According to a naïve view sometimes apparent in the writings of moral philosophers, ‘ought’ often expresses a relation between agents and actions – the relation that obtains between an agent and an action when that action is what that agent ought to do. It is not part of this naïve view that ‘ought’ always expresses this relation – on the contrary, adherents of the naïve view are happy to allow that ‘ought’ also has an epistemic sense, on which it means, (...) roughly, that some proposition is likely to be the case, and adherents of the naïve view are also typically happy to allow that ‘ought’ also has an evaluative sense, on which it means, roughly, that were things ideal, some proposition would be the case.1 What is important to the naïve view is not that these other senses of ‘ought’ do not exist, but rather that they are not exhaustive – for what they leave out, is the important deliberative sense of ‘ought’, which is the central subject of moral inquiry about what we ought to do and why – and it is this deliberative sense of ‘ought’ which the naïve view understands to express a relation between agents and actions.2 In contrast, logically and linguistically sophisticated philosophers – with a few notable exceptions3 – have rejected this naïve view. According to a dominant perspective in the interpretation of deontic logic and in linguistic semantics, for example, articulated by Roderick Chisholm (1964) and Bernard Williams (1981) in philosophy and in the dominant paradigm in linguistic semantics as articulated in particular by.. (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)

If you ought to perform a certain act, and some other action is a necessary means for you to perform that act, then you ought to perform that other action as well – or so it seems plausible to say. This transmission principle is of both practical and theoretical significance. The aim of this paper is to defend this principle against a number of recent objections, which (as I show) are all based on core assumptions of the view called actualism. (...) I reject actualism, provide an alternative explanation of its plausible features, and present an independent argument for the transmission principle. (shrink)

Actualists hold that contrary-to-duty scenarios give rise to deontic dilemmas and provide counterexamples to the transmission principle, according to which we ought to take the necessary means to actions we ought to perform. In an earlier article, I have argued, contrary to actualism, that the notion of ‘ought’ that figures in conclusions of practical deliberation does not allow for deontic dilemmas and validates the transmission principle. Here I defend these claims, together with my possibilist account of contrary-to-duty scenarios, against Stephen (...) White’s recent criticism. (shrink)

Deference principles are principles that describe when, and to what extent, it’s rational to defer to others. Recently, some authors have used such principles to argue for Evidential Uniqueness, the claim that for every batch of evidence, there’s a unique doxastic state that it’s permissible for subjects with that total evidence to have. This paper has two aims. The first aim is to assess these deference-based arguments for Evidential Uniqueness. I’ll show that these arguments only work given a particular kind (...) of deference principle, and I’ll argue that there are reasons to reject these kinds of principles. The second aim of this paper is to spell out what a plausible generalized deference principle looks like. I’ll start by offering a principled rationale for taking deference to constrain rational belief. Then I’ll flesh out the kind of deference principle suggested by this rationale. Finally, I’ll show that this principle is both more plausible and more general than the principles used in the deference-based arguments for Evidential Uniqueness. (shrink)

Possible worlds semantics faces a range of difficulties for at least certain types of modals, especially deontic modals with their distinction between heavy and light permissions and obligations. This paper outlines a new semantics of modals that aims to overcome some of those difficulties. The semantics is based on an a novel ontology of modal objects, entities like obligations, permissions, needs, as well as epistemic states, abilities, and essences. Moreover, it is based on truthmaking, in the sense of Fine’s recent (...) truthmaker semantics. (shrink)

I propose a unified solution to two puzzles: Ross's puzzle and free choice permission. I begin with a pair of cases from the decision theory literature illustrating the phenomenon of act dependence, where what an agent ought to do depends on what she does. The notion of permissibility distilled from these cases forms the basis for my analysis of 'may' and 'ought'. This framework is then combined with a generalization of the classical semantics for disjunction — equivalent to Boolean disjunction (...) on the diagonal, but with a different two-dimensional character — that explains the puzzling facts in terms of semantic consequence. (shrink)

