Question

When a "unique" individual is always defining itself and being defined by the generalized social categories of the modern state (i.e. brother, sister, friend, etc.) this is known as the term

Answer 1

The term you're referring to is "social identity." Social identity encompasses how individuals define themselves and are defined by society based on various social categories, roles, and relationships, including those within the modern state, such as family roles (brother, sister), friendships (friend), and other social roles. It's about how an individual's identity is shaped by their affiliation with different social groups and categories.