The Logics of Deontic (In)Consistency (LDI's) can be considered as the deontic counterpart of the paraconsistent logics known as Logics of Formal (In)Consistency. This paper introduces and studies new LDI's and other paraconsistent deontic logics with different properties: systems tolerant to contradictory obligations; systems in which contradictory obligations trivialize; and a bimodal paraconsistent deontic logic combining the features of previous systems. These logics are used to analyze the well-known Chisholm's paradox, taking profit of the fact that, besides contradictory obligations do (...) not trivialize in LDI's, several logical dependencies of classical logic are blocked in the context of LDI's, allowing to dissolve the paradox. (shrink)

I present a novel account of unconditional obligation and of its relationship to conditional obligation and bring this account to bear upon Chisholm's puzzle concerning contrary-to duty obligation.

This paper offers a two dimensional variation of Standard Deontic Logic SDL, which we call 2SDL. Using 2SDL we can show that we can overcome many of the difficulties that SDL has in representing linguistic sets of Contrary-to-Duties (known as paradoxes) including the Chisholm, Ross, Good Samaritan and Forrester paradoxes. We note that many dimensional logics have been around since 1947, and so 2SDL could have been presented already in the 1970s. Better late than never! As a detailed case study (...) illustrating the power of 2SDL, we examine the system DL of Deontic Logic of Andrew Jones and Ingmar Pörn offered in 1985 to solve the Chisholm paradox of Contrary to Duties. The critical examination is done using logics and methods available in 1985 and solutions are proposed using what was available in 1985. (shrink)

James Wm. Forrester, Being Good and Being Logical. Philosophical Groundwork for a New Deontic Logic. Armonk and London, M.E. Sharpe, 1996. Pp.x+332.

It is argued that Ross's Paradox in deontic logic is a problem which should be taken seriously, and which can be given a solution which also solves some other wellknown paradoxes and the traditional problems with conditional obligation.

I argue that normative requirements should be interpreted as the conditional obligations of dyadic deontic logic. Semantically, normative requirements are conditionals understood as restrictors, the prevailing view of conditionals in linguistics. This means that Modus Ponens is invalid, even when the premises are known.

This article surveys a range of current views on the semantics of imperatives, presenting them as more or less conservative with respect to the Truth-Conditional Paradigm in semantics. It describes and critiques views at either extreme of this spectrum: accounts on which the meaning of an imperative is a modal truth-condition, as well as various accounts that attempt to explain imperative meaning without making use of truth-conditions. It briefly describes and encourages further work on a family of views lying somewhere (...) in the middle. On such views, an imperative will semantically determine, without having as its meaning, a modal truth-condition, which figures centrally in accounting for various aspects of its meaning. (shrink)

The paper discusses the potential value of a deontic approach to database specification. More specifically, some different types of integrity constraints are considered and a distinction is drawn between necessary (hard) and deontic (soft) constraints.Databases are compared with other normative systems. A deontic logic for database specification is proposed and the problems of how to react to, and of how to correct, or repair, a situation which arises through norm violation are discussed in the context of this logic. The limitations (...) of the proposed logic and possible modifications and extensions of it are analysed. (shrink)

Conditionals that contain a modality in the consequent give rise to a particular semantic phenomenon whereby the antecedent of the conditional blocks possibilities when interpreting the modality in the consequent. This explains the puzzling logical behaviour of constructions like "If you don't buy a lottery ticket, you can't win", "If you eat that poison, it is unlikely that you will survive the day" and "If you kill Harry, you ought to kill him gently". In this paper it is argued that (...) a semantic version of the Ramsey Test provides a key in the analysis of such constructions. The logic for this semantics is axiomatized and some examples are studied, among them a well-known puzzle for contrary-to-duty obligations. (shrink)

The crucial feature of obligation sentences to which the puzzles point is that such sentences, and evaluative sentences more generally, are defeasible. They may be warranted, given some information, only to be defeated by further information. A theory that recognizes this no longer needs to see conditional obligation as anything more than a simple combination of unary obligation and the conditional.

