Paul Nelson has another interesting post about methodological naturalism and the rules of science:

Intelligent causation, I said to Ron, seemed to me to have been unjustifiably excluded from the roster of candidate hypotheses for the origin of life. Life could have been designed. That might have happened, as an empirical possibility, and whatever is possible ought not to be excluded from science a priori. (Some possible states of affairs might turn out not to be the case, of course, but that is a matter for empirical inquiry, not definitions.)

Of course design is possible and could have happened, Ron said to me, tucking into his meal. That's not the problem.

This answer stunned me, and today, almost 23 years later, I can still experience the sense of amazement and shock. One grows accustomed to positivism after a while, and the familiar "science" and "religion" categories had been well-buttressed by multiple lines of argument from very bright people indeed on the 10th floor (albeit with the glaring inconsistencies mentioned above, e.g., 'Wait until Duane Gish sees this new transitional fossil!' -- and with a long historical record of shifting definitions and practices of science shoved to one side). I fumbled out a reply to Ron: But that's not fair, I protested. Where was the justification?

Ron shrugged. You're right, he continued, it isn't fair.

I agree that the a priori exlusion of intelligent design as a cause for the complexity and elegance of life seems to be quite arbitrary. Jason Rosenhouse at Evolutionblog critiques Nelson's post. Here's an interesting tidbit:

The situation is actually very simple. If Nelson or any other ID advocate believes that science ought to introduce supernatural thinking into its standard repertoire than the test they have to pass is very simple: Go discover something. Stop with the abstract philosophizing, stop levelling bogus charges about the bigotry and closed-mindedness of mainstream scientists, and stop whining about just wanting to follow the evidence wherever it leads. Scientists have given all due consideration to such evidence as ID folks provide, and they have rightly found it worthless. If Nelson believes they have made an error, let him go into the lab and prove them wrong in the only currency scientists care about: progress towards taming the chaos of nature.

So Rosenhouse is arguing that scientists are rejecting intelligent design a posteriori (after considering all the evidence). While I would dispute his assertion that scientists have given "all due consideration" to the evidence for ID, I would agree with the sentiment that ID proponents should go into the labs and discover new evidence for design. I believe that one fruitful area of research is the area of biomimetics. In any case, it's a good sign when people actually start asking for evidence for design instead of dismissing it by definition.