Monday, February 16, 2009

Mutations and Increasing Genetic Information - An Analogy

A good friend recently put forward the genetic mutation that causes Down's Syndrome (a doubling of the 21st chromosome) as an example of a mutation resulting in an increase in genetic information. This is important because such increases in genetic information are vital if evolution as it is understood today has really occurred (the genome of a bacterium is far smaller than that of a higher animal, such that genetic information must have increased over time if some past bacterium evolved into today's higher animals). In addition, Intelligent Design advocates routinely argue that no such increases of information do occur, essentially destroying the premise upon which the evolutionary process is based.

There may be other examples of supposed increases of genetic information, but I believe I have a metaphor and an understanding of information that thoroughly refutes this one example (Down's Syndrome).

Imagine a library with thousands of books, all original, no duplicates. This is similar to the genome of a human, though really less extensive. Now, the Down's Syndrome duplication is like receiving a second copy of one of those books. At first, this does seem like an increase in information, since you now have more pages, more words, and more letters in the library. But this is deceptive. It is deceptive because information is not in essence a matter of numbers and letters but of meaning. Having two copies of John Calvin's Institutes (one of the larger works in my own library) or Dr. Seuss's Cat in the Hat (a very short work) does not increase the total meaning contained in the library. As you read the two copies, you cannot learn anything new from the second that you couldn't from the first. In fact, unless you have some sentimental affection for the duplicated book, you could easily see how the duplicate is a problem for the library, taking up space better used for some other original work.

Now, an evolutionist might argue that the duplicate could evolve into another new book. He may concede that it may not contain new information, but argue that it does contain the building blocks for new information. Surely, Calvin's Institutes contains enough letters and words to create Dr. Seuss's Cat in the Hat. The problem is this: according to evolution this must occur in a non-directed process. I could arrange the Institutes into any number of shorter works myself, but that is a completely different thing. Also, this supposition results in innumerable steps in between the Institutes and the Cat in the Hat that are gibberish, which we do not see in the genetics of any creature, but we should because this process should be on-going. Finally, this process could only create books shorter than or equal to the original, so that more complicated forms and functions cannot derive from less complicated ones, contrary to evolutionary theory.

I can think of other problems with this example of increasing genetic information, but I believe that the above argument is sufficient to reject it. What say you?

1 comment:

Tim said...

I think you're right. The Down's Syndrome argument could be clarified as a type-token confusion. An extra copy of a chromosome is a new information token, not a new information type. Information is carried by, but is not identical to, its tokens, or physical substrata.

Someone might argue that with new information tokens, we not only have more raw material, we also have more potential relationships among the material, thus more potential complexity for the "library" as a whole. The problem then, of course, is that the new relationships distort all of the other relationships that make the whole meaningful, or, in biological terms, healthy. Thus mutations like Down Syndrom--which is the mildest of several kinds of human chromosome duplication--are destructive of the form of the whole. Living things are far more precisely balanced than libraries.