This book is a defence of the philosophy of common sense broadly in the spirit of Thomas Reid and G.E. Moore. It breaks new ground by drawing on the work of Aristotle, contemporary evolutionary biology and psychology, and historical studies on the origins of early modern philosophy. Part One offers new answers to the questions: What counts as a common sense belief? Why should common sense beliefs be considered default positions?, and Why is it that philosophers so frequently end up denying what we all know to be true? Part Two defends common sense beliefs from specific challenges from prominent philosophers on topics from metaphysics to ethics.