‎ ‎ ‎ ‎ ‎ ‎ ‎‎ ‎ ‎ ‎ ‎ ‎ ‎Dismantling the Entropy Argument for a Cosmic Beginning

Introduction

The Second Law of Thermodynamics is often employed by religious apologists to defend the thesis that the universe has not always existed. The idea is that if the universe were infinitely old, it should have run out of usable energy by now due to entropy’s relentless increase in closed systems. Yet, we see order and usable energy all around us, implying the universe hasn’t been around forever. Think of the universe as a giant wind-up toy. The 2nd Law says it’s always unwinding -- energy spreads out, disorder (entropy) grows, and eventually, it will stop because there’s no more "spring" left to drive it. If the toy had been unwinding forever, it would’ve stopped an infinite time ago. But it’s still ticking -- stars burn, planets spin, life exists. That is supposed to imply it had to be "wound up" at a starting point, not infinitely long ago.

Some versions of this argument are very old. For instance, Friedrich Engels (1820–1895), the atheist communist who collaborated with Karl Marx to develop communist theory, rejected the Second Law because he concluded it proves that entropy had an ultimate starting point in the past. He wrote to Marx: “You cannot imagine anything stupider.” The idea of gradual equalization of temperatures, or, as it would later be formulated, increasing entropy, led to a world “that begins in nonsense and ends in nonsense.” Although the second law was seen as “the finest and highest perfection of materialism,” it envisaged a progressive cooling of the universe. Such a development implied “the original hot condition, from which things cooled off, absolutely inexplicable, even absurd, thus presupposes a God.” [1] (For more on this, see Kragh, 2004)

I want to make the case that we don’t have to throw out the second law of thermodynamics to believe in the idea of a universe that lasts forever. I’ll explain that it’s possible to have both an eternal universe and the second law without any conflict.

Objections to the Entropy Argument:

