Contrary-to-Duty Scenarios, Deontic Dilemmas, and Transmission Principles

Contrary-to-Duty Obligations

We investigate under what conditions contrary-to-duty (CTD) structures lacking temporal and action elements can be given a coherent reading. We argue, contrary to some recent proposals, that CTD is not an instance of defeasible reasoning, and that methods of nonmonotonic logics are inadequate since they are unable to distinguish between defeasibility and violation of primary obligations. We pro...

Henry Prakken and Marek Sergot Dyadic Deontic Logic and Contrary-to-duty Obligations

One of the main issues in the discussion on standard deontic logic (SDL) is the representation of contrary-to-duty (CTD) obligations. A well-known example is Forrester’s (1984) paradox of the gentle murderer: it is forbidden to kill, but if one kills, one ought to kill gently. Intuitively, one would feel that these sentences are consistent, but in SDL no (obvious) consistent formalisation is av...

Normative Requirements and Contrary-to-Duty Obligations

A logic for deontic dilemmas

The possibility of deontic dilemmas poses a significant problem for deontic logic. Here I review some proposals to resolve this problem, and then offer a new account. This is a simple modification of standard deontic logic that enables the system to accommodate deontic dilemmas without inconsistency and without deontic explosion, while at the same time accounting for the range of genuinely vali...

Remedial Interchange, Contrary-to-Duty Obligation and Commutation

This paper discusses the relation between deontic logic and the study of conversational interactions. Special attention is given to the notion of remedial interchange as analysed by sociologists and linguistic pragmaticians. This notion is close to the one of contrary-to-duty (reparational) obligation, which deontic logicians have been studying in its own right. The present article also investi...