Anarchism is the political philosophy which holds ruling classes and the state to be undesirable, unnecessary and harmful, or alternatively as opposing authority and hierarchical organization in the conduct of human relations. Anthropologist David Graeber has noted that while the major Marxist schools of thought always have founders (e.g. Leninism, Trotskyism and Maoism), schools of anarchism "almost invariably emerge from some kind of organizational principle or form of practice", citing anarcho-syndicalism, individualist anarchism and platformism as examples.