In The Philosophical Quarterly, ethicist Peter Singer reviews Ethics for a Broken World: Imagining Philosophy After Catastrophe: Tim Mulgan’s first clever idea was to ask how Western moral and political philosophy might look to people living fifty or a hundred years from now if, during the interim, the basic necessities for supporting life become much more difficult to obtain than they are now. Climate change is the obvious way in which this might happen. … Mulgan’s second clever idea was to present his answer to the question he had posed in the form of a series of transcripts of a class held in the broken world on the history of philosophy. …