Imperatives cannot be true or false, so they are shunned by logicians. And yet imperatives can be combined by logical connectives: "kiss me and hug me" is the conjunction of "kiss me" with "hug me". This example may suggest that declarative and imperative logic are isomorphic: just as the conjunction of two declaratives is true exactly if both conjuncts are true, the conjunction of two imperatives is satisfied exactly if both conjuncts are satisfied—what more is there to say? Much more, (...) I argue. "If you love me, kiss me", a conditional imperative, mixes a declarative antecedent ("you love me") with an imperative consequent ("kiss me"); it is satisfied if you love and kiss me, violated if you love but don't kiss me, and avoided if you don't love me. So we need a logic of three -valued imperatives which mixes declaratives with imperatives. I develop such a logic. (shrink)

Besides pure declarative arguments, whose premises and conclusions are declaratives (“you sinned shamelessly; so you sinned”), and pure imperative arguments, whose premises and conclusions are imperatives (“repent quickly; so repent”), there are mixed-premise arguments, whose premises include both imperatives and declaratives (“if you sinned, repent; you sinned; so repent”), and cross-species arguments, whose premises are declaratives and whose conclusions are imperatives (“you must repent; so repent”) or vice versa (“repent; so you can repent”). I propose a general definition of argument (...) validity: an argument is valid exactly if, necessarily, every fact that sustains its premises also sustains its conclusion, where a fact sustains an imperative exactly if it favors the satisfaction over the violation of the imperative, and a fact sustains a declarative exactly if, necessarily, the declarative is true if the fact exists. I argue that this definition yields as special cases the standard definition of validity for pure declarative arguments and my previously defended definition of validity for pure imperative arguments, and that it yields intuitively acceptable results for mixed-premise and cross-species arguments. (shrink)

Besides pure declarative arguments, whose premises and conclusions are declaratives, and pure imperative arguments, whose premises and conclusions are imperatives, there are mixed-premise arguments, whose premises include both imperatives and declaratives, and cross-species arguments, whose premises are declaratives and whose conclusions are imperatives or vice versa. I propose a general definition of argument validity: an argument is valid exactly if, necessarily, every fact that sustains its premises also sustains its conclusion, where a fact sustains an imperative exactly if it favors (...) the satisfaction over the violation proposition of the imperative, and a fact sustains a declarative exactly if, necessarily, the declarative is true if the fact exists. I argue that this definition yields as special cases the standard definition of validity for pure declarative arguments and my previously defended definition of validity for pure imperative arguments, and that it yields intuitively acceptable results for mixed-premise and cross-species arguments. (shrink)

"Surrender; therefore, surrender or fight" is apparently an argument corresponding to an inference from an imperative to an imperative. Several philosophers, however (Williams 1963; Wedeking 1970; Harrison 1991; Hansen 2008), have denied that imperative inferences exist, arguing that (1) no such inferences occur in everyday life, (2) imperatives cannot be premises or conclusions of inferences because it makes no sense to say, for example, "since surrender" or "it follows that surrender or fight", and (3) distinct imperatives have conflicting permissive presuppositions (...) ("surrender or fight" permits you to fight without surrendering, but "surrender" does not), so issuing distinct imperatives amounts to changing one's mind and thus cannot be construed as making an inference. In response I argue inter alia that, on a reasonable understanding of 'inference', some everyday-life inferences do have imperatives as premises and conclusions, and that issuing imperatives with conflicting permissive presuppositions does not amount to changing one's mind. (shrink)

There is a growing interest in how people conceptualise the legal domain for the purpose of legal knowledge systems. In this paper we discuss four such conceptualisations (referred to as ontologies): McCarty's language for legal discourse, Stamper's norma formalism, Valente's functional ontology of law, and the ontology of Van Kralingen and Visser. We present criteria for a comparison of the ontologies and discuss the strengths and weaknesses of the ontologies in relation to these criteria. Moreover, we critically review the criteria.

In this reply, I raise some questions about the account of "normativity" given by Joseph Rouse. I discuss the historical form of disputes over normativity in such thinkers as Kelsen and show that the standard issue with these accounts is over the question of whether there is anything added to the normal stream of explanation by the problem of normativity. I suggest that Rouse’s attempt to avoid the issues that arise with substantive explanatory theories of practices of the kind criticized (...) in The Social Theory of Practices leads to a result that is uninformative, and the strategy raises the question of whether there is anything there to explain and thus whether there is any necessity to appeal to the kind of anomalous explanations the normativist offers. Key Words: Kelsen • normativity • Mauss • naturalism • practices. (shrink)

This paper presents a belief revision operator that considers time intervals for modelling norm change in the law. This approach relates techniques from belief revision formalisms and time intervals with temporalised rules for legal systems. Our goal is to formalise a temporalised belief base and corresponding timed derivation, together with a proper revision operator. This operator may remove rules when needed or adapt intervals of time when contradictory norms are added in the system. For the operator, both constructive definition and (...) an axiomatic characterisation by representation theorems are given. (shrink)

