The Second Law of Thermodynamics also holds for open systems

The ‘common-questions section’ of BioLogos states: "The second law is only valid in closed systems with no external sources of energy. Since the Earth receives continual energy from the Sun, the second law does not apply". (see: Does thermodynamics disprove evolution? - Common Question - BioLogos ) This is statement is incorrect, and needs adjustment.

The 2nd Law captures the fundamental property of physical reality that the disorder of a system increases if the sum of all energy flows that pass its boundaries is zero. It is evident that this sum is zero for a closed system. However, the sum is also zero if the energy flows that enter an open system are equal to the energy flows that leave it! Notice that all physical systems are open. Closed systems only exist in theory.

Illustration: Let Earth2 be identical to our Earth, except the presence of living organisms. Move Earth2 from a dark place in the universe into the light of the Sun. Draw an imaginary sphere around Earth2 with a radius of 100,000 kilometers. Measure the energy flows entering or leaving this sphere. Initially, the sum of the energy flows that enter the sphere will be greater than the sum of the energy flows leaving it, because Earth2 is warming up. After some time equilibrium will be reached and on average the sum of all energy flows that pass the sphere around Earth2 will be zero. According to the 2nd Law, the disorder on Earth2 will increase. Complex molecules that are produced from simple molecules by natural processes as lightning, wind, rain, heating, cooling, radiation, tectonic forces, etcetera, will fall apart sooner or later; the larger the molecules that are formed, the sooner.

For a more elaborate discussion of the 2nd Law and its implications for Prigogine’s theory that chaos can produce order, see:

Dr. William DeJong

The Second Law is valid for the entire universe. However, locally, a flow of energy may increase order, while the overall order decreases. The energy that is released by the Sun will increase its entropy, but can be used on Earth to decrease entropy (currently through photosynthesis). The increase at the ‘sun-side’ of the equation is larger than the decrease on Earth. In my opinion, this is where your example goes wrong: you cannot take the Sun out of the equation.



Dr. DeJong,

I certainly can’t contradict the statements that I’ve selected in the quote box above. But if you and I both agree that natural evolutionary processes on the Earth are powered by the Sun, then before the existing sentence(s) can be struck – how would you word the replacement sentence?

I once had a very long and intense discussion with a supervisor. He asked me to explain the difference between Selecting “A” vs. “B” in the database we were analyzing at work. Unfortunately, the difference between “A” and “B” was not in the words used, but in the timing of when a word was used (a week earlier vs. a week later).

So when I offered my “narrative” for how to make the distinction, he complained that my words were the same. And no matter how I worded the two criteria - - he said “the same!, the same!”.

So then I asked him if he agreed that there was a timing difference in the criteria. He said “Yes, I certainly do.” So, I replied, since you and I are looking at the very same computer screen, and you agree that there is a timing difference in the criteria - - how would You write the narrative that would explain the distinction?

He sat looking at the screen for 2 minutes. Then he looked at me. Then he said “You are wrong.” and stood up and walked away.

And so … that is the problem with trying to delete a sentence without working out how to replace the sentence before deletion!

Your correction is good here … except that I think you have the terms reversed. Since Entropy (delta S) = Q / T – that would mean the sun is decreasing its entropy as it gives away heat, and that the earth is increasing entropy as it receives the same. But the earth’s increase (delta S) is bigger than the sun’s decrease since earth is at a lower temperature.

The common (very real) way to illustrate this is when an ice cube melts in a room. The room’s entropy (apart from the ice) goes down, while the ice cube’s entropy rises by an even greater amount. But your point is well-taken. Localized entropy can fall and does so all the time (fortunately!) at the expense of entropy rising somewhere else even more. That is why order can come from disorder on a routine basis - because energy drives it.

First of all, @WilliamDJ, welcome to the blog! I see you joined just a day ago, and we are very glad to have you here.

Next, help me disentangle your identity.

