Thursday, November 29, 2012

The second law of thermodynamics

The laws of thermodynamics, especially the second one, are the favorites of creationists and apologists. Which is rather ironic (and hypocritical), really. Usually they oppose science and think that it's the work of the devil and exists just to discredit the existence of God. Of course when some creationist figured out that they could use the laws of thermodynamics to argue against "evolutionism" (which is really just a made-up term), the status of that part of science immediately jumped to completely credible and well-established fact (much unlike the rest of science, which is just a bunch of lies invented to deceive the faithful.)

Anyways, no such apologist actually understands the laws of thermodynamics. They have a vague "pop-culture version" of it, but that doesn't stop them from proudly announcing their understanding of it as well-established scientific hard fact.

(Unfortunately, scientists themselves are partly to blame. Personally I blame mostly Stephen Hawking and his book A Brief History of Time, which popularized the misconception that the the second law of thermodynamics means that everything must go towards chaos, and order increasing is a physical impossibility. Hawking may be a brilliant scientist, but I think he has done more harm than good at popularizing it in a manner that avoids misunderstandings.)

The creationist version of the second law is: Everything must always go towards disorder. Order cannot increase on its own.

Most creationists, and even many non-believers, swallow that without a second thought, even though it's extremely easy to disprove. I myself am increasing order right now, by writing this article. Am I breaking the second law of thermodynamics? If order can never increase, doesn't it mean exactly that? I have proven the second law false, so where's my Nobel prize?

A creationist will immediately object and say that I'm increasing order by using my consciousness and intelligence. That it's different. The order is not increasing "on its own." The obvious counter to that is: Where exactly does the second law of thermodynamics specify such an exception? The second law does not say "chaos must always increase, except if acted upon by an intelligent being." Nowhere will you see anything like that.

But I don't even have to resort to an intelligence increasing order. It happens in nature all by itself all the time.

For example, lava is molten rock material. It's basically just a completely amorphous blob of mineral molecules with extremely little order. Then thermodynamics happen: The blob of lava starts releasing its heat to its environment and therefore cooling down. Sometimes something awesome happens: As the lava solidifies and forms a rock, inside this rock crystals may form. Crystals are highly-ordered mineral molecules. (The extreme ordering of the molecules is what makes them crystals.)

So, nothing acted on the rock. No intelligence, no external force, no design. The lava just cooled down, releasing heat, and all by itself the completely chaotic amorphous blob transformed into highly-ordered crystal molecules.

Was the second law once again completely broken? Clearly order increased tremendously, with no external action. Why isn't this a huge mystery and open question in physics? Why isn't this called "the great crystal anomaly" or something similar? Are scientists in a huge conspiracy to not to talk about this?

No. The problem is that this is all just a huge misunderstanding of the second law of thermodynamics. Creationists just don't understand it.

What the second law says is that the total amount of entropy in a closed system never decreases. There's nothing in the law that says that entropy cannot decrease locally (as long as entropy increases somewhere else in the system by at least that much, so that its total amount remains the same or increases.)

There's nothing in the cooling lava that breaks this law. The amount of chaos inside the rock may have decreased, but that just means that the amount of chaos somewhere else has increased by at least that much. (In this particular case it was the heat that the rock released, which increases the entropy of the environment.)

There's nothing different with me writing this article: By doing so I'm consuming energy and releasing it in a form that has higher entropy. As the order of certain things increase when I write this, the amount of energy available for useful work overall decreases by at least that much (and in practice more.) In other words, I'm actually increasing (overall) chaos by writing this article, not decreasing it (even though order is increasing locally.) That's because I'm consuming energy, and releasing waste energy that increases entropy. The order is not coming from nothing.

(If you understand that notion, you can also understand why the second law implies that no perpetual motion machine is possible. It's the exact same principle: No machine can produce more useful work than the energy it consumes.)

There is nothing in the formation of stars, planets, molecules and living beings that would break the second law of thermodynamics. What the law is saying is simply that the if the amount of order (more precisely, energy available for useful work) increased somewhere, it means that it decreased by at least that much somewhere else.

Creationists cannot understand this, and in fact they refuse to understand this. The laws of thermodynamics are their pet arguments, so they simply cannot accept being wrong about them.

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