second Law argument, because as I’ve explained there is no entropy associated with the arrangement of the tiles.

In fact, spacial order can and often does arise out of spacially disordered systems during the course of energy transfer. Ever seen a convection cell? How about cloud bands in a hurricane? Lightning? Spacial order often serves to lower a system’s resistance to energy flow, and so is quite in keeping with the Second Law.

Comments? I’d particulary be interested in the conversion factor from units of information to units of entropy (not that such a conversion exists, but it must if information has entropy).

#3

I don’t pretend to understand this stuff in any depth, but I thought that information entropy was a different concept than thermodynamic entropy. So the box of marbles undergoes an increase in information entropy when it is shaken from an ordered state into an unordered state, even though the thermodynamic entropy does not change.

It was also my understanding that information entropy also can be used to put an “arrow” on the direction of time, so that if you see a movie of a box of marbles being shaken from an unordered state into an ordered state, you know the movie is running backwards.

#4

Perhaps, but this is not a Second Law argument.

#5

Neophyte,

At first apoximation you should be giving us a lecture rather than ask us to restrict ourselves to your narrow confines.

You tossed out the concept of entropy. How does enthalpy find it’s way into you scheme?

#6

If people want to speak in terms of entropy proper, then the answer is simple - the theory of evolution is possible under the 2nd Law of Thermodynamics the same way that, say, refridgeration is possible. Refridgerators move heat from a state of greater entropy (equal temperature inside and outside) to a state of less entropy (colder in the fridge). This is a local violation of the 2nd Law - the fridge, being plugged in to the wall, is using electrical energy produced elsewhere to make the fridge colder on a local level, even though the sum total of entropy is greater in a general sense as soon as you consider the power plant - greater energy is expended than is usefully gained.

When you consider Earth as a local system, we get a heck of a lot of energy from the Sun. A plant growing up from a seed is a “violation” of the 2nd Law just as much as evolution would be - but it doesn’t violate the 2nd Law because the solar system as a whole is expending more energy in “building” the plant than is being “gained” by the plant.

#7

[quote=Exporter]Neophyte,

At first apoximation you should be giving us a lecture rather than ask us to restrict ourselves to your narrow confines.

You tossed out the concept of entropy. How does enthalpy find it’s way into you scheme?
[/quote]

Uhhh - entropy and enthalpy are both thermodynamic state variables.

Entropy, is a state variable and has dimensions of joules per degree kelvin and is defined as follows:
delta S = dQ (rev)/T where S is entropy, Q is energy and T is absolute temperature. The change in entropy S at a constant temperature T, is the change in energy divided by the absolute temperature of the object./

Enthalpy is also a state function, has dimensions of joules and is defined in a constant pressure system as follows:
delta H = delta U + p delta V where H is enthalpy, U is internal energy, p is pressure and V is volume. It is is a measure of the total change in energy of a system.

#8

hecd2, You asked me,“Why, precisely did you ask?”. Neophyte started this thread with the concept that entropy was important to evolution as a real phenominon. I assumed he (Neophyte) was limiting his question to entropy, since that is what he said.

If we are to “go all the way” with evolution, then we must go back to the first organisms - enuceated bacteria. And before that we had to have the precursors of proteins& carbohydrates. Ultimately the more highly developed organisms were the result of embryonic differeniation. Compare a dog to an enucleated bacteria, with the assuption that in the dog’s ontogeny or phylogeny and we find a single-celled animal.Use either.

hecd2, the reason I asked Neophyte ,“How does Enthapy find it’s way into your scheme”, was that I consider enthalpy more pertinate than entropy when considering the development of an organism. This is because these organisms are in a closed system, except for the energy from the sun. hecd2, I am open to you thoughts. ( PS The universe seems to prefer disorganization to organization)

#9

Absurd.

This is indeed a clear example of energy transfer from human to tile arrangement, else there is no evolutionary reason for tiles to arrange themselves.

Their useless abstract orginazation further proves that we did not evolve unless expensive organized tile patterns are a considered a human show of fiscal responsibility thus enabling ideal mate selection.

#10

Exporter,

I apologise if I came across as belittling, it certainly wasn’t my intent. Given that I’m hoping to clarify why the typical creationist appeal to the Second Law of Thermodynamics is not a good tactic, it seemed reasonable to ask that we limit discussion to the thermodynamic definition of entropy.

One of my limitations is that I don’t always expand the shorthand in my head, and I did it in my first post. I inadvertantly left out a dimension in the units of entropy, the correct units are Joules per kilogram-Kelvin, and neglected to clarify that “entropy” is used to describe two distinct properties. I apologise, and I’ll edit the post in bold to avoid further confusion. Hazards of proofreading yourself – I see Alec beat me to it.

