As far as Barthes’s works are concerned, “concepts must remain somewhat blurry”, as Claude Coste used to write. Trying to define these concepts usually proves a tricky task : their interactions with one another are unstable, under a pen which continuously modifies the scope of the words. This/these movement(s) will be studied here, based on two cases, as we encounter the inchoate dimension of Barthes’s works : first, that of language’s fascism ; then, that of the constellation of three concepts : mimesis, mathesis, and semiosis.