This paper describes and compares the first step in modern semantic theory for deontic logic which appeared in works of Stig Kanger, Jaakko Hintikka, Richard Montague and Saul Kripke in late 50s and early 60s. Moreover, some further developments as well as systematizations are also noted.

In common treatments of deontic logic, the obligatory is what is true in all deontically ideal possible worlds. In this article, I offer a new semantics for Standard Deontic Logic with Leibnizian intensions rather than possible worlds. Even though the new semantics furnishes models that resemble Venn diagrams, the semantics captures the strong soundness and completeness of Standard Deontic Logic. Since, unlike possible worlds, many Leibnizian intensions are not maximally consistent entities, we can amend the semantics to invalidate the inference (...) rule which ensures that all tautologies are obligatory. I sketch this amended semantics to show how it invalidates the rule in a new way. (shrink)

I defend the following version of the ought-implies-can principle: (OIC) by virtue of conceptual necessity, an agent at a given time has an (objective, pro tanto) obligation to do only what the agent at that time has the ability and opportunity to do. In short, obligations correspond to ability plus opportunity. My argument has three premises: (1) obligations correspond to reasons for action; (2) reasons for action correspond to potential actions; (3) potential actions correspond to ability plus opportunity. In the (...) bulk of the paper I address six objections to OIC: three objections based on putative counterexamples, and three objections based on arguments to the effect that OIC conflicts with the is/ought thesis, the possibility of hard determinism, and the denial of the Principle of Alternate Possibilities. (shrink)

The paper builds on the basically Humean idea that A is a cause of B iff A and B both occur, A precedes B, and A raises the metaphysical or epistemic status of B given the obtaining circumstances. It argues that in pursuit of a theory of deterministic causation this ‘status raising’ is best explicated not in regularity or counterfactual terms, but in terms of ranking functions. On this basis, it constructs a rigorous theory of deterministic causation that successfully deals (...) with cases of overdetermination and pre-emption. It finally indicates how the account's profound epistemic relativization induced by ranking theory can be undone. Introduction Variables, propositions, time Induction first Causation Redundant causation Objectivization. (shrink)

Recently, Bengt Hansson presented a paper about dyadic deontic logic,2 criticizing some purely axiomatic systems of dyadic deontic logic and proposing three purely semantical systems of dyadic deontic logic which he confidently called dyadic standard systems of deontic logic (DSDL1–3). Here I shall discuss the third by far most interesting system DSDL3 which is operating with preference relations. First, I shall describe this semantical system (Sections 1.1–1.3). Then I shall give an axiomatic system (Section 1.4) which is proved to be (...) correct (Section 2) and complete (Section 3) with respect to Hansson's semantics. Finally, in face of these results Hansson's semantics will be discussed from a more intuitive standpoint. After emphasizing its intuitive attractiveness (Section 4.1) I will show that two objections often discussed in connection with preference relations do not apply to it (Section 4.2 and 4.3); more precisely, I will show that the connectedness condition for preference relations can be dropped and that, in a sense, it is not necessary to compare two possible worlds differing in infinitely many respects. (What exactly is meant by this, will become clear later on.) Yet there is a third objection to Hansson's semantics which points to a real intuitive inadequacy of DSDL3. A way of removing this inadequacy, which corresponds to Hansson's own intuitions as well as to familiar metaethical views, is suggested, but not technically realized (Section 4.4). In the last section (section 4.5) I shall briefly show that DSDL3 is decidable, as expected. (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)

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)

Are moral judgements objective? This is a question of great complexity, and in what follows I shall try to cast some light on what it means, and on how it might be answered.

Are moral judgements objective? This is a question of great complexity, and in what follows I shall try to cast some light on what it means, and on how it might be answered.

My first paper on the Is/Ought issue. The young Arthur Prior endorsed the Autonomy of Ethics, in the form of Hume’s No-Ought-From-Is (NOFI) but the later Prior developed a seemingly devastating counter-argument. I defend Prior's earlier logical thesis (albeit in a modified form) against his later self. However it is important to distinguish between three versions of the Autonomy of Ethics: Ontological, Semantic and Ontological. Ontological Autonomy is the thesis that moral judgments, to be true, must answer to a realm (...) of sui generis non-natural PROPERTIES. Semantic autonomy insists on a realm of sui generis non-natural PREDICATES which do not mean the same as any natural counterparts. Logical Autonomy maintains that moral conclusions cannot be derived from non-moral premises.-moral premises with the aid of logic alone. Logical Autonomy does not entail Semantic Autonomy and Semantic Autonomy does not entail Ontological Autonomy. But, given some plausible assumptions Ontological Autonomy entails Semantic Autonomy and given the conservativeness of logic – the idea that in a valid argument you don’t get out what you haven’t put in – Semantic Autonomy entails Logical Autonomy. So if Logical Autonomy is false – as Prior appears to prove – then Semantic and Ontological Autonomy would appear to be false too! I develop a version of Logical Autonomy (or NOFI) and vindicate it against Prior’s counterexamples, which are also counterexamples to the conservativeness of logic as traditionally conceived. The key concept here is an idea derived in part from Quine - that of INFERENCE-RELATIVE VACUITY. I prove that you cannot derive conclusions in which the moral terms appear non-vacuously from premises from which they are absent. But this is because you cannot derive conclusions in which ANY (non-logical) terms appear non-vacuously from premises from which they are absent Thus NOFI or Logical Autonomy comes out as an instance of the conservativeness of logic. This means that the reverse entailment that I have suggested turns out to be a mistake. The falsehood of Logical Autonomy would not entail either the falsehood Semantic Autonomy or the falsehood of Ontological Autonomy, since Semantic Autonomy only entails Logical Autonomy with the aid of the conservativeness of logic of which Logical Autonomy is simply an instance. Thus NOFI or Logical Autonomy is vindicated, but it turns out to be a less world-shattering thesis than some have supposed. It provides no support for either non-cognitivism or non-naturalism. (shrink)