Are you this theological William Dejong? Amendments to the Belgic Confession?

Or this scientific William Dejong , the one who wrote the article to which you link?

I imagine it is #2, but can’t be sure. Let us know?

Now about your argument. I see a few strange twists, that end up being so misleading as to bring about the wrong conclusion.

  1. Why do we need to remove living organisms? Whether or not there are living organisms, we expect exactly the same result. Life is not exempt from the 2nd law, nor can it alter its progression. This removal of life seems to betray where you are going with this, proposing life or intelligence as the reason we see complexity. However, and this is important to recognize, this is not actually solution because life and intelligence are also subject to the 2nd law.

  2. Let us for a moment grant that you are right, that an open system with net zero energy flux is subject to the 2nd law. To be clear, this does not at all describe the relevant compartment: the crust of the earth where life resides. This is compartment clearly does not have net zero energy flux. Rather it has a net energy flux into it, so we are not at all surprised that order increases within it by natural means.

Given these twists, it is clear that the 2nd law has really nothing to do with assessing the plausibility of evolution. Sorry.

I would also point out that your argument neglects the limits of the 2nd law too. Did you know that it is not actually a hard law in physics, but a consequence of the statistics of large numbers? Consequently, for a long time, it has been predicted that at small enough time and length scales, the 2nd law is violated, and we can see an increase in order in a closed system.

This has even been directly observed: Second law broken | Nature I could link to several studies here. But basically, the 2nd law only applies on macroscopic scale, not at a microscopic level.

Of course, remember that DNA and the key works of life is on the molecular scale, and this is the exact domain we expect there to be 2nd law violations. The complexity of life is ultimately rooted in the complexity of DNA. So even if you were right that the earth’s crust is net energy zero (it is not), that would still not be strong enough of a claim to prove that molecular processes cannot become more complex. In fact, this is exactly the place that is known to violate the 2nd law, because here at this scale we see violations all the time.


The BioLogos statement is wrong. The 2nd Law applies to the Earth; what doesn’t apply is the statement of the law for isolated systems.

That’s also wrong. First, because entropy isn’t really disorder. Second, and more importantly, your statement only applies to isolated systems (those with no exchange of energy or matter with their surroundings), not to systems where the energy flows sum to zero. What you’re talking about isn’t the 2nd Law of Thermodynamics, and isn’t in general true. For a system that is exchanging energy with its surroundings, you have to calculate both the net energy flow and the net entropy flow. The entropy flow for Earth is enormous, since the photons carrying energy from the sun have very different entropy than the photons carrying energy away from the Earth.

There’s absolutely no need to invoke violations of the 2nd Law to explain life or evolution, and I think it’s a mistake to go down that path.

Not least because the Second Law of Thermodynamics is actually meaningless at the molecular level, since it is all about the statistical thermodynamic properties of large numbers of atoms and molecules.


Well of course there is no need to reference the 2nd Law violations. The fact that the earth is not a net zero system is more than enough to show the 2nd law does not apply here.

Still, the 2nd law argument against evolution make a great deal of hay about how the 2nd law has never been shown to be violated. This, of course, is false. It is regularly violated in systems with small numbers, because the 2nd law is really an emergent behavior that relies on the statistics of large numbers. If there are not large numbers, it does not hold.

Why not point out that this “Law” has real limits and is violated? Seems like there is value there. Why not point out all the problems with the argument?

I think the point being made here is that this isn’t really a violation of the 2nd law, any more than my picking up a spoon is a violation of the law of gravity. Maybe if you put “violation” in scare quotes, your point would still be preserved. Any local system can (and many do) have decreases in entropy, and the 2nd law is perfectly fine with this – it simply states that any local decrease of entropy comes with an unavoidable price tag: an even bigger entropy increase somewhere else so that total entropy is never decreasing.


