HILLEL STEINER'S bookAn Essay on Rights1proposes and develops an intriguing suggestion: that we should approach the discussion of justice at “the elementary particle level”. “The elementary particles of justice” Steiner tells us “arerights”:Rights are the items which are created and parcelled out by justice principles. We learn something about justice by examining the formal or characteristic features of rights. These features constrain the possible content of justice principles in much the same sense as architectural precepts must be informed by the properties of the construction materials they orchestrate.2