Criticism or rejection of cosmopolitanism comes from many sources: from nationalism, ethnic loyalties, communitarian accounts of the sources of meaning, obligation and identity, and relativist rejections of universal morality; from accusations of Western hegemony in the name of universal values, and fears of (imposed) world government or "cosmopolis"; and from the insistence on the priority of national security in the face of a threatening world of terrorist threats, fundamentalist agendas, economic competition and environmental conflict. These sources of rejection will be examined and largely disarmed. Whilst some forms of opposition are simply mistaken, most rejections of cosmopolitanism stem from a failure to understand it in its most plausible form. Whilst some forms of cosmopolitanism are indeed to be questioned, such as dogmatic fundamentalisms, religious or political (including the dogmatic forms of neo-liberalism), we must not throw out the baby with the bathwater, but retain a flexible cosmopolitanism which is justified dialogically through cross-cultural dialogue as well as by individual intellectual reflection, combines a modest universalism with respect for diversity (within limits), favors multiple levels of governance, local, regional and global, and combines global solidarity and responsibility with other levels of particularistic solidarity and relationship in community.