Apologies for the delay...
Why does all this matter?
I guess there are two effects that I see. One is relational, the other epistemological, but they're very closely intertwined.
Relationally, it becomes very hard to take other human beings seriously. Reductionism becomes the best approach. We think we can analyse the behaviour of another in much the same way that we would analyse the behaviour of an animal. You hear people say things like "love is just a combination of hormones" - meaning, I think, initially, other people's experience of love. Conversation becomes farcical on this view. The fact that we do actually have conversations, and do actually fall in love, betrays that the ratio-empiricist view does not capture all our experiencs: there is a Thou out there behind the face of this human being. Thank God for inconsistency in this regard!
There is an alarming possibility here. Most recently I have heard several people deconstruct their own experience of love in the way demanded by ratio-empiricism. What is happening? I suspect that we are seeing the loss of the primacy of the subject. People are applying their reductionist understanding of the Other to themselves. I cannot believe that this really reflects their experience of being themselves; it is a stifling interpretive grid. Unable to view others as truly human, they come to view themselves as less than human as well. We truly do need other people to know ourselves at all.
Epistemologically, acquiring knowledge becomes all take and no give, or perhaps no receive. In a world where I am the only subject, all learning is by analysis and systematisation of what I experience around me. This seems to lead into the loss of a concept of testimony. Although philosophers acknowledge that testimony is one of the most basic and common speech acts, and although in actual fact we would all have to admit that the overwhelming majority of what we know has been learned through testimony, ratio-empiricism tends to distrust it. In the absence of a genuine other, what can testimony be?
This then has an effect on the way we approach texts, for example (there is at least one person reading this who knows that I am now trespassing on his area of expertise. I'll try not to leave dirty footprints). Is it not inevitable that a text becomes an object to be manipulated in any direction we see fit on this worldview? After all, we cannot be assured of the existence or significance of the author (and this is as true for a living - even a present - author as it is for a dead or absent one), so why should we not take a text in whatever way we choose? I wonder whether ratio-empiricism makes knowing inherently violent...
To this whole worldview, Christianity asks three questions:
1. Given the fact that your worldview cannot account for central human experiences, why should we follow it?
2. Given that all your arguments against Christianity are based on this worldview, why should we take them seriously?
3. Have you considered that ultimate reality might be personal?