Kant pursued his inquiry into the links between reason and religion into his final years. His last major complete work is his extraordinary and in many ways disconcerting Religion within the Limits of Reason Alone. At first encounter there seems to be a great distance between this convoluted work, with its numerous discussions of Scripture and of Christian dogma, of ancient authors and of anthropology, of comparative religion and of church governance, its speculations on etymology and on ethical associations, and the abstract arguments that lie behind the Postulates of Practical Reason of the Critique of Practical Reason.

The publication of Religion within the Limits of Reason Alone got Kant into wearisome troubles with the anxious Prussian censors. At first consideration this is a surprising response to a work that seems more respectful of established faith than his numerous earlier writings on religion, which had brought him no trouble. Christian concerns and Christian Scriptures are in evidence throughout the book. It consists of four long linked essays, the first published in 1792 and the others in 1793. Each takes up an ancient and resonant thematisation of good and evil. The first discusses the common root of good and evil in human freedom; the second the conflict between good and evil; the third the victory of good over evil; and the last the life lived in service of the good. This sequence follows a traditional Christian articulation of human origins and destiny: original sin, temptation, conversion and ministry are moments of the encounter of the pilgrim soul with good and evil. This Christian tenor is sustained by numerous discussions of Christian scripture.

Yet Kant's underlying line of thought appears to question rather than to endorse much of Christian faith and tradition. His task, he asserts, is that of the philosophical theologian, who approaches religion within the limits of reason. This task, he insists, is quite different from that of the biblical theologian, who defends ecclesiastical faith by appealing to church authority to guide his reading of Scripture, and whose defence of faith does not appeal to reason. The discussions of Christian Scripture in Religion within the Limits of Reason Alone, however, are to be reasoned. Indeed, in the preface to the second edition Kant asserts that ‘reason can be found not only to be compatible with Scripture but also at one with it’ (R 6:13; 11).