The official blog of University of Missouri Skeptics, Atheists, Secular Humanists, & Agnostics

Luke Muehlhauser on Dawkins: the “explanation” issue

(I meant to post this yesterday; my apologies for the delay..)

Last week, I introduced readers to Less Wrong. This week, I’ll add a related recommendation: the personal blog of Less Wrong’s fourth highest-rated contributor, Luke Muelhauser (known on Less Wrong as lukeprog). It’s called Common Sense Atheism, and the subtitle identifies it as being about…the same thing I’m about:

Atheism is just the beginning;
now it’s time to solve the harder questions.
Ironically, I’m going to start off by taking issue with one (or several) of Luke’s posts. This shouldn’t be misconstrued: we probably see eye-to-eye on well over 90% of atheism-related topics. But Luke does fall victim to an unfortunate temptation one sees with a lot of sophisticated atheists: criticizing Richard Dawkins.

“What?!” you say. “Since when is criticizing Richard Dawkins an offense? We atheists aren’t supposed to have any infallible leaders or sacred cows!” Good point. I’m actually talking about Dawkins’ perfectly good argument against the existence of God, expounded at length in The God Delusion. Because, you see, that argument isn’t wrong.

Luke thinks otherwise. Specifically, there are at least two things he thinks are wrong about it: (1) that Dawkins assumes the dubious principle that a good explanation must be explicable in turn; and (2) the argument is logically invalid: its conclusion doesn’t follow from its premises.  In this post I’ll deal with the first issue.

It’s true that Dawkins does write
To explain [something] by invoking a supernatural Designer is to explain precisely nothing, for it leaves unexplained the origin of the Designer.

However, it’s a misunderstanding to interpret this as invoking the idea that every explanation must leave nothing unexplained. Dawkins’ whole point, which he emphasizes repeatedly, is that an intelligent designer falls into a class of hypotheses — the complex or statistically improbable ones — that especially “require explanation”. I put that phrase in quotes to underscore that there is a technical, probability-theoretic point being made here. The problem with God as an explanation is that he’s more improbable than the phenomenon he’s being invoked to explain. That doesn’t mean design couldn’t ever actually be an explanation, of course;  after all, we know from human experience that we ourselves design artifacts, so design must be, in some sense, the “right” explanation for these. So what’s the difference?

Explanation should be thought of as making improbability go away. The way you explain something is by showing that something apparently improbable is actually an inevitable byproduct of something non-improbable. Always. But how are we doing that in the case where we explain a human-designed watch by reference to its human creator? The answer is that, while humans may be complex and statistically improbably a priori, they are not nearly so improbable given all the other evidence we have about their existence. Notice that we’re not inferring the existence of humans from the existence of watches! We already know humans exist, and we already know they make watches. If we didn’t have other evidence that humans existed, then indeed the design argument wouldn’t be a good one for the existence of watches, either! If you wanted to invoke design in that case, you would need to provide an explanation of the designer.

We in fact have a very good explanation for the existence of humans: evolution by natural selection. Once we have such an improbability-dissolving explanation — what Daniel Dennett calls a crane — in hand, it’s permissible to invoke humans as an explanation without incurring an improbability penalty. In effect, then, it’s evolution which is really doing the work of explaining how we end up with complex watches! This is why we can get away with explaining complex human artifacts by design.

In the case of God, the point is that theists don’t have any good way of dissolving the improbability. They’re trying to infer the existence of God from the existence of complexity, and in so doing they’re just pushing the whole problem — getting complexity to arise out of simplicity — back a level. This is what Dawkins is pointing out.

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This entry was posted on May 2, 2011 by in Author: James Cook.
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