 When we raise questions about the scope of justice, we are asking about when principles of justice take effect and among whom. We have already, when discussing Hume, encountered the idea that there might be circumstances in which justice becomes irrelevant – circumstances in which resources are so abundant that it is pointless to allocate individual shares, or, as Hume also believed, in which resources are so scarce that everyone is permitted to grab what he can in the name of self-preservation. But even in circumstances that are less extreme than these, questions about scope arise. Who can make claims of justice, and who might have the corresponding obligation to meet them? Does this depend on the kind of thing that is being claimed? If comparative principles are being applied, who should be counted as part of the comparison group? Do some principles of justice have universal scope – they apply whenever agent A acts towards recipient B, regardless of the relationship between them – while others are contextual in character, applying only within social or political relationships of a certain kind? The present section examines some of these questions in greater detail.