At the heart of the Bayesianism is a rule, Conditionalization, which tells us how to update our beliefs. Typical formulations of this rule are underspecified. This paper considers how, exactly, this rule should be formulated. It focuses on three issues: when a subject’s evidence is received, whether the rule prescribes sequential or interval updates, and whether the rule is narrow or wide scope. After examining these issues, it argues that there are two distinct and equally viable versions of Conditionalization to (...) choose from. And which version we choose has interesting ramifications, bearing on issues such as whether Conditionalization can handle continuous evidence, and whether Jeffrey Conditionalization is really a generalization of Conditionalization. (shrink)

Logical geometry systematically studies Aristotelian diagrams, such as the classical square of oppositions and its extensions. These investigations rely heavily on the use of bitstrings, which are compact combinatorial representations of formulas that allow us to quickly determine their Aristotelian relations. However, because of their general nature, bitstrings can be applied to a wide variety of topics in philosophical logic beyond those of logical geometry. Hence, the main aim of this paper is to present a systematic technique for assigning bitstrings (...) to arbitrary finite fragments of formulas in arbitrary logical systems, and to study the logical and combinatorial properties of this technique. It is based on the partition of logical space that is induced by a given fragment, and sheds new light on a number of interesting issues, such as the logic-dependence of the Aristotelian relations and the subtle interplay between the Aristotelian and Boolean structure of logical fragments. Finally, the bitstring technique also allows us to systematically analyze fragments from contemporary logical systems, such as public announcement logic, which could not be done before. (shrink)

We defend three controversial claims about preference, credence, and choice. First, all agents (not just rational ones) have complete preferences. Second, all agents (again, not just rational ones) have real-valued credences in every proposition in which they are confident to any degree. Third, there is almost always some unique thing we ought to do, want, or believe.

This paper proposes a semantics for free choice permission that explains both the non-classical behavior of modals and disjunction in sentences used to grant permission, and their classical behavior under negation. It also explains why permissions can expire when new information comes in and why free choice arises even when modals scope under disjunction. On the proposed approach, deontic modals update preference orderings, and connectives operate on these updates rather than propositions. The success of this approach stems from its capacity (...) to capture the difference between expressing the preferences that give rise to permissions and conveying propositions about those preferences. (shrink)

Many philosophers argue that the error theory should be rejected because it is incompatible with standard deontic logic and semantics. We argue that such formal objections to the theory fail. Our discussion has two upshots. First, it increases the dialectical weight that must be borne by objections to the error theory that target its content rather than its form. Second, it shows that standard deontic logic and semantics should be revised.

Some intuitive normative principles raise vexing 'detaching problems' by their failure to license modus ponens. I examine three such principles (a self-reliance principle and two different instrumental principles) and recent stategies employed to resolve their detaching problems. I show that solving these problems necessitates postulating an indefinitely large number of senses for 'ought'. The semantics for 'ought' that is standard in linguistics offers a unifying strategy for solving these problems, but I argue that an alternative approach combining an end-relational theory (...) of normativity with a comparative probabilistic semantics for 'ought' provides a more satisfactory solution. (shrink)

Standard deontic logic (SDL) is defined on the basis of possible world semantics and is a logic of alethic-deontic modalities rather than deontic modalities alone. The interpretation of the concepts of obligation and permission comes down exclusively to the logical value that a sentence adopts for the accessible deontic alternatives. Here, we set forth a different approach, this being a logic which additionally takes into consideration whether sentences stand in relation to the normative system or to the system of values (...) under which we predicate the deontic qualifications. By taking this aspect into account, we arrive at a logical system which preserves laws proper to a deontic logic but where the standard paradoxes of deontic logic do not arise. It is a logic of strictly-deontic modalities DR. (shrink)

Titelbaum Oxford studies in epistemology, 2015) has recently argued that the Enkratic Principle is incompatible with the view that rational belief is sensitive to higher-order defeat. That is to say, if it cannot be rational to have akratic beliefs of the form “p, but I shouldn’t believe that p,” then rational beliefs cannot be defeated by higher-order evidence, which indicates that they are irrational. In this paper, I distinguish two ways of understanding Titelbaum’s argument, and argue that neither version is (...) sound. The first version can be shown to rest on a subtle, but crucial, misconstrual of the Enkratic Principle. The second version can be resisted through careful consideration of cases of higher-order defeat. The upshot is that proponents of the Enkratic Principle are free to maintain that rational belief is sensitive to higher-order defeat. (shrink)

