Friday, December 26, 2008

God and philosophers I: The Ontological Argument

When Laura Sizer and I teach History and Philosophy of Science & Religion, we use Thomas Aquinas' five ways of proving God's existence as the starting point of our conversation. It allows us to talk about cosmology and the First Cause arguments, evolution and the Design arguments, and it also allows us to discuss the problem of miracles. However, we usually skip the Ontological argument - even though it is really fun to think about. So here is an excellent article in Boston review that provides a nice primer for the Ontological argument and also the argument from design. If you have any remote interest in the philosophical underpinnings of these arguments, this will be an excellent place to start:

The traditional arguments for God’s existence are very much worth our attention, though, for at least three reasons: they are of great intrinsic interest; popular discussions of them often fail to pin down their defects; and one argument, the “design argument,” has had a new lease on life as the intellectual underpinning of the intelligent design movement.

Before turning to some of the arguments, who or what is God supposed to be? Zeus, Thor, Ganesh? Alternatively, the depersonalized Deus sive natura (God or nature) that got Spinoza excommunicated from Amsterdam’s Jewish congregation? The philosophical literature focuses on the God of the Abrahamic tradition: a person who is all-knowing, all-good, and all-powerful. Is there any reason to think that God, so conceived, exists?

Arguments for the existence of God are usually divided into those whose premises may be known from the armchair, and those whose premises are the result of experiment and observation. The best-known armchair argument is called (following Kant’s unhelpful terminology) the “ontological argument,” while the design argument (also called the “teleological argument”) is the main representative of empirical arguments. Let us start from the armchair.

Here is the full analysis of the Ontological Argument:

The ontological argument was first developed by the eleventh-century monk St. Anselm, who spent his formative years at Bec Abbey in Normandy and later became Archbishop of Canterbury. Anselm was a central figure in early scholasticism, which brought the logical and metaphysical apparatus of Aristotelianism to bear on the interpretation of Christian texts.

In chapter two of his Proslogion (“Address”), Anselm considers the Fool of Psalm 14, who “hath said in his heart: There is no God.” Anselm argues that the Fool’s position is self-undermining: the very act of denying that God exists shows that God does exist. It is as if the Fool were to say, very foolishly, “I am not speaking.”

God, Anselm says, is a perfect being, “a being than which nothing greater can be conceived.” We may assume that any ignorance or malice or feebleness detracts from greatness, so Anselm’s God is all-knowing, all-good, and all-powerful. Just for simplicity, let us also assume that there could be at most one perfect being, so Anselm’s God is unique. Anselm then draws a distinction between “existing in the mind” (or “in thought,” or “in the understanding”) and “existing in reality.” When a painter intends to paint a picture of, say, a dragon, the picture, and the dragon, exist in his mind but not in reality. When he has finished putting paint on canvas, the picture, but not the dragon, also exists in reality. Dragons—as opposed to pictures of dragons, or the word “dragon”—exist only in the mind. Conversely, there are many things that exist only in reality: a certain rock at the bottom of the Pacific, say, which no one has ever seen.

Having explained this distinction, Anselm observes that the Fool must admit that God exists in his mind, just as the Fool must admit that a dragon exists in the painter’s mind. Dragons, of course, exist only in the mind. The Fool will say the same of God. Anselm thinks the Fool can be hoisted by his own petard.

Here we come to the crucial step in Anselm’s argument. An entity that exists only in the mind, he thinks, is not as great—not so perfect—as one that exists in reality. I imagine a dry martini: unfortunately it exists only in my mind. You imagine a martini, shake the gin and vermouth, and add the olive: happily for you, the martini exists both in your mind and in reality. According to Anselm, the martini that exists only in the mind is less perfect than the martini that also exists in reality—and after a long day at the office, this can sound quite convincing. Similarly, a being that only exists in the Fool’s mind is not as perfect as one that also exists in reality. So if God exists only in the Fool’s mind, the Fool is not thinking of a perfect being, because a perfect being also exists in reality. Equivalently: if the Fool is thinking of a perfect being, then God exists in reality. The very existence of atheists, Anselm concludes, shows that “something than which greater cannot be conceived undoubtedly exists both in the mind and in reality.”

Still, the ontological argument may be an exception to the rule. A more urgent cause for concern was given by Gaunilo, an elderly monk at an abbey a few days ride from Bec. In his In Behalf of the Fool, Gaunilo considers an island than which no greater island can be conceived, “abundantly filled with inestimable riches.” (Dennett alludes obliquely to Gaunilo when he asks his reader to consider “the most perfect ice-cream sundae.”) Presumably an island that exists only in the mind is not as great as a similar island that also exists in reality. But then Anselm’s reasoning proceeds just as well, and we can conclude that a perfect island exists, which is absurd. We know a great deal about islands, and although some of them are undoubtedly very agreeable, improvement is always possible.

