Kiesewetter defends the normativity of rationality by presenting a new solution to the problems that arise from the common assumption that we ought to be rational. He provides a defence of a reason-response conception of rationality, an evidence-relative account of reason, and an explanation of structural irrationality in relation to these accounts.

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)

(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)

“S ought (not) to see to it that p at t” is true iff an intention on the part of S to see to it that p at t is (in) correct. From this truth condition follows an understanding of the conceptual role of ought-claims in practical inference: ought-claims are interchangeable with intentions having the same content. From this conceptual role, it is quite clear why first-person, present-tense ought-judgments, and just those, motivate: failure to be motivated is a failure of (...) rationality. The point and purpose of 'ought' is mainly to express the results of practical reasoning performed on premises held hypothetically, an exercise of which there are many varieties. Our capacity for normative thought and language is a consequence of, and intimately related to, our capacity for practical thought. (shrink)

This book offers a state-of-the-art introduction to the basic techniques and results of neighborhood semantics for modal logic. In addition to presenting the relevant technical background, it highlights both the pitfalls and potential uses of neighborhood models – an interesting class of mathematical structures that were originally introduced to provide a semantics for weak systems of modal logic. In addition, the book discusses a broad range of topics, including standard modal logic results ; bisimulations for neighborhood models and other model-theoretic (...) constructions; comparisons with other semantics for modal logic ; neighborhood semantics for first-order modal logic, applications in game theory ; applications in epistemic logic ; and non-normal modal logics with dynamic modalities. The book can be used as the primary text for seminars on philosophical logic focused on non-normal modal logics; as a supplemental text for courses on modal logic, logic in AI, or philosophical logic ; or as the primary source for researchers interested in learning about the uses of neighborhood semantics in philosophical logic and game theory. (shrink)

Our preferences determine how we act and think, but exactly what the mechanics are and how they work is a central cause of concern in many disciplines. This book uses techniques from modern logics of information flow and action to develop a unified new theory of what preference is and how it changes. The theory emphasizes reasons for preference, as well as its entanglement with our beliefs. Moreover, the book provides dynamic logical systems which describe the explicit triggers driving preference (...) change, including new information, suggestions, and commands. In sum, the book creates new bridges between many fields, from philosophy and computer science to economics, linguistics, and psychology. For the experienced scholar access to a large body of recent literature is provided and the novice gets a thorough introduction to the action and techniques of dynamic logic. (shrink)

There has been considerable debate regarding the relative merits of two theses about moral obligation known as actualism and possibilism. Both theses seek to give expression to the general idea that one ought to do the best one can. According to actualism, one’s obligations turn on what would happen if one chose some course of action, whereas, according to possibilism, they turn on what could happen if one chose some course of action. There are two strands to the debate: the (...) substantive verdicts that the two theses render in particular cases, and the accounts that they yield of the conceptual structure of moral obligation. Possibilism is conceptually appealing, whereas actualism is not, but the latter may seem to render superior substantive verdicts. In this paper, it is argued that, by turning from the objectivist’s emphasis on what is actually best to the prospectivist’s emphasis on what one’s evidence indicates is best, possibilists can provide an account of moral obligation that is both conceptually and substantively attractive. (shrink)

This paper defends a counterexample to Modus Tollens, and uses it to draw some conclusions about the logic and semantics of indicative conditionals and probability operators in natural language. Along the way we investigate some of the interactions of these expressions with 'knows', and we call into question the thesis that all knowledge ascriptions have truth-conditions.

