An explanation of the functioning of the economy based on the theories of the philosopher Karl Marx (1818–1883). This includes the labour theory of value, and a theory of exploitation by which surplus value is appropriated by capitalists. The latter argument has been extended to cover exploitation of less developed countries by more developed countries. The theory predicts the rise of monopolies, the immiserization of the proletariat, an eventual breakdown in capitalist society due to under-consumption, and its replacement by a socialist economy. See also socialism.