Ian McEwan's modern classic "Atonement" starts with a kind of Agatha Christie setup. There is a crowded manor; there are hidden agendas. Briony, the girl at the center of the events, believes that she sees a sexual assault. (What she really sees is just sex.) Because of class tensions, the wealthy people in the manor turn on an innocent young man. He is accused of a crime. The accusation ruins at least two lives. Suddenly, as in "To the Lighthouse," the camera pans out. We're in the midst of World War II--we move from one family's suffering to *cosmic* questions about suffering. The cosmic story does not diminish the domestic story. The two tales exist side by side. Something similar happens in "What We Can Know," McEwan's new novel. We're in a small drama; the year is sometime around 1999. Francis is a Philip Larkin-ish poet, a bully, a climate-change skeptic, a narcissist. He has written a poem--apparently in tribute to his wife Vivi...