In a sense, any positive legal system can be considered as a body of prescriptive statements. Prescriptive statements represent indications of models of conduct. They include most often the linguistic expression "ought" (or "ought not") which works as a link between the grammatical subject and the predicate of the relevant sentence. Accordingly, prescriptive statements have also been called "ought-statements." This name has been mainly adopted in order to contrast prescriptive statements with descriptive statements, which are accordingly called "is-statements."
Another label for prescriptive statements is "deontic statements" or "statements having a deontic quality." Deontic quality imports a conceptual reflexion or conceptualization of the oughtsign. Both in a general sense and in a specific legal sense, deontic quality constitutes a central concern of legal thought on its theoretically highest level. Inquiries according to different views and perspectives have been developed about this topic. Different approaches have been followed. There has been, on the one hand, a merely semantic approach in which the "ought" has been viewed as a special modality of reasoning. On the other hand, there has been an approach in which the legal ought has been referred to requirements of justice and needs of social life.
These approaches either have at times developed independently of each other or have evolved in interference with each other. In this field mutual independence and mutual uncontrolled interference are both to be regarded as negative states of affairs. A comprehensive and satisfactory approach is here possible only through a general view of jurisprudence, able to conciliate and harmonize its formal requirement with its ethical and social ones. Only a unitary and yet differentiated jurisprudential approach can in fact offer a ground for a historical understanding of the past multiform relevant literature and an adequate and up-to-date theoretical view, able to match these different and yet converging requirements.
"The Meaning and Role of Prescriptive and Descriptive Statements: Particularly in the Legal Universe of Discourse,"
Syracuse Journal of International Law and Commerce:
1, Article 12.
Available at: http://surface.syr.edu/jilc/vol3/iss1/12