Nicholas Wolterstorff discusses the ethics of belief which Locke developed in Book IV of his Essay Concerning Human Understanding, where Locke finally argued his overarching aim: how we ought to govern our belief, especially on matters of religion and morality. Wolterstorff shows that this concern was instigated by the collapse, in Locke’s day, of a once-unified moral and religious tradition in Europe into warring factions. His was thus a culturally and socially engaged epistemology. This view of Locke invites a new interpretation of the origins of modern philosophy. He maintained that instead of following tradition we ought to let ‘reason be our guide.’ Accordingly, after discussing Hume’s powerful attack on Locke’s recommended practice, Wolterstorff argues for Locke’s originality and emphasizes his contribution to the ‘modernity’ of post-sixteenth-century philosophy.