This paper offers a two dimensional variation of Standard Deontic Logic SDL, which we call 2SDL. Using 2SDL we can show that we can overcome many of the difficulties that SDL has in representing linguistic sets of Contrary-to-Duties (known as paradoxes) including the Chisholm, Ross, Good Samaritan and Forrester paradoxes. We note that many dimensional logics have been around since 1947, and so 2SDL could have been presented already in the 1970s. Better late than never! As a detailed case study (...) illustrating the power of 2SDL, we examine the system DL of Deontic Logic of Andrew Jones and Ingmar Pörn offered in 1985 to solve the Chisholm paradox of Contrary to Duties. The critical examination is done using logics and methods available in 1985 and solutions are proposed using what was available in 1985. (shrink)

A new deontic logic, Action Type Deontic Logic, is presented. To motivate this logic, a number of benchmark cases are shown, representing inferences a deontic logic should validate. Some of the benchmark cases are singled out for further comments and some formal approaches to deontic reasoning are evaluated with respect to the benchmark cases. After that follows an informal introduction to the ideas behind the formal semantics, focussing on the distinction between action types and action tokens. Then the syntax and (...) semantics of Action Type Deontic Logic is presented and it is shown to meet the benchmarks. Finally, possibilities for further research are indicated. In the appendix, decidability of the satisfiability of formulas is proved via a technique known from monadic First Order Logic. (shrink)

We provide a retrospective of 25 years of the International Conference on AI and Law, which was first held in 1987. Fifty papers have been selected from the thirteen conferences and each of them is described in a short subsection individually written by one of the 24 authors. These subsections attempt to place the paper discussed in the context of the development of AI and Law, while often offering some personal reactions and reflections. As a whole, the subsections build into (...) a history of the last quarter century of the field, and provide some insights into where it has come from, where it is now, and where it might go. (shrink)

In this article I respond to the eight critical essays in this issue that evaluate the claims in my book with Gerhard Øverland, Responding to Global Poverty: Harm, Responsibility, and Agency.

In this article I respond to the eight critical essays in this issue that evaluate the claims in my book with Gerhard Øverland, Responding to Global Poverty: Harm, Responsibility, and Agency.

This paper presents a nonmonotonic deontic logic based on commonsense entailment. It establishes criteria a successful account of obligation should satisfy, and develops a theory that satisfies them. The theory includes two conditional notions of prima facie obligation. One is constitutive; the other is epistemic, and follows nonmonotonically from the constitutive notion. The paper defines unconditional notions of prima facie obligation in terms of the conditional notions.

This paper investigates some aspects of the semantics of deontic should-conditionals. The main objective is to understand which actual world facts make deontic statements true. The starting point for the investigation is a famous puzzle known as Chisholm’s Paradox. It is important because making sense of the data in Chisholm-style examples involves arriving at some conclusion regarding the interaction between what we consider ideal and what is actually true. I give an account of how facts affect the evaluation of should (...) formulated in a way that does not predict that the divergence between ideals and facts leads to contradictions. The proposed semantics for should and should-conditionals allows for factual detachment without giving rise to paradoxes. The proposal has several parts: a situation-based semantics for the modal should, a view of the propositions embedded under should that allows aspect to play a crucial role in anchoring propositions to the context set, and a proposal for if-clauses that distinguishes between epistemic if-clauses and if-clauses in the scope of should, treating the latter as restrictors on the quantificational domain of the modal. (shrink)

The article argues for a parallelism between the interpretation of deontic modals and the interpretation of counterfactuals. The main claim is that dependencies between facts play a role in the resolution of both types of modality: in both cases, facts ‘stand and fall’ together. The article provides two types of evidence supporting this claim: (i) evidence that comes from the interaction between primary and secondary duties (as presented in contrary-to-duty imperatives) and (ii) evidence that comes from the possibility of reproducing (...) well-known counterfactual puzzles in the domain of deontic statements. The article argues that the semantics of deontic modals needs to be stated in a way that pays attention to dependencies between facts and illustrates this with a proposal building on work on counterfactuals by Kratzer and Veltman. (shrink)

In Meyer’s promising account [7] deontic logic is reduced to a dynamic logic. Meyer claims that with his account “we get rid of most (if not all) of the nasty paradoxes that have plagued traditional deontic logic.” But as was shown by van der Meyden in [4], Meyer’s logic also contains a paradoxical formula. In this paper we will show that another paradox can be proven, one which also effects Meyer’s “solution” to contrary to duty obligations and his logic in (...) general. (shrink)

