I’ve never really had a nice relationship with the ontological argument from Anselm. When I first heard of it, it seemed strange that existence would be greater than non-existence, so I pushed it aside. About 2 years later, I realised that existence could maybe be bootstrapped from other properties, like power. But by then I had come to realise the distinction between epistemology and ontology, and struggled to believe that this argument wasn’t confusing the two at some point. That’s where I’m at at the moment: existence-in-mind just doesn’t seem comparable to existence-in-reality in the way that’s needed for the argument to work. Maybe I’m wrong, but that’s where I’m at[1].

Many people talk about Anselm’s ontological argument as *the* ontological argument. But, like many theistic arguments (and arguments in general, I suppose), to call it *the* ontological argument is a bit misleading. There are a number of ontological arguments out there, and Anselm’s one is but one of them. Descartes had another ontological argument which Leibniz worked on a bit, and in the 20th century we’ve had modal ontological arguments coming from Norman Malcolm, Charles Hartshorne, and Alvin Plantinga. Another “class” of ontological arguments are the so-called “Gödelian” ontological arguments. Kurt Gödel, the famous mathematician of Gödel’s Incompleteness Theorems, developed his argument using the primitive idea of a “positive property”. The arguments that follow this approach, like Gödel’s before them, are developed as formal axiomatic system with a theorem at the end that says that there is a God-like being who exists. Jordan Sobel showed, in 1987, that Gödel’s axioms also imply that every true proposition is necessarily true. This argument from Sobel is called the “modal collapse argument”, and it shows that Gödel’s argument is unsound. However, since then, there have been a number of Gödelian ontological arguments which have been formulated so as not to fall prey to the modal collapse argument. These have come from Curtis Anderson, Allen Hazen, Robert Koons, and Petr Hajek, to name four. And, then there’s the recent “Modal Perfection Argument” from Robert Maydole.

Of prime importance to this blog post is yet another Gödelian ontological argument formulated by Alexander Pruss[2]. While I’m not convinced by Anselm’s, Descartes, and many of the other ontological arguments, this one does certainly seem plausible to me. I’ll sketch it briefly in this post.