Evolution and Entropy, Again

I just got an email from someone who had read my essay about evolution and the second law of thermodynamics and thought he had found a flaw in it. It made me realize that the discussion there is rather technical and mathematical, and I ought to write up the basic idea in a clear and non-mathematical way. So here goes.

The thermodynamic argument against evolution goes something like this:

1. Evolution involves an increase of order, and therefore a decrease of entropy.
2. The second law of thermodynamics says that entropy never decreases.
3. Therefore, evolution contradicts the second law of thermodynamics.

Let's first consider (1.). In order to establish this, one would have to show that the body of a human being has less thermodynamic entropy than an equal mass of bacteria  (for instance). Now, this may in fact be true, but no one has ever proven such a thing, to my knowledge. Without proving (1.), the argument can't get off the ground.

Secondly, even if (1.) is true, the argument fails, because (2.) is wrong: the second law of thermodynamics doesn't say that entropy never decreases.

In fact, entropy decreases spontaneously in lots of natural settings: for instance, when a pond freezes over in winter. Ice has much less entropy than liquid water - if it were impossible for entropy to decrease then it would be impossible for ponds to freeze over.



So what does the second law of thermodynamics say? It says that there can't be a decrease of entropy in one place without a compensating increase of entropy somewhere else. In the case of the pond, the heat escaping from the water during the freezing process causes an increase of entropy of the air over the pond.

If you wanted to prove that the freezing of the pond violates the second law of thermodynamics, you would have to calculate the entropy decrease of the water, calculate the entropy increase of the air, and show that the latter is less than the former.

In the case of evolution, you would have to calculate the entropy decrease due to cells being "organized" into higher life forms, which, we already noted, has never been done. Then you would have to show there was no compensating increase of entropy elsewhere. This second step is what I addressed in my essay. If we take the whole Earth as our system, then we find there is an absolutely enormous increase of entropy due to the radiation of heat energy into space. This entropy increase is so large that no possible decrease of entropy due to evolution would cause a violation of the second law of thermodynamics.

Freaks of Nature

I just finished reading Evolution, Me, and Other Freaks of Nature, an enjoyable Young Adult novel about a girl caught between her convictions and her church. On the recording I listened to, author Robin Brande interviewed biologist and author Kenneth R. Miller, on whom she modeled the main teacher character in the book, Ms. Shepherd. Ms. Shepherd, like Miller, is both a scientist and a person of faith.

The interview made me think again about something that seems to me a big problem for anyone who thinks they can reconcile modern science and Christianity; namely, that evolution is a process that necessarily involves a tremendous amount of suffering. I can understand that, logically speaking, there is no problem with saying that evolution is the means by which God chose to create life on earth, including human life. But evolution's creative engine is the violent death through starvation or predation of most of the individual organisms that have ever lived. How do you reconcile that with the loving Christian God? I don't recall ever finding an answer to that, in Miller's book or anywhere else.

So, recalling that I had a copy of Finding Darwin's God on my bookshelf, I pulled it out to see what I could find. A section entitled "No More Mr. Nice Guy," begins like this:

Of all the concerns expressed by Christians with respect to evolution, the strangest, the least logical, the most bizarre is the idea that evolution is too cruel to be compatible with their notion of a loving God.

OK, this sound very promising: Miller is going to proceed to explain why this complaint is illogical and bizarre, right? Well, let's see.

Miller says we need to keep two things in mind. First, "cruelty is relative." He points out that his lobster dinner is a cruel death from the point of view of the lobster, but just a good meal for him. Second, "we cannot call evolution cruel if all we are really doing is assigning to evolution the raw savagery of nature itself. The reality of life is that the world often lacks mercy, pity, and even common decency.... Evolution cannot be a cruel concept if all it does is reflect the realities of nature...."

Well, but why not? It seems to me that all Miller has done is to re-state the problem. Life is cruel and frequently involves violent, painful death. Why would a loving, kind, God choose this as her means of creation? Saying that this is just the "reality of nature" doesn't answer the complaint in the least.

From here, Miller goes on to point out that contemporary research into the evolutionary origins of altruism shows that what we often think of as the "good" behaviors can arise out of evolution as well. Fair enough, but it doesn't have anything to do with the original complaint.

OK, so is the objection illogical? Let's try to lay it out as a logical argument from the point of view of a Christian who accepts evolution.

