A person is a being, such as a human, that has certain capacities or attributes constituting personhood, which in turn is defined differently by different authors in different disciplines, and by different cultures in different times and places. In addition to the question of personhood, of what makes a being count as a person to begin with, there are further questions about personal identity and self: both about what makes any particular person that particular person instead of another, and about what makes a person at one time the same person as he or she was or will be at another time despite any intervening changes. The common plural of "person", "people", is often used to refer to an entire nation or ethnic group (as in "a people"). The plural "persons" is often used in philosophical and legal writing.