Saturday, March 25, 2017

The Second Law of Thermodynamics: An excerpt from the Dictionary of Christianity and Science

On April 25, 2017, Zondervan will publish the Dictionary of Christianity and Science. This is the definitive reference book discussing the intersection of Christian faith and contemporary science.  It has been a project that has taken over five years to complete. The four general editors, Paul Copan, Tremper Longman III, Christopher L. Reese, and myself have worked with over 100 outstanding contributors and our amazing editor, Madison Trammel, to bring this book to fruition.

There are a few features of this book that separate it from other such works. While most articles in the dictionary are unbiased, for topics that are controversial among Christians, the Dictionary presents various advocacy articles with opposing views. For instance, different views on evolution and the length of the days of creation are included. These articles represent the viewpoint of the author and are not completely unbiased. This multiple presentation model serves as a great resource for each reader to understand the complexities of the issue and come to his or her own conclusions.

Most of the articles in the Dictionary relate the particular subject to some aspect of Christian thought. For instance, articles on Special Relativity or Conservation of Energy have a concluding paragraph that mentions how some aspect of that subject relates to the character of God. This feature that explicitly discusses the intersection of science and faith distinguishes this reference book from others.

I have written 22 of the 450 or so articles. If you preorder the Dictionary you will get a number of bonus features including a presentation slide deck discussing String Theory which includes one of the articles I wrote on that subject. As an introduction to the Dictionary the rest of this post reproduces the entry I have written on the Second Law of Thermodynamics. This reprint is copyrighted by Zondervan and the four general editors and is used by permission. At the end of this article I briefly discuss the relationship of the second law of thermodynamics to biological evolution. I want to point out that I am not advocating for evolution but just stating facts regarding whether or not evolution violates the second law of thermodynamics.


The second law of thermodynamics describes natural limitations inherent in the amount of useful energy produced by any system. The law has been stated in many different ways that emphasize various applications. Physicist Percy Bridgman writes, "There have been nearly as many formulations of the second law as there have been discussions of it” (Bridgman 1943, 116). Arguably the most common, and useful, formulation states that the entropy of an isolated system will never decrease. Even using this definition there is confusion about what the law means due to colloquial descriptions regarding the concept of entropy.

The mathematical definition of entropy has to do with the natural logarithm of the number of available microstates. The concept of a microstate might be best understood by considering the simple system of two six-sided dice. There is only one microstate available for the dice to roll 12: both must show a six. However, there are six possible microstates available for the dice to roll a 7. The combinations are 1 and 6, 2 and 5, 3 and 4, 4 and 3, 5 and 2, or 6 and 1. Because there are more available microstates, the dice will more often roll a 7. A macroscopic system with more available microstates has a greater entropy than one with fewer microstates. The second law of thermodynamics states that an isolated system will evolve spontaneously to the state with maximum entropy.

Other statements of the second law of thermodynamics can give a broader understanding of its meaning. The simplest statement of the law may simply be that heat will not naturally flow from a colder object to a hotter object. The Kelvin-Planck statement of the law says that it is impossible to make a cyclic device whose sole effect is to transform a given amount of heat completely to work. In other words, it is impossible to make an engine that operates at 100% efficiency. All formulations of the law convey the fact that in any process some amount of useful energy is lost or wasted. Although the total energy of an isolated system is always conserved, the amount of energy that can be used to perform work diminishes with every process.

Apart from the activity of God and supernatural beings within it, the universe is a closed, isolated system. Consequently, the second law of thermodynamics applies to the universe as a whole. The continual increase of the entropy of the universe means that over a long period of time the temperature of the universe will become more uniform and the ability of any process in the universe to perform useful work will diminish. Eventually, the universe will reach an equilibrium temperature, sometimes called the “heat death” of the universe in which it will not be possible to perform any process that can do any useful work.

The term entropy is sometimes used to describe the amount of disorder in a system. Although not a truly accurate definition of entropy, the idea of disorder does correlate with the fact that systems with fewer microstates appear to be more ordered. However, this definition of entropy can lead to misunderstandings of the second law of thermodynamics. For instance, opponents of biological evolution have claimed that evolution violates the second law of thermodynamics since evolution proposes more complex systems have evolved from simpler systems. Of course, evolution does not violate the second law, and if it did, no scientists would believe it. The earth is not a closed system and so life on the earth can become more complex without any thermodynamic problems. Every human life starts very simply as a single cell and develops into a complex organism without violating the second law because the developing embryo is not an isolated system. In the same way, evolution could produce complex life without violating the second law of thermodynamics.

The second law of thermodynamics does provide information about the origin of the universe. Because entropy always increases, the early universe had the minimum entropy. If entropy is loosely associated with the concept of order or disorder, this means that the universe was most ordered at its beginning. Therefore, the Big Bang origin of the universe requires that the “bang” is not like a random disordered explosion, but much more like a maximally ordered beginning. An ordered beginning is just one of the many aspects of the big bang that supports the biblical statement that our universe was created by a superior divine, being.

