Defender's Guide to Science and Creationism

Mark Vuletic


Mutations are rarely beneficial, so they cannot drive evolution. Would you want your house built by a carpenter who made 99 bad houses for every good one?


Superficially clever, this kind of criticism actually rests on a bad analogy; the error it makes is analogous to that made in arguing that the low probability of any particular person winning the lottery translates into a low probability of anyone at all winning the lottery. To see why the criticism is problematic, let us make the creationists' analogy a little more accurate by adding to it reproduction, and see how the situation changes:

Suppose your house were able to reproduce itself. You allow it to reproduce until you have 100 new houses. Then you ask the creationists' carpenter to work on each of the houses, trying to improve them. In the creationist scenario, the carpenter will damage 99 of the houses, but will improve one of them. So what do you do? You throw away the 99 damaged ones, and keep the improved one. Then you allow that one to reproduce itself 100 times. The carpenter goes to work on the 100 copies of the improved house. He damages 99 of them, but improves one of them further. One can easily see that through this process, one will soon end up with a mansion despite the general incompetence of the carpenter.

The problem with the creationists' analogy is that it implicitly assumes only a single chance for mutation to produce a beneficial result. Naturally, if God offers to mutate your DNA, you should refuse, because you are liable to end up worse. However, if God mutates the DNA of every person on earth, someone is bound to end up better than he or she was before. It probably will not be you, but evolution does not require everyone to become improved; even a single improvement will spread as organisms reproduce and compete with one another.

Last updated: 20 Jul 2008

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