A challenge to proponents of Intelligent Design is that there is no scientific evidence for what they believe, and they believe it on what are fundamentally religious or presuppositional grounds.
Well, beliefs are of course consistent with people's metanarratives - most people who have some concept of logic (which rules out a whole crowd of postmodernists) believe things that are consistent with their metanarrative. If they don't, they have to change the metanarrative to fit - a painful process, but necessary if people are going to hang together mentally.
The next question then, is whether my beliefs are consistent with external evidence. Again, I am bound to say that I think this is so. It is normal for people's presuppositions to affect their interpretation of evidence. Part of what underlay the work of Dembski and Behe - which started prior to the supposed "politicization" of ID - was a formal attempt to get people to say under what circumstances design could be reasonably inferred. This was an agenda that was in principle accepted by Darwin, for example, in his statement that if something could be shown not to have arisen by step-by-step processes, his theory would be falsified. But in many cases, if Dembski's and Behe's work in this regard is accepted, it is then ruled outside the scope of science. So these projects having failed to win acceptance, we are left with everybody making observations and interpreting them in accordance with their presuppositions.
Take the plausibility scale in the post below, of evolutionary events of seven different levels. (Or six, if you exclude abiogenesis, which would still need a naturalistic explanation, of course. Had to get that in, didn't I, Allygally?!) The darwinist looks at the fossil evidence, homologies and so on and says - "Belief that darwinism can cover all seven [or six] steps is reasonable. (It has to be, because there is no alternative.)" The proponent of ID looks at the same evidence, and says, "I can accept that evolution is a reasonable explanation of [say] steps 1, 2 and 3, but since I believe in the possibility of external agency as an alternative explanation, I don't accept - and don't have to accept - that it is a reasonable explanation of 4, 5, and 6." Same evidence, different conclusions. The "evidence for Intelligent Design" is the same as the "evidence for darwinism" - but interpreted according to a different set of presuppositions.
Which interpretation is right? Of course, from where I sit, I will tend to think that my interpretation is right - otherwise, I'd be busily revising my metanarrative. And don't think I can't - I used to be a Young Earth Creationist - a metanarrative which is built around a particular way of interpreting the first chapters of Genesis - but I have shifted. Darwinists will believe that their interpretation is right. Is there any way of moving the debate on?
Here's an example based on that plausibility scale, that shows how the debate might be moved on. Can you present scientific evidence that belief in the descent of whales and bats from a common ancestor is better explained by darwinism than it is by non-darwinian means without first presupposing the absence of a designer? In other words, do you have a naturalistic mechanism that reliably explains this? I would argue not. There is evidence, which is interpreted in a particular way by darwinists and in a different way by non-darwinists. What darwinists have is a naturalistic mechanism that is completely untried on this scale, which they assume must be true because they have already decided that the alternative can't be true. Unless a better means for testing the evidence is available, the debate stalls at this point.