Many philosophers think that requirements of rationality are “wide-scope”. That is to say: they are requirements to satisfy some material conditional, such that one counts as satisfying the requirement iff one either makes the conditional’s antecedent false or makes its consequent true. These contrast with narrow-scope requirements, where the requirement takes scope only over the consequent of the conditional. Many of the philosophers who have preferred wide-scope requirements to narrow-scope requirements have also endorsed a corresponding semantic claim, namely that ordinary (...) talk about rationality, despite appearances to the contrary, expresses wide-scope claims. In doing so, they seek to avoid attributing massive error to ordinary speakers. However, it is becoming increasingly clear that the wide-scope semantics inadequately captures the meaning of ordinary talk about rationality. It seems, then, that we are left with a dilemma: either give up the view that requirements of rationality are wide-scope, or accept an implausible semantics for ordinary talk about rationality, or attribute massive error to speakers. In this paper, I argue that this dilemma is only apparent, since we can appeal to a standard kind of contextualist semantics for modals to explain why narrow-scope talk comes out true in virtue of the wide-scope requirements. My view, then, combines wide-scoping about the explanatorily fundamental requirements of rationality with a contextualist variant of a narrow-scope semantics. I argue that this view gives us the best of both worlds, as well as solving related puzzles and challenges for the extant views in the literature. (shrink)

Moti Mizrahi (2013) presents some novel counterexamples to Hypothetical Syllogism (HS) for indicative conditionals. I show that they are not compelling as they neglect the complicated ways in which conditionals and modals interact. I then briefly outline why HS should nevertheless be rejected.

In this paper we present a new model for the requirements analysis of a system. This is a new model based on the multiagent systems paradigm with the aim to support the requirements analysis phase of systems design. This model offers a structured approach to requirements analysis, based on conceptual models defined following a visual modeling language, called dependence networks. The main elements of this visual language are the agents with their goals, capabilities and facts, similarly to the TROPOS methodology (...) [11]. The normative component is present both in the ontology and in the conceptual metamodel, associating agents to roles they play inside the system and a set of goals, capabilities and facts proper of these roles. This improvement allows to define different types of dependence networks, called dynamic dependence networks and conditional dependence networks, representing the different phases of the requirements analysis of the system. This paper presents a requirements analysis model based on normative concepts such as obligation and institution. Our model is a model of semiformal specification featured by an ontology, a meta-model, a graphical notation and a set of constraints. Our model, moreover, allows the definition of the notion of coalition for the different kinds of network. (shrink)

This article proposes a systematic application of recent developments in the logic of preference to a number of topics in deontic logic. The key junction is the well‐known Hansson conditional for dyadic obligations. These conditionals are generalized by pairing them with reasoning about syntactic priority structures. The resulting two‐level approach to obligations is tested first against standard scenarios of contrary‐to‐duty obligations, leading also to a generalization for the Kanger‐Anderson reduction of deontic logic. Next, the priority framework is applied to model (...) two intuitively different sorts of deontic dynamics of obligations, based on information changes and on genuine normative events. In this two‐level setting, we also offer novel takes on vexed issues such as the Chisholm paradox and modelling strong permission. Finally, the priority framework is shown to provide a unifying setting for the study of operations on norms as such, in particular, adding or deleting individual norms, and even merging whole norm systems in different manners. (shrink)

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)

Diagnosis theory reasons about incomplete knowledge and only considers the past. It distinguishes between violations and non-violations. Qualitative decision theory reasons about decision variables and considers the future. It distinguishes between fulfilled goals and unfulfilled goals. In this paper we formalize normative diagnoses and decisions in the special purpose formalism DIO(DE)2 as well as in extensions of the preference-based deontic logic PDL. The DIagnostic and DEcision-theoretic framework for DEontic reasoning DIO(DE)2 formalizes reasoning about violations and fulfillments, and is used to (...) characterize the distinction between normative diagnosis theory and (qualitative) decision theory. The extension of the preference-based deontic logic PDL shows how normative diagnostic and decision-theoretic reasoning — i.e. reasoning about violations and fulfillments — can be formalized as an extension of deontic reasoning. (shrink)

To consequentialize a deontological moral theory is to give a theory which issues the same moral verdicts, but explains those verdicts in terms of maximizing or satisficing value. There are many motivations for consequentializing: to reconcile plausible ideas behind deontology with plausible ideas behind consequentialism, to help us better understand deontological theories, or to extend deontological theories beyond what intuitions alone tell us. It has proven difficult to consequentialize theories that allow for moral dilemmas or that deny that “ought” implies (...) “can.” This article argues that the problem is best solved by allowing impossible actions as inputs into consequentializations. It shows that all other approaches that have been advocated are inadequate. It also argues that progress in consequentialization, and in formal ethics more generally, requires thinking about more than just wrongness and permissibility; we should think about contrary-to-duty obligations and degrees of wrongness as well. (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)

A paradox is presented that the poses new problems for both the truth norm and the knowledge norm of belief.

