What changed at the turn of the century, and underwent an irremediable modification, was knowledge itself as an anterior and indivisible mode of being between the knowing subject and the object of knowledge; if there were those who began to study the cost of production, and if the ideal and primitive barter situation was no longer employed as a means of analysing the creation of value, it is because, at the archaeological level, exchange had been replaced as a fundamental figure in the space of knowledge by production, bringing into view on the one hand new knowable objects (such as capital) and prescribing, on the other, new concepts and new methods (such as the analysis of forms of production).