Recently, Bengt Hansson presented a paper about dyadic deontic logic,2 criticizing some purely axiomatic systems of dyadic deontic logic and proposing three purely semantical systems of dyadic deontic logic which he confidently called dyadic standard systems of deontic logic (DSDL1–3). Here I shall discuss the third by far most interesting system DSDL3 which is operating with preference relations. First, I shall describe this semantical system (Sections 1.1–1.3). Then I shall give an axiomatic system (Section 1.4) which is proved to be (...) correct (Section 2) and complete (Section 3) with respect to Hansson's semantics. Finally, in face of these results Hansson's semantics will be discussed from a more intuitive standpoint. After emphasizing its intuitive attractiveness (Section 4.1) I will show that two objections often discussed in connection with preference relations do not apply to it (Section 4.2 and 4.3); more precisely, I will show that the connectedness condition for preference relations can be dropped and that, in a sense, it is not necessary to compare two possible worlds differing in infinitely many respects. (What exactly is meant by this, will become clear later on.) Yet there is a third objection to Hansson's semantics which points to a real intuitive inadequacy of DSDL3. A way of removing this inadequacy, which corresponds to Hansson's own intuitions as well as to familiar metaethical views, is suggested, but not technically realized (Section 4.4). In the last section (section 4.5) I shall briefly show that DSDL3 is decidable, as expected. (shrink)

This essay is arranged in three sections. In the first I consider interaction problems that can frustrate maximizers. My object here is to add to the kind of case discussed by Gauthier, another in which maximizers would not do well. In the next section I set out conditions under which ‘straight’ or ordinary maximizers could avoid their problems as surely and as easily as could Gauthier's ‘constrained’ maximizers. And in the last section I comment on the relative merits of straight (...) and ‘constrained’ maximization. Attention here is paid first to the suggestion that straight maximizers in view of their problems would choose not to be straight maximizers, would indeed choose to be ‘constrained’ maximizers, and that this shows that there is something wrong with straight maximization. Rejecting this inference, I turn in conclusion to the idea that it follows from the ‘incompleteness’ of straight maximization, from the fact that it is not always possible, that there is something wrong with it. This inference too is rejected. (shrink)