The existence of God is a subject of debate in the philosophy of religion and popular culture. A wide variety of arguments for and against the existence of God can be categorized as metaphysical, logical, empirical, subjective or scientific. In philosophical terms, the question of the existence of God involves the disciplines of epistemology (the nature and scope of knowledge) and ontology (study of the nature of being, existence, or reality) and the theory of value (since some definitions of God include "perfection").