A dynamic semantics for iffy oughts offers an attractive alternative to the folklore that Chisholm's paradox enforces an unhappy choice between the intuitive inference rules of factual and deontic detachment. The first part of the story told here shows how a dynamic theory about ifs and oughts gives rise to a nonmonotonic perspective on deontic discourse and reasoning that elegantly removes the air of paradox from Chisholm's puzzle without sacrificing any of the two detachment principles. The second part of the (...) story showcases two bonus applications of the framework suggested here: it offers a response to Forrester's gentle murder paradox and avoids Kolodny and MacFarlane's miners paradox about deontic reasoning under epistemic uncertainty. A comparison between the dynamic semantic proposal made in this paper and a more conservative approach combining a static semantics with a dynamic pragmatics is provided. (shrink)

Criticism is a staple of the scientific enterprise and of the social epistemology of science. Philosophical discussions of criticism have traditionally focused on its roles in relation to objectivity, confirmation, and theory choice. However, attention to criticism and to criticizability should also inform our thinking about scientific pursuits: the allocation of resources with the aim of developing scientific tools and ideas. In this paper, we offer an account of scientific pursuitworthiness which takes criticizability as its starting point. We call this (...) the apokritic model of pursuit. Its core ideas are that pursuits are practices governed by norms for asking and answering questions, and that criticism arises from the breach of these norms. We illustrate and advertise our approach using examples from institutional grant review, neuroscience, and sociology. We show that the apokritic model can unify several indices of criticizability, that it can account for the importance of criticizing pursuits in scientific practice, and that it can offer ameliorative advice to erstwhile pursuers. (shrink)

The Aristotelian square of oppositions is a well-known diagram in logic and linguistics. In recent years, several extensions of the square have been discovered. However, these extensions have failed to become as widely known as the square. In this paper we argue that there is indeed a fundamental difference between the square and its extensions, viz., a difference in informativity. To do this, we distinguish between concrete Aristotelian diagrams and, on a more abstract level, the Aristotelian geometry. We then introduce (...) two new logical geometries, and develop a formal, well-motivated account of their informativity. This enables us to show that the square is strictly more informative than many of the more complex diagrams. (shrink)

I argue that given standard deontic logic, wide-scope rational requirements entail narrow-scope rational requirements. In particular, the widely-embraced Enkratic Principle entails that if a particular combination of attitudes is rationally forbidden, it is also rationally forbidden to believe that that combination of attitudes is required.

Moral obligation and permissibility are usually thought to be interdefinable. Following the pattern of the duality definitions of necessity and possibility, we have that something’s being permissible could be defined as its not being obligatory to not do it. And that something’s being obligatory could be defined as its not being permissible to not do it. In this paper, I argue that neither direction of this alleged interdefinability works. Roughly, the problem is that a claim that some act is obligatory (...) or permissible entails that there is a moral law, whereas a negative claim that some act is not obligatory or not permissible does not. Nevertheless, one direction of the interdefinability can potentially be salvaged. I argue that, if we do not require the conceptual possibility of moral dilemmas, then there is a way to plausibly define obligation in terms of permissibility. I conclude that permissibility is the only feasible deontic primitive. (shrink)

Many theories of rational belief give a special place to logic. They say that an ideally rational agent would never be uncertain about logical facts. In short: they say that ideal rationality requires "logical omniscience." Here I argue against the view that ideal rationality requires logical omniscience on the grounds that the requirement of logical omniscience can come into conflict with the requirement to proportion one’s beliefs to the evidence. I proceed in two steps. First, I rehearse an influential line (...) of argument from the "higher-order evidence" debate, which purports to show that it would be dogmatic, even for a cognitively infallible agent, to refuse to revise her beliefs about logical matters in response to evidence indicating that those beliefs are irrational. Second, I defend this "anti-dogmatism" argument against two responses put forth by Declan Smithies and David Christensen. Against Smithies’ response, I argue that it leads to irrational self-ascriptions of epistemic luck, and that it obscures the distinction between propositional and doxastic justification. Against Christensen’s response, I argue that it clashes with one of two attractive deontic principles, and that it is extensionally inadequate. Taken together, these criticisms will suggest that the connection between logic and rationality cannot be what it is standardly taken to be—ideal rationality does not require logical omniscience. (shrink)

