A bold, visionary, and mind-bending exploration of how the geometry of chaos can explain our uncertain world—from weather and pandemics to quantum physics and free willCovering a breathtaking range of topics—from climate change to the foundations of quantum physics, from economic modelling to conflict prediction, from free will to consciousness and spirituality—The Primacy of Doubt takes us on a unique journey through the science of uncertainty. A key theme that unifies these seemingly unconnected topics is the geometry of chaos: the beautiful and profound fractal structures that lie at the heart of much of modern mathematics. Royal Society Research Professor Tim Palmer shows us how the geometry of chaos not only provides the means to predict the world around us, it suggests new insights.