(Too late to edit the earlier post - here it is:

[font=Verdana]Entropy is an intensive state property of matter that describes the availability of heat to do work. Its value is dependent solely on the temperature and pressure of the substance, and it is expressed in units of Joules per **kilogram-**degree Kelvin. At absolute zero, a perfect crystal has an entropy of zero. As temperature rises, so does the entropy of the substance. When the substance changes phase (such as when ice melts) its entropy changes even though its temperature does not.

Total entropy is an extensive state property of thermodynamic systems, with units of Joules per degree Kelvin. “Entropy” is used interchangeably to describe both of these properties, with the context usually clarifying which meaning is intended. Engineers are typically interested in changes in total entropy, which is defined as the change in heat divided by the temperature of the body.

[/font]Enthalpy is also state property of matter. Like entropy, it is dependent on temperature and pressure, but is measured in units of Joules per kilogram. It’s a measure of the amount of internal energy of a substance, whereas entropy is a measure of the quality of the energy (its ability to do work).

[font=Verdana][/font]
[font=Verdana]GULaw,
I must disagree with your characterization of the refrigeration cycle. I think that you may be caught up in the distinction between the entropy of the refrigerant at various points in the cycle (which is an intensive property, entropy per unit mass, that cycles up and down as the cycle progresses) and the total entropy of the entire system (which is an extensive property that always increases as the cycle operates). The term Entropy is used for both properties, and the context usually clarifies which meaning is meant.

Refrigerators transfer heat from a high temperature body to a lower temperature body by means of the addition and rejection of an additional amount of heat. It is not possible to separate out this heat addition from an analysis of the cycle, and at no time during the cycle is there a violation of the 2nd Law.

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#11

For example, say you want to extract 1 joule of heat from a box at 100 kelvin, and reject it to a room at 200 kelvin. A theoretically ideal refrigeration cycle will require the addition of 2 joules of energy from an external source, and a total of 3 joules will be rejected to the room. The change in total entropy is -1/100 + 3/200 = 0.005 joule/kelvin for a net increase in total entropy.

Within the refrigeration cycle there are four phases:

1. Compression, in which the pressure and temperature of the working fluid is increased, without changing its intensive entropy, by the addition of energy. At the end of this phase the fluid is hotter than the air in the room.

2. Heat rejection (to the room) at a constant pressure, during which the intensive entropy and temperature of the fluid is decreased.

3. Expansion, in which the pressure and temperature of the working fluid is decreased without changing its enthalpy. At the end of this phase the fluid is colder than the air in the refrigerated space, and is at a lower entropy than at the start of the compression phase.

4. Heat absorption (from the refrigerated space) at a constant pressure, during which the intensive entropy and temperature of the fluid is increased to the same values they had at the start of the compression phase.

You can see that during the cycle heat never flows from a hot object to a cold object. The heat rejected to the room is equal to that absorbed from the refrigerated space plus that added during the compression phase. The cycle fully complies with the statement “there can be no machine whose only effect is to cause heat to flow from a cold body to a warm body”, because it also has the effect of causing heat to flow from a hot body to the warm body. Note also that this is intrinsic to the cycle itself, and is the case even if the source of the added heat is perfectly efficient.

Catholic2003,
In thermodynamics, processes that can only occur in certain directions are called irreversible processes. These processes (such as friction and rapid expansion or compression) always result in an increase in entropy. Not all processes are irreversible, however. Work is reversible - when you use a rotating shaft to raise a weight, there is no change in entropy.

The friction between the marbles themselves and between the marbles and the box are irreversible losses, but the mixing of the marble colors is not. If the camera had been mounted to the box so that you couldn’t see that it was moving, there would be no way to prove through thermodynamics what way the film was being played.

I don’t know much about information theory. I’ve heard that they use the term “entropy” due to some perceived similarity to the thermodynamic concept, and it may be that that discipline may be able to validly claim that the color mixing is irreversible. My background in statistics leads me to think that they can’t, but I won’t explain why because it’s off topic.

In any case if you want to use the information theory definition of “entropy” then you need to be sure to not say that you’re using the 2nd Law of Thermo.

SocaliCatholic,

#12

-Neophyte, you posted that you have a degree in Mechanical Engineering with required Physics classes,etc. Then you came to this Forum to converse with us about the posibility of why the 2ed Law of Thermodynamics cannot validly be used to defeat the Theory of Evolution. Am I correct?

May I observe it is highly unusual for someone who has spent four years gaining a degree in M.E. to be interested in the Theory of Evolution, either positively or negatively.

Is it possible for you to condense your theory? I said theory for I do not think you have proven your case yet. The more complex the molecules of living organisms the more energy it would require to make them, so the Heat of formation would be relative to water which has a heat of formation (Enthapy) of -57.8 kcal/mole.

I would prefer to discuss kcal/mole of organic material than a general and imprecise treatment using entropy. If not then that’s O.K. too. End of story.

JMJ

#13

Exporter,
Nothing I’ve said is a theory of mine, it’s a factual discussion of thermodynamic law that can be found expanded a greater length in any college level text on the subject.

