The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

Science hunts for truths. There’s a haunting image in one of Zadie Smith’s essays that involves a cartoon of Charles Dickens surrounded by all the characters that he’s invented: tubby Mr. Pickwick in an ill-fitting waistcoat, adventurous David Copperfield in a top hat, bedraggled and innocent Little Nell. Smith is writing about authors—in particular, about the out-of-body, in-another-mind experience that a fiction writer feels when she fully inhabits the mind, body, and world of a character that she’s created. That familiarity, or intimacy, feels like a “truth.” “Dickens didn’t look worried or ashamed,” Smith writes of the cartoon. “Didn’t appear to suspect he might be schizophrenic or in some other way pathological. He had a name for his condition: novelist.” Imagine another character now, except surrounded by half-ghosts. Some of these “characters”—like type I interferon, the toll-like receptor, or the neutrophil—are mostly visible, except they exist in the half-light of visibility. We think we know and understand them, but we don’t, really. Some only cast shadows. Some are completely invisible. Some mislead us about their identities. And there are others around us whose presence we cannot even sense. We haven’t even met them, or named them, yet. I, too, have a name for this condition: scientist. We look, we create, we imagine—but find only incomplete explanations for phenomena, even phenomena we may have (partially) discovered through our own work. We cannot inhabit the...