withallyourmind.net

A long time ago I dedicated a couple posts to the examination (and critique) of Dembski’s explanatory filter for detecting design in nature. They are here and here. In this post I would like to discuss an argument for methodological naturalism that has affected how I think about design and evolution. Although I make no claim to do his paper justice, my thoughts in this and my previous posts have been influenced by Michael Murray’s “Natural Providence (or Design Trouble)“.

This argument takes it for granted that design is detectable in the natural world and that it is possible for God (if He exists) to accomplish His designs in the world either through direct intervention or through natural law. These are premises that pretty much any person interested in intelligent design would be willing to grant. The argument then is based on analogy with the following example:

Suppose a friend invites you and a few other people over for a high-stakes poker game and for the sake of integrity suggests a new deck of cards be used for each round. After five rounds, however, you become nearly certain that he has been cheating: he has won each round with a hand of four aces. However, before you have a chance to object, he says he has some very important business to attend to and kicks you and everyone else out of the house. Now, in a situation like this, you seem to have every bit of justification for your belief that your friend had some devious design for the game from the beginning. However, notice this: although you know that he cheated, you still aren’t sure how. It’s possible that he directly intervened in the game by adding in cards from his sleeves or pockets. However, it’s also possible that he instead stacked the decks before the game began. The point is that even if a design belief is justified, it can’t be known whether the design was through intervention or deck-stacking.

The purpose of the story was to give motivation to the argument, which can be loosely set out as follows:
(1) Design by intervention and design by deck-stacking are empirically equivalent after-the-fact.
(2) There are cases of design in the natural world and these are observed after-the-fact.
(3) Therefore, cases of design in the natural world could have been accomplished by intervention or by deck-stacking, and there is no empirical way to know for sure.
(4) God usually works through natural means and, at any rate, science is based principally on empirical evidence.
(5) Therefore, cases of design in the natural world should be presumed to have been accomplished by natural means (at least in the field of science).

Implications:
If this argument works, then it doesn’t seem to leave much, if any, room within natural science for design inferences. However, it does have the advantage of allowing scientists to maintain justification for design beliefs that have been shown to have been accomplished by natural means. For example, suppose Behe believes the bacterial flagellum arose as a result of design. However, suppose he turns out to be wrong that there is no natural mechanism capable of accomplishing this. If the argument above works, he is still justified in his belief that it was designed.
One potential objection, at lest by Christians, to this argument will be that it leads to a sort of deism. This is simply untrue, for even if there are no empirical reasons to prefer intervention to deck-stacking, there may be Scriptural or theological reasons to prefer intervention. For example, the first creation of life or of humankind, due to their religious significance may be reasonably thought to have been accomplished by intervention.

I’d love to hear some people’s thoughts on this argument.