ABSTRACTTaking its cue from Hannah Arendt’s comment that ‘truth gets lost in the Enlightenment’ and Lessing’s parable of God’s ‘left hand’, this paper traces a historical shift in moral and religious thought: roughly from truth to sincerity. From traditional conceptions of conscience as conditional on the objective truth of its content, the paper moves on, via the Reformation and seventeenth-century Augustinian turn, to early modern debates on toleration and the ‘erring conscience’. It is argued that Pierre Bayle’s Commentaire Philosophique of (...) 1686 can be read as a crucial catalogue for understanding the substitution of truth with sincerity : so that not truth but truthfulness is considered to be essential for moral and religious justification. Moving from Bayle to Immanuel Kant, the paper then shows how many of the same questions rise in Kant’s late essay on theodicy, which is also an essay on sincerity or integrity, via the Book of Job. Through these two thinkers, various themes are connected: from conscience and sincerity to the problem of the conscientious persecutor. Finally, these themes of truth, error and integrity are linked to the modern debate on authenticity, and a framework is proposed for conceptualising these various shifts. (shrink)