Pluralism is defined as a society where multiple groups share political power, and it emphasizes diversity and liberty while critiquing monism and the concentration of state power. The document discusses the evolution of pluralism, particularly in the U.S. and the U.K., highlighting its historical roots, critiques from civil rights and anti-war movements, and the emergence of neo-pluralism, which views state power as fragmented. It also addresses contemporary developments in governance and civil society, with a focus on the importance of social movements and multiculturalism in understanding pluralist dynamics.