Good point @Mervin_Bitikofer. I don’t think @Rene_Fransen has it completely backwards though, he just needs to include “outer space” in the definition of his system. The way I initially read his comment was that within the system of {Sun + outer space}, the radiation of the Sun effectively causes the total entropy to increase. As you said Merv, we have S_{Sun} decreasing, S_{outer space} increasing, and S_{Sun + outer space} increasing. I guess most of the confusion boils down to what we define as our “system” when we talk about entropy.

Then I would reformulate Rene’s comment as follows: The same effect that corresponds with an increase of entropy in {Sun + outer space} can sometimes cause a negligible local decrease in entropy in {outer space}, such as in the case of photosynthesis by a living cell on Earth (located in outer space). But that local decrease will always be insufficient to counteract the increase of total entropy of {Sun + outer space}, meaning that the 2nd law of thermodynamics is still valid.

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Always nice to have a physicist around to explain what I meant ;). The thing about William de Jong’s remark is that he indeed has an odd way to define his ‘system’. I have challenged him on this point repeatedly (recently on a Dutch creationist website), but he perstists in his argument. What it boils down to is that an increase in order does not necessarily violate the Second Law.


Dear Rene, George, Mervin, Joshua, Steve, James, Mervin and Casper,

Thank you for your responses to my post on Jan. 12. Some remarks:

(1) Thermodynamics studies real physical systems, which are always open; closed systems only exist in theory. Therefore the 2nd Law holds for open systems! The information at the common-questions section of Biologos: "The second law is only valid in closed systems with no external sources of energy. Since the Earth receives continual energy from the Sun, the second law does not apply", is thus incorrect and needs adjustment.

(2) I have applied the 2nd Law to Earth2, which is identical to our Earth, except the presence of living organisms, to investigate what will happen when Earth2 is placed in the free flowing continual energy of the Sun. It appears that on Earth2 disorder will increase ever further. You can verify this at home: Take a rock and attach it with a rope to the ceiling; take some soda water and put a bit of ammonia in it, and spray this solution on the rock. Put the wetted rock in the light of a strong lamp, and observe what happens.

(3) The theory can be proposed that during an interval of time [t1, t2] matter starts ordering itself at position P1 within the sphere of 100.000 km around Earth2, resulting in a decrease of the entropy; and that simultaneously matter disorders at position P2 within the system, resulting in an increase of the entropy. If the increase at P2 is larger than the decrease at P1, the entropy within the system as a whole increases, as prescribed by the 2nd Law. This theory, however, is false. According to the 2nd Law, a system ultimately transforms into its most probable state, if the sum of the entering and outgoing energy flows is zero. The probability of the state of the entire system at t1 is bigger than the probability of the state of the system at t2, because the differences within the system at t1 are smaller than the differences at t2. This means that the entropy in the entire system is decreasing. This is in contradiction with the 2nd Law.

(4) The 2nd Law captures the fundamental characteristic of our physical reality that every system ultimately moves towards its most probable state and its lowest energy level. This is also the case for molecules as the DNA. Fortunately the DNA is protected against this decay. See the article I wrote with Prof. dr. Hans Degens, at: Also see: Ten misconceptions about how the DNA changes at:

(5) Natural processes are decay processes in contrast to industrial processes, which are make processes. Empirical science has studied decay and make processes for ages yet and revealed that make processes require directed energy to antagonize natural decay. A theory that claims that natural processes have making and innovating power, ultimately comes in conflict with empirical science.

What is Earth2? There is only one earth.

Perhaps the Biologos statement could use some rewording to help avoid this misunderstanding. You are correct that the 2nd law applies to the earth (as it presently is … as well as to your hypothetical, lifeless earth2). I think the intent of the Biologos statement (as I read it in its context) is that … the second law does not apply in the way some creationists have attempted to use it as a disproof of evolution.