In this article I defend that Floridi’s Theory of Strongly Semantic Information – TSSI – is correct while encompassing the Veracity Thesis, which guides the semantic information definition as “p is information if and only if p is constituted by meaningful, truth well-formed data”. I argue that the theory is not arbitrary because it deals with important philosophical conundrums, mainly by avoiding the Bar-Hillel and Carnap paradox (1953) generated from the classical theory of semantic information. First, one of the classic (...) theory’s main result is discussed: the production of “too much informative sentences to be true”. Then the motivations to elaborate a “logic of being informed” are summarized and it is shown how the KTB-IL system is built and modelled keeping the veracity axiom among its axioms – K or A4. Finally the TSSI is examined and defended by showing that it aletically restricts the extension of the classic concept of information, avoiding problems with tautologies and contradictions. The TSSI offers an original solution by capturing our modal intuitions concerning informativeness as a basic notion. (shrink)

Normative systems have been advocated as an effective tool to regulate interaction in multi-agent systems. The use of deontic operators and the ability to represent defeasible information are known to be two fundamental ingredients to represent and reason about normative systems. In this paper, after introducing a framework that combines standard deontic logic and non-monotonic logic programming, deontic logic programs (DLP), we tackle the fundamental problem of equivalence between normative systems using a deontic extension of David Pearce’s Equilibrium Logic and (...) its monotonic basis, the logic of Here-and-There. We also show how deontic logic programs can be used to represent and reason about normative systems, and establish a strong connection with input-output logic. (shrink)

This paper argues for contrastivism about the deontic modals, 'ought', 'must', and 'may'. A simple contrastivist semantics that predicts the desired entailment relations among these modals is offered.

(See also the separate entry for the volume itself.) This introduction has three parts. The first providing an overview of some main lines of research in deontic logic: the emergence of SDL, Chisholm's paradox and the development of dyadic deontic logics, various other puzzles/challenges and areas of development, along with philosophical applications. The second part focus on some actual and potential fruitful interactions between deontic logic, computer science and artificial intelligence. These include applications of deontic logic to AI knowledge representation (...) in legal systems, to modelling computer systems where it is expected that sub-ideal states will emerge and require countermeasures, to norm-governed human interactions with computer systems, and to the representation of some features of multi-agent systems where different agent-like computer systems interact with one another. The third and final part briefly groups and previews the papers in the anthology. (shrink)

Consider three cases: -/- Turn: A trolley is about to kill five innocent strangers. You can turn the trolley onto me, saving the five and killing me. -/- Hurl: A trolley is about to kill five innocent strangers. You can hurl me at the trolley, saving the five and paralyzing me. -/- TurnHurl: A trolley is about to kill five innocent strangers. You can turn the trolley onto me, saving the five and killing me. You can instead hurl me at (...) the trolley, saving the five and paralyzing me. -/- Most find the following four claims intuitively plausible: -/- (1) It is permissible to turn the trolley onto me in Turn. (2) It is impermissible to hurl me at the trolley in Hurl. (3) It is impermissible to turn the trolley onto me in TurnHurl. (4) It is permissible to hurl me at the trolley in TurnHurl. -/- But how does turning go from permissible to impermissible, and hurling from impermissible to permissible, when both alternatives are available? I argue that such “secondary permissibility” claims are explained by contrastive consent. Even if I do not consent to being harmed, it is likely I’ll consent to being hurled at the trolley rather than being turned onto. (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)

Imperatives cannot be true, but they can be obeyed or binding: `Surrender!' is obeyed if you surrender and is binding if you have a reason to surrender. A pure declarative argument — whose premisses and conclusion are declaratives — is valid exactly if, necessarily, its conclusion is true if the conjunction of its premisses is true; similarly, I suggest, a pure imperative argument — whose premisses and conclusion are imperatives — is obedience-valid (alternatively: bindingness-valid) exactly if, necessarily, its conclusion is (...) obeyed (alternatively: binding) if the conjunction of its premisses is. I argue that there are two kinds of bindingness, and that a vacillation between two corresponding variants of bindingness-validity largely explains conflicting intuitions concerning the validity of some pure imperative arguments. I prove that for each of those two variants of bindingness-validity there is an equivalent variant of obedience-validity. Finally, I address alternative accounts of pure imperative inference. (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)

James E. Tomberlin [6] has recently argued that the logical systems of conditional obligation proposed by Azizah al-Hibri [1] and Peter Mott [5] are incapable of resolving at least one variant of the notorious contrary to duty imperative paradox, formulated originally by Chisholm [2]. Tomberlin concedes that these systems offer the very best of the' “conditional obligation approach” to deontic logic and concludes his critical discussion with the pessimistic remark that “the best of this approach is simply not good enough. (...) Deontic logic … is obliged to turn elsewhere for its proper formulation and resolution of the deontic paradoxes”. Below I argue that Tomberlin's three central arguments against al-Hibri and Mott are fallacious. (shrink)

