Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-09-19T21:05:56Z No. of bitstreams: 2 Barros, Toni Cézar P. F..pdf: 1070248 bytes, checksum: c077f85b2926645e0b58a66a7f389dd4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Cláudia Bueno (claudiamoura18@gmail.com) on 2014-09-28T02:24:15Z (GMT) No. of bitstreams: 2 Barros, Toni Cézar P. F..pdf: 1070248 bytes, checksum: c077f85b2926645e0b58a66a7f389dd4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-09-28T02:24:15Z (GMT). No. of bitstreams: 2 Barros, Toni Cézar P. F..pdf: 1070248 bytes, checksum: c077f85b2926645e0b58a66a7f389dd4 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-17 / There are two questions about deontic logic that appear frequently in the literature on the subject. The first concerns the legitimacy and the second the deontic paradoxes. The first of these, however, is not the main concern of this paper, we assume, alongside Castañeda the thesis that there are logical relationships, not only between propositions, but also among imperatives and norms. Thus, the main focus of this paper will be to investigate deontic paradoxes, and in particular, the Castañeda‟s solution. This solution involves a distinction between propositions and practitions as well as between imperatives and norms. We also show the advantage of this solution compared to other solution named scope deontic operator. Finally, we analyze Lou Goble‟s criticism to Castañeda‟s solution and objections to this criticism. / Há duas questões acerca da lógica deôntica que aparecem com frequência na literatura sobre o tema. A primeira diz respeito à sua legitimidade e a segunda aos paradoxos deônticos. A primeira destas, entretanto, não é a principal preocupação deste trabalho: assumiremos, ao lado de Castañeda, a tese que há relações lógicas, não somente entre proposições, mas também entre imperativos e entre normas. Assim, o foco principal deste texto consistirá em investigar o problema dos paradoxos deônticos e, em particular, a proposta de solução de Castañeda aos mesmos. Tal solução envolve a distinção entre proposições e practições, bem como entre imperativos e normas. Também mostraremos a vantagem desta solução em relação às outras, denominadas de soluções de escopo do operador deôntico. E, por fim, analisaremos a crítica de Lou Goble à solução de Castañeda e objeções a esta crítica.

In this thesis, the main focus is on deontic logic as a tool for formal representation of moral reasoning in natural language. The simple standard system of deontic logic (SDL), i.e. the minimal Kripkean modal logic extended with the deontic axiom, stating that necessity (interpreted as obligation) implies possibility (interpreted as permission), has often been considered inadequate for this aim, due to different problems, e.g. the so-called deontic paradoxes. A general survey of deontic logic and the problems with SDL is made in chapter 1. In chapter 2, a system denoted Classical Deontic-Modal logic (CDM1) is defined. In this system, there is a primary obligation operator indexed to sets of possible worlds, and a secondary requirement operator, defined in terms of strictly necessary conditions for fulfilling an obligation. This secondary operator has most of the properties of the necessity operator in SDL. In chapters 3 and 4, it is argued that CDM1 is able to handle the SDL problems presented in chapter 1 in an adequate way, and the treatment of these problems in CDM1 is also compared with their treatment in some other well-known deontic systems. In chapter 5, it is argued that even though the problems related to quantification in modal contexts are relevant to deontic logic, these issues are not specific to deontic logic. In chapter 6, the relations between some controversial features of moral reasoning, such as moral dilemmas and “non-standard” deontic categories like supererogation, and deontic logic are discussed. It is shown how CDM1 can be modified in order to accommodate these features.