By Alex Byrne
Boston Review, January/February 2009

Edited by Andy Ross

The four horsemen of atheism, Richard Dawkins, Daniel Dennett, Sam Harris, and Christopher Hitchens, have all published books sharply critical of belief in God. They all agree that belief in God is a kind of superstition.

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) the ontological argument, while the design argument (also called the teleological argument) is the main representative of empirical arguments.

The ontological argument was first developed by the eleventh-century monk St. Anselm, who argued that the very act of denying that God exists shows that God does exist. Anselm says God is a perfect being. An entity that exists only in the mind, he thinks, is not as perfect as one that 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."

The argument proves too much. Something must be wrong. Anselm's talk of "existing in reality" and "existing in the mind" is misleading. If something exists anywhere at all, it exists in reality, because to exist in reality is simply to exist, period. The observation that dragons exist in the mind but not in reality is better stated as follows: people think of dragons, but dragons do not exist.

Both Dawkins and Hitchens suggest that Kant uncovered Anselm's mistake. Kant claims that existence is not a property or a feature of a thing. To say that dragons exist is to say that there are dragons. A perfect being has all the perfections but not the property of existing, because there is no such property. But 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 claim to be thinking of a perfect being. On one reading, the claim asserts that there is a perfect being, and the thinker is thinking about it. Anselm has given us no reason to suppose that this reading is true, because he has not shown us that there is a perfect being. On the other reading, the claim simply characterizes the thinker's thought, which is consistent with a Godless universe. Anselm is thus caught in dilemma.

The design argument received one of its most careful and elaborate formulations from William Paley, an eighteenth-century English clergyman and philosopher. Paley contrasts two objects: a stone and a watch. The stone requires no explanation in terms of a designer. The watch is another matter, for on examination we perceive "that its several parts are framed and put together for a purpose." Paley thinks the watch must have had a maker, even if "we had never known an artist capable of making one." Paley then considers terrestrial flora and fauna and their intricate parts. How could such a complicated mechanism as the eye have arisen, he asks, if not by the action of a designer?

Unlike the ontological argument, the design argument is not supposed to prove God's existence. Rather, it is an inference to the best explanation. The inference can be overturned by more evidence. We now know that the best explanation of the apparent design of the eye is not "the hand of an artificer" but Darwinian evolution.

This reply hinges on the assumption that modern biology can explain all instances of apparent design. Here the biochemist Michael Behe argues that evolution by natural selection cannot explain what he calls irreducible complexity. According to Behe, a process of small step-by-step alterations of the sort found in natural selection is wildly unlikely to produce irreducibly complex systems. But the design argument fails even if Behe is right.

David Hume presented the key objections. The argument does not indicate anything about what the designer is like. Terrestrial biology might be the product of long trial and error. The designer could have died long ago. And we can hardly presume that there was exactly one designer. At best, the design argument shows that some designer or designers, whose motives, talents, and present whereabouts are all unknown, existed at some time.

Paley's strategy for dismissing no-design alternatives wholesale is to object to the specific evolutionary theories of his day. But Paley offers no argument for choosing the general hypothesis of an unknown designer or designers operating by unknown means over the general hypothesis of an unknown blind process operating by unknown means. Paley had no reason, other than the failure of his imagination, to dismiss the hypothesis of "causes without design."

Behe exactly recapitulates Paley's mistake. Behe asks whether an as-yet-undiscovered natural process would explain biochemical complexity and claims that "if there is such a process, no one has a clue how it would work." But intelligent design is in the same boat: if there is such a process, no one has a clue how it would work either.

The design argument has received attention recently as the fine-tuning argument. The universe is fine-tuned for life, and this fact needs an explanation. One explanation is that our universe is only one of many universes. If universes exist in boundless variety, each with a distinct set of basic physical laws, then the fact that the laws of our universe are apparently made for life would seem to be nothing to get excited about. This "multiverse hypothesis" is a "no-design" explanation of the data. Dawkins argues that the multiverse hypothesis should be preferred over the "God hypothesis" because the former is simpler. This is debatable.

Hume's objections apply equally well to the fine-tuning argument for the existence of God. The fine-tuning argument is silent on the number and attributes of any designers. And there is no reason to favor the design hypothesis over any other hypothesis. Hume compares the structure of the universe to structures found in mathematics: perhaps "the whole economy of the universe is conducted by a like necessity, though no human algebra can furnish a key."

Philosophy has come up empty.