Picking up from the post below about Knowing God, two questions probably do not challenge us on an everyday basis when we read the Bible, listen to a sermon or have a theological conversation over coffee. But every so often we should consider:
"(a) if 'reason' is impaired through sin, how can we make any claim to know the truth?
(b) how can Scripture be the only valid guide to doctrine when there are disagreements over its interpretation and the doctrines that are derived from it?"
One possible answer to both questions is that Christians are nuts. That is, a Christian claim to know God is irrational. There is something of a respectable history to that answer, running through the theologies of Kierkegaard and Barth (for instance but at risk of over simplifying the sophistication of their work), so that the Christian claim to know God is focused on God disclosing God to us, independent of any rational apprehension of God, and disagreements over interpretation are a fog created by trying to understand the Bible with our fallen minds. One difficulty with heading along such a line of reception of revelation is that it can work quite well among generally level-headed Christians and it can have disastrous effects among Christians prone to following a leader who turns out to be, well, nuts.
Actually, the answer I want to propose is arguably not deeply different from the above paragraph. If our reason is impaired then it needs repair. Reason can scarcely repair itself (since we would not know, in the nature of things, whether the repair was successful) so the repair needs to come from outside of ourselves and from a source capable of fixing it. In short, reason can be repaired by God and the mender is the Holy Spirit. (We could also use language of redemption: reason has fallen into slavery, serving sin but Christ has redeemed it for free service in the kingdom of light). Our claim to know the truth of God is a claim that our minds are able to be renewed by God working within us so that our reasoning faculty truthfully comprehends God - this is what is disclosed to us about the working of the Holy Spirit in Romans, notably and summarily in Romans 12:1-2. But this theological claim looks philosophically irrational as a foundation of knowledge comes from beyond reason. Fallen rationality plus gifted spirituality equals true knowledge.
In turn, this claim smacks against the second question above. If God has repaired our minds why do we not all think coherently and harmoniously, as, indeed, Paul urges in Philippians 2:1-5? Surely, on the analysis advanced here, continuing disagreements over the interpretation of Scripture are testimony to God's inability to completely heal our minds? Further, do such disputes not call into question the purity of divine revelation through Scripture. No one disputes clean water when all drink it. Disputes arise over brackish water. One claims it is salty, another that it is dirty.
That will do for today. More whenever I can come back to the matter.