Proponents of intelligent design creationism are always talking about the "miraculous" ways in which the world fits together -- the vertebrate eye, the blood clotting cascade and so on. They claim that if even one piece is missing, the whole shebang will stop working. They've been repeatedly shown to be wrong. The whole idea of irreducible complexity is going nowhere.There's another problem with intelligent design. A lot of things in the world don't look so intelligently designed. Would an intelligent designer have us ingest food and water and transport it to the stomach through a tube that's shared with the tube taking oxygen to our lungs? A designer who would build us so that the Heimlich maneuver had to be invented seems pretty stupid to me.
Here's another example from today's issue of Science.
It's long been known that many animals acquire protective chemicals from symbionts that live with or within them. The aphid Acyrthosiphon pisum, for example, gains protection against a parasitoid wasp when it's "infected" by a bacterium, Hamiltonella defensa. Now it may seem a little odd that an intelligent designer would leave A. pisum unprotected without the bacterium, but maybe the bacterium is really common and it was "easier" that way.1
But it doesn't stop there.
The light gray bar on the left side of the figure shows the fraction of A. pisum individuals parasitized when they are uninfected. The dark gray bar on the right side of the figure shows the fraction of individuals parasitized when they are infected with Hamiltonella, but the Hamiltonella aren't infected with the virus. No difference. It's only when individuals are infected with Hamiltonella that is itself infected with the virus that they are protected against parasitism (black bar in the middle).2
That strikes me as a system that might have been designed by Rube Goldberg, not an intelligent designer.3
1Why it should be necessary for an intelligent designer to take the easy way out is a question for another day.
2The numbers above the bars are the sample sizes. The row of asterisks over the middle black bar is shorthand for "it is very, very, very, unlikely that the difference between this bar and the other two is the result of chance."
3Rube Goldberg was a brilliant cartoonist, but I definitely would not have hired him as an engineer.
Oliver, K., Degnan, P., Hunter, M., & Moran, N. (2009). Bacteriophages Encode Factors Required for Protection in a Symbiotic Mutualism Science, 325 (5943), 992-994 DOI: 10.1126/science.1174463
Just to play Devil's advocate :)
or I guess Jesus's advocate, in this case?
I would argue that were all Acyrthosiphon pisum immune to the parasites, it would be at the cost of another species. Since the wasps need to reproduce, and do so by using the aphid as their host, then yes, a designer would create such a system so that not all aphids are immune to the parasites.
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http://noamgr.wordpress.com
They claim that if even one piece is missing, the whole shebang will stop working
What strikes me as bizarre about that claim is that it wouldn't be a very "intelligent design" to design a system such that a single failure would cause the whole system to fail. Surely, an intelligent designer would give bodily systems multiple redundancies, in case something happened to one part.
Noam, I'll grant that a designer would create a system where some aphids are susceptible to parasitism so that the wasps can reproduce. But why would an intelligent designer make that susceptibility depend not only on whether or not the aphid was infected by a particular bacterium but also on whether that aphid was infected by a virus? Doesn't sound like a very reliable, well-designed system to me.
Hm. Here I suppose most creationists would play the "God works in mysterious ways that we will never understand" card.
Though it's almost always possible to reason backwards and make what sounds like a compelling argument. In this case, a more inventive creationist could bring up the point that if all the bacteria were deadly to the parasites, and since these bacteria are transmitted easily (from parent to offspring, and amongst individuals), the immunity would soon spread to the entire population.
The virus however, (if I remember the paper correctly) loses its effect as the bacteria reproduce, and thus there are always aphids who are available to be infected.
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I think this sounds like a compelling argument. The problem, of course, is the backwards reasoning, where I start with the assumption of a creator, and then fit the evidence by asking "why would he have done such and such." But I think many people can be swayed by this sort of argument without finding that fault.
You and I realize that the creator here is not necessary at all. Complex systems like these can and do evolve on their own and are perfectly explainable by evolution: the wasp/aphid relationship would not have lasted too long if it were not sustainable on either end (either by all aphids becoming immune to the parasites, or all of them being destroyed by the parasites).
That is, however, different from claiming that the creator/intelligent designer does not exist. I happen not to be a believer, but that is a philosophical position, not a scientific hypothesis. Science is truly agnostic. It neither affirms nor denies the existence of a creator. It simply provides explanations for natural phenomena that do not involve her.