In this groundbreaking book, Steven Forde argues that John Locke's devotion to modern science deeply shaped his moral and political philosophy. Beginning with an account of the classical approach to natural and moral philosophy, and of the medieval scholasticism that took these forward into early modernity, Forde explores why the modern scientific project of Francis Bacon, Pierre Gassendi, Robert Boyle and others required the rejection of the classical approach. Locke fully subscribed to this rejection, and took it upon himself to provide a foundation for a compatible morality and politics. Forde shows that Locke's theory of moral 'mixed modes' owes much to Pufendorf, and is tailored to accommodate science. The theory requires a divine legislator, which in turn makes natural law the foundation of morality, rather than individual natural right. Forde shows the ways that Locke's approach modified his individualism, and colored his philosophy of property, politics and education.