the world has opened up different dimensions of validity; to the extent that each dimension of validity has its own standards of truth and falsity and its own modes of justification for determining these, one may say that what has been opened up are dimensions of rationality" (Cooke, 1994). However, before the idea of communicative rationality can be described, the other direction of Habermas's formal pragmatic analyses of communication needs to be explained. This direction looks towards the idealized presuppositions of communication. Ideal presuppositions of communication When individuals pursue actions oriented towards reaching an understanding, the speech acts they exchange take on the weight of a mutually recognized validity. This means each actor involved in communication takes the other as accountable for what they have said, which implies that good reasons could be given by all to justify the validity of the understanding that is being achieved. Again, in most situations the redemption of validity claims is not an explicit undertaking (except in discourses, see below). Instead, each actor issues a "warranty" of accountability to the other, which only needs to be redeemed if certain validity claims are thrown into question. This suggests that the validity claims raised in every communicative interaction implicitly tie communication to argumentation. It is here that the idealized presuppositions of communication arise. Habermas claims that all forms of argumentation, even implicit and rudimentary ones, rest upon certain "idealizing suppositions," which are rooted in the very structures of action oriented towards understanding. These "strong idealizations" are always understood as at least approximately satisfied by participants in situations where argumentation (and communication) is thought to be taking place. Thus, when during communication it is discovered that the belief that these presuppositions are satisfied is not justified it is always taken as problematic. As a result, steps are usually taken to reestablish and maintain the belief that they are approximately satisfied, or communication is simply called off. The most basic of these idealized presuppositions is the presupposition that participants in communicative exchange are using the same linguistic expressions in the same way. This is an obvious but interesting point, which clearly illustrates what an idealized presupposition is. It is a presupposition because communication would not proceed if those involved did not think it was at least approximately satisfied (in this case that a shared language was being used). It is idealized because no matter how closely it is