A cosmopolitan ethic invites both an appreciation of the rich diversity of values, traditions and ways of life and a commitment to broad, universal principles of human rights that can secure the flourishing of that diversity. Despite the tension between universalism and particularism inherent in this outlook, it has received much recent attention in education. I focus here on one of the dilemmas to be faced in taking cosmopolitanism seriously, namely, the difficulty of judging what is just in the context of an increasingly divergent public—and classroom—discourse about values, rights and equality. I propose in what follows that judgement cannot rely on any script, even one as attractive, perhaps, as cosmopolitanism. To explore what is at stake in making judgements in an educational context, I draw on both Hannah Arendt’s and Emmanuel Levinas’s notions of judgement and thinking. The paper discusses the educational significance of thought and judgement as conditions for reframing the universalism–particularism problem found in a cosmopolitan ethic. My argument is that there is a world of difference between educating for cosmopolitanism, which entails a faith in principles, and ‘thinking cosmopolitan’, which entails a hope in justice for my neighbours.