The extent to which law can actually guide behavior by providing its subjects with reasons to act was questioned by a highly influential group of jurists in the first half of the 20th century, the so-called school of legal realism. American legal realists have argued that our ability to predict the outcome of legal cases based on legal norms is rather limited. In the most difficult cases, which are usually decided by the courts of appeal, the legislation itself is radically uncertain as to the outcome of the cases. Legal realists believed that lawyers interested in the predictive question of what the courts will actually decide in difficult cases need to conduct sociological and psychological research to develop theoretical tools that allow us to predict legal outcomes. Thus, legal realism was primarily an attempt to introduce the social sciences into the field of jurisprudence for predictive purposes. The extent to which this scientific project has been successful is controversial. In any case, legal realism has paid very little attention to the question of the normativity of law, that is, to the question of how the law guides behavior in cases where it seems sufficiently precise. A second, hotly debated question about jurisprudential methodology is whether first-rate legal theories are inherently evaluative. The above views on the correct purpose of first-order legal theories have different implications for this second question. But before explaining this, we must first clarify the issue. In view of the above-mentioned doubts about conceptual analysis, several views have been suggested that first-order legal theories are primarily about describing and explaining the nature of the right itself, and not any concept of it. Reductionist and naturalist views fall into this category. (As mentioned below, such views should not entirely avoid the salon methods just described, but to the extent that these methods remain feasible, a very different explanation of their defensability should be given.) Hobbes` criticism of secular custom was that it was not always recognizable by a community and that what claimed to be the basis of law could be seriously challenged.
Therefore, he was not authoritarian and offered no reason for his subjects to act. Coca-Cola`s suggestion that knowledge of the law had the precondition of “artificial reason” was rejected by Hobbes. He argued that if the law depended on jurists as mediators between the king or queen and their subjects, the law would not be sufficient to inform the actions of the people. In chapters 5 and 6, Postema, again benevolently, discusses the views of a later generation of realist-influenced theorists under the rubrics of “law and economics” and “critical jurisprudence,” but again finds no real innovation in philosophical legal theory. With regard to “commercial jurisprudence”, Postema pays the greatest attention to the views of American judge Richard Posner, by far the most prolific contributor to this literature; but Postema finally finds in it a crude pragmatism combined with a fairly common form of legal realism (cf. “Posner`s confusion”, 210 n17). Postema`s discussion of “critical jurisprudence,” which includes both the views of “critical legal studies” and feminist writers, is more interesting and persuasive, but ultimately leads to little progress beyond orthodox notions of the nature of law.258 For example, while the ideas that “the law is masculine” or “the law governs in a masculine way” may be considered metaphysical theses, in feminist literature they turn out to be expressions that refer to how the law has been misused, rather than what it essentially is. Nevertheless, Postéma`s discussion here is valuable in itself, as it provides one of the clearest and most sympathetic philosophical presentations I have come across on feminist critique of the long-standing ideal of objectivity in law as a means of gender oppression (240-256), developed by Catherine MacKinnon and others since the 1980s. The main conclusion of legal positivism, namely that the conditions of legal validity are determined by social facts, involves two distinct affirmations called 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` idea that law is essentially an instrument of political sovereignty, and they argued that the fundamental source of legal validity lies in the facts that constitute political sovereignty.
The law, they thought, is fundamentally the command of the sovereign. Later, legal positivists modified this view, arguing that social rules, not facts about sovereignty, are the foundations of law.