One very popular assumption in the epistemological literature is that belief and assertion are governed by one and the same epistemic norm. This paper challenges this claim. Extant arguments in defence of the view are scrutinized and found to rest on value-theoretic inaccuracies. First, the belief-assertion parallel is shown to lack the needed normative strength. Second, I argue that the claim that assertion inherits the norm of belief in virtue of being an expression thereof rests on a failed instance of (...) deontic transmission. Third, the inheritance argument from the norm for action is proven guilty of deontic equivocation. Last but not least, it is argued that, on a functionalist normative picture, assertion and belief are governed by different epistemic norms, in virtue of serving different epistemic functions. (shrink)

There has been a recent surge of work on deontic modality within philosophy of language. This work has put the deontic logic tradition in contact with natural language semantics, resulting in significant increase in sophistication on both ends. This chapter surveys the main motivations, achievements, and prospects of this work.

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)

The verdicts standard consequentialism gives about what we are obligated to do crucially depend on what theory of value the consequentialist accepts. This makes it hard to say what separates standard consequentialist theories from non-consequentialist theories. This article discusses how we can draw sharp lines separating standard consequentialist theories from other theories and what assumptions about goodness we must make in order to draw these lines. The discussion touches on cases of deontic constraints, cases of deontic options, and cases involved (...) in the so-called "actualism"/"possibilism" debate. What emerges is that there are various interesting patterns relating the different commitments of consequentialism, different principles about obligation and about goodness, and different rules concerning how facts about values determine facts about obligation. (shrink)

Conditional logics were originally developed for the purpose of modeling intuitively correct modes of reasoning involving conditional—especially counterfactual—expressions in natural language. While the debate over the logic of conditionals is as old as propositional logic, it was the development of worlds semantics for modal logic in the past century that catalyzed the rapid maturation of the field. Moreover, like modal logic, conditional logic has subsequently found a wide array of uses, from the traditional (e.g. counterfactuals) to the exotic (e.g. conditional (...) obligation). Despite the close connections between conditional and modal logic, both the technical development and philosophical exploitation of the latter has outstripped that of the former, with the result that noticeable lacunae exist in the literature on conditional logic. My dissertation addresses a number of these underdeveloped frontiers, producing new technical insights and philosophical applications. -/- I contribute to the solution of a problem posed by Priest of finding sound and complete labeled tableaux for systems of conditional logic from Lewis' V-family. To develop these tableaux, I draw on previous work on labeled tableaux for modal and conditional logic; errors and shortcomings in recent work on this problem are identified and corrected. While modal logic has by now been thoroughly studied in non-classical contexts, e.g. intuitionistic and relevant logic, the literature on conditional logic is still overwhelmingly classical. Another contribution of my dissertation is a thorough analysis of intuitionistic conditional logic, in which I utilize both algebraic and worlds semantics, and investigate how several novel embedding results might shed light on the philosophical interpretation of both intuitionistic logic and conditional logic extensions thereof. -/- My dissertation examines deontic and connexive conditional logic as well as the underappreciated history of connexive notions in the analysis of conditional obligation. The possibility of interpreting deontic modal logics in such systems (via embedding results) serves as an important theoretical guide. A philosophically motivated proscription on impossible obligations is shown to correspond to, and justify, certain (weak) connexive theses. Finally, I contribute to the intensifying debate over counterpossibles, counterfactuals with impossible antecedents, and take—in contrast to Lewis and Williamson—a non-vacuous line. Thus, in my view, a counterpossible like "If there had been a counterexample to the law of the excluded middle, Brouwer would not have been vindicated" is false, not (vacuously) true, although it has an impossible antecedent. I exploit impossible (non-normal) worlds—originally developed to model non-normal modal logics—to provide non-vacuous semantics for counterpossibles. I buttress the case for non-vacuous semantics by making recourse to both novel technical results and theoretical considerations. (shrink)

