Alex Byrne in the Boston Review on what supposed proofs philosophers have come up with over the centuries for the existence of a deity. The following was the most interesting to me:
Unlike the ontological argument, the design argument is not supposed to prove God’s existence. Rather, it is an “inference to the best explanation,” like the inference that there are mice in the kitchen because this hypothesis best explains the missing cheese. The hypothesis of a designer is one of many possible “scientific explanations” of Paley’s watch on the heath, and similarly of the eye. The frequent complaint that intelligent design is “not science” (as opposed to “bad science”) only succeeds in muddying the waters.
David Hume’s Dialogues Concerning Natural Religion (published posthumously in 1779) presented the key objections, more than twenty years before Natural Theology. Two of Hume’s objections are especially acute. First, if the argument works at all, its conclusion is much weaker than might have been hoped. The argument does not indicate anything about what the designer is like: whether it is benevolent or a suitable object of worship. Even the intelligence of the designer is up for grabs—terrestrial biology might be the product of long trial and error, with the designer’s many previous attempts “botched and bungled.” Or perhaps the designer is “a stupid mechanic,” who imitated other much cleverer designers who practiced their art in far-off galaxies. Further, the designer could have died long ago—the eye and such might have been “the production of old age and dotage in some superannuated deity.” And finally, since the design of something complicated is usually a collective endeavor—“A great number of men join in . . . framing a commonwealth,” for example—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. The proponent of the argument is at liberty afterwards “to fix every point of his theology, by the utmost license of fancy and hypothesis.” Perhaps life on Earth was designed over millions of years by successive committees of incompetent and thoroughly despicable space aliens, who are now fortunately all dead.