One of the things I would want to challenge in the average evangelical doctrine of revelation is its simplicity. I am using the word here in its technical sense, as something which does not have parts, is not capable of further analysis, stands as a monad. I think that is the way the doctrine of revelation works in most evangelicalism. There are no gaps in it.
To put that more concretely, what I mean is that when evangelicals talk about revelation they tend to move straight to Scripture, and thence directly to doctrine, with the assumption that they have not in any way changed the subject in so doing. The position is that revelation is to do with the Bible - God is revealed in Scripture - and the Bible is essentially a system of doctrine, or at least a mine of potential doctrine that is just waiting for the exegete (and theologian, although the latter is looked on a little suspiciously on the whole) to dig up and arrange in orderly fashion. Revelation, Scripture, doctrine - basically the same thing. The only potential gap relates to human error; I may have misread Scripture and extracted the wrong doctrine from it. Nevertheless, fundamentally, revelation is simple.
I'm sketching a caricature here, but not one, I think, which is too far from life. Caricature can be helpful; one may be quite unaware of one's larger than average nose until the caricaturist exaggerates it. The exaggeration does not make the subsequent realisation that the nose is, indeed, rather on the large side any less true.
My quibbles with this sort of understanding of Scripture are manifold, but my two big theological objections are these:
1. This makes revelation textual, which is not easily assimilated to the picture of revelation which is actually given in the text of Scripture. It removes the backward question, the question of reference, from theological consideration. We must ask 'do historical events stand behind this testimony?' - if we do not, we are essentially saying that it is indifferent whether the events recorded in Scripture actually happened. (We can, after all, construct our systems of doctrine regardless of the answer to the question). If Christianity is about anything - if the Bible is about anything - it is about stuff that actually happened. There is, therefore, a gap between revelation in history and its record in Scripture. This should not be considered a threatening gap. If the witnesses are trustworthy - if their testimony is indeed authorised and guaranteed by God - then the gap is simply a recognition that there is an event and testimony to an event, and these things are two, not one, though they stand in the closest possible relation. We must not be trapped inside the Bible, but must allow the Bible to point beyond itself to the reality behind the text.
2. The doctrine I have described makes God's revelation of himself unproblematic. That is to say, it assumes that it is an easy thing for human beings to know God - just read the book, pick out the doctrines! But that, again, flies in the face of the Scriptural witness, which again and again insists that it is a hard thing for humans to know God - hard in particular for the omnipotent Deity!
Why are the gaps - the recognition that revelation, Scripture, and doctrine are far from identical - so threatening? Perhaps because we cannot conceive of a way in which non-identity and identity can be affirmed at once; which is not surprising, since with man this is impossible - but with God...