This work explores the hypothesis that natural language is a tool for changing a language user's state of mind and, more specifically, the hypothesis that a sentence's meaning is constituted by its characteristic role in fulfilling this purpose. This view contrasts with the dominant approach to semantics due to Frege, Tarski and others' work on artificial languages: language is first and foremost a tool for representing the world. Adapted to natural language by Davidson, Lewis, Montague, et. al. this dominant approach (...) has crystalized as truth-conditional semantics: to know the meaning of a sentence is to know the conditions under which that sentence is true. Chapter 1 details the animating ideas of my alternative approach and shows that the representational function of language can be understood in terms of the more general function of changing representational mental states. Chapters 2-4 argue that the additional resources of this more general conception of meaning allow us to explain certain phenomena involving conditionals and grammatical mood that truth-conditional semantics does not. In the analysis of these specific phenomena and the articulation of the general approach on offer, it emerges that this approach combines insights and benefits from both use-theoretic and truth-theoretic work on meaning. (shrink)

Trying to overcome Dugundji’s result on uncharacterisability of modal logics by finite logical matrices, Kearns and Ivlev proposed, independently, a characterisation of some modal systems by means of four-valued multivalued truth-functions , as an alternative to Kripke semantics. This constitutes an antecedent of the non-deterministic matrices introduced by Avron and Lev . In this paper we propose a reconstruction of Kearns’s and Ivlev’s results in a uniform way, obtaining an extension to another modal systems. The first part of the paper (...) is devoted to four-valued Nmatrices, including Kearns’s and Ivlev’s. Besides proving with full details Kearns’s results for T, S4 and S5, we also obtain a characterisation of the system B by four-valued Nmatrices with level valuations. Concerning Ivlev’s results, two new modal systems are introduced and char.. (shrink)

This paper concerns the relationship between transitivity of entailment, omega-inconsistency and nonstandard models of arithmetic. First, it provides a cut-free sequent calculus for non-transitive logic of truth STT based on Robinson Arithmetic and shows that this logic is omega-inconsistent. It then identifies the conditions in McGee for an omega-inconsistent logic as quantified standard deontic logic, presents a cut-free labelled sequent calculus for quantified standard deontic logic based on Robinson Arithmetic where the deontic modality is treated as a predicate, proves omega-inconsistency (...) and shows thus, pace Cobreros et al., that the result in McGee does not rely on transitivity. Finally, it also explains why the omega-inconsistent logics of truth in question do not require nonstandard models of arithmetic. (shrink)

There is a strong case to be made for thinking that an obscure logic, KR, is better than classical logic and better than any relevant logic. The argument for KR over relevant logics is that KR counts disjunctive syllogism valid, and this is the biggest complaint about relevant logics. The argument for KR over classical logic depends on the normativity of logic and the paradoxes of implication. The paradoxes of implication are taken by relevant logicians to justify relevant logic, but (...) considerations on the normativity of logic show that only some of the paradoxes of implication are genuine. KR avoids all the genuine paradoxes of implication, unlike classical logic. Overall, KR avoids the genuine paradoxes of implication and avoids the major objection to relevant logics. This combination of features provides strong reason to give KR a place in the conversation about the right logic. (shrink)

Khemlani et al. (2018) mischaracterize logic in the course of seeking to show that mental model theory (MMT) can accommodate a form of inference (, let us label it) they find in a high percentage of their subjects. We reveal their mischaracterization and, in so doing, lay a landscape for future modeling by cognitive scientists who may wonder whether human reasoning is consistent with, or perhaps even capturable by, reasoning in a logic or family thereof. Along the way, we note (...) that the properties touted by Khemlani et al. as innovative aspects of MMT‐based modeling (e.g., nonmonotonicity) have for decades been, in logic, acknowledged and rigorously specified by families of (implemented) logics. Khemlani et al. (2018) further declare that is “invalid in any modal logic.” We demonstrate this to be false by our introduction (Appendix A) of a new propositional modal logic (within a family of such logics) in which is provably valid, and by the implementation of this logic. A second appendix, B, partially answers the two‐part question, “What is a formal logic, and what is it for one to capture empirical phenomena?”. (shrink)