1. God created life on earth.
2. Life on earth arose through evolution.
3. Therefore, God chose evolution as his means of creation.
4. Evolution involves the suffering and death of living creatures.
5. Therefore, God chose a means of creation that involves suffering of living creatures.

How can Miller resist this argument? (1) is a basic assumption in Christian thought, and I don't think Miller would try to deny this. (2) is well-established scientifically and clearly accepted by Miller. You could object to (3) by saying God didn't have any choice in her means of creation - but this would deny God's omnipotence. Miller also clearly recognizes that (4) is true. So I don't see any way Miller can resist the conclusion (5).


The only response I know of to this argument is along the lines of "Sometimes suffering is necessary so that a greater good can come about." Miller doesn't make any attempt at such an argument, but it is a common response to the problem of evil. But does it make any sense in this context? I don't think so: surely, if God is omnipotent, and if her goal was to produce intelligent, moral, beings, she could have just zapped all of us into existence - plants, animals, humans, and all - without going through all the pain of millions of years of evolution.

The Usefulness of Useless Debate

Before I was barred (without any explanation) from posting, I used to spend a lot of time over at Crosswalk Forums, often debating evolution and the age of the earth. At first I thought that there was so much evidence in favor of the accepted scientific view that I would certainly be able to convince the doubters. But I soon realized that there were many ways people evaded the inevitable. Some just buried their heads in the sand and denied the evidence, or said it was unreliable, or faked, or whatever. But others were actually thoughtful, and even well-informed. One in particular was studying biochemistry, and knew much more about genetics than I do. Yet he refused to give up his anti-evolution stance.

Still, it was an interesting intellectual exercise to try to present the evidence in the clearest possible way. And, I thought, even if I wasn't convincing any of my debate opponents, maybe some of those lurkers were getting something of a clearer view of science and its methods.

Just around the time I got banned, someone else posted a poll asking how many forum participants had gone from young-earth creationism (YEC) to evolution/old-earth, and vice versa, as well as who had not changed their stance. Of course, there were many YECs who had remained YEC, as well as those who had been and remained convinced of evolution.

What really surprised me, though, was that there were more who had become convinced of evolution through participation in the forums, than had gone the other way. This in spite of the fact that every argument I posted was immediately inundated with links to, or arguments from, Answers in Genesis and the like.

So I feel strongly that, no matter how useless the debate seems, no matter how unyielding our debate opponents may be, this kind of debate makes an impact.

We Have The Fossils - We Win!

If you spend any time arguing with creationists (I used to do a fair amount of this), it's helpful to have some actual data on hand. I'm a math-geeky guy, so I like charts and stuff. One of my favorites is from an old post on Panda's Thumb.

It shows an unbroken increase in brain size (cranial capacity) over the past 3 million years. The magnitude of this increase is just astounding: from 400 ml (about the size of a chimp's) to around 1200 ml - a tripling of brain matter!

The thing is, there's really an astonishing amount of evidence for human evolution: a dozen extinct hominid species comprising hundreds of fossils. Compare that to the number of chimpanzee fossils that have been found: zero! Some religious folk admit that the evidence for evolution is overwhelming, and accept that it was the way all animals and plants came about - except for humans, who were specially created by God. Given the fossil evidence, though, it would be much easier to make the case for special creation of chimps!

Brain size is, of course, not the only important difference between humans and other animals. But there are some profound advantages to focusing on a single characteristic like this. In the usual way of discussing evolution, one classifies the fossils into different species and talks about the average characteristics of each species, "Homo habilis had an average cranial capacity of 500 ml," etc. But then, creationists point to the "jumps" in brain size between species and shout, "Gaps in the fossil record!" The graph, on the contrary, shows that there really are no gaps in the brain size record. Likewise, when discussing one species at a time, creationsists will try to call them "just another ape" or else "just ancient humans." Show them this graph and ask them where they draw the line between apes and humans.

Finally, the graph refutes the creationist claim that the theory of evolution makes no testable predictions. The link between brain size and age in hominid fossils is a clear prediction of Darwin's theory: if humans evolved from smaller-brained primates, then there must have been primates with intermediate brain sizes. At the time Darwin made his proposal, there was no fossil evidence to back it up. (Only one Neanderthal fossil was known at the time, and no other ancient hominids.) The discovery over the last century of all these intermediate fossils provides resounding confirmation of the theory - regardless of whether these species were on the direct line of human ancestry or not.

(NB: the title of this post is stolen from this bumper sticker.)