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The Common Sense Law of Physics

Granville Sewell


While the first formulations of the second law of thermodynamics were all about heat, about thermal entropy, many general physics texts generalize the second law beyond thermodynamics, with statements such as “In an isolated system, the direction of spontaneous change is from order to disorder” (Classical and Modern Physics, Kenneth Ford, 1973), and give examples of irreversible “entropy” increases that have nothing to do with thermal entropy, such as tornados turning towns into rubble, explosions destroying buildings, or fires turning books into ashes.

In these examples, “entropy” is generally used simply as a synonym for “disorder.” In a 1970 Smithsonian article, for example, Isaac Asimov (Smithsonian, Volume 1, August 1970, p. 4) writes:

We have to work hard to straighten a room, but left to itself, it becomes a mess again very quickly and very easily…. How difficult to maintain houses, and machinery, and our own bodies in perfect working order; how easy to let them deteriorate. In fact, all we have to do is nothing, and everything deteriorates, collapses, breaks down, wears out — all by itself — and that is what the second law is all about.

The development of civilizations on a barren planet would seem to be a spectacular violation of these more general statements of the second law. How could a few fundamental, unintelligent, forces of physics alone rearrange the fundamental particles of physics into human brains, computers, jet airplanes, and Apple iPhones?

Asimov recognizes the problem in his Smithsonian article. He writes:

You can argue, of course, that the phenomenon of life may be an exception [to the second law]. Life on earth has steadily grown more complex, more versatile, more elaborate, more orderly, over the billions of years of the planet’s existence. From no life at all, living molecules were developed, then living cells, then living conglomerates of cells, worms, vertebrates, mammals, finally Man. And in Man is a three-pound brain which, as far as we know, is the most complex and orderly arrangement of matter in the universe. How could the human brain develop out of the primeval slime? How could that vast increase in order (and therefore that vast decrease in entropy) have taken place?

But Asimov concludes that there is no conflict with the second law here, because:

Remove the sun, and the human brain would not have developed…. And in the billions of years that it took for the human brain to develop, the increase in entropy that took place in the sun was far greater; far, far greater than the decrease that is represented by the evolution required to develop the human brain.

This “compensation” argument, used by every physics text which discusses evolution and the second law to dismiss the claim that what has happened on Earth may violate the more general statements of the second law, was the target of my article “Entropy, Evolution, and Open Systems,” published in the proceedings of the 2011 Cornell meeting Biological Information: New Perspectives (BINP).

In that article, I showed that the very equations of entropy change upon which this compensation argument is based actually support, on closer examination, the common sense conclusion that “if an increase in order is extremely improbable when a system is isolated, it is still extremely improbable when the system is open, unless something is entering which makes it not extremely improbable.” The fact that order can increase in an open system does not mean that computers can appear on a barren planet as long as the planet receives solar energy. Something must be entering our open system that makes the appearance of computers not extremely improbable, for example: computers.

My BINP article includes a section entitled “The Common Sense Law of Physics,” which uses a little humor to show how silly Asimov’s compensation argument really is:

I was discussing the second law argument with a friend recently, and mentioned that the second law has been called the “common sense law of physics.” The next morning he wrote: “Yesterday I spoke with my wife about these questions. She immediately grasped that chaos results in the long term if 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 a vacation, leaving a dog, a 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 sunlight, wind, and other animals, probably not.'”

Imagine trying to tell my friend’s wife that, provided her house is an open system, the fact that chaos is increasing in the rest of the universe — or on the sun, provided sunlight enters through the door — means that chaos could decrease in her house while she is gone. Even if the door is left open, it is still extremely improbable that order in the house will improve, unless something enters that makes this not extremely improbable — for example, new furniture or an intelligent human.

Suppose we take a video of a tornado sweeping through a town, and run the video backward. Would we argue that although a tornado turning rubble into houses and cars represents a decrease in entropy, tornados derive their energy from the sun, and the increase in entropy outside the Earth more than compensates the decrease seen in the video, so there is no conflict with the second law? Or would we argue that what we were seeing was too difficult to quantify, so we can’t be sure there is a problem? Some things are obvious even if they are difficult to quantify.

In Signature in the Cell, Stephen Meyer appeals to common sense, in applying the second law to information: “Most of us know from our ordinary experience that information typically degrades over time unless intelligent agents generate (or regenerate) it. The sands of time have erased some inscriptions on Egyptian monuments. The leak in the attic roof smudged the ink in the stack of old newspapers, making some illegible…. Common experience confirms this general trend — and so do prebiotic simulation experiments and origin-of-life research.”

I have found that Darwinists, after reading this article, or my more recent 2013 Bio-Complexity article (both of which are reproduced in my Discovery Institute Press book In the Beginning and Other Essays on Intelligent Design) quickly see how silly the compensation argument is, and immediately retreat to the original, early, statements of the second law, saying that the second law of thermodynamics should never have been generalized beyond thermodynamics, and evolution does not violate the second law as applied to thermal entropy. Nevertheless, I’m sure general physics texts are still being written that apply it much more generally, and still dismiss the spectacular increase in order seen on our planet by saying, entropy can decrease in an open system.

Many others who read the article will ask, How could an idea as dumb as the compensation argument have been believed by so many intelligent scientists, for so long? That’s a question that many people are finally starting to ask about Darwinism itself.

Image: The Sun, whose energy will not tidy your house for you no matter how long you wait, by HalloweenNight [CC BY-SA 4.0], via Wikimedia Commons.

Granville Sewell

Granville Sewell is professor of mathematics at the University of Texas El Paso. He has written four books on numerical analysis, most recently Solving Partial Differential Equation Applications with PDE2D, John Wiley, 2018. In addition to his years at UTEP, has been employed by Universidad Simon Bolivar (Caracas), Oak Ridge National Laboratory, Purdue University, IMSL Inc., The University of Texas Center for High Performance Computing and Texas A&M University, and spent a semester (1999) at Universidad Nacional de Tucuman on a Fulbright scholarship, and another semester (2019) at the UNAM Centro de Geociencas in Queretaro, Mexico.