This paper generalizes the preface paradox beyond the conjunctive aggregation of beliefs and constructs an analogous paradox for deontic reasoning. The analysis of the deontic case suggests a systematic restriction of intuitive rules for reasoning with obligations. This proposal can be transferred to the epistemic case: it avoids the preface and the lottery paradox and saves one of the two directions of the Lockean Thesis (i.e., high credence is sufficient, but not necessary for rational belief). The resulting account compares favorably (...) to competing proposals; in particular, we can formulate the rules of correct doxastic reasoning without reference to probabilistic features of the involved propositions. (shrink)

It is an appealing idea that deontic modality is a modality of the open future, and that the indeterminacy of the open future is the key, within natural language, to understanding the deontic modal puzzles that form the traditional subject-matter of deontic logic. In this paper, I pull together three well-studied strands of indeterminism—Thomason (1980)’s settledness operator, the modal base of Kratzer (1981, 1991)’s analysis of modals, and Stalnaker (1978)’s notion of diagonal acceptance—to argue for two theses governing a deontic (...) logic for natural language. -/- The first thesis makes a claim about postsemantic truth, and is couched in terms of Stalnaker’s dagger operator. The second concerns what it is for an act to be permissible, when agents exercise partial control over their obligations as well as their bodily movements. (shrink)

Desires matter. What are desires? Many believe that desire is a motivational state: desiring is being disposed to act. This conception aligns with the functionalist approach to desire and the standard account of desire's role in explaining action. According to a second influential approach, however, desire is first and foremost an evaluation: desiring is representing something as good. After all, we seem to desire things under the guise of the good. Which understanding of desire is more accurate? Is the guise (...) of the good even right to assume? Should we adopt an alternative picture that emphasizes desire's deontic nature? What do neuroscientific studies suggest? -/- Essays in the first section of the volume are devoted to these questions, and to the puzzle of desire's essence. In the second part of the volume, essays investigate some implications that the various conceptions of desire have on a number of fundamental issues. For example, why are inconsistent desires problematic? What is desire's role in practical deliberation? How do we know what we want? -/- This volume will contribute to the emergence of a fruitful debate on a neglected, albeit crucial, dimension of the mind. (shrink)

This paper presents a short survey of recent developments in stit theories, with an emphasis on combinations of stit and deontic logic, and those of stit and epistemic logic.

In this paper I argue that deontic modals are hyperintensional, i.e. logically equivalent contents cannot be substituted in their scope. I give two arguments, one deductive and the other abductive. First, I show that the contrary thesis leads to falsity; second, I argue that a hyperintensional theory of deontic modals fares better than its rivals in terms of elegance, theoretical simplicity and explanatory power. I then propose a philosophical analysis of this thesis and outline some consequences. In Section 1 I (...) introduce and define deontic modality and hyperintensionality. In Section 2 I give a reductio for the hyperintensionality of deontic modals. If the argument is sound, a useful corollary is that deontic modals are also non-intensional, and therefore possible-world semantics accounts are illfitted for them. I then show how the main result can be strengthened or weakened by varying the definition of logical validity. In Section 3 I give an abductive argument for the hyperintensionality of deontic modals, arguing that with a single move we are able to solve many paradoxes and puzzles traditionally troubling deontic logic. I present a version of a hyperintensional deontic logic in an appendix, which I prove is sound and complete with respect to a version of truthmaker semantics. (shrink)

