There’s been a rather tired argument making its way around the theist blogosphere of late, arguing that DNA is a code, and codes are designed things. The very fact of it being a code proves that there must have been someone who designed the code.
As usual, this argument comes down to using words improperly. A code, by the strictest definition, is in fact something designed by intelligent beings. It is a system of symbols that either arbitrarily or by some system represent various things. The alphabet I’m using to write this blog is a code. There’s nothing about the individual letters that have any inherent meaning. They don’t do anything in and of themselves. By agreement between multiple humans, we have a legend, or a key, which most of us learned in grammar school. By using this legend, we can look at anything in the code “English” and through substitution, come to the knowledge of the concepts sybolized by the various letters.
This is the traditional idea of a code, and it is what theists think they mean when they argue that DNA is a code. The thing is, DNA is not that kind of a code. DNA is a a polymer, which is composed of individual chemical units called nucleotides. There are four types of these nucleotides, and we humans have decided to call them adenine, guanine, cytosine, and thymine. These names are not entirely arbitrary, but in the end, there’s nothing magical about them. We could call them Blob, Clob, Dob, and Emu, and they’d still be the same. Our language — the code we humans use to communicate — is just a way for us to give each other information and keep things separate in our own minds.