One fundamental question, and perhaps fundamental divide, between many who are secular or would like to see “the secular” take root and those who, like myself, do not label themselves as such, is the natural/unnatural distinction. I do not mean by this one’s gut reaction to circumstances, such as, “eating food is natural” or “genocide is unnatural”. Rather, at root, there is a basic metaphysical contention here: what is the make-up of “what there is”. The main question, then, is whether there is a division of this “is”.
For the orthodox Christian (small “o” so as to be inclusive), there is indeed a division of the “is” and it is absolutely fundamental. It is so fundamental, in fact, that quite frankly Christianity would not be intelligible at all without it, and it informs every single aspect of the Christian’s life (whether in practice or in beliefs). That is, there is indeed a divide between the natural and the unnatural; but what could this be?
It is tempting to say that the divide we all argue over is the physical/non-physical divide. That is, whether we are all, deep down, monist materialists, monist idealists, or some form of dualist. Do we let in the “spooky” non-physical into our scope of reality? This, however, is not the fundamental divide. Regardless of whether one is any form of those three options there still remains the natural/unnatural question. Indeed, there are Christian materialists as well as idealists, and there are still great numbers of dualists out there (despite the best efforts of the Churchlands).
No, indeed, the fundamental divide is more basic than even this contention. It is the divide between the Cosmos, on the one hand, and God, on the other. For the orthodox Christian, reality is split into the created and the uncreated. It really does matter, for other purposes, whether the created order of reality is monistic or dualistic, but that is not the basic contention. The basic breakdown is between God and everything that is not God; God is the unnatural, the Supernatural, and all else is the natural. This, of course, clearly means that even such entities as angels and demons are natural (plain and simple, in the same way as you and I). Aliens, quarks, gravity, human minds, qualia, and skunks are all, fundamentally, natural. (It is an interesting question whether numbers, and the structure of mathematics, and certain universals are natural or supernatural, but that is for another post.)
One important point of this consideration, of course, is that what counts as natural (and this really should be a patently obvious point!) is not neatly divided up and sorted out by our current latest and greatest theory of physics. Why some persist in thinking that the boundary of physics is the boundary of the real is truly a mind-boggling phenomenon. Most of us ordinary folk still live (in our minds) in a Newtonian world, thinking that if some phenomenon cannot be explained by a push-pull mechanism it must be “unnatural” and hence not real. A smaller number live in the hypnotic world of quantum physics (which often enough is an unwitting excursion into the murky waters of metaphysics, a recent book by Stephen Hawking being an apt example). Regardless of where we find ourselves in respect to science, however, we should be able to recognise the basic point that even scientists must approach their work with theories, apply theories, and often construct theories, for example theories about what laws of nature are (many of which are, well, not always accurate or strictly speaking deducible from equations and experiments).
Much of the naturalist/supernaturalist debate that seems to be all the rage currently would go to the wayside if this basic Christian understanding were in fact understood. Not only would it benefit most Christians to become familiar with the notion of a cosmos (as opposed to a universe), it would help with discussions with our secular friends (this has been my experience).