Empiricism today implies the dispassionate scrutiny of facts. But Jessica Riskin finds that in the French Enlightenment, empiricism was intimately bound up with sensibility. In what she calls a 'sentimental empiricism', natural knowledge was taken to rest on a blend of experience and emotion. Riskin argues that sentimental empiricism brought together ideas and institutions, practices and politics. Recasting the Age of Reason by stressing its conjunction with the Age of Sensibility, Riskin offers an entirely new perspective on the development of modern science and the history of the Enlightenment.