Life and the Underlying Principle Behind the Second Law of Thermodynamics
Author’s note: If you trust your own common sense (recommended), you can just watch the short (6 minute) video “Evolution Is a Natural Process Running Backward” and save yourself some time. Or watch the short video “A Mathematician’s View of Evolution.” Otherwise, read on.
Extremely Improbable Events
The idea that what has happened on Earth seems to be contrary to the more general statements of the second law of thermodynamics is generally rebutted1 by noting that the Earth is an open system, and the second law only applies to isolated systems.
Nevertheless, the second law is all about probability and there is something about the origin and evolution of life, and the development of human intelligence and civilization, that appears to many to defy the spirit, if not the letter, of the second law even if the Earth is an open system. There seems to be something extraordinarily improbable about life.
In a 2000 Mathematical Intelligencer article2 I claimed that:
The second law of thermodynamics — at least the underlying principle behind this law — simply says that natural forces do not cause extremely improbable things to happen, and it is absurd to argue that because the Earth receives energy from the Sun, this principle was not violated here when the original rearrangement of atoms into encyclopedias and computers occurred.
One reader noted in a published reply3 to my article that any particular long string of coin tosses is extremely improbable, so my statement that “natural forces do not cause extremely improbable things to happen” is not correct. This critic was right, and I have since been careful to state (for example in a 2013 BIO-Complexity article4) that the underlying principle behind the second law is that
Natural (unintelligent) forces do not do macroscopically describable things that are extremely improbable from the microscopic point of view.
Extremely improbable events must be macroscopically (simply) describable to be forbidden; if we include extremely improbable events that can only be described by an atom-by-atom (or coin-by-coin) accounting, there are so many of these that some are sure to happen. But if we define an event as “macroscopically describable” when it can be described in m or fewer bits, there are at most 2m macroscopically describable events. Then if we do 2k experiments and define an event as “extremely improbable” if it has probability less than 1/2n we can set the probability threshold for an event to be considered “extremely improbable” so low (n >> k+m) that we can be confident that no extremely improbable, macroscopically describable events will ever occur. And with 1023 molecules in a mole, almost anything that is extremely improbable from the microscopic point of view will be impossibly improbable. If we flip a billion fair coins, any particular outcome we get can be said to be extremely improbable, but we are only astonished if something extremely improbable and simply (macroscopically) describable happens, such as “only prime number tosses are heads” or “the last million coins are tails.”
Temperature and diffusing carbon distribute themselves more and more randomly (more uniformly) in an isolated piece of steel because that is what the laws of probability at the microscopic level predict: it would be extremely improbable for either to distribute itself less randomly, assuming nothing is going on but diffusion and heat conduction. The laws of probability dictate that a digital computer, left to the forces of nature, will eventually degrade into scrap metal and it is extremely improbable that the reverse process would occur, because of all the arrangements atoms could take, only a very few would be able to do logical and arithmetic operations.
This principle is very similar to William Dembski’s observation5 that you can identify intelligent agents because they are the only ones that can do things that are “specified” (simply or macroscopically describable) and “complex” (extremely improbable). Any box full of wires and metal scraps could be said to be complex, but we only suspect intelligence has organized them if the box performs a complex and specifiable function, such as “playing DVDs.”
Extension to Open Systems
So does the origin and evolution of life, and the development of civilization, on a previously barren planet violate the more general statements of the second law of thermodynamics? It is hard to imagine anything that more obviously and spectacularly violates the underlying principle behind the second law than the idea that four fundamental, unintelligent, forces of physics alone could rearrange the fundamental particles of physics into computers, science texts, nuclear power plants, and smart phones. The most common reply to this observation is that all current statements of the second law apply only to isolated systems, for example, “In an isolated system, the direction of spontaneous change is from an arrangement of lesser probability to an arrangement of greater probability” and “In an isolated system, the direction of spontaneous change is from order to disorder.”6
Although the second law is really all about probability, many people try to avoid that issue by saying that evolution does not technically violate the above statements of the second law because the Earth receives energy from the sun, so it is not an isolated system. But in the above-referenced BIO-Complexity article4 and again in a 2017 Physics Essays article7 I pointed out that the basic principle underlying the second law does apply to open systems; you just have to take into account what is crossing the boundary of an open system in deciding what is extremely improbable and what is not. In both I generalized the second statement cited above6 to:
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.
