Examining the rhetorical notion of ethos at the crossroads of disciplines, this article builds up an integrated model attempting to reconcile Bourdieu's theory of language and power with pragmatic views of illocutionary force. For the sociologist, the authority of the orator depends on his institutional position; for Ducrot or Maingueneau, drawing on Aristotle, the image of the orator is built by the discourse itself. Analyzing political as well as literary texts, this essay takes into account the institutional position of the speaker; his "prior ethos" (the image his audience has of him before he takes the floor); the distribution of roles inherent in the selected genre and the stereotypes attached to these roles; and the verbal strategies through which the speaker builds an image of self in his discourse. "Argumentative analysis" thus explores a dynamic process in which social, institutional, and linguistic elements are closely connected.