  The main insight of legal positivism, that the conditions of legal validity are determined by social facts, involves two separate claims which have been labeled The Social Thesis and The Separation Thesis. The Social Thesis asserts that law is, profoundly, a social phenomenon, and that the conditions of legal validity consist of social—that is, non-normative—facts. Early legal positivists followed Hobbes’ insight that the law is, essentially, an instrument of political sovereignty, and they maintained that the basic source of legal validity resides in the facts constituting political sovereignty. Law, they thought, is basically the command of the sovereign. Later legal positivists have modified this view, maintaining that social rules, and not the facts about sovereignty, constitute the grounds of law. Most contemporary legal positivists share the view that there are rules of recognition, namely, social rules or conventions which determine certain facts or events that provide the ways for the creation, modification, and annulment of legal standards. These facts, such as an act of legislation or a judicial decision, are the sources of law conventionally identified as such in each and every modern legal system. One way of understanding the legal positivist position here is to see it as a form of reduction: legal positivism maintains, essentially, that legal validity is reducible to facts of a non-normative type, that is, facts about people’s conduct, beliefs and attitudes.