(Click here for Arguments for Fred #2)
"Teleology" is the study of purpose. In its basic form the teleological argument (the "argument from design") goes thus: with its complex physical laws and underlying structure the universe looks as if it was designed. If it was designed, there must be a purpose behind the design, and therefore there must have been a designer who had an intention - a purpose - when he, she or it designed the universe.
Appearances, however, can be deceptive. Just because the universe looks designed doesn't necessarily mean it was designed by a designer. Charles Darwin showed how the so-called design of life is explained by natural processes. But what about DNA, the digital genetic code that we now know lies at the heart of living cells, orchestrating these natural processes? That code must have come from somewhere. Computer code (whether down-and-dirty machine code, or its more abstract source-code variant) is produced by software developers. But just because computer code is written by computer programmers, we cannot legitimately infer that this is the only process that can produce complex information, digital or otherwise. Look at the Mandelbrot set, for example, which appears to be infinitely complex, yet is generated by a very simple equation.
In logical terms the problem with the design argument is that all conclusive evidence of design we have so far come across is evidence of design by humans. We have no conclusive evidence of design by any other entities, so we cannot extrapolate from what is essentially a sample of one. If the only example of design - where we know beyond doubt who the designer was - is design that we must classify as "human design", we are unable to say which characteristics of human design must necessarily apply to all examples of design.
Creationists and Intelligent Design proponents don't make this distinction; they simply say that if something looks designed, it must have been designed. This is a blinkered, parochial view that owes more to fear of the unknown than to logical consistency.
We don't know where DNA originally came from. We don't know a lot of things, but scientists are working on them, and will continue to do so while there remain things that we don't know. That's what science is about. If science knew everything, there would be no point to scientific inquiry. To quote the late, great Carl Sagan: "Really, it's okay to reserve judgment until the evidence is in."
UPDATE 2009-08-29: Click here for AfF #4
Are religious people a bit thick?
9 minutes ago