There is a renewed debate about modus ponens. Strikingly, the recent counterexamples in Cantwell, Dreier and MacFarlane and Kolodny are generated by restricted readings of the ‘if’-clause. Moreover, it can be argued on general grounds that the restrictor view of conditionals developed in Kratzer and Lewis leads to counterexamples to modus ponens. This paper provides a careful analysis of modus ponens within the framework of the restrictor view. Despite appearances to the contrary, there is a robust sense in which modus (...) ponens is valid, owing to the fact that conditionals do not only allow for restricted readings but have bare interpretations, too. (shrink)

In this paper, I will discuss some examples of the so-called contrary-to-duty paradox, a well-known puzzle in deontic logic. A contrary-to-duty obligation is an obligation telling us what ought to be the case if something forbidden is true, for example: ‘If she is guilty, she should confess’. Contrary-to-duty obligations are important in our moral and legal thinking. Therefore, we want to be able to find an adequate symbolisation of such obligations in some logical system, a task that has turned out (...) to be difficult. This is shown by the so-called contrary-to-duty paradox. I will investigate and evaluate one kind of solution to this problem that has been suggested in the literature, which I will call the ‘counterfactual solution’. I will use some recent systems that combine not only counterfactual logic and deontic logic, but also temporal logic, in my analysis of the paradox. I will argue that the counterfactual solution has many attractive features and that it can give a fairly satisfactory answer to some examples of the contrary-to-duty paradox, but that it nevertheless has some serious problems. The conclusion is that, notwithstanding the many attractive features of the solution, there seem to be other approaches to the paradox that are more promising. (shrink)

We investigate under what conditions contrary-to-duty (CTD) structures lacking temporal and action elements can be given a coherent reading. We argue, contrary to some recent proposals, that CTD is not an instance of defeasible reasoning, and that methods of nonmonotonic logics are inadequate since they are unable to distinguish between defeasibility and violation of primary obligations. We propose a semantic framework based on the idea that primary and CTD obligations are obligations of different kinds: a CTD obligation pertains to, or (...) pre-supposes, a certain context in which a primary obligation is already violated. This framework is presented initially as an extension of Standard Deontic Logic (SDL), a normal modal logic of type KD, and is illustrated by application to a series of examples. The concluding section is concerned with some resemblances between CTD and defeasible reasoning. We show first that the SDL-based framework contains a flaw and must be adjusted. A discussion of possible adjustments, including an alternative treatment in terms of a preference-based semantics, reveals difficulties that are reminiscent of problems in defeasible reasoning and intensional accounts of defeasible conditionals. (shrink)

The paper is devoted to the problem of formal representation of prescriptive obligation, i.e., the obligation concerning the way in which an action is to be performed. Improper representation of prescriptive obligation leads to Forrester's Paradox. In the paper I first present a new version of Forrester's Paradox that generalizes the observation on which the original version is based. Then I challenge the two existing solutions to the paradox. I reject the solution of H.-N. Castañeda and analyze problems to which (...) the solution of W. Sinnott-Armstrong leads. I conclude the paper with a proposal for how to improve Sinnott-Armstrong's solution. (shrink)

This paper discusses the relation between deontic logic and the study of conversational interactions. Special attention is given to the notion of remedial interchange as analysed by sociologists and linguistic pragmaticians. This notion is close to the one of contrary-to-duty (reparational) obligation, which deontic logicians have been studying in its own right. The present article also investigates the question of whether some of the aspects of conversational interactions can fruitfully be described by using formal tools originally developed in the study (...) of iterated belief change. I here adapt the latter tools to deontic logic, and attempt an account of remedial interchange (and, more generally, contrary-to-duty reasoning) in terms of commutation. This account brings the dynamics of obligations to the fore. (shrink)

