This work mainly deals with a statement of Ferdinand de Saussure, describing language as « milieu intermédiaire » (which might be named in english : « intermediary mental space », in accordance to Fauconnier’s « mental space ») ; Saussure’s statement was only in spoken form, but fortunately transcribed by listeners of his lectures in Geneva. Freely inspired from Nietzsche‘s Genealogy of morals, this study means to enquire into the main XXth century linguistic schools (neo-grammarians, structuralism, generative grammar, fonctionalism, cognitive sciences as with Varela and Rosch), which should make it possible to elaborate a new orientation of this science (justifying the claim of a « fondation constitutive »). This research aims at thoroughly recasting the method through the screen of phenomenology (including recourse to the « Gestalt », of the same-named psychology). The « intermediary mental space » is to be seen as an eq! uivalent of the semantic fields, which had led me to survey – as an important part of my work - the studies of the precursors in this direction, Jost Trier and Els Oksaar, but through a critical approach of their work.
