As defined by Aristotle, rhetoric is "the faculty of observing in any given case the available means of persuasion" (Rhetoric I:2 rev. Oxford trans., 1355b:27-28). The inquiry on the means of persuasion is the very purpose of rhetoric since this discipline emerged from the needs of the citizens to win their cases in the new democratic institutions of ancient Greece (Kennedy, 1998, pp. 191-214). The problem, as Perelman and Obrechts-Tyteca (1958) put it, is that the force of an argument is not only uneasy to define (is it a normative or a descriptive concept?) but it also would be difficult to study since it depends both on the aim of the discussion and on the nature of the audience (pp. 610-617).
In the introduction of his Theory of Communicative Action, Habermas (1984) uses several times the concept of the "force of the better argument" (e.g., pp. 24, 25, 28, 36, 42). One might therefore expect Habermas's reflection on argumentation to be of great help for rhetoricians. However, as conceived by Habermas (1984), the "force of the better argument" refers not only to a rhetoric-free force but also to a force that can only exist in the absence of rhetoric. The aim of this paper is to reflect on this incompatibility between rhetoric and argumentation in the Habermasian approach.
A "CONSTRAINT-FREE FORCE"
Although Habermas does not clearly define the "force of the better argument", it is the only "force" he seems to tolerate in his ideal speech situation:
Participants in argumentation have to presuppose in general that the structure of their communication, by virtue of features that can be described in purely formal terms, excludes all force-whether it arises from within the process of reaching understanding itself or influences it from the outside-except the force of the better argument (and thus that it also excludes, on their part, all motives except that of a cooperative search for the truth). (Habermas, 1984, p. 25)
It seems that the idea of "the force of the better argument" relies on a dissociation between a "force" that is acceptable and a "force" that is not. Behind this dissociation lies the long lasting opposition between "convincing" and "persuading", that is, following Perelman & Olbrechts-Tyteca (1958, p. 36), between a force that would convince any rational being and a force that would only persuade a given audience in a given context. But for the force of conviction to exist, the communication should, in Habermas's view, be free from...