The common sense law of physics

_{Granville Sewell

July 29, 2010

Intelligent Design}

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I was discussing the second law argument with a scientist friend the other day, and mentioned that the second law is sometimes called the “common sense law of physics”. This morning he wrote:

Yesterday I spoke with my wife about these questions. She immediately grasped that chaos results on the long term when she would stop caring for her home.

I replied:

Tell your wife she has made a perfectly valid application of the second law of thermodynamics. In fact, let’s take her application a bit further.

Suppose you and your wife go for vacation, leaving a dog, cat and a parakeet loose in the house (I put the animals there to cause the entropy to increase more rapidly, otherwise you might have to take a much longer vacation to see the same effect). When you come back, you will not be surprised to see chaos in the house. But tell her some scientists say, “but if you leave the door open while on vacation, your house becomes an open system, and the second law does not apply to open systems…you may find everything in better condition than when you left.”

I’ll bet she will say, if a maid enters through the door and cleans the house, maybe, but if all that enters is wind, rain and other animals, probably not.

This is an application of the main point in chapter 5 of my new book : “If an increase in order is extremely improbable when a system is closed, it is still extremely improbable when the system is open, unless something is entering that makes it NOT extremely improbable.”

For a slightly more technical version of this story, complete with a mathematical analysis of the equations for entropy change, see my video .

(For those who don’t watch the video, or give up on it before the end, and thus don’t understand what this story has to do with evolution, I should include the punch line):

If we found evidence that DNA, auto parts, computer chips and books entered through the Earth’s atmosphere at some time in the past, then perhaps the appearance of humans, cars, computers, and encyclopedias on a previously barren planet could be explained without postulating a violation of the second law here. But if all we see entering is radiation and meteorite fragments, it seems clear that what is entering through the boundary cannot explain the increase in order observed here.

Comments

uoflcard at 7 NiceUpright BiPed_{July 29, 2010
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Collin, Did your professor empirically showed you what the difference between high order energy and low order energy is? I think Granville's argument is as elegant as it gets. From his argument it should be clear that you just need to ask for an empirical analysis of what effects can be achieved by "high order sunlight" entering a pre-biotic earth. Here we can ask, based on empirical observation, does it make it more or less probable for order to increase (i.e. entropy to decrease)?mullerpr_{July 29, 2010
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Collin, In my book I define "order" to be the opposite of "entropy"; when entropy has a quantitative meaning, I define order to be the negative of entropy; where it is more vague (such as in my story above), "order" is equally vague. So with my definition, order is exactly as scientific a concept as entropy, I just prefer to talk about order increasing rather than entropy decreasing, etc, because it is more intuitive. In any case, a precise definition of order or entropy is not necessary here (and difficult, because there are many types of entropy and thus many types of order, and each has to be defined). But every application of the second law involves using probability at the microscopic level to predict macroscopic change. And the laws of probability apply to open systems as well as to closed system, the only difference is you have to take into account what is entering (or leaving) the open system before applying the laws of probability. So will the house be more ordered or chaotic when the family returns? You just have to consider the laws of probability, and if the door is open, first take into account what goes through the door!Granville Sewell_{July 29, 2010
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I'm having a hard time understanding what the definition of order is here. Complexity does not equal order as I understand it. I had a professor in college says that the second law does not preclude evolution because the earth is being constantly bathed in "high-order energy." Radiation from the sun is high on the order scale, as opposed to heat which is at the bottom. Was he wrong?Collin_{July 29, 2010
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Keep in mind that allowing sentient beings to be in the system at t=0 is an extremely gracious assumption as far as the analogy to abiogenesis theory is concerned. The most common response to the 2nd Law objection to abiogenesis I've heard is: "Ancient Earth wasn't a closed system! There was radiation from the sun!" This never made sense to me. I'm not a thermodynamics expert, but when I studied it in school my understanding of the 2nd Law was that a system could only decrease in entropy if it were open to a source that directly reduced the entropy of the characteristic in question. For example, the entropy of an internal combustion engine (inverse of Potential Energy, PE) can decrease only if fuel (or a source of PE) is supplied. What makes most materialist responses (including the obligatory "Heil! Darwin!" on the wikipedia entry of the 2nd Law of Thermodynamics) irrelevant is that we aren't talking about just order developing. As argued in Meyer's Signature in the Cell, order is not unique to life, and it is not what defines life; it is functionally specified, complex information (FSCI) that is required for any level of life that we know of, and it is that that must have been produced at the beginning of life. The only way the open/closed system argument applies to this situation is if it is open to an input of FSCI! Radiation from the sun is irrelevant, as are demonstrations of ice crystals forming in non-equilibrated systems. If FSCI can produced via only law and chance (without pre-programmed intelligence, as every attempt at demonstrating this has used) OR if we can produce life without FSCI, then these objections will have merit. Until then, they are a waste of time.uoflcard_{July 29, 2010
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I suppose that if the door were open, then rats could come into the house. They would be attracted by the dog food. The dog would eat the rats forming a symbiotic relationship. I know that is far fetched, but I do suppose that some order could enter the system. It just wouldn't be the order that one would desire. Despite that, I doubt that there could be a net increase in order over time.Collin_{July 29, 2010
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So Granville: When/how do you think we lost our faith in common sense? When/how do you think it can be restored?allanius_{July 29, 2010
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I quoted in the book and video from "College Physics", a typical attempt to argue that evolution does not violate the second law:
It is true that evolution of life from inert matter to its present forms represents a large decrease in entropy for living systems. But it is always possible for the entropy of one part of the universe to decrease, provided the total change in entropy of the universe increases.
Some other authors appear to feel a little silly implying that increases in entropy on other planets can compensate for decreases on Earth, so they are careful to explain that compensation only works locally; for example in "Order and Chaos" the authors write (also quoted in the book):
In a certain sense the development of civilization may appear contradictory to the second law...Even though society can effect local reductions in entropy, the general and universal trend of entropy increase easily swamps the anomalous but important efforts of civilized man. Each localized, man-made or machine-made entropy decrease is accompanied by a greater increase in entropy of the SURROUNDINGS [my emphasis], thereby maintaining the required increase in total entropy.
Of course the whole idea of compensation, whether by distant or nearby events, makes no sense whatever, the correct interpretion is illustrated by this quotation from my book:
The fact that order is disappearing in the next room does not make it any easier for computers to appear in our room---unless this order is disappearing INTO our room, and then only if it is a type of order that makes the appearance of computers not extremely improbable, for example, computers.
And of course I go on to look at the usual equations for entropy change and show that they support this last, common sense, interpretation, not the absurd "compensation" interpretation. There's a Youtube version at: http://www.youtube.com/watch?v=dyAjvOJiOes&feature=related which is identical except the intro and postscript have been deleted. Granville Sewell_{July 29, 2010
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I love the simplicity of this argument.bFast_{July 29, 2010
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Would you mind putting this video on a page with a proper title and description so we can share this around facebook please.Gods iPod_{July 29, 2010
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