This article seeks to clarify Joseph Raz’s contention that the task of the legal theorist is to explain the nature of law, rather than the concept of law. For Raz, to explain the nature of law is to explain the necessary properties that constitute it, those which if absent law would cease to be what it is. The first issue arises regarding his ambiguous usage of the expression “necessary property”. Concurrently Raz affirms that the legal theorist has the following tasks: (...) (a) explain the essential properties of that which the concept of law refers to, which exists independently from any concept of law; (b) explain the essential properties of law given our concept of law. After trying to dissolve the ambiguity of Raz’s argument, I conclude that based on his methodological commitments the only possible task for a legal philosopher would be conceptual analysis, understood as the task of explaining our concept of law. (shrink)