Peter Koller's lecture at the Holberg Prize Symposium 2007. The Symposium was in honor of Holberg Prize laureate 2007 Ronald Dworkin. Peter Koller is Professor of Legal and Social Philosophy at the University of Graz. The central emphasis of his research is problems of political theory, such as the analysis of political terms and ideas and the normative assessment of social institutions and relations, focusing in particular on questions of social justice, political freedom and social equality, democracy and international order. Also the continuing examination of themes in moral philosophy, in particular the establishment of moral standards and the question of moral behaviour in a morally defective social environment. Less