Philosophers like G.H. von Wright and D. Makinson have pointed to serious challenges regarding the foundations of deontic logic. In this paper, I suggest that to deal successfully with these challenges a reconsideration of the research program of the discipline is useful. Some problems that have troubled this particular field of logical study for decades may disappear or appear more tractable if we view them from the perspective of a language game introduced by D. Lewis involving three characters: the Master, (...) the Slave and the Kibitzer. The adoption of this perspective opens a natural approach to a new layout of the domain of deontic studies. I propose dividing deontic logic into six sub-areas which are distinguished by their focus on the different idioms typical of the individual players, by conceiving the language game as either being static or as dynamic and by the aims of the logical inquiry. What kind of insights the proposed perspective provides is illustrated by an analysis of the so-called Ross paradox—a problem that has troubled deontic logic since its origins and, though it was many times pronounced solved, still keeps coming back ‘alive and kicking’. (shrink)

This paper is concerned with removing the identity schema from the axiomatic basis of deontic conditionals. This is in order to allow a stipulated ideal to be contrary or opposite in nature to the fact it is predicated upon. It is desirable, or so it is argued, to retain the order-theoretic orientation of preferential semantics towards the analysis of deontic conditionals, more specifically of maximality semantics in the tradition from Bengt Hansson. So understood, the problem involves abstracting away the settledness (...) assumption that is built in to maximality semantics. This is the assumption that what is optimal given ϕ is that which all the best ϕ-states have in common, notably ϕ itself. We propose a solution based on a strict and finite preference relation over which deontic conditionals are evaluated by letting ϕ-states evolve freely, as fate or fortune would have it, into different possibly ensuing optima that may but need not be ϕ-states themselves. The result is a deontic conditional that does not have identity. This new conditional is shown to be a proper generalization of the Hansson conditional. Hansson’s conditional can be recovered in the new idiom as a special case. Indeed, the new semantics is general enough to cover several apparently very different conceptions of deontic conditionality. For instance, the input/output logic known as basic output is a sublogic of the new system. This is somewhat surprising and suggests that there may yet be unity to be had in the field of deontic logic. (shrink)

This paper generalises classical revision theory of the AGM brand to sets of norms. This is achieved substituting input/output logic for classical logic and tracking the changes. Operations of derogation and amendment—analogues of contraction and revision—are defined and characterised, and the precise relationship between contraction and derogation, on the one hand, and derogation and amendment on the other, is established. It is argued that the notion of derogation, in particular, is a very important analytical tool, and that even core deontic (...) concepts such as that of permission resists a satisfactory analysis without it. By way of illustration the last section of the paper analyses the much debated concept of positive permission, of which there turns out to be more than one kind. (shrink)

Legal realism comes in two main versions, namely American legal realism and Scandinavian legal realism. In this article, I shall be concerned with the Scandinavian realists, who were naturalists and non-cognitivists, and who maintained that conceptual analysis is a central task of legal philosophers, and that such analysis must proceed in a naturalist, anti-metaphysical spirit. Specifically, I want to consider the commitment to ontological naturalism and non-cognitivism on the part of the Scandinavians and its implications for their view of the (...) nature of law. I argue that the Scandinavians differ from legal positivists in that they reject the idea that there are legal relations, that is, legal entities and properties, and to varying degrees defend the view that law is a matter of human behavior rather than legal norms, and that they do not and cannot accept the idea that there is a ‘world of the ought’ in Kelsen's sense. I also argue, more specifically, that the objection to non-naturalist theories raised by the Scandinavians—that there is and can be no connection between the higher realm of norms and values and the world of time and space—is convincing, and that Kelsen's introduction of a so-called modally indifferent substrate does nothing to undermine this objection. In addition, I argue that the Scandinavians can account for the existence of legal relations that do not presuppose the existence of morally binding legal norms by embracing conventionalism about the existence of the sources of law, while pointing out that in doing so they would also be abandoning their legal realism for legal positivism. Finally, I argue that the implications for legal scholarship of the realist emphasis on human behavior instead of legal norms is not well explained by the realists and appear to amount to little more than a preference for teleological interpretation of legal norms. (shrink)

It is common to think that what theory of linguistic vagueness is correct has implications for debates in philosophy of law. I disagree. I argue that the implications of particular theories of vagueness on substantive issues of legal theory and practice are less far-reaching than often thought. I focus on four putative implications discussed in the literature concerning (i) the value of vagueness in the law, (ii) the possibility and value of legal indeterminacy, (iii) the possibility of the rule of (...) law, and (iv) strong discretion. I conclude with some methodological remarks. Delineating questions about conventional meaning, the metaphysics/metasemantics of (legal) content determination, and norms of legal interpretation and judicial practice can motivate clearer answers and a more refined understanding of the space of overall theories of vagueness, interpretation, and law. (shrink)

