Friday 24 February 2012

Intention in the genetic code

I commented in the previous post that John Maynard Smith argues[1] that there is intention in the genetic code, and also that the genetic code uses arbitrary symbolism. The argument is that evolution has selected the genetic codes - the specific DNA sequences together with biochemistry to decode the sequences - for specific purposes. Thus, the DNA sequences and the biochemistry that ends up with the growth of my eyes exists in order to produce an eyes - which themselves exists so that I can see.

In other words, this code was selected by evolution so that I can see.

Contrast this with the tree rings. When you cut down a tree you can find out how old the tree is by counting the rings, so the rings contain information about the age of the tree. But there was no intention for the tree rings to contain that information, it is a chance by-product of the way a tree grows.  The  information in the DNA sequences that are the instructions for building an eye are by contrast there with the intention of building an eye. Furthermore, they are arbitrary, in the sense that other instructions to build an eye would do just as well, provided they built an eye.  I'm not a biologist, but I guess that different organism use slightly different biochemistry to grow eyes, and certainly there are different types of eye which all nevertheless still serve the same function of seeing.

Notice, incidentally, that this is in no way suggesting that the genetic mutations that led to the ability to grow eyes were themselves intentional (there's no intelligent design in here).  The intention came from the competitive advantage of having eyes, or, rather, being able to see, which led to the selection of the organisms containing mutations that led to eyes.

In conclusion: tree rings are, in the dichotomy of Floridi, natural [environmental] information; and genetic information is semantic [non-natural] information.

(A peacock's tail is also, by the way, semantic information from this line of argument.)

JabRef References output
Ref 1
Smith, J.M.
The Concept of Information in Biology
Davies, P. and Gregersen, N. (ed.)
Information and the Nature of Reality
Cambridge University Press, 2010, pp. 123-145

No comments: