# “I Fought the (2nd) Law & the Law Won”

No, today’s title doesn’t mean this post is about misremembered lyrics to 60’s songs. This is a different law, and one even harder to win against. Today, I want to review some basics of thermodynamics that point to the need for a nonmaterial, transcendent, first cause of the universe. This is a problem for atheists because the most reasonable candidate for that position is the God whose existence they deny. Let’s jump in.

The first and second laws of thermodynamics may be summarized as follows: 1) energy is neither created nor destroyed, but only changes form, and 2) the amount of usable energy in any closed system is always decreasing. The first deals with the quantity of energy, while the second deals with the quality of that energy. The measure of that decrease in usable energy is called entropy. A low-entropy system is highly ordered with much energy available to do work. A high-entropy system is approaching (or has reached) a state of uniform, random distribution, with little to no usable energy available. What does this have to do with anything? Let me quote from my college thermodynamics textbook:

Since no actual process is truly reversible, we can conclude that the net entropy change for any process that takes place is positive, and therefore the entropy of the universe, which can be considered to be an isolated system, is continuously increasing. … Entropy increase of the universe is a major concern not only to engineers but also to philosophers and theologians since entropy is viewed as a measure of the disorder  (or “mixed-up-ness”) in the universe.

$S_{gen} = \Delta S_{total} \begin{cases} >0 & \text{irreversible process}\\ = 0 &\text{reversible process}\\ < 0 & \text{impossible process} \end{cases}$

This relation serves as a criterion in determining whether a process is reversible, irreversible, or impossible.[1]

There’s a couple of relevant statements in that section. One is that the entropy of the universe is an issue for philosophers and theologians as well as engineers. The textbook author correctly realizes the implications of the 2nd Law. It has been our consistent observation that usable energy does not increase without a contribution from outside the system being studied. At best, it stays constant, like the idealized reversible process mentioned in the text (that doesn’t actually exist), but otherwise it’s always decreasing. And it can’t have been decreasing forever or the amount of usable energy in the universe would be exhausted already. This leads to the second noteworthy statement above:  the last case of the system entropy equation above defines what is an impossible process. Now, in science, we don’t take words like impossible lightly. This isn’t like watching a basketball game and seeing an “impossible” shot. No, this is more than just our typical hyperbole. If the universe is an isolated physical system that can never increase in total usable energy, and is clearly decreasing, then we have to recognize that there had to be a starting value. If the fuel tank of our universe is getting closer to “Empty”, there had to be a “Full” at one time. Things run down, disperse, and seek equilibrium, or their lowest energy state. We see this with our own sun, which should burn out in roughly 5 billion years.[2] And this is happening throughout our world, our solar system, our galaxy, our universe. Closer to home, this irreversible dispersal of energy is also why we have to keep our coffee cup on a warmer to keep it from equalizing to room temperature; it’s why we have to do preventative maintenance to keep our equipment from rusting if it’s exposed to the environment; it’s why perpetual motion machines are simply not possible.[3] Consider how bluntly Sir Arthur Eddington, the astronomer who first observationally confirmed Einstein’s theory of relativity, put it:

The Law that entropy increases—the Second Law of Thermodynamics—holds, I think, the supreme position among the laws of Nature. If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations— then so much for Maxwell’s equations. If it is found to be contradicted by observation— well, these experiments do bungle things sometimes. But if your theory is found to be against the Second Law of Thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation[4]

Now, perhaps you might say that that initial description of the universe as an isolated system is rendered inaccurate by the existence of a multiverse. Although completely unsupported by any scientific observation, and believed to be beyond the ability to ever observe by our event horizon, the multiverse is a popular escape for many – a kind of magic place where anything is possible.[5] Well, that might make our universe an open system briefly, until you simply label the multiverse as your isolated system, with our universe being one subsystem and the surroundings – i.e. the rest of the multiverse – being another subsystem in the arbitrary isolated system. So, appealing to the multiverse to get around the 2nd law doesn’t really help.

Maybe there is an escape in the idea of a cyclical universe that recycles itself. Consider then this statement from Alexander Vilenkin:

It is said that an argument is what convinces reasonable men and a proof is what it takes to convince even an unreasonable man. With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape, they have to face the problem of a cosmic beginning.[6]

But what are we to do if there is a definite beginning to the universe and it can’t simply have existed eternally? Things always require a cause outside of themselves to come into existence. And that’s what worries atheist scientists. When you’re talking about all of our physical reality, what’s outside of that? Nothing according to a materialistic worldview. And so their presuppositions actually make them close-minded to viable options – options that match up with our daily commonsense observations: basic cause and effect, that things don’t simply pop into existence for no reason, that things running down can’t be running down forever. The Second Law reminds us of our finitude [Is 51:6], the existence of a beginning [Gen 1:1], and by implication, the need for a Beginner. And the Second Law… always wins. Take care 🙂

[1] Yunus A. Çengel, Michael A. Boles, Thermodynamics: An Engineering Approach, 2nd Edition, (Ney York: McGraw-Hill, 1994), pp.304-5.
[2] http://www.space.com/14732-sun-burns-star-death.html
[3] In fact, a perpetual motion machine is defined as a device that violates either the 1st or 2nd Laws of Thermodynamics. But their inviolability is why the US Patent Office has not accepted patent applications for perpetual motion machines since 1918. Thermodynamics, p. 255-257.
[3] Arthur Eddington, The Nature of the Physical World, 1929, Ch 4.
[4] In the words of Alan Guth, “anything that can happen will happen—and it will happen infinitely many times.” Quoted by Paul Steinhardt in “Theories of Anything“.
[5] Alexander Vilenkin, Many Worlds in One, 2006, p.176, quoted in  William Lane Craig’s Reasonable Faith (3rd edition), p. 140.