Moral judgements have to be universalizable. There are many problems with this thesis (U). The problems to be dealt with here, are: (i) What is the connection between U and justifiablility? (ii) Is U a logical thesis? (iii) Is U analytically true? (iv) Is U adaquate? (v) Is utilitarianism a logical consequence of U?

According to some critics Carnap's philosophy is "reflectioness", i.e. without epistemic content. In contrast to this assertion this essay will show that in the writings of Carnap's semantical period, especially in "Empiricism, Semantics, and Ontology", the fundamentals of an epistemology are developed. It may be called linguistic internalism. The exposition of frameworks are interpreted as an epistemological foundation of semantics. Several problems within this project are discussed, e.g. the determination of domains of frameworks, ontological existence sentences, the relation between theories and frameworks and limits of rationality.

There is a plurality of good reasons for action. An adequate theory of practical rationality has to be compatible with it even if it requires certain modifications of our everyday practices of reasoning. Usual theories of practical rationality do not pass this test. It is envisaged how to revise adequately our understanding of practical rationality.