I argue that when determining whether an agent ought to perform an act, we should not hold fixed the fact that she’s going to form certain attitudes (and, here, I’m concerned with only reasons-responsive attitudes such as beliefs, desires, and intentions). For, as I argue, agents have, in the relevant sense, just as much control over which attitudes they form as which acts they perform. This is important because what effect an act will have on the world depends not only (...) on which acts the agent will simultaneously and subsequently perform, but also on which attitudes she will simultaneously and subsequently form. And this all leads me to adopt a new type of practical theory, which I call rational possibilism. On this theory, we first evaluate the entire set of things over which the agent exerts control, where this includes the formation of certain attitudes as well as the performance of certain acts. And, then, we evaluate individual acts as being permissible if and only if, and because, there is such a set that is itself permissible and that includes that act as a proper part. Importantly, this theory has two unusual features. First, it is not exclusively act-orientated, for it requires more from us than just the performance of certain voluntary acts. It requires, in addition, that we involuntarily form certain attitudes. Second, it is attitude-dependent in that it holds that which acts we’re required to perform depends on which attitudes we’re required to form. I then show how these two features can help us both to address certain puzzling cases of rational choice and to understand why most typical practical theories (utilitarianism, virtue ethics, rational egoism, Rossian deontology, etc.) are problematic. (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)

Some sacrifices—like giving a kidney or heroically dashing into a burning building—are supererogatory: they are good deeds beyond the call of duty. But if such deeds are really so good, philosophers ask, why shouldn’t morality just require them? The standard answer is that morality recognizes a special role for the pursuit of self-interest, so that everyone may treat themselves as if they were uniquely important. This idea, however, cannot be reconciled with the compelling picture of morality as impartial—the view that (...) we are each anyone’s equal. I propose an alternative Self-Other Symmetric account of our moral freedom: the limits on what morality may demand of us are set by the duties we owe to ourselves. I begin with a defense of the Self-Other Symmetry: the idea that we owe the same duties to ourselves—and have the same rights against ourselves—as any relevantly similar other. Because we are consenting parties to our own actions, I argue, our rights against ourselves do not function like the rights of unwilling others. Instead, they play a permissive function, allowing us to block the demand to give up what is ours. I conclude by uniting, aggravating, and trying to solve some paradoxes of supererogatory permissions, guided by the idea that morality cannot be reduced to a ranking of options from best-to-worst. Rights against oneself are an irreducible second dimension, one that we need if we are to unify rights and supererogation into an impartial moral vision. (shrink)

In the present paper we model the Navya-Nyāya analysis of Vedic and secular injunctions and prohibitions by means of Giordani’s and Canavotto’s system ADL of dynamic deontic logic. Navya-Naiyāyikas analyze the meaning of injunctions and prohibitions by reducing them to plain indicative statements about certain properties whose presence or absence in the enjoined or prohibited action serves as a criterion for the truth or falsity of the “inducing” or “restraining knowledge”, a kind of qualificative cognition instilled in the recipient of (...) an injunction or prohibition. Thus, Navya-Naiyāyikas have found their own way to solve Jørgensen’s Puzzle concerning the very idea of a deontic logic as a tool to analyze arguments based on sentences which do not seem to be truth-apt. The teleological aspect of the Navya-Nyāya characterization of an enjoined or prohibited action can also give a clue to solutions of other puzzles and paradoxes which have beset the development of deontic logic in the West. A specific contrary-to-duty puzzle from the Indian tradition is related to the śyena, a malefic sacrifice meant for harming one’s enemy. The Vedic injunction to perform such a sacrifice runs counter to a religious practitioner’s duty not to harm a living being. In the present paper we examine the cogency of the very different solutions to this dilemma suggested by the Mīmāṃsaka Prabhākara on the one hand and the Navya-Naiyāyika Gaṅgeśa on the other hand. (shrink)

Define teleology as the view that requirements hold in virtue of facts about value or goodness. Teleological views are quite popular, and in fact some philosophers (e.g. Dreier, Smith) argue that all (plausible) moral theories can be understood teleologically. I argue, however, that certain well-known cases show that the teleologist must at minimum assume that there are certain facts that an agent ought to know, and that this means that requirements can't, in general, hold in virtue of facts about value (...) or goodness. I then show that even if we grant those 'ought's teleology still runs into problems. A positive justification of teleology looks like it will require an argument of this form: O(X); if X, then O(Y); therefore O(Y). But this form of argument isn't in general valid. I conclude by offering two positive suggestions for those attracted to a teleological outlook. (shrink)

We present a new axiomatization of the deontic fragment of Anderson's relevant deontic logic, give an Andersonian reduction of a relevant version of Mally's deontic logic previously discussed in this journal, study the effect of adding propositional quantification to Anderson's system, and discuss the meaning of Anderson's propositional constant in a wide range of Andersonian deontic systems.

