Saturday, September 17, 2011

“Intelligent design” creationists never define “intelligence”

Long ago, commenting on a post at Uncommon Descent, I called on William Dembski to explain what intelligence is. He responded with his standard evasion — something like “If SETI is searching for intelligence, then intelligence must have scientific legitimacy.” Unsurprisingly, the “Expelled” expelled me from his site for raising a question he didn’t want to address again.

In ethology and scientific psychology, intelligence is a hypothetical construct, not a physically real entity. You can’t cut open an organism and find intelligence, any more than you can thirst. Studies that address intelligence always define it operationally. Just as the thirst of a rat may be defined as the number of hours it has been deprived of water, the intelligence of a person may be defined as his or her score on a paper-and-pencil test. Although we know that there is a physiological basis for thirst, thirst is itself hypothetical. Similarly, density of neural connections is correlated with performance on “intelligence” tests, but intelligence remains hypothetical.

I’ve spent a fair amount of time perusing SETI documents. The use of “intelligence” is entirely casual. Some in the project have preferred “civilization” to “intelligence.” SETI scientists explicitly assume that ET thinks as they do about how to contact a distant civilization. There’s implicitly an operational definition of intelligence in that.

In contrast, intelligence does some mighty heavy lifting in ID creationism. IDCists believe that non-material intelligence, and nothing else, creates special kinds of physical information. But what is intelligence? Ruling out matter and energy, we’re left apparently with information. So information creates information ex nihilo? That’s a nonstarter. Intelligence must have a special ontological status.

Gee, what could this entity that creates physical stuff out of nothing be? Do you suppose that IDCists believe that creative intelligence is spiritual in essence? There is, of course, no way for it to be anything but in the belief systems of almost all of them. Far be it from me to criticize personal belief in creative intelligence. But I have huge problems with people who pretend to have raised a challenge to evolutionary theory that is scientific, when they know that it is at core spiritual.

Monday, September 12, 2011

Impugning randomness convincingly?

I haven’t finished reading “Impugning Randomness, Convincingly” [pdf], by Yuri Gurevich and Grant Olney Passmore, but I’ll go ahead and share its remarks about our old pal William A. Dembski:

The idea that specified events of small probability do not happen seems to be fundamental to our human experience. And it has been much discussed, applied and misapplied. We don’t — and couldn’t — survey here the ocean of related literature. In §2 we gave already quite a number of references in support of Cournot’s principle. On the topic of misapplication of Cournot’s principle, let us now turn to the work of William Dembski. Dembski is an intelligent design theorist who has written at least two books, that are influential in creationist circles, on applications of “The Law of Small Probability” to proving intelligent design [TDI, NFL].

We single out Dembski because it is the only approach that we know which is, at least on the surface, similar to ours. Both approaches generalize Cournot’s principle and speak of independent specifications. And both approaches use the information complexity of an event as a basis to argue that it was implicitly specified. We discovered Dembski’s books rather late, when this paper was in an advanced stage, and our first impression, mostly from the introductory part of book [TDI], was that he ate our lunch so to speak. But then we realized how different the two approaches really were. And then we found good mathematical examinations of the fundamental flaws of Dembski’s work: [Wein] and [Bradley].

Our approach is much more narrow. In each of our scenarios, there is a particular trial $T$ with well defined set $\Omega_T$ of possible outcomes, a fixed family $\mathcal{F}$ of probability distributions — the innate probability distributions — on $\Omega_T$, and a particular event — the focal event — of sufficiently small probability with respect to every innate probability distribution. The null conjecture is that the trial is governed by one of the innate probability distributions. Here events are subsets of $\Omega_T$, the trial is supposed to be executed only once, and the focal event is supposed to be specified independently from the actual outcome. By impugning randomness we mean impugning the null hypothesis.

Dembski’s introductory examples look similar. In fact we borrowed one of his examples, about “the man with a golden arm” [i.e., Nicholas Caputo]. But Dembski applies his theory to vastly broader scenarios where an event may be e.g. the emergence of life. And he wants to impugn any chance whatsoever. That seems hopeless to us.

Consider the emergence of life case for example. What would the probabilistic trial be in that case? If one takes the creationist point of view then there is no probabilistic trial. Let’s take the mainstream scientific point of view, the one that Dembski intends to impugn. It is not clear at all what the trial is, when it starts and when it is finished, what the possible outcomes are, and what probability distributions need to be rejected.

The most liberal part of our approach is the definition of independent specification. But even in that aspect, our approach is super narrow comparative to Dembski’s. There are other issues with Dembski’s work; see [Wein, Bradley].

I’ve changed the reference numbers to tags that are meaningful to many of you. TDI and NFL are Dembski’s The Design Inference and No Free Lunch, respectively. James Bradley wrote “Why Dembski’s Design Inference Doesn’t Work” [pdf] for BioLogos, and Richard Wein wrote Not a Free Lunch But a Box of Chocolates for TalkOrigins.

Sunday, September 4, 2011

I was wrong about the Ninth Circuit opinion

In my last post, I exhibited a knee-jerk response to language in an opinion of the Ninth Circuit Court of Appeals. I’ve edited it to indicate my errors. I’m not terribly embarrassed to have forgotten Edwards v. Aguillard, and failed to recognize it as the source of various creationist watchwords. However, I have no excuse for failing to see that the court addressed the behavior of a history, not science, teacher.

I apologize for the errors, and thank Glenn Branch and Robert Luhn of the NCSE for gently setting me straight.