Semantic Considerations about Deontic Logic, with Special Reference to Jurisprudence

Abstract

In this paper, Schmill begins by systematizing the different approaches that have been offered in order to formalize a certain set of concepts, namely, the normative concepts, Two main approaches are outlined by Schmill: the ‘reductionist’ and the ‘non-reductionist’ approaches. The ‘reductionists’ claim that deontic logic can be reduced to alethic modal logic (A.R. Anderson). Those adhering to the ‘non-reductionist’ approach claim that deontic logic is construed either by introducing the O- and P- operators ex novo into propositional logic or by adding a propositional constant ‘S’ (which may be interpreted as a sanction) and an axiom stating the possibility of the negation of ‘S’ ( Ms ) to alethic modal logic.

Schmill goes on to describe the semantics of the formal systems belonging to both the reductionist and non-reductionist approaches using Hintikka’s notions of model sets and model systems. He then offers an interpretation of the sentences belonging to the object language (the formulas of modal logic) as well as of those sentences belonging to the metalanguage (sentences which belong to the semantics of the formal system under consideration). The former sentences are considered part of Positive Jurisprudence, while the latter are supposed to constitute what has traditionally been called General, or Pure, Jurisprudence.

As has been seen, the interpretation of sentences of modal logic is, carried out by means of model sets. In his interpretation, however, Schmill considers the latter to be descriptions of norms belonging to some particular, undetermined legal system. As for the interpretation of the sentences of the metalanguage, that is, those sentences which state the membership relation between formulas of modal logic and model sets, Schmill considers the relation that holds between model sets as a dependence relation between the legal propositions which they represent. Hence, those conditions which determine the criteria of material consistency of the deontic content of the legal propositions dependent on a specific legal proposition are specified.

The analysis of the concepts of obligation, permission and prohibition has proven to be insufficient in Jurisprudence. Therefore, we have to enrich our analysis by introducing a new concept, that of a faculty (legal power). This concept has often been confused with that of permission or that of authorization. In order to avoid misunderstandings, Schmill defines the concept in the following way: a faculty refers to that content of legal norms which states the different spheres of the norm-creating acts. Therefore we are allowed to say that an individual has a faculty if and only if he is allowed to participate in the norm-creating process by disposition of a higher (legal) norm

Since, following Hans Kelsen, we can say that a behaviour is obligatory only if a legal norm attaches a coercive act, or sanction, to the opposite behaviour and that this norm exists only because it has been created by the exercise of a faculty, it seems clear that obligations, as well as permissions or prohibitions, may be considered products of the exercise of a faculty. Furthermore, we could also say that the exercise of a faculty may fall under the scope of any other deontic operator, that is, it could be obligatory, permitted or forbidden.

Once the concepts of faculty, competence and nullity have been formalized, Schmill shows how the forecasting function of Jurisprudence is subject to the conditions which these operators determine. Finally, Schmill gives an affirmative answer to the question of the possibility of iterating these operators, treating this case as a power-conferring one.

[Álvaro Rodríguez Tirado]