Suppose that John has a moral obligation to stop smoking given that smoking is dangerous to his health. Suppose further that smoking is dangerous to his health. Does it follow that John has a moral obligation to stop smoking? Although intuition inclines one to answer in the affirmative, recent developments in deontic logic apparently call this inference into question. The issue at hand is whether unconditional obligations are detachable from conditional obligations on the basis of purely factual considerations. I believe (...) that they are not. In the course of arguing for this position I defend a novel restricted rule of detachment which is constructed out of both factual and normative components. (shrink)

In this paper I propose violation games as the basis of formal logics to represent and reason about norms, i.e. as the foundation of deontic logic. Deontic logic is an applied non-classical logic reflecting a way in which we conceptualize normative reasoning. By introducing violation games as a fundamental principle of deontic logic, I am introducing a new way of looking at familiar problems in normative reasoning, with the aim of introducing a new approach for handling norms in intelligent systems.

Centered around the analysis of the prescriptive portion of the Vedas, the Sanskrit philosophical school of Mīmāṃsā provides a treasure trove of normative investigations. We focus on the leading Mīmāṃsā authors Prabhākara, Kumārila and Maṇḍana, and discuss three modal logics that formalize their deontic theories. In the first part of this paper, we use logic to analyze, compare and clarify the various solutions to the _śyena_ controversy, a two-thousand-year-old problem arising from seemingly conflicting commands in the Vedas. In the second (...) part, the formalized Mīmāṃsā theories are analyzed and employed to provide alternative perspectives on well-known paradoxes from the contemporary field of deontic logic. Thus, we go from logic to Mīmāṃsā and back again. (shrink)

Conventionalists about promising believe that it is wrong to break a promise because the promisor takes advantage of a useful social convention only to fail to do his part in maintaining it. Anti-conventionalists claim that the wrong of breaking a promise has nothing essentially to do with a social convention. Anti-conventionalists are right that the social convention is not necessary to explain the wrong of breaking most promises. But conventionalists are right that the convention plays an essential role in any (...) satisfactory account of promising. A new conventionalism can explain this by appealing to special features of social conventions. Two of these special features have important implications for any moral requirements they mediate, such as the requirement to keep one's promises and the moral requirements attached to social or occupational roles. First, these requirements will not depend on features of a situation that are inaccessible to typical participants in the convention. Second, these requirements often cannot be tailored to fit the overly unusual circumstances of participants. (shrink)

Lou Goble proposed powerful conditional deontic logics (CDPM) that are able to deal with deontic conflicts by means of restricting the inheritance principle. One of the central problems for dyadic deontic logics is to properly treat the restricted applicability of the principle “strengthening the antecedent”. In most cases it is desirable to derive from an obligation A under condition B, that A is also obliged under condition B and C. However, there are important counterexamples. Goble proposed a weakened rational monotonicity (...) principle to tackle this problem. This solution is suboptimal as it is for some examples counter-intuitive or even leads to explosion. The paper identifies also other problems of Goble’s systems. For instance, to make optimal use of the restricted inheritance principle, in many cases the user has to manually add certain statements to the premises. An adaptive logic framework based on CDPM is proposed which is able to tackle these problems. It allows for certain rules to be applied as much as possible. In this way counter-intuitive consequences as well as explosion can be prohibited and no user interference is required. Furthermore, for non-conflicting premise sets the adaptive logics are equivalent to Goble’s dyadic version of standard deontic logic. (shrink)

Logic has traditionally been construed as a normative discipline; it sets forth standards of correct reasoning. Explosion is a valid principle of classical logic. It states that an inconsistent set of propositions entails any proposition whatsoever. However, ordinary agents presumably do — occasionally, at least — have inconsistent belief sets. Yet it is false that such agents may, let alone ought to, believe any proposition they please. Therefore, our logic should not recognize explosion as a logical law. Call this the (...) ‘normative argument against explosion’. Arguments of this type play — implicitly or explicitly — a central role in motivating paraconsistent logics. Branden Fitelson, in a throwaway remark, has conjectured that there is no plausible ‘bridge principle’ articulating the normative link between logic and reasoning capable of supporting such arguments. This paper offers a critical evaluation of Fitelson’s conjecture, and hence of normative arguments for paraconsistency and the conceptions of logic’s normative status on which they repose. It is argued that Fitelson’s conjecture turns out to be correct: normative arguments for paraconsistency probably fail. (shrink)

