I was rereading my previous post, and I feared that it wasn't written very clearly. What I am looking for is some statement of the form, if God exists, then we could never possibly observe X, where X is whatever physical observation you'd care to plug in. For evolution, statements of this type are possible, and hence evolution is scientific. An example of such a statement would be X = a new species of organism that uses silicon oxides as a genetic material. I would maintain that there is no possible statement of this form that you would be able to make regarding the existence of God. This is a direct consequence of the omnipotence of God. Therefore, if ID postulates that God is the designer, then it is inherently unscientific. However, even if the designer is not God, then ID is unscientific unless a specific test for design is developed or the limitations of the designers capabilities are specified. So far, nobody has done either of these. Until one or the other of these is done, there is no limitation on the possible range of observations that could potentially be made, and hence there is no scientific theory of ID.
And how would that disprove evolution? Why couldn't such an organism evolve?
Or this:
What I am looking for is some statement of the form:
"If ID is the explanation for life, then we could never possibly observe X, where X is whatever physical observation you'd care to plug in."