The respect for one’s conscience is rooted in a broader respect for the human person. The conscience represents a person’s ability to identify the values and goods that inform her moral identity. Ignoring or overriding a person’s conscience can lead to significant moral and emotional distress. Refusals to respect a person’s conscientious objection to cases of killing are a source of incisive distress, since judgments that it is impermissible to kill so-and-so are typically held very strongly and serve as central (...) moral commitments in one’s moral identity. I think it is wrong for a college basketball coach to pay his players, but I think it is really wrong to kill people. This article argues that any and all arguments for not respecting a conscientious objection to abortion commit a deontic fallacy. Briefly, arguments for the permissibility of abortion are structurally such that abortion is at best permissible, not obligatory. Now, arguments to justify overriding or ignoring a person’s objection to performing action (α) must understand action (α) as being obligatory. Thus, arguments for ignoring conscientious objections to performing abortion are incongruent with the actual philosophical justifications for abortion. Such arguments, then, commit a deontic fallacy. (shrink)

In moral dilemmas, where circumstances prevent two or more equally justified prima facie ethical requirements from being fulfilled, it is often maintained that, since the agent cannot do both, conjoint obligation is overridden by Kant's principle that ought implies can, but that the agent nevertheless has a disjunctive obligation to perform one of the otherwise obligatory actions or the other. Against this commonly received view, it is demonstrated that although Kant's ought-can principle may avoid logical inconsistency, the principle is incompatible (...) with disjunctive obligation in standard deontic logic, and that it entails paradoxically that none of the conflicting dilemma actions will in fact occur. The principle appears to provide the only plausible safeguard against deontic antinomy, but cannot be admitted because of its collision with considered moral judgments. (shrink)

This paper articulates an account of imperatives that sensibly supports the idea of a logic of imperative inferences. We rebuke common objections to the very possibility of such a logic, from a perspective based on recent linguistic work on the morphosyntax of imperatives. Specifically, we develop the notion that the content of an imperative sentence includes both a force operator alongside an imperational content to which the force applies. We further argue that this account of the content of imperatives constitutes (...) a plausible and flexible framework to develop a logic of imperative by examining a number of reconstructions of this idea using semantical analogs of widespread modal semantics. After studying the performance of those approaches, we conclude that progress in imperative logic has been hindered by the failure to adopt conflict-tolerant and resource-sensitive semantics, but suggest that such considerations can be incorporated in this flexible framework. Finally, we also propose a simple account of the difference between operators applying to the content of imperatives and imperative operators, in a way that sheds light on some of the issues underlying the usual antinomies. (shrink)

In the emerging literature on judgment aggregation over logically connected proposi- tions, expert rights or liberal rights have not been investigated yet. A group making collective judgments may assign individual members or subgroups with expert know- ledge on, or particularly affected by, certain propositions the right to determine the collective judgment on those propositions. We identify a problem that generalizes Sen's 'liberal paradox'. Under plausible conditions, the assignment of rights to two or more individuals or subgroups is inconsistent with the (...) unanimity principle, whereby unanimously accepted propositions are collectively accepted. The inconsistency can be avoided if individual judgments or rights satisfy special conditions. (shrink)

The thesis defended, the “guise of the ought”, is that the formal objects of desires are norms (oughts to be or oughts to do) rather than values (as the “guise of the good” thesis has it). It is impossible, in virtue of the nature of desire, to desire something without it being presented as something that ought to be or that one ought to do. This view is defended by pointing to a key distinction between values and norms: positive and (...) negative norms (obligation and interdiction) are interdefinable through negation; positive and negative values aren’t. This contrast between the norms and values, it is argued, is mirrored, within the psychological realm, by the contrast between the desires and emotions. Positive and negative desires are interdefinable through negation, but positive and negative emotions aren’t. The overall, Meinongian picture suggested is that norms are to desires what values are to emotions. (shrink)

Overview of fundamental work in deontic logic.

The new field of judgment aggregation aims to merge many individual sets of judgments on logically interconnected propositions into a single collective set of judgments on these propositions. Judgment aggregation has commonly been studied using classical propositional logic, with a limited expressive power and a problematic representation of conditional statements ("if P then Q") as material conditionals. In this methodological paper, I present a simple unified model of judgment aggregation in general logics. I show how many realistic decision problems can (...) be represented in it. This includes decision problems expressed in languages of classical propositional logic, predicate logic (e.g. preference aggregation problems), modal or conditional logics, and some multi-valued or fuzzy logics. I provide a list of simple tools for working with general logics, and I prove impossibility results that generalise earlier theorems. (shrink)