It is time to recommence 'hostilities' with Edward Ockham. (I do thank him for engaging my ideas.)
I lately made two claims. One is that existence entails completeness. The other is that completeness does not entail existence. In support of the second claim, I wrote:
Why can't there be complete nonexistent objects? Imagine the God of Leibniz, before the creation, contemplating an infinity of possible worlds, each of them determinate down to the last detail. None of them exists or is actual. But each of them is complete. One of them God calls 'Charley.' God says, Fiat Charley! And Charley exists. It is exactly the same world which 'before' was merely possible, only 'now' it is actual.
To this Edward responds:
I say: if the God of Leibniz is contemplating something, then there is something he is contemplating. And I say that if each of them is determinate down to the last detail, some things are equivalent to them. And if each of them is complete, at least one of them is complete. All of the consequents imply existential statements, and whatever follows from the consequent, follows from the antecedent. I may be wrong, but all of this looks like an elementary example of the quantifier shift fallacy. If it is possible that a unicorn exists, it does not follow that some unicorn is such that it possibly exists. 'Possibly Ex Fx' does not imply 'Ex possibly Fx'.
But doesn't our friend make a mistake in his very first sentence? He moves from
a. God is contemplating something
b. Something is such that God is contemplating it.
But in intentional contexts quantifier exportation fails. Ironically, Edward taxes me with a quantifier shift fallacy when he commits one himself!
Furthermore, Edward is insulting the divine omnipotence and omnsicience. For he is saying in effect that God cannot bring before his mind a completely determinate intentional object -- an object whose mode of existence is merely intentional -- without that object being actual. But surely God can do that: he can conceive of a world that is fully determinate but only possibly existent. Such a world enjoys esse intentionale only. It exists only as an accusative of the divine intellect. What then must be added to make it real or actual or existent? The theist can say that the divine will must come into play. God wills that one of the possible worlds enjoy, in addition to esse intentionale, esse reale as well. Let there be Charley!
(Other questions arise at this point which are off-topic, for example, why Charley over Barley? Why Charely over any other world? Must God have a reason? And what would it be? Would it be because Charley is the best of all possible worlds? Is there such a things as the BEST of all possible worlds? Why some world rather than no world? And so on.)
You don't have to believe in God to appreciate the point I am making. The point is that existence cannot be identified with completeness. Admittedly, everything that exists -- in the mode of esse reale of course -- is complete, but there is more to existence than completeness. The theological imagery is supposed to help you understand the ontological point. All I need for my argument is the conceivability of the God of Leibniz. If you can conceive such a God, then you can conceive the irreducibility of existence to completeness. And if so, you can grasp that completeness does not entail existence.
In the end the dispute may come down to a profound and irresolvable difference in intuitions. For some of us existence is a deep (thick) topic, for others it is superficial (thin). I say it is deep. Part of what that means is that it cannot be explicated in broadly logical terms: not in terms of indefinite identifiablity, or property-possession, or instantiation, or completeness, or anything else.