“All reality is iconoclastic.” When C.S. Lewis—or ‘Jack’ as his friends called him—penned that line in 1961, he was writing about God’s proclivity for repeatedly smashing our inevitably half-baked notions about Him. But much the same can be said for what reality does to our own cultural icons as well. And, if nothing else, Lewis himself has become a cultural icon for many American evangelicals, identified by many as the 20th century’s Christian intellectual par excellence.

With his compelling personal story of becoming England’s “most reluctant convert,” his towering intellect, and his inimitable eloquence, American evangelicals’ lionization of Lewis is certainly understandable. But when we attempt to lionize people we often ironically end up...