Idealism—it's a no-brainer
I am not a philosophical idealist, by which I mean that I do not believe that the only reality is mind/consciousness. But if the only alternative to idealism was materialism (the view that nothing exists but matter) then idealism wins hands down. It's a no-brainer! (Excuse the pun.)
After all, doubting the reality of consciousness is as close to impossible as anything gets. Of course, there are hard-core materialists that try very hard to do precisely this, but don't hold your breath! Success is as far from them as it ever has been and as far as it ever will be. Doubting the reality of matter, however, is a different kettle of fish. That is indeed possible. After all, we only have access to it via the mediation of consciousness.
Idealism can be imagined to be true (even if it is false) but while I suppose that one can possibly make sense of the claim "materialism is a possible state of affairs in an alternative universe," I am at a loss to understand how anyone can even imagine that believing "materialism is the truth about our world" is even possible. The very imagining of its truth is inexplicable in purely materialist terms and so if one can imagine that the proposition is true then the proposition must be false. Or so it seems to me.
After all, doubting the reality of consciousness is as close to impossible as anything gets. Of course, there are hard-core materialists that try very hard to do precisely this, but don't hold your breath! Success is as far from them as it ever has been and as far as it ever will be. Doubting the reality of matter, however, is a different kettle of fish. That is indeed possible. After all, we only have access to it via the mediation of consciousness.
Idealism can be imagined to be true (even if it is false) but while I suppose that one can possibly make sense of the claim "materialism is a possible state of affairs in an alternative universe," I am at a loss to understand how anyone can even imagine that believing "materialism is the truth about our world" is even possible. The very imagining of its truth is inexplicable in purely materialist terms and so if one can imagine that the proposition is true then the proposition must be false. Or so it seems to me.
Comments
The idea of person, mind, love, etc. ever arising from non-person seems to me a much greater leap to make than to see person as a continuation, emanating from eternal transcendent Person, Love.
It's really quite breathtaking to contemplate that each of us is a fragment that came from Person, our own little bits of person being on journeys of becoming and returning to the Source. :). The alternative of nihilism just depresses me to no end.
Besides theists and naturalists/materialists, Lewis mentions the third possibility of dualists, who see Person and non-person/material having always just coexisted, neither coming from the other. Have you ever come across real, live Dualists? Seems like they must be a rare breed?
C. S. Lewis is thinking along precisely these lines. It's an age-old and classic criticism of materialism.
Dualism is a term that can cover a range of different views. Cartesian dualism is one of them and it is certainly an alternative to idealism and materialism in that is seems both mind and matter as having reality as as being irreducible to each other. This view is also riddled with problems.
Perhaps we need to rethink matter.
Some kind of God-creation dualism is essential for Christianity, as you say. We have to be very careful how we spell that out as dragons lurk close by various ways of doing it.
You sound like you'd enjoy John Scottus Eriugena, a ninth century Christian chappy. We have an excellent book on his Christology coming out and that discusses his doctrine of creation at length. It will be called "A Celtic Christology" (Eriugena was Irish). Your thoughts are not unlike his.
Am very interested in learning more about the whole Celtic Church history, in general. (I've kind of got off onto odd tangents in some books recently on the legends of Christ and Joseph of Arimathea having been in Britain at various points -- wonder if there's any kernel of truth to all those stories about Cornwall, Somerset, Glastonbury...but that's a whole other rabbit trail. :) )