In a recent paper, “How Facts Make Law” (Greenberg 2004; hereafter HFML), I launch an attack on a fundamental positivist doctrine. I argue that non-normative facts cannot themselves determine legal norms. In response, Ram Neta (2004) defends the view that non-normative social facts, such as practices, are sufficient to determine norms, including both moral and legal norms. Neta’s paper provides a useful opportunity to address a spelled-out version of this view, which in various forms is widely held in philosophy of law and other areas of philosophy.Neta’s leading idea is that descriptive facts – practices – can alone provide a full account of normativity. He first argues that, in all normative domains, descriptive facts in part determin...