In this and the following chapter, I shall discuss Habermas' moral theory. However, since my aim is only to argue that his rationalistic argument for certain moral principles is invalid, I deliberately leave out many aspects of his theory. In fact, I intend to explain no more and no less of Habermas' so-called “discourse-ethics” than is needed to present his rationalistic argument and my criticism of it. Bluntly put, I think that one of Habermas' central arguments for his discourse ethics is rationalistic, though his discourse ethical approach itself is not. Consequently, my argument will not be directed at his discourse ethics as such but only at this rationalistic argument. In this chapter I present his discourse ethics and his rationalistic argument, and in chapter 9 my criticism of the latter.

THE BASIC IDEAS

Since discourse is one of Habermas' central concepts, I need to start by saying a few words about it. According to Habermas, if a practice is to count as discourse, then the participants in the practice must make certain pragmatic presuppositions (see 2.2): they must unavoidably presuppose that their interaction is (to a sufficient extent) regulated by certain conditions. We need to distinguish between two Habermasian ways of speaking about the presuppositions of discourse as unavoidable.