Base and Productive Forces:

So we have to say that when we talk of ‘the base’, we are talking of a process and not a state. And we cannot ascribe to that process certain fixed properties for subsequent deduction to the variable processes of the superstructure. Most people who have wanted to make the ordinary proposition more reasonable have concentrated on refining the notion of superstructure. But I would say that each term of the proposition has to be revalued in a particular direction. We have to revalue ‘determination’ towards the setting of limits and the exertion of pressure, and away from a predicted, prefigured and controlled content. We have to revalue ‘superstructure’ towards a related range of cultural practices, and away from a reflected, reproduced or specifically dependent content. And, crucially, we have to revalue ‘the base’ away from the notion of a fixed economic or technological abstraction, and towards the specific activities of men in real social and economic relationships, containing fundamental contradictions and variations and therefore always in a state of dynamic process.

Raymond Williams, Base and Superstructure in Marxist Cultural Theory. 1973.