[zuffen]

9 Creationism avoids the issue of mechanism. If evolution holds, we know roughly how it works. The mechanisms by which life arises are inherent in the theory.
If creationism holds, we still don’t know how anything happened, except that we can say, “Some god did it”. (Let’s not even go close to the question of whose god this might be.) You can’t cheat by disallowing the mechanisms of evolutionary theory, only to give the steering wheel of those mechanisms over to some unseen entity. Either those mechanisms work or they don’t.

Concede for a moment that a creator exists. Point to any complex biological feature, and ask how it came into existence. If it did not arise through natural pressures on slowly-changing populations (which are obviously insufficient to cause change), then how did it come about? Did mammary glands just pop onto the torsos of the first female mammals? For that matter, did the mammal itself just pop into existence? Did some old being sit down with clay, make a man, and breathe life into it?

You can see how rapidly this gets ridiculous. Once you stipulate design, you must stipulate a mechanism to effect that design, even if that mechanism is spontaneous appearance through mystic intervention.

Where is this mechanism?

10 Remember you can’t have both worlds. What biological features of species are complex enough to warrant design?

If one feature in a species has been designed, then why not a slightly-less-complex feature? And an even slightly-less-complex feature? This is almost proof by induction: if one very complex feature has been designed, it follows that all features must have been, no matter how simple.

(Just a slightly hyperbolic aside: you have to wonder where it would stop. If differences between species must be designed, then so too must differences between individuals. One could as well argue that god has gone to the trouble of giving you lots of hair, while your wife’s former high-school boyfriend is now bald by divine design. I don’t know how many people believe this sort of thing, but I do know quite a few of them personally. Some of them I don’t know run countries.)

Directed change would mean all observations that point towards gradual biological change are false. It would mean that the hand of god is the only means by which change could take place. See number 9.

Above all, remember this …

Creationism is a truly exceptional claim, staggering in its import. It cannot be proven by someone who says, ‘I see something I don’t understand, therefore an infinite being must exist.’ That only demonstrates the limitations of human understanding.

In fact, creationists should be able to offer stupendous, irrefutable proofs.

They can’t.