Ontological Arguments for the Existence of God: Overview

Greetings,

With the topic of Monday's meeting turning to ontological arguments for the existence of God, I though it would be helpful to provide a little bit of background and explain what is meant by such arguments. I'll number the things I say in case people want to address or take issue with specific parts. As always, if I got something wrong, please let me know.

What Is an Ontological Argument for God's Existence?
1. Such arguments seek to show one of two things: either that God necessarily exists, or it is impossible that God does not exist (which is slightly different, but often sufficient to establish that God exists).
2. "Ontology" refers to "being" or "existence". Such arguments do not necessarily need to show that one knows God exists or believes in God; this is an "Ontological" argument, not an "Epistemological" argument.
3. Ontological arguments are, when argued correctly, deductively valid. This means that, in all possible outcomes, if the premises are true, then the conclusion (the existence of God) is necessarily true. There is no possible way that the premises could all be true at the same time and yet the conclusion be false. Thus, to attack an ontological argument you must deny one of the premises. Part of the goal is to make the premises as noncontroversial as possible, which strengthens the argument.

What Are Some Historical Examples of Ontological Arguments?*
1. Dr. Papazian has actually done what I believe is some fairly novel research on Diogenes of Babylon's ontological argument. This is not typically considered the earliest ontological argument, and I know relatively little about it, but it certainly deserves mentioning. If Dr. Papazian wants to share a bit, I'll certainly edit this point.
2. The earliest commonly-accepted ontological argument was given by St. Anselm in Proslogion. His argument was one of "reductio ad absurdum"-- that is, one would derive a contradiction if God does not exist; thus, God exists.
3. Descartes took the next major leap forward; I believe that he put forward three ontological arguments in his Meditations on First Philosophy. It's been awhile, but I'm fairly certain that he did not argue that it is is impossible that God not exist; he actually argued for the "positive" existence of God.
4. Leibniz thought that Descartes did a good job, but failed to show that the idea of a being with all possible perfections (i.e. God) was necessarily non-contradictory. He didn't establish any new ontological arguments, but he thought that he filled in a whole in Descartes' arguments.

And, after Leibniz, things go in all sorts of different directions.

Who Attacked Ontological Arguments?
1. Hume thought that he could negate the possibility of an ontological argument by asserting that a priori truths are necessarily trivial/analytic. As ontological arguments depend on a priori truths, they were therefore trivial and did not tell anything new about reality.
2. Kant had a particularly scathing critique of ontological arguments. He asserted that existence is not a predicate, not a "simple property" as Leibniz might have stated. I'm actually going to leave that alone for now-- to explain it would be another whole blog post. However, as far as I'm aware, his is the only objection to ontological arguments which is universally accepted to be problematic for ontological arguments by philosophers, even if it might be surmountable.

So, there you go. Interested? Shoot me (Zach Sherwin) an email and come to the meeting on Monday evening at a local restaurant! I can send you details, if you're interested. Lastly, if you want to read my own rendition of the ontological argument, check out my post here.

Have a great day!

*Please note that I am no expert on any philosophical subject, and do not claim any sort of authoritative knowledge. I wouldn't cite this post in a paper, if I were you. I'm sure that my posts are filled with minor errors and oversights. If there's anything blatant or particularly malicious in nature, let me know and I'll do my best to resolve it. Thanks!