At ID The Future, Jay Richards has written an essay in response to this question, which - as my comments on objections to his book Privileged Planet sought to - moves on into more metaphysical territory. I think he is saying that even agreeing to disagree on metaphysical claims isn't necessarily the end point of such discussion: we may end up at a point where we can see that one answer to metaphysical questions may be demonstrably more correct than others.
Some liberal Christians would argue against this approach. They argue, in effect, that God must only be known by faith; if anything gives me confidence in the existence of God, it actually undermines my faith. Denyse O'Leary gives an example of this in "By Design or By Chance?" - but I've lent my copy out, so I can't quote it verbatim. This is based on a mistaking of biblical faith for existential faith. Francis Schaeffer talks about this in "'Faith' vs Faith", which is an appendix to his book, Escape from Reason. The two words are the same, but they mean almost the exact opposite. Christian faith is reasonable, not irrational; it is faith in an object, not faith as an arbitrary feeling; it is open to verification. Schaeffer might have had confidence that it would be the case, but his theology looks more reasonable in the light of developments in science since his death.
