In response to what Jeff was asking let me make some clarification of my views.
To me, naturalism is not a transparent idea by any stretch of the imagination. What is it that makes something "natural?" I could say that I was a naturalist, but that my naturalism includes a lot of things most naturalists don't believe in, such as a psychons (which used to be called souls), angelons (which used to be called angels, and one triune theon, who used to be called God. The guy that directed my doctoral dissertation once came up with the idea that the "physical" or " is just what scientific theory quantifies over, some scientific theories quantify over God, therefore that would make God physical, (and therefore natural).
Is location in space and time sufficient to make something natural or physical? Well, I think it likely that the soul has a location, so does that make the soul physical? Or maybe the soul is some different kind of physical particle that science hasn't discovered yet. Surely science hasn't found everything, so we can't say that all that exists is what science has found already.
My concept of what is required for naturalism is as follows:
1. The base level, whether we call it natural, material, or physical, is causally closed.
2. Everything above that level supervenes on the physical/material/natural.
3. Physics is mechanistic. The base level lacks intentionality, purpose, normativity, and subjectivity.
An interesting question is whether Thomas Nagel comes out as a naturalist on this model. He's not a theist, be he does want to put the mental on the ground floor of reality, so he wouldn't qualify on my view. But he's an atheist. (A real one). I would recommend J. P. Moreland's response in Philosophia Christi to Mind and Cosmos.