Abstract

I examine six proposed systems of deontic logic, focusing on two fundamental questions: What are the deontic words "obligatory", "forbidden", and "permitted" about?, and What are the correct forms of moral deliberation? In Chapters 1-6, I examine and criticize von Wright's claim that deontic words are about act-properties, Jaakko Hintikka's claim that they apply to act-individual/act-property complexes, von Wright's claim that they are about generic states of affairs, Peter Geach's position that deontic words are auxiliary verbs which saturate ordinary verbs, the result being a property of human agents, Hector-Neri Castaneda's position that they apply to practitions and von Wright's claim that a viable deontic logic must contain two sets of deontic operators, one set which applies to act-individuals and one set which applies to act-properties. With respect to forms of moral deliberation, I discuss Loewer and Belzer in Chapter 3, Castaneda in Chapter 5, and von Wright in Chapter 6. Finally, in Chapter 7, I construct prototypes of two programs which emulate, in different ways, real moral agents. On the basis of discussion in Chapters 1-6, I conclude that ought-modified practitions are the kinds of conclusions reached in moral deliberation, act-individual/act-property complexes play a major role as premises of moral arguments, and there are three strongly viable possibilities on which to base forms of moral deliberation: rules of deontic detachment , the postulate for genuine deontic detachment , and forms of moral deliberation extracted from the definitions of deontic concepts . The first program is implemented in PROLOG. Its deliberative mechanism is based on the integration of the postulate for genuine deontic detachment and the forms of moral deliberation extracted from the definitions of deontic concepts. The second program is implemented in Defeasible PROLOG, which is an enhancement of PROLOG, developed by Donald Nute. The deliberative mechanism of the second program is based on the rules of deontic detachment which, for the most part, are already contained in Defeasible PROLOG