That is to say, under the influence of productive work and its needs, men build their form of society, their State, their religion, their philosophy and science. The material production is the substructure or the groundwork, while the corresponding political, religious, and philosophical systems are the superstructure. And in such a manner that the superstructure corresponds to the foundation, lends it strength, and promotes its development. The foundation is material, and the superstructure is the psychical reflex and effect. In broad outlines this conception may be illustrated somewhat as follows: Primitive human groups lived under Communism and were organised according to blood relationship. Their deities have the characteristics of their natural environment, and reflect the physical effects of this environment upon the primitive mental life of the "savage"; their religion, their morality, and their laws promote the communal life and the tribal discipline. Feudal society is based on the possession of land by the nobles and on the industrial labour of the corporations of the towns. The inherited religious ideas are soon transformed in accordance with the dominant interests of these historical periods (primitive Christianity became a State religion); all religious, ethical, and philosophical ideas antagonistic to these interests were fought and persecuted. The middle-class society, which is based on personal property, is endeavouring to sweep away all vestiges of communal and corporation rights, to set free the individual, to mobilise labour and property, to abolish Feudalism and the old Church and monasterial institutions, and to put in their place the individual relation between man and God, or the personal conscience (the Reformation), introducing individual rights as well; it struggles against the independent sovereignty of the feudal domains, and labours for a united national territory, which will afford greater scope to trade and commerce; it supports Absolutism, so long as the latter is in conflict with the feudal lords; and when, afterwards, Absolutism is a hindrance to the development of middle-class society, this also is fought and a constitutional monarchy or a republic demanded. And all this takes place not because certain human intelligences, by reason of more intense thought, or enlightenment, or the call of a supernatural power, are primarily at work, but as a consequence of the influence of the material basis, of the economic foundation of society, upon the mind, which translates and transforms these external realities into religious, juridical, and philosophic conceptions: "It is not the consciousness of men which determines their existence, but, on the contrary, their social existence determines their consciousness."--(Marx, Preface to "Critique of Political Economy.")