A Category Taken Up Across Religious Studies

Otto argued that the numinous could not be taught to someone who had never felt it directly, comparable in this respect to how color cannot be explained to someone who has never seen, which placed his account in some tension with purely rational or comparative approaches to religion that assume religious concepts can be fully analyzed and communicated through argument and definition alone. He nonetheless devoted much of the book to comparative discussion, tracing what he identified as expressions of the numinous across a range of traditions including Christianity, Judaism and various non-Western religions, presenting the category as cross-culturally recurrent even while insisting on its resistance to full rational explanation.

The Idea of the Holy became one of the most influential works in twentieth century religious studies, and Otto's terminology, especially the phrase mysterium tremendum and the broader concept of the numinous, entered standard scholarly vocabulary well beyond his own specific theological framework, taken up by historians of religion including Mircea Eliade, who developed related but distinct accounts of the sacred building in part on Otto's foundational distinction between the numinous and the merely rational or moral dimensions of religious life.