On admet en général qu’il y a deux sortes de concepts normatifs : les concepts évaluatifs, comme bon, et les concepts déontiques, comme devoir. La question que soulève cette distinction est celle de savoir comment il est possible d’affirmer que les concepts évaluatifs sont normatifs. En effet, comme les concepts déontiques semblent constituer le coeur du domaine normatif, plus le fossé entre les deux sortes de concepts est grand, moins il paraîtra plausible d’affirmer que les concepts évaluatifs sont normatifs. Après (...) avoir présenté les différences principales entre les concepts évaluatifs et les concepts déontiques, et montré qu’il y a plus qu’une différence superficielle entre les deux sortes de concepts, j’examinerai la question de la normativité des concepts évaluatifs. Il deviendra apparent que même s’il s’agit de concepts ayant des fonctions différentes, il existe un grand nombre de relations entre les concepts évaluatifs, d’une part, et les concepts de devoir et de raison, d’autre part.It is generally accepted that there are two sorts of normative concepts : evaluative concepts, such as good, and deontic concepts, such as ought. The question that is raised by this distinction is how it is possible to claim that evaluative concepts are normative. As deontic concepts appear to be at the heart of normativity, the more there is a gap between evaluative and deontic concepts, the less it appears plausible to say that evaluative concepts are normative. After having presented the main differences between evaluative and deontic concepts, and shown that there is more than a superficial difference between the two sorts of concepts, the paper turns to the question of the normativitity of evaluative concepts. It will become clear that even if these concepts have different functions, there are a great many ties between evaluative concepts, on the one hand, and the concepts of ought and of reason, on the other hand. (shrink)

This chapter presents a new semantics for inductive empirical knowledge. The epistemic agent is represented concretely as a learner who processes new inputs through time and who forms new beliefs from those inputs by means of a concrete, computable learning program. The agent’s belief state is represented hyper-intensionally as a set of time-indexed sentences. Knowledge is interpreted as avoidance of error in the limit and as having converged to true belief from the present time onward. Familiar topics are re-examined within (...) the semantics, such as inductive skepticism, the logic of discovery, Duhem’s problem, the articulation of theories by auxiliary hypotheses, the role of serendipity in scientific knowledge, Fitch’s paradox, deductive closure of knowability, whether one can know inductively that one knows inductively, whether one can know inductively that one does not know inductively, and whether expert instruction can spread common inductive knowledge—as opposed to mere, true belief—through a community of gullible pupils. (shrink)

We define a family of intuitionistic non-normal modal logics; they can be seen as intuitionistic counterparts of classical ones. We first consider monomodal logics, which contain only Necessity or Possibility. We then consider the more important case of bimodal logics, which contain both modal operators. In this case we define several interactions between Necessity and Possibility of increasing strength, although weaker than duality. We thereby obtain a lattice of 24 distinct bimodal logics. For all logics we provide both a Hilbert (...) axiomatisation and a cut-free sequent calculus, on its basis we also prove their decidability. We then define a semantic characterisation of our logics in terms of neighbourhood models containing two distinct neighbourhood functions corresponding to the two modalities. Our semantic framework captures modularly not only our systems but also already known intuitionistic non-normal modal logics such as Constructive K and the propositional fragment of Wijesekera’s Constructive Concurrent Dynamic Logic. (shrink)

Belief revision from the point of view of doxastic logic. Logic Journal of the IGPL, 3(4), 535–553. Segerberg, K. (1995). Conditional action. In G. Crocco, L. Fariñas, & A. Herzig (Eds.), Conditionals: From philosophy to computer science, Studies ...