G3-style sequent calculi for the logics in the cube of non-normal modal logics and for their deontic extensions are studied. For each calculus we prove that weakening and contraction are height-preserving admissible, and we give a syntactic proof of the admissibility of cut. This implies that the subformula property holds and that derivability can be decided by a terminating proof search whose complexity is in Pspace. These calculi are shown to be equivalent to the axiomatic ones and, therefore, they are (...) sound and complete with respect to neighbourhood semantics. Finally, a Maehara-style proof of Craig’s interpolation theorem for most of the logics considered is given. (shrink)

There are plenty of classic paradoxes about conditional obligations, like the duty to be gentle if one is to murder, and about “supererogatory” deeds beyond the call of duty. But little has been said about the intersection of these topics. We develop the first general account of conditional supererogation, with the power to solve familiar puzzles as well as several that we introduce. Our account, moreover, flows from two familiar ideas: that conditionals restrict quantification and that supererogation emerges from a (...) clash between justifying and requiring reasons. (shrink)

This paper compares the recently proposed Robust Full Computational Tree Logic to model robustness in concurrent systems with other computational tree logic -based logics. RoCTL* extends CTL* with the addition of the operators Obligatory and Robustly, which quantify over failure-free paths and paths with one more failure respectively. This paper focuses on examining the succinctness and expressiveness of RoCTL* by presenting translations to and from RoCTL*. The core result of this paper is to show that RoCTL* is expressively equivalent to (...) CTL* but is non-elementarily more succinct. That is, RoCTL* does not add any expressive power over CTL*, but can represent some properties using vastly reduced formulae. We present a translation from RoCTL* into CTL* that preserves truth but may result in non-elementary growth in the length of the translated formula, as each nested Robustly operator may result in an extra exponential blowup. However, we show that this translation is optimal in the sense th.. (shrink)

abstract Moralism is often charged with being ineffective, rude, hypocritical, and intolerant. This article challenges all of those claims, first using evidence from social science to argue that moralism can be effective in changing others’ behaviour, serving as a remedy against the important problems of moral ignorance and weakness of will. Next, the apparent problems of rudeness, hypocrisy, and intolerance are argued to be either illusory or overstated. Finally, examples of unethical moralism are reviewed and a prudential type of moralism (...) is differentiated and defended. (shrink)

abstract Moralism is often charged with being ineffective, rude, hypocritical, and intolerant. This article challenges all of those claims, first using evidence from social science to argue that moralism can be effective in changing others’ behaviour, serving as a remedy against the important problems of moral ignorance and weakness of will. Next, the apparent problems of rudeness, hypocrisy, and intolerance are argued to be either illusory or overstated. Finally, examples of unethical moralism are reviewed and a prudential type of moralism (...) is differentiated and defended. (shrink)

Formalising deontic concepts, such as obligation, prohibition and permission, is normally carried out in a modal logic with a possible world semantics, in which some worlds are better than others. The main focus in these logics is on inferring logical consequences, for example inferring that the obligation O q is a logical consequence of the obligations O p and O. In this paper we propose a non-modal approach in which obligations are preferred ways of satisfying goals expressed in first-order logic. (...) To say that p is obligatory, but may be violated, resulting in a less than ideal situation s, means that the task is to satisfy the goal p ∨ s, and that models in which p is true are preferred to models in which s is true. Whereas, in modal logic, the preference relation between possible worlds is part of the semantics of the logic, in this non-modal approach, the preference relation between first-order models is external to the logic. Although our main focus is on satisfying goals, we also formulate a notion of logical consequence, which is comparable to the notion of logical consequence in modal deontic logic. In this formalisation, an obligation O p is a logical consequence of goals G, when p is true in all best models of G. We show how this non-modal approach to the treatment of deontic concepts deals with problems of contrary-to-duty obligations and normative conflicts, and argue that the approach is useful for many other applications, including abductive explanations, defeasible reasoning, combinatorial optimisation, and reactive systems of the production system variety. (shrink)

In “Gentle Murder, Or The Adverbial Samaritan”, James William Forrester presents what he describes as “the most powerful version yet put forward” of Lennart Åqvist's Good Samaritan paradox in deontic logic. Forrester suggests that the paradox may make it necessary to reject the standard deontic inference principle. This desperate conclusion, as Forrester acknowledges, would imply that all of standard deontic logic “must be in a bad way”. But Forrester's “paradox” is not nearly so deep or intractable as he maintains.

