Communism is a sociopolitical movement that aims for a classless society structured upon communal ownership of the means of production and the end of wage labour and private property. The exact definition of communism varies and it is commonly used interchangeably with socialism, however, communist theory contends that socialism is just a transitional stage on the way to communism. A variety of different forms of communism have developed, each based upon the ideas of different political theorists, usually as additions or interpretations of various forms of Marxism, the collective philosophies of Karl Marx. Marxism-Leninism is the synthesis of Vladimir Lenin's contributions to Marxism, such as how a revolutionary party should be organised; Trotskyism is Leon Trotsky's conception of Marxism and Maoism is Mao Tse Tung's interpretation of Marxism to suit the conditions of China at that time. Communist theory generally states that the only way to solve the problems existing within capitalism is for the working class, referred to as the proletariat, who is the main producer of wealth in society and is exploited by the capitalist class, as explained in theories such as surplus value, to replace the bourgeoisie as the ruling class to establish a society without class divisions, called socialism, as a prelude to attempting to achieve the final stage of communism. Pure communism, or the stage in history after socialism, refers to a classless, stateless society, one where decisions on what to produce and what policies to pursue are made in the best interests of the collective society with the interests of every member of society given equal weight in the practical decision-making process in both the political and economic spheres of life. Karl Marx, as well as some other communist philosophers, purposely never provided a detailed description as to how communism would function as a social system. In the communist manifesto, Marx lays out a 10-point plan advising the redistribution of land and production to achieve his social ideals. However, Marx fervently denies that this plan is to be carried out by any specific group or "class". According to Marx, communal ownership of the means of production and the end of wage labour inevitably arises due to contradictions and class conflicts existing in capitalism, and the communists are merely professors who help frame struggles in terms of class struggle. In this way, communism avoids the contradiction of creating a new class to replace the old one. The origins of communism are debatable, and there are various historical groups, as well as theorists, whose beliefs have been subsequently described as communist. Some theorists have considered hunter-gatherer societies to adhere to a form of primitive communism, whilst historical figures like Plato and Thomas More have been described as espousing early forms of the ideology. The communist movement as it is known today largely took shape in the nineteenth century, when it was developed. In the twentieth century, revolutions led to openly communist governments taking power in many countries, leading to the creation of states like the Soviet Union, the People's Republic of China and the Republic of Cuba. In modern usage, communism is often used to refer to the policies of these governments, which were one party systems operating under centrally planned economies and a state ownership of the means of production. Most of these governments based their ideology on Marxism-Leninism. These systems, sometimes referred to as state socialism are argued by many, including those on the left, that states never made an attempt to transition to a communist society, while others even argue that they never achieved socialism. In the 20th and 21st centuries democratic elections led to communist, and communist inspired, governments being elected in other parts of the world such as in Chile and Venezuela. Today, although communism is a less influential political force compared to what it was in much of the twentieth century, there are still powerful communist and aligned socialist movements in many parts of the world, especially southern Asia and South America, and since the Economic crisis of 2008 there has been a resurgence of interest in communist theory, especially the theories of Karl Marx.