What makes a ritual performance an instance of one ritual and not another? When we observe unfamiliar rituals, how do we know where one ends and the next begins? Is there a principled way of distinguishing mere preparations from the ritual proper? Can rituals change, and how do we know if they have changed? Current ritual studies methods give us no systematic means of answering such questions. Individuation is a familiar and fundamental concept in philosophy, and it should belong to the methodological toolbox of every student of ritual. This paper provides a solid introduction to some basic problems in ritual studies theory, illustrated by detailed examples from Episcopal liturgy and ritual in New Ireland (Papua New Guinea).