Modernity and morality in Habermas's discourse ethics

Discourse ethics is originally conceived as a programme of philosophical ju stification of morality. This depends on the formal derivation of the moral principle (U) from non-moral principles. The moral theory is supposed to f all out of a pragmatic theory of meaning. The original programme plays a ce ntral role in Habermas's social theory: the moral theory, if true, provides good evidence for the more general theory of modernization. But neither Ha bermas nor his followers have succeeded in providing a formal derivation. T his essay shows how and why Habermas's proposed derivation is impossible. A s if aware of the lacuna, Habermas has recently suggested that (U) can be d erived by 'abduction' rather than deduction. The proposal draws heavily on modernization theory; hence the only justification for (U) now available to him rests on premises drawn from that theory. The original programme of th e justification of morality has thus given way to the weaker programme of t he philosophical elucidation of morality. Further, since Habermas's moral t heory is no longer justified independently of modernization theory, but at least partly by it, the moral theory cannot without circularity provide evi dence for the modernization theory.