The Ontological Argument - valid or debunked?

[Neo-Scholastic]

Your still missing the point, Chad.  We can order things in terms of purity.  We can't order things in terms of greatness, except by subjective preference.

I think our difference is largely a semantic one that turns on the definition of greatness. As a fact the Pyramid of Giza is greater than Chartres Cathedral in terms of its size and mass whereas in my opinion Chartres Cathedral is the greater because it is more sublime.

....what the Scholastics have traditionally held to be the case is totally irrelevant.  That's just a weak argument from authority.

I believe you misunderstand why I made reference to the Scholastic Doctors. As a general rule I object when people substitute modern definitions for the traditional definitions on which various arguments rely. For example, the terms "substance" and "movement" had entirely different meanings to the Schoolmen than they do for me and you. If someone wants to critique a traditional Christian apologetic that does back to the Middle Ages, then it is right and proper that they use the same traditional definitions as those who presented the apologetic in the first place.

The same for "greatness". While I admit that I am unaware of any specific reference to greatness as a metaphysical attribute, I feel that the relevant references to greatness generally point back to the idea that a specimen is great to the extent that it participates in its genus. It is also important that from Aristotle to Aquinas in terms of usage goodness and being were essentially synonymous. So really, to say "Maximally Great Being" in a modern way would be "That which most Completely Exists."

As an aside, I personally find WLC annoying because he presents traditional arguments by wrapping them in modern modal logic. That is a recipe for confusion.