Wikipedia: Ontological argument

Showing revision 9

The ontological argument for the existence of God was first proposed by the medieval philosopher [St. Anselm]?. Ontology as a philosophical subdiscipline is concerned with the nature of being. While Anselm himself did not propose an ontological system he was very much concerned with the nature of being. He argued that there are necessary beings -- things which can not not exist -- and contingent beings -- things that can not exist. The ontological argument for the existence of God in all of its interpretations and forms ends with a statement like "God exists and is a necessary being". A very colloquial version of Anselm's conclusion is "God can't not exist." This is obviously a controversial position, and the ontological argument has a long history of detractors and defenders.

In order to understand the place this argument has in the history of philosophy, it is important to understand the essence of the argument as Anselm first conceived it.

A key to understand the ontological argument is understanding the idea of "perfections."

There are various kinds of so-called perfections. Size, intelligence, beauty, power, benevolence, and so forth -- all these qualities are called perfections. And there are various degrees of these perfections. What is more intelligent is more perfect as regards intelligence; what is more beautiful is more perfect as regards beauty; and so forth.

Here's a short, and very general description of the ontological argument.

: Anselm, and many others, define God as the perfect being. This means that he has all the perfections to the greatest conceivable degree. Indeed it seems that all of the monotheistic religions make the claim that there is nothing greater than God.

: In fact, Anselm would say if someone were ever to conceive of some greater degree of perfection, than he or she previously conceived of, then they must regard God as having that greater degree of perfection.

: According to Anselm this proves that God exists, since claiming that God is only imaginary entails a logical contradiction. To see why this is so take a look at these two suppositions.

: 1) Someone has a concept of the greatest conceivable being, which they call God.
: 2) This concept of God as the greatest conceivable being exists only in his or her mind.

: St. Anselm says that these two suppositions contradict each other because for both 1 and 2 to be true, the following must also be true:

: A) It is possible to have an idea of the greatest conceivable being.
: B) And that this most perfect conceivable being is just imaginary.

: But in that case the idea of God is as a being that is only imaginary; so it is not a concept of the greatest conceivable being, because a being that actually exists is a greater being, more perfect, than a being that merely exists in only in the imagination. Existence is a perfection, just like power, beauty, and so forth. So, the concept of the greatest conceivable being, must be a concept of a being that actually exists. A being that didn't exist wouldn't be the greatest conceivable being.

: That means that the second supposition, that the concept of God exists only in our minds, contradicts the first supposition, that we have a concept of God.

: This leads to Anselm's conclusion that if someone has a concept of God, then God necessarily exists. Since, it is impossible to deny the first supposition, because lots of people do seem to have a concept of God as the most perfect being, the only solution is to throw out 2.

Of course, Anselm does not present the argument in this form, he presents it as a prayer directed to God. Obviously Anselm thought this argument was valid and persuasive, and it still has many defenders, but there have also been a number of people who claim that the ontological argument, at least as Anselm articulated it, does not stand up to strict logical scrutiny.

Some of those who've argued that the ontological argument fails are content to leave it at that, either because they don't believe that God exists, or because they believe the existence of God is demonstrated on other grounds. Others, like [Alvin Plantinga]?, Kurt Gödel, Gottfried Leibniz and Aquinas have reformulated the argument in order to create stronger versons of the argument.

I made a quick stab at cleaning up the above. The rest is still as Larry wrote it -- Mark Christensen.

I'm just going to focus in on a few objections to the argument. The basic trouble seems to be that we have, it appears, simply conceived God into existence. Surely it's very strange to think that all we have to do is to conceive of God as existing, and it follows from that alone that we have good reason to believe that God exists. But let's not jump the gun here; I'm going to present three traditional objections and then present another one of my own.

One traditional criticism of the argument is that existence is not a perfection, because existence is not a property. If existence were a property of items, including God, then it might be a perfection. But since it's not a property, it cannot be a perfection; only properties of things can be perfections of things. Now, we have previously encountered this notion, that existence is not a property, in our discussion of metaphysics. I rather doubt that this view is correct. There are better objections to be made, then, that do not depend on dubious presuppositions like this.

So a second traditional criticism is to say that, even if existence is a property, it is nonetheless still not a perfection. Either something exists or it doesn't; there aren't any degrees of existence. Something can't be more or less existent. So that's a reason to think that existence isn't a perfection. But to this St. Anselm might reply that, even granted that there aren't degrees of existence, surely existence is more perfect than nonexistence; and in any case, something that exists is greater than something that doesn't. That is certainly plausible. So let us look for more objections.

So here's a third, famous objection to the ontological argument, raised by Anselm's contemporary, Gaunilo. Gaunilo invited us to think of the greatest, or most perfect, conceivable island; I don't know what would make the island perfect, but say it's sunny, green, great beaches, skiing in the hills, who knows. No such island exists, right? But in that case we aren't thinking of the greatest conceivable island, because the greatest conceivable island would exist, as well as having all those other desirable properties. Since we can conceive of this greatest or most perfect conceivable island, then it must exist.

Of course, this is a silly argument. But, Gaunilo says, this argument no worse than Anselm's. In the same way, you could, if you wanted to, "prove" the existence of the most perfect hamburger, the most perfect dumpster, or the most perfect toilet. That's absurd! But Anselm's argument isn't any worse than these. So Anselm's argument isn't any good either.

See also:

Gödel's ontological proof

/Talk