Final answer:
The concept where individuals accept moral and political obligations as societal members is the social contract, an unwritten agreement between citizens and the state.
Step-by-step explanation:
The belief that individuals must accept certain moral and political obligations as members of society is part of the philosophical concept known as the social contract. Philosophers like Hobbes, Locke, and Rousseau all discussed the idea of a social contract, which is the understanding that there is an unwritten agreement between the government and the people it governs. According to this theory, individuals consent to surrender certain freedoms and submit to the authority of the state in exchange for protection of their remaining rights, and the maintenance of social order.