Inaccurate metaphors for DNA often used by creationists and I.D.ists: blueprint, computer code, etc.

Inaccurate metaphors for DNA
  1. DNA functions as a “blueprint?”

    The ‘blueprint’; metaphor is especially poor. Consider what a blueprint is. It is a scale schematic used to represent a structure. If you have a blueprint of a hotel, you have a schematic of how to build that hotel. The blueprint tells you everything you need to know - how high the ceilings are, how long each wall is, how many steps are in each flight of stairs. Furthermore, you know that 1 inch on the blueprint represents, say, 1 meter in the actual hotel. From the blueprints, you can precisely construct the hotel. But there is more to a blueprint than this. The information conveyed in a blueprint works both ways - you can use a blueprint to construct a hotel, and from a fully constructed hotel, you can derive a blueprint. If a wall in the hotel is 3m in length, you can draw a wall on the blueprint 3 inches long. The information is reversible. You can go from blueprint to structure and from structure to blueprint.

    This is where the analogy with DNA fails. DNA does not work as a blueprint because the information is not reversible. DNA does contain information necessary to construct an organism, but if you examine a fully formed organism, you cannot reconstruct the original DNA sequence. You cannot measure the length of a nose or determine the color of an eye, and then write out the specific sequence needed to create these features. So, DNA does not share the characteristics of a blueprint.

    Rather, DNA is more like a recipe. A recipe tells you what ingredients you need and in what manner to combine them in order to create a pie. But if you have a pie, you cannot examine it, even in the most minute of detail, and work out the exact recipe that was used. The information contained in a recipe is not reversible, just as the information spelled out by our genes is not reversible.

  2. DNA functions like a “computer code?” (or like an “encyclopedia” according to Ann Gauger of the Discovery Institute, whatever that means).

    The ‘computer code’ metaphor is also a poor one, for multiple reasons (this particular analogy is popularized by Discovery Institute fellow, Stephen C. Meyer). The way a computer code works is that the exact sequence of the code - the precise order of the binary 1s and 0s - spells out exactly what operations the computer must perform. But in genetics, the sequence is only part of the picture. Just as important are genetic regulatory networks - which genes are turned on at what times and in combination with which other genes. Phenotypes are not simply the result of particular gene sequences but the result of specific gene-gene (or gene network-gene network) interactions.

    But DNA bears little relation to a “code” in a more fundamental way. Consider exactly what a “code” is. A code is a system of arbitrary symbols used to represent ideas and objects. In a sense, language itself is a “code;” the symbol “dog” represents that furry tetrapod with a waggly tail, for example. In a code, the symbols themselves have no inherent meaning. The letter “d” is meaningless by itself, as are the letters “o” and “g”. It is only in combination that they derive meaning, and their meaning is derived from the idea that they represent. Furthermore, they only have meaning because we give them meaning. “Dog” is merely the label we apply to Fido; in a universe without sentient beings, “dog” would be meaningless. DNA does not fit this description at all. DNA is not arbitrary in any way; each letter of the genetic “code” placed in a certain order constitutes an actual biological compound. ACCGTCGA might be the gene for determining how long your toe hair is, but unlike a code, A, C, T and G each have their own non-arbitrary meaning. And this meaning exists independently of human sentience, it exists because certain molecules stick together and move about naturally in reference to one another. And those molecules would keep doing just that even if sentient being didnʼt exist at all.

    What DNA is, is a polymeric chemical that follows a dynamic chemical process, governed by universal physical rules. It is only a “code” in the same sense that the natural process known as nuclear fusion is a “code” for how stars produce light.

    Nor does the genetic code necessarily need a designer/creator, since physical complexity can increase from the basic assumption of fundamental physical laws, and theoretically it could eventually form self-catalytic chain reactions that could evolve further complexity such that “coding systems” that worked faster, better or left behind a greater abundance of some self-catalytic chain reactions over others, would proliferate.

The Origin of Life, Abiogenesis

Experimental evidence concerning how life began and exactly how the earliest reproducing organisms evolved may be hypothetical but the cosmos does appear like one enormously old experiment continually mixing energies and atoms. The cosmos is quite an active laboratory.

How is I.D. going to prove that such an experiment on such a massive scale could never produce self-reproducing molecules and then living organism? And after self-reproduction begins, itʼs a matter of some molecules reproducing greater ratios than others.

The Inevitability of Lifeʼs Origin?

Snowflakes, sand dunes, tornadoes, stalactites, graded river beds, and lightning are just a few examples of order coming from disorder in nature; none require an intelligent program to achieve that order. In any nontrivial system with lots of energy flowing through it, you are almost certain to find order arising somewhere in the system. If order from disorder is supposed to violate the 2nd law of thermodynamics, why is it ubiquitous in nature?

From the standpoint of physics, there is one essential difference between living things and inanimate clumps of carbon atoms: The former tend to be much better at capturing energy from their environment and dissipating that energy as heat. Jeremy England, a 31-year-old assistant professor at the Massachusetts Institute of Technology, has derived a mathematical formula that he believes explains this capacity. The formula, based on established physics, indicates that when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life.
Englandʼs theoretical results are generally considered valid. It is his interpretation — that his formula represents the driving force behind a class of phenomena in nature that includes life — that remains unproven. But already, there are ideas about how to test that interpretation in the lab. “Heʼs trying something radically different,” said Mara Prentiss, a professor of physics at Harvard who is contemplating such an experiment after learning about Englandʼs work. “As an organizing lens, I think he has a fabulous idea. Right or wrong, itʼs going to be very much worth the investigation.”

Yes, cells are complex, and thereʼs a natural reason for that. In fact, recent experiments indicate that replicating molecules that are more complex and that work in series can out-reproduce other replicating molecules that work alone. So complexity appears to be favored even on a biochemical level. See the new book, “What is Life?: How Chemistry becomes Biology” by Addy Pross and these other books on modern day biochemical research into the origin of life and rising complexity in the genome.

Bacteria as well as viruses, ruled the earth all by themselves for two billion years or more before larger more complex eukaryotic cells (of which we humans are composed) ever arose. Bacteria exchange DNA packets endlessly with other bacteria as well as absorb DNA passively when they encounter it. Sounds like a jury-rigged process of DNA exchange on a trial and error and on a massive scale, doing so for over a billion years. What might that NOT evolve into?

1 comment:

  1. This is very interesting to me. One of the hangups I still have with letting go of theism completely is the complexity of the cell, particularly how DNA seems to be nothing more than a library of information from which RNA copies are made which are in turn read by ribosomes to produce protiens.

    Even after reading your excellent and informative post, I'm still having trouble getting past this information aspect of DNA. I see how the code analogy isn't perfect, since the amino acids have their own "meaning" or function outside of the replication and protein production processes, but I still can't get past this information aspect of DNA.

    Does it not function as a sort of database? After all, its only use seems to be to store information that can be copied when needed. It still strains credulity for me to imagine a database, an information copying mechanism, and information reading and interpreting mechanism all arising independently with no outside coordinating force.

    This is not to say that I am an ID proponent, just that I can sympathize with where they're coming from. I realize that nature has always had the ability to surpass what our puny minds consider possible, and I have little doubt that the same will turn out to be the case with abiogenesis. But until it does, I don't think we should be so dismissive of the ID crowd's viewpoint.

    -Kelly

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