I think there’s a good case to be made for a necessary being (NB), driven by an argument from contingency. But what else can we say about the NB?
I think a lot about the nature of this NB, and have been oscillating between different conceptions. At one pole is a conception of a chaotic and indifferent mega-cosmos which contains every non-contradictory thing as an actual or latent part. Then, I consider incrementally “tamer” NB’s which are shaped by additional necessary features.
To start, it certainly seems plausible that a broad range of logical and mathematical truths are necessary. Perhaps all reality must contain some minimum degree of order, so it can be grasped by reason (although I don’t see why our local physical laws should be thought specifically necessary). Much more controversially, my study of the mind/body problem leads me to suspect all concrete existence is necessarily experiential or proto-experiential in character. And, going further on a limb, where there is experience, there is value: perhaps value and morals are somehow grounded in the nature of the necessary being.
But this project of “taming Chaos” gets increasingly problematic.
Coming at this from the other direction, most people who posit an NB are theists who believe in a personal God with various attributes who sometimes acts as an agent within the world. I don’t see right now how I’d ever get to this conception.
What seems most clear is that the NB must be the maximum instance of existence. Any more specific or idiosyncratic depiction of God runs the risk of being inconsistent with this. (I thought Mark Johnston, in his book Saving God, is good on this point, when he argues that if God is the “highest one”, any devotion to a more specific and hence lesser deity can be seen as idolatry.) This is where “divine simplicity” breaks down, too: the only arguably “simple” NB is the metaphysically maximal one.
Once you layer God with attributes which are derived from human properties, and most obviously if you make God an actor in an earthly drama (rather than him “in whom we live and move and have our being”), it seems clear you’re no longer talking about the NB.
Comments welcome -- this is difficult stuff!