Even regarding your lifeless “Earth2”, there will presumably still be countless cases of localized decreases of entropy. Every time some magma cools and crystallizes into a bit of hardened mineral, or a snowflake forms out of the highly disordered gaseous water, entropy has dramatically decreased in that small bit of matter by it giving up its heat to the cooler matter around it, thereby increasing the surrounding matter’s entropy even more (and thus satisfying the 2nd law). Your hypothetical earth could have all these processes going on without a shred of life.

You impose an assumption on your “Earth2” (your OP above) that after it has warmed up it reaches an equilibrium, after which it has a net energy exchange of zero with its surroundings outside the 100 km boundary. But this assumption doesn’t hold in real life. There are always new dis-equilibria forming (courtesy of diurnal rotation and all manner of other changes and fluctuations constantly going on … with and without any life) and many (all?) phenomena happen as a result of systems seeking to return to equilibrium from their disturbed states. Weather happens because of this. So there are countless opportunities for energy exchanges to enable localized decreases in entropy. And all this is entirely physical, and applies to the real earth, open system as it is.

[several word correction edits done since original post]


As I noted in my previous response, you have not applied the 2nd Law to any version of Earth. You have applied a law of your own devising, one that is not a valid statement about the universe we observe.


Returning to the BioLogos article that started this thread, it’s concluding thoughts include these:

“There are many examples of order arising from disorder in nature. . . . .The Second Law of Thermodynamics also has interesting implications for cosmology, as it requires that universe began in a highly ordered state.”

As much as I’m sure everyone would like to wrestle over the minutiae … the Big Picture is pretty simple.

Most everybody accepts the Big Bang, yes? And in the Big Bang, God creates the smallest, most intense, spot of energy in the Universe - - for, indeed, it IS the Universe! In an instantly expanding sphere of energy, complex things begin to happen. Cosmologists have named these complexities:

The first phase that most science-aware readers will recognize is:

The Quark Epoch: Within a second afte the Big Bang, Quarks and electrons appear out of the energy. As the Universe expands, energy “cools”… This leads to the Photon Epoch.

Photon Epoch: Within 10 seconds of the Big Bang proceeding for the next 380,000 years, quarks are “freezing” together, producing neutrons and protons… The universe has become a “foam” of these heavy particles along with electrons and photons. The sky “goes black” as photons get the room to travel freely, but there are still no stars!

Dark Ages: From 380,000 to 150 million years, a fog of matter spreads out and begins to “clump” together, drawn by gravitational pull of these specks of matter … no stars have yet appeared. But the intense pressures at the center of these clumps begins to heat matter into increasingly hot masses… and they become LOCALIZED Hot Spots that we know as blazing stars!

Star-Making Era 150 Million Years to now… the first massive but “metal-poor” stars form, fusing hydrogen and helium into new elements: conceptualized as first, “Helium burning”, followed by “Carbon burning”, then Neon, Oxygen, and Silicon burnings, creating elements up to and including Iron and Nickel.

When a star’s fuel diminishes to the point where its nuclear fire is unable to resist the denser gravity of these heavier elements, the star is more inclined to explode into a Super Nova, filling space with dust heavy in iron.

Stars forming out of dust high in the heavier elements, from Carbon to Iron, begin the next step in the evolutionary
formation of new elements, in various processes inside the star and in successive supernovae.

This chart below should help people visualize how the lighter elements evolve into the the heavier molecules, with increasingly complex electron orbits!

So … in a Universe where we all acknowledge the 2nd Law of Thermodynamics, we also can see that this is not a law that prevents complex things from happening, especially if God is at work!

1) Out of energy comes sub-atomic particles.
2) Out of particles come molecules of Hydrogen and Helium.
3) Out of Helium and Hydrogen we get vast galaxy sized clouds of clumping gases via gravity.
4) Gravity creates cosmically local hot spots that become stars with solar systems.
5) Stars convert lighter elements into heavier elements before exploding.
6) Stars made of heavier clumps of these elements create a second evolution of elements.