I’d be hard pressed to condense it any further without resorting to a bunch of math (which I’m trying to avoid), but here goes: “There is no conversion factor from units of ‘information’ to Joules/(kg*K)”.

I believe that the discussion you propose would not extend to the 2nd Law, only to the 1st. The way you phrased the question makes me think we’re speaking different languages. I’ll have to sleep on it.

A blessed evening to all.

#14

You give me the name of a college level text book that purports that the Theory of Evolution has not been defeated by the 2ed Law of Thermodynamics and I will buy the book for you. I simply do not believe it.

Why? Because the wedding of Physics and Biology on a theoretical level has not been done yet.

Do you have a question or possibly a statement on Theology, Apologetics or the Early Fathers? Those are valid areas of inquiry.

#15

[quote=Exporter]Why? Because the wedding of Physics and Biology on a theoretical level has not been done yet.
[/quote]

Maybe not physics and biology, but chemistry and biology are very intimately linked. Spontaneous chemical reactions are determined by Gibbs free energy (dG = dH - TdS), where a spontaneous reaction occurs when dG < 0. A reaction can be spontaneous with dS < 0 (ie increased disorder) if dH is sufficiently negative.

Peace

#16

Gold. While I am dancing around, can I use this quote on other threads? I thought physics was superior to biology?

#17

The “Table” of Science rests on the Legs of

1. Mathematics
2. Physics
3. Chemistry
4 Biology
5 Geology

With all of them bound together with Logic. We can say that all the other sub-sciences stem from the “Big Five”.
:clapping:

#18

I really have no problem deferring to you here. As much as I love physics (it tends to be my leisure reading), it’s not exactly my primary focus

#19

[quote=Exporter]You give me the name of a college level text book that purports that the Theory of Evolution has not been defeated by the 2ed Law of Thermodynamics and I will buy the book for you. I simply do not believe it.

Why? Because the wedding of Physics and Biology on a theoretical level has not been done yet.

Do you have a question or possibly a statement on Theology, Apologetics or the Early Fathers? Those are valid areas of inquiry.
[/quote]

Wait, that’s not how argumentation works.

There is a claim that thermodynamic laws prove the impossibility of evolution. I’ve demonstrated that this claim is based on an erroneous understanding of those laws by clarifying the definition of terms, showing that a correct understanding of thermodynamics does not support the claim, and by showing that the assumptions of the claim lead to a violation of thermodynamic law. I’ve also provided a hint at what must be demonstrated in order to show that my understanding of thermodynamics is wrong. The text I referenced was “Thermodynamics for Engineers” by Cengel and Bowles, but any college text on the subject will do nicely.

Thus far, no one has disputed the technical merits of what I’ve said. I grant that this is thick stuff, it required 3 months in the classroom and 12 years of experience for me to be able to spend a mere 4 hours crafting a document that would accurately explain it in layman’s terms, to answer erroneous claims that took 30 seconds to make. I only just now discovered that pondering this topic doesn’t give me a migraine any more.

It is unreasonable in the extreme to dismiss thermodynamics as a valid area of inquiry, when the claim made relies on exactly that area, and no other, for its justification. If my understanding of thermodynamics is erroneous, please explain where my error is. If you simply do not agree with my conclusion because you just don’t believe it, very well - just don’t blame your opinion on thermodynamic laws.

Believe it or not, I’m on your side. As I said at the start, this discussion is NOT intended to make any comment about whether or not there is a Creator, but rather to discuss the limits of what can be proven using thermodynamics (which can no more disprove evolution than it can prove creation). It is quite simply the wrong tool to use, and trying to use it anyway doesn’t help make your case.

#20

Neophyte and ChemCatholic have made interesting statements.

Neophyte has said," believe that the discussion you propose would not extend to the 2nd Law, only to the 1st. The way you phrased the question makes me think we’re speaking different languages. I’ll have to sleep on it."

Yes we must be approaching Evolution with different languages. Is it possible that your Engineering book is written in a strictly Physical mode? I am corious why an Engineering book treats Evolution. Is it in an “off-hand” way?

One of your comments reminds me of some of my own thoughts. We are told in the 1st Chapter of John,"In the begining there was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. And all things were made by him: and without him was made nothing that was made.

I am a Chemist with a background in Microbiology. ( I may have forgotten as much as I knew). I’ve dabbled with ions and molecules. I’ve measured some of the energy changes resulting from reactions. Often I have considered what was the original cause of atoms, ions and energy. We know that at least in a few cases we can revert matter back into energy, i.e.,nuclear reactions. I have heard that there was the Word, and the Word was made light. Ah, light, light is energy. A God could convert the energy of light into subatomic particles, couldn’t he? Once He had those He could allow them to coalesce into atoms with much energy left over. Once the varied atoms, via gravitation formed planets and suns, we had solar systems. Then the fun stuff started happening.

But it all came from energy or rather - Light. We’ve pushed it back to Light. What Laws were in effect then?

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