“Families, authority, communities, and social ranks are the empirical-sociological concretization of the abstract philosophical-praxeological categories and concepts of property, production, exchange, and contract. Property and property relations do not exist apart from families and kinship relations.”

“Every change in the social order, every revolution in property relations, is the necessary consequence of the creation of new forces of production which no longer fit into the old property relations. Private property has not always existed. When, towards the end of the Middle Ages, there arose a new mode of production which could not be carried on under the then existing feudal and guild forms of property, this manufacture, which had outgrown the old property relations, created a new property form, private property. And for manufacture and the earliest stage of development of big industry, private property was the only possible property form; the social order based on it was the only possible social order.”

Friedrich Engels (1820–1895) German social scientist, author, political theorist, and philosopher

“As long as Property exists, it will accumulate in Individuals and Families. As long as Marriage exists, Knowledge, Property and Influence will accumulate in Families.”

John Adams (1735–1826) 2nd President of the United States

“What will be the influence of communist society on the family? It will transform the relations between the sexes into a purely private matter which concerns only the persons involved and into which society has no occasion to intervene. It can do this since it does away with private property and educates children on a communal basis, and in this way removes the two bases of traditional marriage – the dependence rooted in private property, of the women on the man, and of the children on the parents.”

Friedrich Engels (1820–1895) German social scientist, author, political theorist, and philosopher

“Thus, though the Fascist conception of property refused to countenance collective possession as such, individual ownership rights were understood to be strictly subordinate to collective discipline. It was not the individual ownership of property that concerned Fascists, but it subordination to collective control. Property was understood to perform social functions rather than to manifest individual rights. It was clear that the conception of property as a social function was broad enough to include socialization of the means of production, should that be required by the national interests as interpreted by the state.”

A. James Gregor (1929–2019) American political scientist

“Carnap calls such concepts as point, straight line, etc., which are given by implicit definitions, improper concepts. Their peculiarity rests on the fact that they do not characterize a thing by its properties, but by its relation to other things. Consider for example the concept of the last car of a train. Whether or not a particular car falls under this description does not depend on its properties but on its position relative to other cars. We could therefore speak of relative concepts, but would have to extend the meaning of this term to apply not only to relations but also to the elements of the relations.”

Hans Reichenbach (1891–1953) American philosopher

“The entire revolutionary movement necessarily finds both its empirical and its theoretical basis in the movement of private property – more precisely, in that of the economy. This material, immediately perceptible private property is the material perceptible expression of estranged human life. Its movement – production and consumption – is the perceptible revelation of the movement of all production until now, i. e., the realisation or the reality of man. Religion, family, state, law, morality, science, art, etc., are only particular modes of production, and fall under its general law. The positive transcendence of private property as the appropriation of human life, is therefore the positive transcendence of all estrangement – that is to say, the return of man from religion, family, state, etc., to his human, i. e., social, existence. Religious estrangement as such occurs only in the realm of consciousness, of man’s inner life, but economic estrangement is that of real life; its transcendence therefore embraces both aspects. It is evident that the initial stage of the movement amongst the various peoples depends on whether the true recognised life of the people manifests itself more in consciousness or in the external world – is more ideal or real. Communism begins where atheism begins (Owen), but atheism is at the outset still far from being communism; indeed it is still for the most part an abstraction. The philanthropy of atheism is therefore at first only philosophical, abstract philanthropy, and that of communism is at once real and directly bent on action.”

Karl Marx book Economic and Philosophic Manuscripts of 1844

“The sole "property" of matter with whose recognition philosophical materialism is bound up is the property of being an objective reality, of existing outside the mind.”

Vladimir Lenin (1870–1924) Russian politician, led the October Revolution

“The slave frees himself when, of all the relations of private property, he abolishes only the relation of slavery and thereby becomes a proletarian; the proletarian can free himself only by abolishing private property in general.”

Friedrich Engels (1820–1895) German social scientist, author, political theorist, and philosopher

“Market exchange requires a combination of both state and customary institutions. For any developed system of commodity exchange there must be a legal system inscribing and protecting rights to individual or corporate property. There must be a body of contract law with criteria for distinguishing between voluntary and involuntary transfers of goods and services, and courts to adjudicate in such matters. However, the evolution of law is not simply a matter of legislative construction; a great deal of law grows out of custom and precedent. Property and contract law are not exceptions. Consequently, the existence of property and exchange is tied up with a number of legal and other institutions, e. g. government, political system, and common societal values.”

Geoffrey Hodgson (1946) British economist