Lessons

by Ian McEwan

there was one little story, a celebrated thought experiment, well known even to those who had never heard of quantum mechanics. Schrödinger’s cat. A cat concealed in a steel chamber is either killed or not by a randomly activated device. The cat’s state is not known until the chamber is opened. In Schrödinger’s account it is both alive and dead until that moment. In the good outcome, at the reveal, a wave function collapses, the live cat jumps into the arms of its owner, while its other version continues as dead in a universe inaccessible to the owner or her cat. By extension, the world divides at every conceivable moment into an infinitude of invisible possibilities. The Multiple Worlds theory seemed to Roland no less improbable than Adam and Eve in the Garden of Eden. Both were powerful stories and he often summoned the cat when an uncertain matter was about to be resolved. A general election count, the gender of a baby, a football score. The cat came to him in his son’s form, that morning in bed when the phone rang and a policeman spoke. Lawrence was simultaneously in a police cell waking with a hangover, or on a brushed steel surface under a sheet, in a morgue. Two states, both real, in perfect equilibrium and he could no longer bear the policeman’s politeness—he was asking Roland to confirm his address. Whatever a wave function was, it was about to collapse, and he could do it himself. Heave it over the edge. “Where is he? What are you telling me?” “And postcode, if y...