Here we find a horizontal analysis of Michel Foucault's thought in what distinguishes it: the use of language. I refer to the conceptual framework, the specific terminology employed by this illustrious author as he seeks to give intelligibility to a critical stance that aims to investigate historical events in what they have as the most concrete: human action stripped of any universal a priori, inserted in its own context, in its specific moment: its contingency. This monograph reveals itself then as an effort to study the philosophy of ideas as proposed by Foucault, identifying in the specific instrumentalisation of concepts and in the analytical stance chosen to employ them the fundamental point from where the power of Foucauldian thought emanates for critical incursions into the present - something for which the study exercise carried out for the process that resulted in this monograph intends to serve as a basis.