Sunday, July 09, 2006


Biological Information I: The Medium Is Too the Message

Creationists are extremely fond of saying that information can be created only by intelligence, therefore evolution is false. (I include advocates of "intelligent design" here; more on that some other time.) George Gilder, the futurist, has an article in this vein on National Review Online. The article is subscriber-only, but the Discovery Institute has a copy. Gilder's contention is that DNA is information, and that "[w]herever there is information, there is a preceding intelligence." His italics, because this is the center of his argument.

The misunderstandings of all sorts of things come thick and fast, so I gave up trying to fisk the entire article; there's just too much nonsense. I'll limit myself to the place where he most goes off the rails.

Gilder talks about Claude Shannon's theory of communication. Gilder follows most creationists in calling it a theory of information, which is the foundation of much of his confusion. Shannon was concerned about communicating information over potentially noisy telephone lines; he wanted to know how fast information could be transmitted while still allowing the user to select the correct message from all the possibilities. He specifically said that the meaning is irrelevant; what counts is sufficiently accurate communication.

Gilder correctly says that Shannon separated the information from the channel across which it's transmitted.
Crucial in information theory was the separation of content from conduit — information from the vehicle that transports it. ... In my book Telecosm (2000), I showed that the most predictable available information carriers were the regular waves of the electromagnetic spectrum ... . Whether across time (evolution) or across space (communication), information could not be borne by chemical processes alone, because these processes merged or blended the medium and the message, leaving the data illegible at the other end.
What Gilder misses here is that DNA is not a transmission channel, rather it's a storage medium. The information in DNA is copied from one generation to the next, with occasional mutation.

Gilder has a section titled "The Medium [Is] Not the Message". This is a reference to an aphorism of Marshall McLuhan, who is most famous for saying "The medium is the message". It's easy to misunderstand this: McLuhan meant (approximately) that the social effects of the availability of a new medium -- printing press, television, Web -- are more important than any specific content.

Gilder continues to miss the biological point:
Information is defined by its independence from physical determination: If it is determined, it is predictable and thus by definition not information. ...
Then maybe DNA isn't information. Or maybe the news is the same in each generation.
Biologists commonly blur the information into the slippery synecdoche of DNA, a material molecule, and imply that life is biochemistry rather than information processing.

Gilder seems to treat information as a sort of Platonic non-substance, floating above the material world. But information always has a material representation. On paper it's ink, in a wire it's fluctuating current, in an optical fiber it's a flux of photons. The fundamental problem with Gilder's analysis is that in chemistry, and by extension biology, the medium is the message -- there's no way to separate them. If you define information as something that makes something happen, in chemistry that something is the shapes of the molecules. If you want to say that life is information processing, then you have to say that the shape of the molecule is the information, and the chemical reaction is the processing. An alternative is to abandon the idea that DNA is information, or that life is information processing. Gilder never really establishes that point, he only asserts it.

If you want to say that DNA is a computer, or that life processes are computer-like, then you have to admit that each enzyme is its own processor, and that also its own code. There is no possible way to separate the code from the processor. But as Gilder says, this is one of the key features of a computer. So where does that leave the computer metaphors?

Gilder has a lot of high-flying rhetoric, but horrible science. Biologists feel that Dawinism, in its modern incarnation, is increasingly illuminating life. In a manner that is completely characteristic of "intelligent design" rhetoric, Gilder gives not the slightest hint of how science might use this "new aim" to "solve the grand challenge problems". The new aim is not ultimately redemptive; on the contrary, it remains ultimately blinding.

Creationists are fond of pointing to the many times that the scientific establishment refused to accept ideas that ultimately triumphed. The implication is that "intelligent design" will join that group. (They forget that scientific ideas are accepted on the basis of evidence, and that new ideas need new evidence, not just rhetoric.) Gilder, for his part, takes a gratuitous swipe at the idea of parallel universes as a response to some of the explanatory problems that science faces. He says that "[t]he effort to explain the miracles of our incumbent universe by postulating an infinite array of other universes is perhaps the silliest stratagem in the history of science. " Funny, that's just what Martin Luther said about Copernicus's idea that the earth moves.

ADDED LATER: Tom Schneider's Web site applies Shannon's theory to molecular machines. More on this when I've digested Schneider's stuff.