Then in Physics Essays7 I illustrated this tautology by showing that the entropy associated with any diffusing component X (if X is diffusing heat, this is just thermal entropy) can decrease in an open system, but no faster than it is exported through the boundary. Since this “X-entropy” measures disorder in the distribution of X, we can say that the “X-order” (defined as the negative of X-entropy) can increase in an open system, but no faster than X-order is imported through the boundary.
In this analysis the rate of change of thermal entropy (S) was defined as usual by:
where Q is heat energy and T is absolute temperature, and the rate of change of X-entropy (Sx) was defined similarly by:
where C is the density (concentration) of X. In these calculations (which, remember, are just illustrating a tautology) I again assumed that nothing was going on but diffusion and heat conduction (diffusion of heat). I had first published this analysis in my reply “Can ANYTHING Happen in an Open System?”8 to critics of my Mathematical Intelligencer article2 and again in an appendix of a 2005 John Wiley text, The Numerical Solution of Ordinary and Partial Differential Equations9and again in Biological Information: New Perspectives.10
Everyone agrees that, in an isolated system, natural forces will never reorganize scrap metal into digital computers, because this is extremely improbable. If the system is open, it is still extremely improbable that computers will appear, unless something is entering the system from outside which makes the appearance of computers not extremely improbable. For example, computers.
Application to Our Open System
Now let’s consider just one of many events that have occurred on Earth (and only here, it appears) that seem to be extremely improbable: “From a lifeless planet, there arose spaceships capable of flying to its moon and back safely.” This is certainly macroscopically describable, but is it extremely improbable from the microscopic point of view? You can argue that it only seems extremely improbable, but it really isn’t. You can argue that a few billion years ago a simple self-replicator formed by natural chemical processes, and that over the millions of years natural selection was able to organize the duplication errors made by these self-replicators into intelligent, conscious, humans, who were able to build rockets that could reach the moon and return safely.
I would counter that we with all our advanced technology are still not close to designing any self-replicating machine11; that is still pure science fiction. When you add technology to such a machine, to bring it closer to the goal of reproduction, you only move the goal posts, as now you have a more complicated machine to reproduce. So how could we believe that such a machine could have arisen by pure chance? And suppose we did somehow manage to design, say, a fleet of cars with fully automated car-building factories inside, able to produce new cars, and not just normal new cars, but new cars with fully automated car-building factories inside them. Who could seriously believe that if we left these cars alone for a long time, the accumulation of duplication errors made as they reproduced themselves would result in anything other than devolution, and eventually could even be organized by selective forces into more advanced automobile models? So I would claim that we don’t really understand how living things are able to pass their complex structures on to their descendants without significant degradation, generation after generation, much less how they evolve even more complex structures.
Many have argued12 that the fine-tuning for life of the laws and constants of physics can be explained by postulating a large or infinite number of universes, with different laws and constants. So some might be tempted to argue that if our universe is large enough, or if there are enough other universes, the development of interplanetary spaceships might occur on some Earth-like planets even if extremely improbable. But if you have to appeal to this sort of argument to explain the development of civilization, the second law becomes meaningless, as a similar argument could be used to explain any violation of the second law, including a significant decrease in thermal entropy in an isolated system.
Conclusions
There are various ways to argue that what has happened on Earth does not violate the more general statements of the second law as found in physics texts. The “compensation” argument, which says that “entropy” can decrease in an open system as long as the decrease is compensated by equal or greater increases outside, so that the total entropy of any isolated system containing this system still increases, is perhaps the most widely used1. Since in this context “entropy” is just used as a synonym for “disorder,” the compensation argument, as I paraphrased it in Physics Essays7, essentially says that extremely improbable things can happen in an open system as long as things are happening outside which, if reversed, would be even more improbable! This compensation argument is not valid even when applied just to thermal entropy, as the decrease in an open system is limited not by increases outside, but by the amount exported through the boundary, as I’ve shown7, 8, 9, 10. Since tornados derive their energy from the sun, the compensation argument could equally well be used to argue that a tornado running backward, turning rubble into houses and cars, would not violate the second law either.
But there is really only one logically valid way to argue that what has happened on Earth does not violate the fundamental principle underlying the second law — the one principle from which every application and every statement of this law draws its authority. And that is to say that it only seems impossibly improbable, but it really is not, that under the right conditions, the influx of stellar energy into a planet could cause atoms there to rearrange themselves into nuclear power plants and digital computers and encyclopedias and science texts, and spaceships that could travel to other planets and back safely.
And although the second law is all about probability, very few Darwinists are willing to make such an argument; they prefer to avoid the issue of probability altogether.
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