Schmitt’s theologisation of sovereignty has been subjected, 50 years later, to a ‘quarter turn’ by Foucault’s move from issues of domination to issues of government. After a further 30 years, radicalising Foucault, Agamben’s archaeology of economy adds another ‘quarter turn’: the structure that emerges once the old European conjugality of facticity and validity, of praxis and being, emptied of all bonds, links, and loops, gives way to the bare opposition ‘bipolarity’. The new constellation provides the old legal-theoretical problem of rules (...) unsuspended from a ruler who would authorise them, with a new, unexpected, political content and with a change of epistemic paradigm. (shrink)

The author investigates how the conception of legal validity as a specific mode of existence, adopted by Kelsen in Allgemeine Theorie der Normen (General Theory of Norms), can be reconciled with a conception of the legal system in which conflicts of legal norms remain of logical concern. To this end he makes use of Ludwig Wittgenstein's picture theory of the proposition as set out in the Tractatus Logico-Philosophicus. The conclusion is that in order to reconcile the two conceptions, the legal (...) system itself must be conceived of as consisting of three sub-systems, namely, (i) a sub-system of perceptible legal judgments, (ii) a sub-system of valid legal conditions, and (iii) a sub-system of observable social practices. (shrink)

In this paper we investigate the role of performative contradictions in legal discourse. First of all we identify the argumentative roles of performative contradictions and two possible interpretations of them. With this done, we show that one use of performative contradictions can be fruitfully applied in analysing normative speech acts implementing norm enactment, namely, those speech acts that are designed to produce new legal norms. We conclude the paper by showing that our analysis provides strong support for Robert Alexy's claim-to-correctness (...) thesis, according to which speech acts of the norm-enacting kind raise a claim to correctness. (shrink)

This paper presents a new language for isomorphic representations of legalknowledge in feature structures. The language includes predefinedstructures based on situation theory for common-sense categories, andpredefined structures based on Van Kralingens frame-based conceptualmodelling language for legal rules. It is shown that the flexibility of thefeature-structure formalism can exploited to allow for structure-preservingrepresentations of non-primitive concepts, and to enable various types ofinteraction and cross- reference between language elements. A fragment of theDutch Opium Act is used to illustrate how modelling and reasoning (...) proceed in practice. (shrink)

The author discusses a number of issues in the theory of legal sources. The first topic is whether sources should be conceived of as acts or texts. The alternatives are connected with two competing theories of legal interpretation (viz., the cognitive theory and the sceptical theory), which entail different concepts of legal rules and law‐making. The second topic is whether a “formal” or a “material” criterion of recognition of sources should be preferred. The third section is devoted to the analysis (...) of rules of change. Four theories of rules of change are discussed, and five kinds of such rules are distinguished. The fourth section concerns judicial law‐making, with special reference to the creation of new legal rules by constitutional courts. (shrink)

This paper presents an approach for legal compliance checking in the Semantic Web which can be effectively applied for applications in the Linked Open Data environment. It is based on modeling deontic norms in terms of ontology classes and ontology property restrictions. It is also shown how this approach can handle norm defeasibility. Such methodology is implemented by decidable fragments of OWL 2, while legal reasoning is carried out by available decidable reasoners. The approach is generalised by presenting patterns for (...) modeling deontic norms and norms compliance checking. (shrink)

A critical analysis of Kelsen’s theory leads to a broad concept of custom, which covers diverse types of customary norms, where the always required conviction of legal bindingness depends on different types of factual and normative reasons. In it we should include a strict concept of custom or legal usage, derogating custom, custom of general international law, custom that establishes an unwritten constitution, custom that establishes a new written constitution, judicial custom which creates a rule of precedent and custom newly (...) expressed in the judicial application of customary rules. The basic norm could be formulated as a constitutive norm: ‘If the norms created through the first historical constitution are effective, then the first historical constitution are valid.’ It is thus a customary constitutive rule that recognizes the first historical constitution as valid law. Norms which establish sources of law are constitutive rules, they can be customary norms or legislated norms, but if they are legislated, they have their validity recognized by, directly or indirectly, a constitutive customary norm. By using a broad concept of custom as a conventional practice, Hart implies that general recognition of a customary rule, together with the practice that accompanies it, are sufficient conditions of validity. A doctrine of recognition that is arrived at by means of criticism and a rational reconstruction of the doctrines of Kelsen and Hart regains the essential theses of the traditional recognition theory of Bierling and Engisch. (shrink)

