One of the popular albeit controversial ideas in the last century of moral philosophy is that what we ought to do is explained by our reasons. And one of the central features of reasons that accounts for their popularity among normative theorists is that they can conflict. But I argue that the fact that reasons conflict actually also poses two closely related problems for this popular idea in moral philosophy. The first problem is a generalization of a problem in deontic (...) logic concerning the existence of conflicting obligations. The second problem arises from a tension between the fact that reasons can conflict and a model of how reasons explain ‘ought’s that has been widely accepted. Having presented each of these problems, I develop a unified solution to them that is informed by results in both ethics and deontic logic. An important implication of this solution is that we must distinguish between derivative and nonderivative reasons and revise our conception how it is that reasons explain ‘ought’s. (shrink)

In a recent paper, Sven Danielsson argued that the ‘original paradoxes' of deontic logic, in particular Ross's paradox and Prior's paradox of derived obligation, can be solved by restricting the modal inheritance rule. I argue that this does not solve the paradoxes.

It is argued that the distinction between the normative and the descriptive interpretation of norm sentences can be regarded as a distinction between two kinds of utterances. A norm or a directive has as its content a normative proposition. A normative utterance of a normative proposition in appropriate circumstances makes the proposition true, and an assertive utterance has as its truth-maker the norm system to which it refers. This account of norms, norm-contents, and utterances of norm sentences solves Jørgensen's problem: (...) logical relations among norms can be defined in the usual way in terms of the truth-conditions of the normative propositions which form their content. There is no distinction between the logic of norms and the logic of normative propositions; in this respect the present account differs from Carlos Alchourrón and Eugenio Bulygin's account of the logic of normative propositions. Se argumenta que la distinción entre la interpretación normativa y la descriptiva de las oraciones normativas puede ser considerada como una distinción entre dos tipos de emisiones. Una norma o directiva tiene como su contenido una proposición normativa. Una emisión normativa de una proposición normativa en circunstancias apropiadas hace verdadera la proposición y es el sistema de normas al que se refiere una emisión asertiva el que la hace verdadera. Esta concepción de normas, contenidos de normas y emisiones de oraciones normativas resuelve el problema de Jörgensen: las relaciones lógicas entre normas pueden ser definidas de manera usual en términos de las condiciones de verdad de las proposiciones normativas que forman su contenido. No hay diferencia alguna entre la lógica de normas y la lógica de proposiciones normativas; en este aspecto la presente concepción difiere de la concepción de la lógica de proposiciones normativas de Carlos Alchourrón y Eugenio Bulygin. (shrink)

In 1926, Ernst Mally proposed a number of deontic postulates. He added them as axioms to classical propositional logic. The resulting system was unsatisfactory because it had the consequence that A is the case if and only if it is obligatory that A. We present an intuitionistic reformulation of Mally’s deontic logic. We show that this system does not provide the just-mentioned objectionable theorem while most of the theorems that Mally considered acceptable are still derivable. The resulting system is unacceptable (...) as a deontic logic, but it does make sense as a lax logic in the modern sense of the word. (shrink)