1. The second law is not a fundamental or absolute law (like the law of gravity); it is just a statistical regularity (similar to ‘coins land on heads or tails’). Violations are possible (like a coin landing on its edge), even if statistically unlikely for systems as large as the entire universe. There are so many more ways to be high-entropy (chaotic, disorderly) than to be low-entropy (arranged, orderly) that almost anything a system might do will move it toward higher entropy. But there is nothing fundamentally problematic with entropy reduction in closed systems [2], [3], [4].
2. Not only are violations of the second law possible, but they are also real and well-documented. Micro-physical systems, given that the second law is primarily a large-scale statistical regularity, frequently break it. This observation has been made in laboratory experiments. The probability of entropy increasing, rather than decreasing, rises as larger and larger systems are taken into account. Therefore, if one intends to conduct an experiment likely to observe such reductions, working with just a handful of particles is more appropriate, a feat accomplished by experimenters in 2002 [2], [4]. This could be relevant as it is universally held by cosmologists that the early universe was microscopic. If it remained that way indefinitely, entropy could have been increasing and decreasing from eternity.
3. The main problem with the entropy argument is that we cannot definitively claim that entropy will always increase. It is more accurate to say that entropy typically increases. As Henri Poincaré proved, despite being an extremely rare event in large scales, there will be instances when entropy spontaneously decreases, leading to the recurrence of previous entropic states (if certain conditions are met). If we consider an infinitely old universe (such as Boltzmann’s universe), then the very small chance of such reductions in entropy becoming a reality becomes highly likely -- indeed, inevitable. With infinite time, it’s anticipated to happen endlessly [2], [3], [4], [5]. Read my brief examination of objections concerning the plausibility of this hypothesis here.
4. The second law posits that the entropy of large systems tends to either increase or remain constant, but not decrease. Nevertheless, it is perfectly conceivable that entropy remained constant (i.e., did not grow) for an infinite amount of time and only initiated its growth at a finite point in the past (say, at the Big Bang). In such a case, it would still be possible for the universe to have existed eternally and we wouldn’t even need an entropy reversal or reduction. This possibility implies that the beginning of entropy does not entail the beginning of the universe; only the beginning of entropy growth [5]. Physicist D. C. Choudhury proposed a model which posits that, prior to the beginning of entropy growth “the universe was initially very regular (i.e., in a state of zero entropy)”, but that a spontaneous event triggered something similar to “an explosion (big bang) analogous to that of the initiator at the center of the bomb which provides neutrons to begin the chain reaction resulting in explosion.” [11] Perhaps the universe was like a bomb that remained in that state of zero entropy for eternity and then “exploded” or decayed due to a spontaneous quantum phenomenon at the Big Bang.
5. The entropy argument presupposes that the universe is a closed system. However, this assumption has been forcefully challenged by prominent physicists. For instance, Adolf Grünbaum pointed out that an “inherent limitation on the applicability of the… entropy concept to the entire universe lies in the fact that it has no applicability at all to a spatially infinite universe.” E. A. Milne, reacting to another physicist embracing the heat-death thesis, provides a similar response: “Jeans’s own studies in the realm of the second law of thermodynamics were all concerned with the kinetic theory of gases, in which the specimen under discussion is supposed walled around in a finite vessel; and to such systems the notion of a heat-death is applicable. But by no means is the same result to be predicted of the whole universe.” Similarly, Landau and Lifshitz, authors of Statistical Physics, clarified that “in the general theory of relativity the universe as a whole must be regarded not as a closed system, but as one which is in a variable gravitational field. In this case the application of the law of increase of entropy does not imply the necessity of statistical equilibrium.” [6] Following the same line of reasoning, quantum gravity pioneer Christoff Wetterich stated: “The argument that the universe has to settle to some thermodynamic state -- this is just not true. Look at our universe. Do you see that things go to thermal equilibrium? Things started almost in thermal equilibrium, and then structures have grown. So they are not at all going in the direction of local thermal equilibrium. And why not? Because you have gravity. You have an instability -- gravitational attraction -- and in the presence of instability, the thermodynamic arguments do not work anymore. So you just see it when you look out at the universe. It started almost in thermal equilibrium and moves away from it. ... Entropy is actually not such a universal and robust concept. ... It is a quantity that is relatively well-defined only for equilibrium processes, whereas cosmology obviously is not an equilibrium.” [12] Physicist Brian Pitts voiced the same opinion, saying that “thermodynamical claims of increasing entropy and the like probably are unreliable in the absence of an adequate treatment of the thermodynamics of gravitation itself. Gravitation has a long range and cannot be screened, in contrast to typical textbook thermodynamics systems, so many standard features of thermodynamics (such as positive specific heats, spatial homogeneity of systems of in equilibrium, and the proportionality of entropy to volume) can fail for gravitation.” [13] Finally, Willem B. Drees points out that even though the universe may not be open in the sense of having interactions with an external environment, it is open in the sense that “the entropy ‘is carried away into the expanding space’ by the background radiation, [and so] the expansion works as if there is an environment, although there is none.” [9]
6. In the 19th century, the Catholic philosopher and physicist Caspar Isenkrahe argued that an increasing function doesn’t necessarily require a starting point. If that is correct, it is plausible that the universe’s entropy has been continuously increasing forever with no beginning. More recently, some prominent physicists have revived and explored this idea, proposing that the universe might not have an equilibrium state; in that case, there is no maximum entropy for the universe to obtain, and so, even if the entropy has been increasing forever, the universe wouldn’t reach an equilibrium [4], [10]. In other words, it is possible that we find ourselves in a closed system where there is no maximum possible entropy. If entropy can just grow forever, then any state is a state of low entropy, because it is low compared to the maximum, which is infinite. As cosmologist Alan Guth admitted, “an interesting feature of this picture is that the universe need not have a beginning.” [7]
7. Proponents of the entropy argument also fail to consider the possibility that there might be an undiscovered natural process within the universe that periodically reduces its entropy, preventing an entropy or heat death (e.g., Roger Penrose’s Conformal Cosmology or Loop Quantum Cosmology). This idea may be considered speculative, but no more so than unproven concepts like immaterial or divine entities. Indeed, it may even be less speculative and much more plausible since it only invokes types of substances we already know exist, namely, physical substances and mechanisms, implying it is much more methodologically conservative than supernatural hypotheses [5].
8. This argument depends on the assumption that the universe doesn’t receive any energy from an external source. It remains possible that there are physical substances of a radically different nature beyond the known universe that intermittently or periodically supply energy to counteract the continuous rise in entropy. If that is the case, then entropy will reverse again in the distant future, perhaps trillions of years after the last black hole in existence has dissipated away through Hawking radiation [3].
9. While the second law is valid within the observable part of the universe, its applicability to the entire universe remains uncertain. As cosmologist Sean Carroll explained: “The idea that the 2nd Law implies the universe began to exist is obviously wrong. It assumes that the 2nd Law is universal, which it might not be. … The Second Law definitely comes about because of the configuration of matter in our local region of the universe… That doesn’t necessarily mean that it’s not universal — by “local region” we mean the part of the universe we can see, and by definition we can’t see what things are like elsewhere. The 2nd Law might apply everywhere in the real universe, or it might not.” [8] And if parts of the unobservable universe do not obey this law, they could serve as the external and eternal sources that periodically pour energy into our system.

References:

[1] Sperber, Jonathan. Karl Marx: A Nineteenth-Century Life. p.417. WW Norton & Company, 2013.

[2] Carroll, Sean. A Universe Out of Chaos in Discover Magazine, 2011. (link)

[3] Fodor, James. Unreasonable Faith: How William Lane Craig Overstates the Case for Christianity. Ockham Publishing Group, 2022.

[4] Linford, Daniel. Notes for Majesty of Reason Interview. 2023. (pdf)

[5] Lataster, Raphael. The Case Against Theism. Cham, Switzerland: Springer, 2018

[6] Smith, George H. Atheism: The Case Against God. Prometheus Books, 2010.

[7] Guth, Alan. 2014: What Scientific Idea is Ready For Retirement? The Universe Began In A State Of Extraodinarily Low Entropy in Edge. (link)

[8] Terrab, Younes. Did God Cause the Universe to Begin to Exist? An Extensive Refutation of William Lane Craig’s Case for The Kalam Cosmological Argument. MS thesis. 2019.

[9] Drees, Willem B. Beyond the Big Bang: Quantum Cosmologies and God. Open Court Publishing, 1990.

[10] Kragh, Helge S. Entropic Creation: Religious Contexts of Thermodynamics and Cosmology. Routledge, 2016. (pdf)

[11] Choudhury, D. C. Resolution of Cosmological Singularity and a Plausible Mechanism of the Big Bang. AIP Conference Proceedings. Vol. 610. №1. American Institute of Physics, 2002.

[12] Phil Halper (aka Skydivephil), Eternal universe? Slow Freeze Cosmology, Youtube, 2025. (link)

[13] Pitts, J. Brian. Does the Big Bang Demystify Creation in the Finite Past? 25 Jan. 2006.