Gaunilo’s objection is that the argument proves too much; something must be wrong, but Gaunilo doesn’t tell us what. So what is wrong with it?

The first thing to note is that Anselm’s talk of “existing in reality” and “existing in the mind” is misleading. Possums exist in Australia and New Zealand, but not in Antarctica. If “existing in reality” were like “existing in Australia,” then there might be some other realm distinct from reality where things exist. But that’s wrong: if something exists anywhere at all, it exists “in reality,” because to exist in reality is simply to exist, period. Similarly, if “existing in the mind” were like “existing in New Zealand,” then if dragons exist in the mind then they must exist. But there are no such creatures—dragons do not exist. The observation that dragons exist in the mind but not in reality is, then, better stated as follows: people think of dragons, but dragons do not exist.

Let us return now to the assumption that Anselm tries to reduce to absurdity: that a perfect being exists only in the Fool’s mind. Unpacked, the assumption is this: (a) the Fool is thinking of a perfect being, and (b) no perfect being exists—that is, in a complete inventory of reality, we will not find a being than which nothing greater can be conceived.

So the crucial step in Anselm’s argument is this: if (b) is true, and no perfect being exists, then (a) must be false—the Fool is not thinking of a perfect being, because a perfect being has, among its other perfect-making properties or features, existence. Put the other way round: if (a) is true—if the Fool is genuinely thinking of a perfect being—then (b) must be false, and so God, the perfect being, exists.

Both Dawkins and Hitchens suggest that Kant uncovered Anselm’s mistake—and Kant certainly had an influential objection. In his Critique of Pure Reason he claims that “‘Being’ is evidently not a real predicate,” by which he means that existence is not a property or a feature of a thing. To say that dragons are green, or scaly, or ferocious, is to attribute certain properties or features to dragons. To say that dragons exist is not to attribute yet another property to them, it is simply to say that there are dragons. And if existence is not a property or feature of things, Anselm’s argument fails: a perfect being has all the perfections, including the properties of being all-good and all-knowing, but not including the property of existing, simply because there is no such property.

Kant is on to something here. If existence is a property of things, it is a rather peculiar one: you can find a blue marble, and also a non-blue marble (a red one, say), but you cannot find a nonexistent marble—a marble that lacks the property of existing. Of course, that does not mean Kant is right: a peculiar property is still a property. And in fact, according to many philosophers, Kant is wrong: existence is indeed a property, albeit a very undiscriminating one, because everything has it.

A better objection to Anselm’s argument is that he has conflated two readings of “The Fool is thinking of a perfect being.” Compare “J. R. R. Tolkien is thinking of a scaly existing dragon,” which can be read in two ways. On one reading, this sentence can be more perspicuously rendered as, “There is a scaly existing dragon, and Tolkien is thinking about it.” On that reading, the sentence is true only if at least one scaly dragon exists. But on the second, more natural reading, “Tolkien is thinking of a scaly existing dragon” can be true even if dragons do not exist. Let us ask the man himself: “Hey, Tolkien, what are you thinking about?” He replies: “I am thinking about a dragon.” “Oh, I see, you are thinking about an imaginary dragon.” “No, I am thinking about a real flesh-and-blood dragon.” Tolkien was not a postmodernist whose novels are populated with paradoxical, metaphysically insubstantial, nonexistent dragons—he wrote and thought about existing dragons. But for all that, dragons do not exist.

Now there is a similar ambiguity for “The Fool is thinking of a perfect being.” On one reading, it means, “There is a perfect being, and the Fool is thinking about it.” On the other reading, it simply characterizes the Fool’s thought: the Fool is thinking of a perfect being in the innocuous sense in which Tolkien is thinking of a scaly existing dragon.

Anselm is thus caught in dilemma. What is the intended reading of (a), “The Fool is thinking of a perfect being”? If it is “There is a perfect being, and the Fool is thinking about it,” then God’s existence immediately follows. However, Anselm has given us no reason at all to suppose that, on this reading, (a) is true, because he has not already shown us that there is a perfect being. On the alternative reading, where (a) is read as simply characterizing the Fool’s thought, we may grant that (a) is true, but it is perfectly consistent with a Godless universe.

There are other versions of the ontological argument, and the exact interpretation of the argument in chapter two of the Proslogion is a matter of dispute. Descartes offered an Anselm-inspired argument in his Meditations (it was this version that Kant criticized), and other variants can be found in Anselm’s own writings. These arguments have been subject to elaboration and repair at the hands of contemporary philosophers, Plantinga included. Graham Oppy’s Ontological Arguments and Belief in God is an exhaustive survey. However, although this work has produced much enlightenment about topics of interest to metaphysicians, it is pretty clear that a philosopher in search of God has to rise from the armchair.

Read the full article here. The followup post will be on the Design Argument.