What is the fine-grained topic of the following text: A key debate revolves around the ethical sense of purity and impurity: how early and widely was this notion applied; how did it complement concrete ritual practices of purification and abstention; in other words, in a perspective of continuity and change, how were the inner/mental and outer/corporeal dimensions of purity harmonised ? Only return the topic.
The ethical sense of purity and impurity in early ritual practices.