I think the following argument is sound, at least if the conditionals are material.
- (Premise for reductio) Naturalism is true.
- (Premise) If naturalism is true, nothing is numinous.
- (Premise) If naturalism is true, and F is a simple concept that someone has, then at least one individual's having the concept F is caused by something that falls under F.
- (Premise) The concept of the numinous is simple.
- (Premise) Someone has a concept of the numinous.
- If naturalism is true, there is something numinous. (3, 4)
- Naturalism is not true. (2, 5)
Perhaps, though, the naturalist will say that the numinous is something subjective and merely intramental, and thus deny 2. But:
- (Premise) There could be a numinous deity.
- (Premise) Necessarily, if a deity exists, it's not subjective.
- (Premise) If the numinous is subjective, it is always necessarily subjective.
- Therefore, the numinous can never be subjective.
- (Premise) If something is numinous, it is in some respect greater than us.
- (Premise) Nothing merely intramental is greater than us.
- Therefore, the numinous is not merely intramental.