Monday, 18 February 2013

Debating creationists

A couple of days ago I stupidly got into an online debate with a creationist. I have a general rule not to do this, as it's a futile waste of energy - but, probably once a year or so my willpower fails and I get dragged in!

After a bit of back-and-forth about the usual stuff the creationist - I'll call him "John", because that was his name - made the claim that evolution violated the 2nd law of thermodynamics. This immediately took me back about a decade in time to when I first had a debate online about these things and someone brought up the same argument. Even then, with no real scientific knowledge beyond what I didn't remember from school I felt that the argument was unlikely to be true. It's what got me interested in learning science again and I've spent some time since then reading and studying science with the Open University and generally taking an interest in religion, scepticism and atheism.

So I made my responses to "John" and of course they were dismissed as I fully expected they would be and I ended the conversation when he accused me of redefining the 2nd law to fit my purposes, when, whether he knew it or not, that was exactly what he had done. Now I'm back to thinking about this argument again, hence this post.

The definition that "John" had clearly been taught to trot out was that "natural systems break down over time, not improve" which, if you wanted to explain the concept to a six year old is probably ok (but even then a smart six year old would pretty quickly realise that it couldn't be that simple). As evolution increases complexity over time, it must violate the 2nd law. This simplified creationist definition missed out one very crucial element of the law which is present in the definition I then used: "in a closed system entropy always increases". Entropy very simply put is a measure of disorder, so the main difference between the two definitions is the part about a closed system. If a system is closed, i.e. no energy can enter it from outside, the energy inside it will eventually become evenly distributed throughout the system, or to put it another way, without energy input from outside, the system will inevitably become more and more disordered until it reaches a maximum point of disorder.

As a universal law, there are many ways of stating the 2nd law - in my studies with the OU I came across at least five or six that relate it to various physical processes. It was independently formulated nearly 200 years ago by Sadi Carnot and Rudolf Clausius, and has been restated in other ways by such scientific giants as Lord Kelvin and Ludwig Boltzmann. Darwin's theory of evolution by natural selection is now over 150 years old. The fact these two cornerstones of science have lasted side by side for so long might make you doubt claims that they are mutually exclusive, but this doesn't seem to worry creationists.

For evolution to violate the 2nd law, it would have to be taking place in a closed system, and that is the part the creationists leave out - for pretty obvious reasons. The system within which life on Earth has evolved is, of course, the Earth. Now I think it's safe to say that the Earth as a system does receive a not inconsiderable amount of energy from an outside source - and I know now I sound like I'm making statements of the bleeding obvious here - that source is of course the Sun.

You would think that having explained that, the creationist would say "well, stone the crows, of course you're right on that one - I'll never use that argument again". Yeah, that doesn't happen. But as it is so clearly and obviously wrong, I still think it's one of the few chances of getting a creationist at least to ponder it for a moment. But, I thought, maybe I could come up with an analogy that would make it even simpler to get. So here goes.

Saying evolution violates the 2nd law of thermodynamics is equivalent in many ways to saying a rocket launching a satellite into orbit violates the law of gravity - if that sounds ridiculous, well that's the point. Here's why. I could loosely define the law of gravity (in the same way creationists loosely define the 2nd law of thermodynamics) as something like this: "all unsupported things will fall towards the earth". Using this definition I could claim a rocket launching a satellite violates this law, hence all orbiting satellites were put there in situ by God. As before, the vague definition misses out the obvious addition of a vast supply of energy, in this case let's say it's the fuel inside a stonking great Saturn V rocket. The rocket simply uses this supply of energy to overcome the downward force of gravity. At no point does it violate the law, it simply uses energy to overcome it. The same happens with evolution - it has a vast supply of usable energy from the Sun which it uses to overcome the tendency to disorder described by the 2nd law of thermodynamics.

To push the analogy perhaps beyond useful simplicity, you could also say the creationists insistence on ignoring all the scientific evidence that supports evolution is akin to them claiming God must have put all the satellites in orbit because rockets violate the law of gravity, all the while ignoring not only rocket science itself but also the discarded "fossils" left behind by a three-stage rocket such as the Saturn V. ("Where are the transitional stages??" I hear them cry in my head).

I'd like to think that even a completely brainwashed creationist like "John" might feel a little tickle of scepticism about what they have been told if it could be explained like that - maybe put a dent in the wall of wilfull blindess or the barrage of bible verses - but I'm probably being wildly optimistic. However, next time I'm presented with the argument I'll simply say "claiming evolution violates the 2nd law of thermodynamics is just like claiming a rocket violates the law of gravity" and leave it at that. Maybe that'll get 'em thinking. It would certainly save me some time ;)