Jonas Salk

On April 12, 1955, the announcement that Jonas Salk’s polio vaccine was safe and effective sent church bells ringing across America. Within a decade, polio cases in the United States dropped by over ninety-six percent. Salk became the most famous scientist in the world—and then did something stranger than accepting the fame. He began asking a question that had almost nothing to do with virology: now that the species has the power to alter its biological trajectory, does it have the wisdom to do it well? This question consumed the remaining four decades of his life, producing a philosophical framework that placed humanity at a pivot point between two fundamentally different modes of existence. He called them Epoch A and Epoch B—the long competitive phase of expansion and acquisition versus the unfamiliar cooperative phase that the S-curve of growth demands when it begins to bend. The tools of Epoch A, he argued, had become powerful enough