21 March 2008

The Logical Sins of the Intelligent Design Movement

Yesterday evening, Professor PZ Myers reported on his blog that he had been expelled from a screening of the soon-to-debut film "Expelled: No Intelligence Allowed", a documentary which argues that Intelligent Design(ID) is presently suppressed in the mainstream by Big Science and which deserves to be taken seriously. In the frenzy of comments to follow this post (1000+) one responder posted a link. The poster offered it, colorfully, with "have you seen this bullshit, btw?" The link led to a supposed list of ID-based research. (Notice the mascot of the ID advocates, the bacterial flagellum, on the flag.) The research offered as evidence illustrates well a common practice amongst the ID crowd. Parading fallacious arguments and capitalizing on general ignorance of logical validity.

Allow me to clarify.

The argument presented on site claims
The following is an edited extract from a Nature paper. It is an example of real ID research. Notice that the designers only used evolutionary techniques to very slightly tweak the enzymes scaffold structure that had been designed with “borrowed components” from existing enzymes tacked together. The novel active site was completely intelligently designed.
Let's translate this to argument form:
(1)The structure created by these scientists was designed intelligently.
(2)This structure is complex and alive.
(3)Therefore, all things which are complex and alive are designed.

It's the watchmaker argument all over again. Essentially, this poster has taken the compositional fallacy and enlarged it to cosmological scale. Both the watchmaker argument and this poster's claim make the same error.
(1)X possesses properties A and B.
(2)Y possesses property A.
(3)Therefore, Y possesses property B.
An absolute, complete non sequitur. By this same fallacious logic, all women are male since they both sexes are human (possess the property of humanity). All arguments based on complexity that intend to prove design--and Percy Bysshe Shelley pointed out in his 1811 essay "The Necessity of Atheism", for which we he was kicked out of Oxford, we cannot even begin talking about a designer until we can prove design--all such arguments eventually break down to this sort of fallacy.

The famous watchmaker argument comes from William Paley. He argued that if one found a watch, one would assume someone had made it. Design was a priori apparent from the structure of the watch. From this we are, by analogy, supposed to move to a conclusion that all complexity requires a designer. This is blatantly fallacious. Just because all watches have watchmakers, and all shoes have shoemakers, does not mean all universes must have universe-makers.

What about the alternative? Does natural explanation fair any better on logical grounds? Unsurprisingly, it does.

The argument against design is founded on a 700 year-old principle called Ockham's Razor. "Given two explanations of a phenommenon, choose the one that entails the least premises." This idea makes intuitive sense to all rational individuals. If I say to you "I can't find my keys. Either I misplaced them, or someone broke into my house, stole the keys, did not take anything else, and perfectly covered his/her tracks" you would tell me I probably just lost them by applying the principles of the Razor.

The Razor is the heart of the argument against design. By explaining the phenomena we observe around us without invoking a god, any supernatural power is rendered an unnecessary premise and is thus removed from the equation. There's no fallacy here.

In its quarter-century (or thereabouts) of existence, ID has never provided evidence for itself. ID advocates constantly try to shoot holes in evolution and then say "See? It must have been God!" Forgetting for a moment that their "holes" have been consistently disproved, there remains a fallacy. Even if an ID advocate could one day dismantle evolution and disprove it, this would do absolutely nothing to advance the cause of ID. To argue:
(1)Theory A and theory B attempt to explain phenommenon X.
(2)Theory A is disproved.
(3)Therefore, theory B is correct.
is a classic example of the false dilemma fallacy, erroneously assuming there are only two possible explanations of a phenommenon. This argument attempts to look like a disjunctive syllogism.
(1)Either X or Y is true.
(2)X is false
(3)Therefore, Y is true.
A disjunctive syllogism only works if that first premise is sound. And in the case of ID v. evolution it most certainly is not sound.

Of course, none of this will ever dissuade the ID fans out there. Despite the mountain of evidence in support of evolution, as compared to the tiny piles of ultimately fallacious arguments against it; despite the continued failure of ID to provide evidence of design; despite the track record of ID advocates for information distortion and general dirty dealing(for example, drawing the false distinction between macro- and micro-evolution)--the movement remains. So long as people continue to believe faith is a good thing, ID will remain credible to some.

And, of course, to those of us of the rational persuasion, it will always remain laughable.

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