The paper introduces a new model of argumentation, the Mixed Game Model, that no longer separates rule-governed competence from actual performance but starts from human beings and their ability of competence-in-performance. Human beings are able to orientate themselves in ever-changing surroundings and to negotiate diverging views in argumentative action games. Argumentation is thus described as a mixed game played by human beings according to principles of probability. These principles include constitutive, regulative and executive principles. Constitutive Principles focus on the basic (...) components of the game, that is, action, dialogue, and coherence as the interplay of different communicative means. Regulative Principles mediate between correlated human abilities and interests. Executive Principles guide the sequencing of action according to cognitive strategies. The mixed game no longer rests on pre-established harmony but describes performance as a non-equilibrial process of negotiation that mediates between order and disorder and is based on the integration of various parameters such as rationality, reason, persuasion and emotion. How the model works is exemplified by an analysis of part of a debate in the European Parliament. (shrink)