This work adopts H. Kelsen’s concept of legal system, proposes a formal definition for such notion, and introduces an operational semantical framework for legal systems that are situated in agent societies. Agent societies are defined. Relevant formal properties of situated legal systems are discussed; the way they are exposed in the operational semantical framework is explained, and their truth formally proved. Also, for the sake of a better understanding of the legal-theoretic assumptions of the paper, recurring issues regarding Kelsen’s theory (...) of law are briefly reviewed. They are put in confrontation with the points of view of R. Dworkin, H. Hart, and J. Raz, and an attempt is made to clarify them from the perspective of the provided formalization. A brief case study in agent-based modeling and simulation of public policy processes is presented, as an illustration of the way of using situated legal systems, and the proposed operational semantical framework, in a practical application. (shrink)

This paper discusses the implications of the ethical theory of Emmanuel Levinas for theoretical debates about legal obligation. I begin by examining the structure of moral reasoning in light of Levinas's account of ethics, looking particularly at the role of the third party (le tiers) in modifying Levinas's primary ethical structure of the face to face relation. I then argue that the primordial role of ethical experience in social discourse, as emphasised by Levinas, undermines theories, such as that of H. (...) L. A. Hart, that propose a systematic distinction between legal and moral species of obligation. (shrink)

This paper introduces a formal concept of ideology and ideological system. The formalization takes ideologies and ideological systems to be situated in agent societies. An ideological system is defined as a system of operations able to create, maintain, and extinguish the ideologies adopted by the social groups of agent societies. The concepts of group ideology, ideological contradiction, ideological dominance, and dominant ideology of an agent society, are defined. An ideology-based concept of social group is introduced. Relations between the proposed formal (...) concept of ideology and the classical concepts of ideology elaborated in social sciences are examined. A computational notation is presented, to support the realization of ideological systems in computationally implemented agent societies. The adequacy of the approach for the formal modeling and analysis of ideological issues is illustrated through three case studies. (shrink)

This essay examines an ambiguity in Hans Kelsen’s theory of a norm. On the one hand, Kelsen claims to adhere to what he considers the ‘is/ought’ dichotomy. Kelsen claims that he is describing what really is. On the other hand, Kelsen seems to be understanding the is/ought dichotomy in a very different manner than that by which his contemporaries or, indeed, today’s readers understand the distinction. The clue to this ambiguity is Kelsen’s understanding of a norm. Although legal existence is (...) said to rest with norms, this existence is very different than an existence constituted from social behaviour. Instead, in Kelsen’s view, a norm is a signifying relation between a sign and a cognitive object. Kelsen’s theory of language, however, is very different from a theory of speech acts. When addressing why a norm is binding, we find that Kelsen’s full theory of language excludes important phenomena in order to retain its purity. (shrink)

The necessity to model the mental ingredients of norm compliance is a controversial issue within the study of norms. So far, the simulation-based study of norm emergence has shown a prevailing tendency to model norm conformity as a thoughtless behavior, emerging from social learning and imitation rather than from specific, norm-related mental representations. In this paper, the opposite stance—namely, a view of norms as hybrid, two-faceted phenomena, including a behavioral/social and an internal/mental side—is taken. Such a view is aimed at (...) accounting for the difference between norms, on one hand, and either behavioral regularities (conventions) on the other. This paper, in particular, is addressed to find out the internal ingredients required for the former distinction, i.e., to model norms as distinct from mere conventions, and defined as behaviors spreading to the extent that and because the corresponding commands and beliefs do spread as well. After a brief presentation of a normative agent architecture, the results of agent-based simulations testing the impact of norm recognition and the role of normative beliefs in the emergence and innovation of social norms are presented and discussed. More specifically, the present work will endeavour to show that a sudden external constraint (e.g. a barrier preventing agents from moving among social settings) facilitates norm innovation: under such a condition, agents provided with a module for telling what a norm is can generate new (social) norms by forming new normative beliefs, irrespective of the most frequent actions. (shrink)

In this article we describe two core ontologies of law that specify knowledge that is common to all domains of law. The first one, FOLaw describes and explains dependencies between types of knowledge in legal reasoning; the second one, LRI-Core ontology, captures the main concepts in legal information processing. Although FOLaw has shown to be of high practical value in various applied European ICT projects, its reuse is rather limited as it is rather concerned with the structure of legal reasoning (...) than with legal knowledge itself: as many other “legal core ontologies”, FOLaw is therefore rather an epistemological framework than an ontology. Therefore, we also developed LRI-Core. As we argue here that legal knowledge is based to a large extend on common-sense knowledge, LRI-Core is particularly inspired by research on abstract common-sense concepts. The main categories of LRI-Core are: physical, mental and abstract concepts. Roles cover in particular social worlds. Another special category are occurrences; terms that denote events and situations. We illustrate the use of LRI-Core with an ontology for Dutch criminal law, developed in the e-Court European project. (shrink)