The paper is motivated by the need of accounting for the practical syllogism as a piece of defeasible reasoning. To meet the need, the paper first refers to ranking theory as an account of defeasible descriptive reasoning. It then argues that two kinds of ought need to be distinguished, purely normative and fact-regarding obligations. It continues arguing that both kinds of ought can be iteratively revised and should hence be represented by ranking functions, too, just as iteratively revisable beliefs. Its (...) central proposal will then be that the fact-regarding normative ranking function must be conceived as the sum of a purely normative ranking function and an epistemic ranking function. The distinctions defends this proposal with a comparative discussion of some critical examples and some other distinctions made in the literature. It gives a more rigorous justification of this proposal. Finally, it starts developing the logic of purely normative and of fact-regarding normative defeasible reasoning, points to the difficulties of completing the logic of the fact-regarding side, but reaches the initial aim of accounting for the defeasible nature of the practical syllogism. (shrink)

The paper is motivated by the need of accounting for the practical syllogism as a piece of defeasible reasoning. To meet the need, the paper first refers to ranking theory as an account of defeasible descriptive reasoning. It then argues that two kinds of ought need to be distinguished, purely normative and fact-regarding obligations (in analogy to intrinsic and extrinsic utilities). It continues arguing that both kinds of ought can be iteratively revised and should hence be represented by ranking functions, (...) too, just as iteratively revisable beliefs. Its central proposal will then be that the fact-regarding normative ranking function must be conceived as the sum of a purely normative ranking function and an epistemic ranking function (as suggested in qualitative decision theory). The distinctions defends this proposal with a comparative discussion of some critical examples and some other distinctions made in the literature. It gives a more rigorous justification of this proposal. Finally, it starts developing the logic of purely normative and of fact-regarding normative defeasible reasoning, points to the difficulties of completing the logic of the fact-regarding side, but reaches the initial aim of accounting for the defeasible nature of the practical syllogism. (shrink)

:A good deal of contemporary moral nonconsequentialism assumes that agents have perfect knowledge about the various features and consequences of their options. This assumption is unrealistic. More often than not, moral agents can only assess with a certain degree of probability the factual circumstances that are morally relevant for their decision making. My aim in this essay is to discuss the problem of moral decisions under risk from the point of view of nonconsequentialism. Basically, I analyze how objective moral principles (...) can be transformed into subjective, decisional prescriptions, and argue that the standard nonconsequentialist approach to moral decision making, which focuses on probability thresholds, is wrong. In accordance with the fundamental postulates of nonconsequentialism, I seek to solve the problem of risk in moral choice by proposing a theory about the marginal moral value of various options. Actions can vary along various dimensions, and each of these dimensions can offer a different moral value function. Nonconsequentialist marginalism can level the playing field with consequentialism. Whereas consequentialism can simply borrow the notion of expected utility from economics, nonconsequentialism must introduce the notion of expectational obligation to formulate a general principle of moral choice under risk. I finally suggest that further empirical work is needed to delineate the shape of various moral value functions that are critical for applying the general principle of moral decision making under risk to well-known cases. View HTML Send article to KindleTo send this article to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle. Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply. Find out more about the Kindle Personal Document Service.DECISIONAL NONCONSEQUENTIALISM AND THE RISK SENSITIVITY OF OBLIGATIONVolume 32, Issue 2Horacio Spector DOI: https://doi.org/10.1017/S0265052516000121Your Kindle email address Please provide your Kindle [email protected]@kindle.com Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Send article to Dropbox To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Dropbox. DECISIONAL NONCONSEQUENTIALISM AND THE RISK SENSITIVITY OF OBLIGATIONVolume 32, Issue 2Horacio Spector DOI: https://doi.org/10.1017/S0265052516000121Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Send article to Google Drive To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about sending content to Google Drive. DECISIONAL NONCONSEQUENTIALISM AND THE RISK SENSITIVITY OF OBLIGATIONVolume 32, Issue 2Horacio Spector DOI: https://doi.org/10.1017/S0265052516000121Available formats PDF Please select a format to send. By using this service, you agree that you will only keep articles for personal use, and will not openly distribute them via Dropbox, Google Drive or other file sharing services. Please confirm that you accept the terms of use. Cancel Send ×Export citation Request permission. (shrink)