Implicit in Mary McCarthy's [Ideas and the Novel] is a historical thesis of the kind called "descendental." Novels used to be wonderful, intelligent things, back in the 19th century, partly because they were full of "explicit ideas"; but today's novel, without ideas, is poorer stuff altogether. There are some minor historical filigrees: Henry James is the turning point, for instance, and Thomas Mann is a 19th-century throwback. But mostly, for Mary McCarthy, the decline of the genre can be charted as a diagonal plunge, from the roman idée of Balzac and Hugo, down through to the dismal present, where the right proportion of idea to narrative is no longer even a dilemma for the novelist. Nowadays, all simply, "ideas are held not to belong in the novel; in the art of fiction we have progressed beyond such simplicities." This last is of course sarcastic. So wry is...