In this paper we present a Gentzen system for reasoning with contrary-to-duty obligations. The intuition behind the system is that a contrary-to-duty is a special kind of normative exception. The logical machinery to formalise this idea is taken from substructural logics and it is based on the definition of a new non-classical connective capturing the notion of reparational obligation. Then the system is tested against well-known contrary-to-duty paradoxes.

Recent years have yielded many discussions on how to endow autonomous agents with the ability to make ethical decisions, and the need for explicit ethical reasoning and transparency is a persistent theme in this literature. We present a modular and transparent approach to equip autonomous agents with the ability to comply with ethical prescriptions, while still enacting pre-learned optimal behaviour. Our approach relies on a normative supervisor module, that integrates a theorem prover for defeasible deontic logic within the control loop (...) of a reinforcement learning agent. The supervisor operates as both an event recorder and an on-the-fly compliance checker w.r.t. an external norm base. We successfully evaluated our approach with several tests using variations of the game Pac-Man, subject to a variety of “ethical” constraints. (shrink)

Amie Thomasson's Norms and Necessity offers a non-factualist theory of the language of metaphysical necessity, centering on the idea that statements of necessity express semantic norms. This article identifies a potential problem for the view by distinguishing two kinds of conditional necessity, investigates a solution derived from a well-known parallel pair of conditional necessities in deontic logic, but finds it is not up to the job. The last part of the paper suggests a different route, largely in keeping with the (...) underlying ideas behind Thomasson's approach. (shrink)

Conciliationism is a view—well, a family of views—in the epistemology of disagreement. The idea, simply put, is that, in a wide range of cases where you find yourself in disagreement with another reasoner about the truth of some proposition, you are rationally obliged to adjust your credence in the direction of hers. Conciliationism enjoys a fair bit of prima facie plausibility. Most versions of it, however, suffer from a common (and rather obvious) problem: self-incrimination. Although there is some recognition in (...) the recent literature on disagreement that there is a problem in this vicinity, it, more often than not, is completely ignored. When it is not completely ignored, both the conciliationists and their critics tend to frame the problem incorrectly. As a result, they end up focusing most of their attention on pseudo-problems rather than the genuine worry. Furthermore, even when they have hit on the genuine worry, conciliationists have tended to give surprising and implausible responses to it. Even by their own lights, conciliationists aren’t justified in believing their conciliationist theses. In this paper, I argue that it’s time to come clean. Time to look for a view on the epistemic significance of disagreement that we can actually be justified in believing. (shrink)

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)

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.

This paper studies intentional action in stit logic. The formal logic study of intentional action appears to be new, since most logical studies of intention concern intention as a static mental state. In the formalization we distinguish three modes of acting: the objective level concerning the choices an agent objectively exercises, the subjective level concerning the choices an agent knows or believes to be exercising, and finally, the intentional level concerning the choices an agent intentionally exercises. Several axioms constraining the (...) relations between these different modes of acting will be considered and discussed. The side effect problem will be analyzed as an interaction between knowingly doing and intentionally doing. Non-successful action will be analyzed as a weakening of the epistemic attitude towards action. Finally, the notion of ‘attempt’ will be briefly considered as a further weakening in this direction. (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)

This article proposes a systematic application of recent developments in the logic of preference to a number of topics in deontic logic. The key junction is the well-known Hansson conditional for dyadic obligations. These conditionals are generalized by pairing them with reasoning about syntactic priority structures. The resulting two-level approach to obligations is tested first against standard scenarios of contrary-to-duty obligations, leading also to a generalization for the Kanger-Anderson reduction of deontic logic. Next, the priority framework is applied to model (...) two intuitively different sorts of deontic dynamics of obligations, based on information changes and on genuine normative events. In this two-level setting, we also offer novel takes on vexed issues such as the Chisholm paradox and modelling strong permission. Finally, the priority framework is shown to provide a unifying setting for the study of operations on norms as such, in particular, adding or deleting individual norms, and even merging whole norm systems in different manners. (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)