Justice Catherine O'Regan, former judge to the South African Constitutional Court and chairperson of the United Nations Internal Justice Council, delivers the University of Edinburgh's 2014 Gifford Lecture. Courts in constitutional democracies face tough questions in developing a principled jurisprudence for the adjudication of claims based on faith. This lecture considers some of the recent jurisprudence from Europe, North America, India and South Africa and discuss key questions including whether it is possible to identify a principled basis for the adjudication of claims based on faith, whether cross-jurisdictional learning is possible and proper and whether different social, political and religious contexts should and do make a difference to answering these questions. This lecture was recorded on Monday 19 May, at the University of Edinburgh's St Cecilia's Hall.