A first approximation to what I want to draw a distinction between is parts of a hypothesis that are correlated with the rest of the parts, and parts that aren't, so that and adding them decreases the probability of the hypothesis more. In the extreme case, if a part of a hypothesis is logically deduced from the other parts, then it's perfectly correlated and doesn't decrease the probability at all.
When we look at a hypothesis, (to simplify, assume that all the parts can be put into groups such that everything within a group has probability 1 conditioned on the other things in the group, and all groups are independent). Usually, we're going to pick something from each group and say, "These are the fundamentals of my hypothesis, everything else is derived from them". And see what we can predict when you put them together. For example, Maxwell's equations are a nice group of things that aren't really implied by each other, and together, you can make all kinds of interesting predictions by them. You don't want to penalize electromagnetics for complexity because of all the different forms of the equations you could derive from them. Only for the number of equations there are, and how complicated they are.
The choice within the groups is arbitrary. But pick a thing from each group, and if this is a hypothesis about all reality, then those things are the fundamental nature of reality if your hypothesis is true. Picking a different thing from each group is just naming the fundamental nature of reality differently.
This of course needs tweaking I don't know how to do for the general case. But...
If your theory is something like, "There are many universes, most of them not fine-tuned for life. Perhaps most that are fine-tuned for life don't have intelligent life. We have these equations and whatever that predict that. They also predict that some of that intelligent life is going to run simulations, and that the simulated people are going to be much more numerous than the 'real' ones, so we're probably the simulated ones, which means there are mind(s) who constructed our 'universe'." And you've worked out that that's what the equations and whatever predict. Then those equations are the fundamental nature of reality, not the simulation overlords, because simulation overlords follow from the equations, and you don't have to pay a conjunction penalty for every feature of the simulation overlords. Just for every feature of the equations and whatever.
You are allowed to get away with simulation overlords even if you don't know the exact equations that predict them, and if you haven't done all the work of making all the predictions with hardcore math, because simulation overlords have a bunch of plausible explanations, how you could derive them from something simple like that, because they are allowed to have causal history. They are allowed to not always have existed. So you can use the "lots of different universes, sometimes they give rise to intelligent life, selection effect on which ones we can observe" magic wand to get experiences of beings in simulations from universes with simple rules.
But Abrahamic and deistic gods are eternal. They have always been minds. Which makes that kind of complexity-reducing correlation impossible (or greatly reduces its strength) for hypotheses with them.
That's what I was trying to get at. If that's not what ontologically basic means, well, I don't think I have any more reason to learn what it means than other philosophical terms I don't know.
Abrahamic Gods are suppposed to be eternal, have minds and not be made of atoms, or other moving parts. That may be hard thing to sell, but complex gods are a mixture of natural and supernatural assumptions.
I am about to graduate from one of the only universities in the world that has a high concentration of high-caliber analytic philosophers who are theists. (Specifically, the University of Notre Dame, IN) So as not to miss this once-in-a-lifetime opportunity, I have sent out emails asking many of them if they would like to meet and discuss their theism with me. Several of them have responded already in the affirmative; fingers crossed for the rest. I'm really looking forward to this because these people are really smart, and have spent a lot of time thinking about this, so I expect them to have interesting and insightful things to say.
Do you have suggestions for questions I could ask them? My main question will of course be "Why do you believe in God?" and variants thereof, but it would be nice if I could say e.g. "How do you avoid the problem of X which is a major argument against theism?"
Questions I've already thought of:
1-Why do you believe in God?
2-What are the main arguments in favor of theism, in your opinion?
3-What about the problem of evil? What about objective morality: how do you make sense of it, and if you don't, then how do you justify God?
4-What about divine hiddenness? Why doesn't God make himself more easily known to us? For example, he could regularly send angels to deliver philosophical proofs on stone tablets to doubters.
5-How do you explain God's necessary existence? What about the "problem of many Gods," i.e. why can't people say the same thing about a slightly different version of God?
6-In what sense is God the fundamental entity, the uncaused cause, etc.? How do you square this with God's seeming complexity? (he is intelligent, after all) If minds are in fact simple, then how is that supposed to work?
I welcome more articulate reformulations of the above, as well as completely new ideas.