Communism includes a variety of schools of thought, which broadly include Marxism and anarchism (anarcho-communism), as well as the political ideologies grouped around both. All of these share the analysis that the current order of society stems from its economic system, capitalism; that in this system there are two major social classes; that conflict between these two classes is the root of all problems in society; and that this situation will ultimately be resolved through a social revolution. The two classes are the working class—who must work to survive and who make up the majority within society—and the capitalist class—a minority who derives profit from employing the working class through private ownership of the means of production. The revolution will put the working class in power and in turn establish social ownership of the means of production, which according to this analysis is the primary element in the transformation of society towards communism. Critics of communism can be roughly divided into those concerning themselves with the practical aspects of 20th century communist states and those concerning themselves with communist principles and theory.
The term "communism" was first coined and defined in its modern definition by the French philosopher and writer Victor d'Hupay. In his 1777 book Projet de communauté philosophe, d'Hupay pushes the philosophy of the Enlightenment to principles which he lived up to during most of his life in his bastide of Fuveau (Provence). This book can be seen as the cornerstone of communist philosophy as d'Hupay defines this lifestyle as a "commune" and advises to "share all economic and material products between inhabitants of the commune, so that all may benefit from everybody's work".
According to Richard Pipes, the idea of a classless, egalitarian society first emerged in Ancient Greece. The 5th-century Mazdak movement in Persia (Iran) has been described as "communistic" for challenging the enormous privileges of the noble classes and the clergy, for criticizing the institution of private property and for striving to create an egalitarian society. At one time or another, various small communist communities existed, generally under the inspiration of Scripture. For example, in the medieval Christian church some monastic communities and religious orders shared their land and their other property (see religious and Christian communism).
Communist thought has also been traced back to the works of the 16th-century English writer Thomas More. In his treatise Utopia (1516), More portrayed a society based on common ownership of property, whose rulers administered it through the application of reason. In the 17th century, communist thought surfaced again in England, where a Puritan religious group known as the "Diggers" advocated the abolition of private ownership of land. In his 1895 Cromwell and Communism, Eduard Bernstein argued that several groups during the English Civil War (especially the Diggers) espoused clear communistic, agrarian ideals and that Oliver Cromwell's attitude towards these groups was at best ambivalent and often hostile. Criticism of the idea of private property continued into the Age of Enlightenment of the 18th century through such thinkers as Jean Jacques Rousseau in France. Later, following the upheaval of the French Revolution communism emerged as a political doctrine.
In the early 19th century, various social reformers founded communities based on common ownership. However, unlike many previous communist communities they replaced the religious emphasis with a rational and philanthropic basis. Notable among them were Robert Owen, who founded New Harmony in Indiana (1825), as well as Charles Fourier, whose followers organized other settlements in the United States such as Brook Farm (1841–1847).