Conflicting Obligations in Multi-agent Deontic Logic

Extending John Horty’s multi-agent deontic logic to moral reasoning with subjective utilities, we provide a language and semantics to study moral reasoning with sentences like ‘Group \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}${\ensuremath{\mathcal{G}}}$\end{document} of agents ought see to it that φ in the interest of group \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}${\ensuremath{\mathcal{F}}}$\end{document}’. We illustrate our deontic logic with a new formal analysis of the Prisoner’s Dilemma, thereby showing that games can be studied fruitfully with our deontic logic. Finally, we prove a characterization theorem on conflicting obligations.