There’s no need to dispute over “Little old Earth” ! We have a Universe full of mega clusters of galaxies,
clusters of galaxies within the mega-clusters, individual galaxies filled with countless solar systems,
with suns busily creating ever more complex molecules and elements … when all we had to start with was just energy and eventually hydrogen!

Pax Vobiscum! The 2nd Law of Thermodynamics is not a deal-breaker on the Evolution of ANYTHING!


All these arguments about the Second Law of Thermodynamics in relationship to evolution completely misunderstand what entropy is and how it works. They are based on this hand-waving, spacey-wacey, timey-wimey layman’s description of entropy as being “the amount of disorder in a system.”

This completely overlooks the fact that entropy is a mathematical concept with a very specific and precise mathematical definition. It can be calculated easily for perfect crystals and ideal gases, but when you try to apply it to biological systems, you’re starting to talk about spherical horses racing in a vacuum.

This means that if you want to demonstrate that the Second Law of Thermodynamics holds for open systems, or that it contradicts evolution, you need to use equations, not words. In other words, show us the maths.

Hi @WilliamDJ,

Thank you for your remarks. They are useful because they show that your reasoning is based on a faulty application and misunderstanding of thermodynamics. I say this in my capacity as a graduate student in astrophysics. In an attempt at clarification, I first want to focus on your first two remarks:

This statement is actually untrue in a very fundamental way. Thermodynamics speaks only and exclusively of theoretical systems. These have traditionally been approximated in experiments by using very contrived physical systems of gas reservoirs and pistons. The statements derived from Thermodynamics actually apply only approximately under very specific circumstances. One of the most basic theoretical requirements for the Second Law of Thermodynamics is that the treatment involves a closed system. The derivation of this law from statistical physics explicitly assumes a closed system. Therefore, even according to Thermodynamics itself, the Second Law is absolutely irrelevant for open systems. Case closed ;).

Your Earth2 is actually more like a hopelessly oversimplified version of what the Earth looked like before the first cells emerged. Let’s call that Earth0. Even on the lifeless Earth0, there were many phenomena that exhibited very large degrees of “order” on a local level. Different events in the pre-biotic climate could dynamically interact to produce, for example, hurricanes. Such events exhibit amazing structure:

Such low points in entropy are possible because of that continually changing environment (made possible by, among other things, the rotation of the Earth, the radiation of the Sun). Different instances of chaotic events can counteract each other to produce “complex” phenomena. We see that happening in modern “lifeless” climatology all the time, e.g., in the case of hurricanes when different air flows collide.

The changing input of this open system Earth0 is why the simplistic application of the Second Law of Thermodynamics fails, even on the theoretical level. To apply this line of reasoning to your little “experiment”, try tying that rock on a rope to a ventilator, such that it swings around (also, make sure it spins around its own axis). The conditions keep changing because the heat of the lamp shines on a different side every new moment. If you want to make it more realistic, find a way to implement some shifting tectonic plates and volcanic activity on your rock (good luck with that :slight_smile: ). That should get your system running with some extremely interesting and complex events!



This is misleading: the Second Law has very wide applicability. There are no truly closed systems in nature, but the Second Law still forbids the construction of perpetual motion machines of the second kind, for example.

You can, in fact, write down forms of the Second Law that are applicable to open systems (those that exchange both matter and energy with surrounding) and to closed systems (those that exchange only energy with surroundings), as well as for ideal isolated systems (those that exchange neither energy nor matter). For example, the Second Law when applied to a system at constant temperature and pressure (a good approximation for lots of biological processes), but that exchanges energy with its surroundings, yields the condition that chemical reactions only occur spontaneously if they decrease the Gibbs free energy.

William’s problem was not that he tried to apply the Second Law to the Earth, which is not an isolated system, but that he did it wrong. The condition dS > 0 is only true for isolated system, and the Earth is not isolated because it exchanges energy with the rest of the universe. Just because the net energy exchange is zero does not mean that it’s isolated.