Modernity and postmodernity are concepts in sociological theory. Modernity refers to a period of history marked by structural differentiation, the Enlightenment, industrialization, and urbanization. Postmodernity is characterized by uncertainty, relativism, and individual freedom in a globalized and interconnected world. Some key thinkers who contributed theories on modernity include Durkheim, Marx, Weber, and Comte. Postmodern thinkers like Lyotard, Habermas, and Foucault analyzed concepts like metanarratives, hyper-reality, and the critique of totalizing theories.