Michael G. Strauss

References and Recommended Reading
Bridgman, P. W. 1943. The Nature of Thermodynamics, 2nd Edition, Harvard University Press.
Giancoli, Douglas. 2014. Physics: Principles with Applications, 7th Edition, san Francisco: Pearson.


  1. Interesting that Eddington in his renounded essay on the second law and times arrow relied heavily on the "shuffling and irreveribility" aspects of this the most varified and controlling in his words secondary law of nature. And while it is true that the earth is an open system the Sun's energy is useful through photosynthesis and the inclusion of some information without which a picked flower in the sun gets hot but doesn't bloom. - A. E. Wildersmith. A reading from Eddingtons On the Running Down of the Universes is is helpful to the layman at least perhaps others as well. Evolution is not restrained by the law because of the precise information incorporated and imposed in biological and chemical processes and without which nothing was created and noth8ng evolved. And information has only a conscious source.I should of course scrape up the funds for an advance copy of said publication.Thanks for your work. Keith

    1. Keith,
      Thanks for your comments. I agree that there are tremendous problems trying to find a way for the proposed mechanisms of evolution to create the complex information within all of life. That is why I am not a proponent of evolution and do not believe that the current theory is adequate to produce the effects its proponents claim it can produce. Yet, I am dismayed when Christians use false arguments to debunk a claim they disagree with. As discussed, in and of itself, the second law does not contradict evolution. However, it is a challenge to evolution and there are lots of other reasons to question the current theory of evolution.

    2. Dr. Strauss,
      If "the second law does not contradict evolution," in what way is "[the second law] a challenge to evolution"?

      Thanks in advance for the clarification.

    3. If the entropy of a system is to decrease (colloquially the system becomes more ordered) then of course the entropy of the environment must increase by more so that the total entropy increases. Most of the time when we see a decrease in entropy, there is a pretty complex mechanism that produces this. Think about things like photosynthesis, reproduction, or the machines that humans make. It is rare for there to be a decrease in entropy without such a complex mechanism. The proposed mechanism for evolution is primarily natural selection acting on random mutations. I'm not sure that mechanism is capable of producing the decrease in entropy necessary for evolution. All the other mechanisms that we know of (at least that I can think of off the top of my head), that decrease entropy seem much more complex than those proposed that drive evolution.

  2. Probably can't afford the ref book but coincidentally I read Eddingtons essay on 2nd law and times arrow last evening..."The Running Down of the Universe" Congrats

  3. I don't have a scientific background, so I'm sure there's something I'm missing here, but could you explain these two statements? They seem contradictory to me.
    1. The second law of thermodynamics states that an isolated system will evolve spontaneously to the state with maximum entropy.
    2. Because entropy always increases, the early universe had the minimum entropy.

    1. I'll try to clarify. The entropy will always increase in any nonreversible process, which is what the first statement says. Any isolated system (like the universe) will continue to evolve to a state with a greater and greater (maximum) entropy. As far as the second statement, the universe began almost 14 billion years ago. Throughout its history, the entropy has continued to increase. That means, that when it began it must have had a really low (minimum) entropy because it has consistently increased since then. Since this low entropy is associated with an ordered state, the beginning of the universe (the Big Bang) was a highly ordered event. If that doesn't clarify things, please continue to ask questions.

  4. Although evolutionists say abiogenesis is independent of evolution it is surely true that evolution cannot occur until raw organic molecules + energy + time organize into amino acids, polymer chains, proteins... right up to DNA, RNA and the cell. WilderSmith notes that the simplest imaginable life form is a true von Neumann machine that replicates itself, detects errors made and repairs itself. No one has yet constructed such a machine even with unlimited exogenous information available to be hybridized in the process and material. Yet no one can account for the semi-infinite informational content that rides on the DNA molecule without which no Neumann machine would or could self organize. The second law does appear to be a barrier to the creation of such a machine by chance from simple molecules or even racemate amino acids..etc. The necessary ordering and enabling information supplied exogenously by conscious intellect is necessary and sufficient but has no source in materialism. Without this hybridization of organics + energy + time + INFORMATION the 2nd law barriers will never be overcome in abiogenesis. Of course after you have a von Neuman machine as the cell then some form of intra speciation can proceed. Inter evolutionary evolution however will require new extensive amounts of information which is again seemingly impossible to get by Darwinian methods, independent of exogenous injection by intellect. The modern ID movement owes much to Dr. WilderSmith who spoke and wrote extensively on the subject from several perspectives in the late 70's through his death in 1995. If this is off topic I apologize in advance.

  5. Ha! I always believed that religion hampers science) As for the entropy in semiconductors so it was my dissertation about semiconductor systems that I recently made a presentation with illustrative examples. Templates by the way you can find here . The purpose of my research was to trace the change in entropy depending on the micro parameters of the system.