The bestselling author of Seven Brief Lessons on Physics illuminates the nature of science through the revolutionary ideas of the Greek philosopher Anaximander. Over two millennia ago, the prescient insights of Anaximander paved the way for cosmology, physics, geography, meteorology, and biology, setting in motion a new way of seeing the world. His legacy includes the revolutionary ideas that the Earth floats in a void, that animals evolved, that the world can be understood in natural rather than supernatural terms, and that universal laws govern all phenomena. He introduced a new mode of rational thinking with an openness to uncertainty and the progress of knowledge.