“ According to the materialist conception of history, the ultimately determining element in history is the production and reproduction of real life. Friedrich Engels
“ The sum of productive forces, capital funds and social forms of intercourse, which every individual and generation finds in existence as something given, is the real basis of what the philosophers hav… Karl Marx
“ In the social production of their existence, men inevitably enter into definite relations, which are independent of their will, namely relations of production appropriate to a given stage in the devel… Karl Marx