I think the contradiction is as follows:
In the first paragraph, the ruleset is distinct from the FC; the FC simply actualizes the ruleset. It makes the theoretical history an actual history. In the second paragraph, the ruleset is the FC. (If I could, I would strike out the part "or chooses one set of rules", since it muddies the issue, and makes the second appear more like the first).
So case 1: the FC actualizes the rules, but is distinct from them; in case 2, the FC is identified with the rules. To me that seems a contradiction.
> So this particular event, if it happened, would actually be in favor of a personal God! For lions, we can trace a history from big bang to earth to life to evolution to lions, everything consistently explained by emergence. Popping into existence would violate conservation laws for example and would make it more likely that a personal God is causing unicorns, not impersonal laws.
I don't know that this follows. Suppose the unicorn popped into existence (let's call this event E). There would be nothing to stop you saying that before time T1, the FC was unable to perform E; but at T1, it was able to do so. And you could say the same thing about conservation of energy, the consistency of emergence, etc etc. So the existence of events such as E would not imply a "willing" FC. You could equally well say that events such as E are, nonetheless, acting according to the FC's necessary actions.
Likewise, the fact that things behave in observably regular ways does not, of itself, imply that the FC is bound to act in a certain way. I would be wrong to use this as an argument in favour of the FC's freedom. Like if I were to say "we know God exists because things act in certain ways, and therefore we can see God is constantly willing them to do so", it would obviously be faulty. And similarly, if event E happened, it would be no argument in my favour.
So there is no connection between the regularity of the universe, and necessity on the FC's part.
So your position cannot arise from empirical considerations; and therefore the following statement, insofar as it claims to be empirical, is faulty:
> given the axioms of mathematics, 2+2=4 is true and not even God can change that. In the same way, as a naturalist, I'm saying that given the laws of our universe (whatever they are) and the initial conditions, lions exist and unicorns don't and even God cannot change that. I'll freely agree that the former is from logic and hence necessarily true. But the later is just from empirical observations.
There is a further problem, though. Let's grant your position that
> the axiomatic rules (physical laws + initial conditions) of our universe causes [lions'] existence from moment to moment.
Of all the possible rulesets that could exist, why this one and not another? (Or if multiverses exist, why this ruleset in our universe?) There are infinite (or at least very many) logical possibilities and therefore infinite or very many possible rulesets. Why this one? We agree that there is no logical necessity about the ruleset being what it is. For me, it's easy to say that God willed such a ruleset out of the infinite ones He could have willed. (To will something just is to bring about X instead of Y, where X contradicts Y, but where X and Y are both possibilities prior to the actualisation of one of them.) Since you have no recourse to willing, what is it about the FC that makes it be (or makes it actualise) one set of rules instead another? Why is it X rather than Y?
We agree that logic is prior to the existence of the universe, so any answer implying that logic doesn't apply here will not be accepted :-)
On that subject, do you think logic precedes the FC? I don't think your position allows logic to be 'downstream', so to speak, of the FC, so I think your argument implies this. But I want to hear your thoughts on this before continuing.
I had to write this in a hurry so hopefully I haven't missed something. Again, I haven't forgotten the talk of hydrogen and oxygen, hopefully will have time to return to it at some point :-)