Overview of fundamental work in deontic logic.

The overall moral status of an option—whether it is required, permissible, forbidden, or something we really should do—is explained by competition between the contributory reasons bearing on that option and the alternatives. A familiar challenge for accounts of this competition is to explain the existence of latitude: there are usually multiple permissible options, rather than a single required option. One strategy is to appeal to distinctions between reasons that compete in different ways. Philosophers have introduced various kinds of non-requiring reasons (...) that do not generate requirements, even if they win the competition. This paper rejects two familiar versions of this strategy, one appealing to merely justifying reasons and one appealing to merely commendatory reasons. It offers a new account of how reasons compete that instead appeals to a sharp distinction between the reasons against an option and the reasons for the alternatives to that option. (shrink)

Ethical theorists often assume that the verb ‘ought’ means roughly ‘has an obligation’; however, this assumption is belied by the diversity of ‘flavours’ of ought-sentences in English. A natural response is that ‘ought’ is ambiguous. However, this response is incompatible with the standard treatment of ‘ought’ by theoretical semanticists, who classify ‘ought’ as a member of the family of modal verbs, which are treated uniformly as operators. To many ethical theorists, however, this popular treatment in linguistics seems to elide an (...) important distinction between agential and non-agential ought-statements. The thought is that ‘ought’ must have at least two senses, one implicating agency and connected to obligations, and another covering other uses. In this paper, I pursue some resolution of this tension between semantic theory and ethical theory with respect to the meaning of ‘ought’. To this end, I consider what I believe to be the most linguistically sophisticated argument for the view that the word ‘ought’ is ambiguous between agential and non-agential senses. This argument, due to Mark Schroeder, is instructive but based on a false claim about the syntax of agential ought-sentences—or so I attempt to show by first situating Schroeder's argument in its proper linguistic background and then discussing some syntactic evidence that he fails to appreciate. Then, I use the failure of this argument to motivate some more general reflections on how the standard treatment of ‘ought’ by theoretical semanticists might be refined in the light of the distinction important to ethical theory between agential and non-agential ought-statements, but also on how ethical theory might benefit from more careful study of the dominant treatment of modals as operators in theoretical semantics. (shrink)

According to deontological approaches to justification, we can analyze justification in deontic terms. In this paper, I try to advance the discussion of deontological approaches by applying recent insights in the semantics of deontic modals. Specifically, I use the distinction between weak necessity modals and strong necessity modals to make progress on a question that has received surprisingly little discussion in the literature, namely: ‘What’s the best version of a deontological approach?’ The two most obvious hypotheses are the Permissive View, (...) according to which justified expresses permission, and the Obligatory View, according to which justified expresses some species of obligation. I raise difficulties for both of these hypotheses. In light of these difficulties, I propose a new position, according to which justified expresses a property I call faultlessness, defined as the dual of weak necessity modals. According to this view, an agent is justified in phi-ing iff it’s not the case that she should [/ought] not phi. I argue that this ‘Faultlessness View’ gives us precisely what’s needed to avoid the problems facing the Permissive and Obligatory Views. (shrink)

Those who want to deny the ‘ought implies can’ principle often turn to weakened views to explain ‘ought implies can’ phenomena. The two most common versions of such views are that ‘ought’ presupposes ‘can’, and that ‘ought’ conversationally implicates ‘can’. This paper will reject both views, and in doing so, present a case against any pragmatic view of ‘ought implies can’. Unlike much of the literature, I won't rely on counterexamples, but instead will argue that each of these views fails (...) on its own terms. ‘Ought’ and ‘can’ do not obey the negation test for presupposition, and they do not obey the calculability or the cancelability tests for conversational implicature. I diagnose these failures as partly a result of the importance of the contrapositive of ‘ought implies can’. I end with a final argument emphasizing the role the principle plays in moral thinking, and the fact that no pragmatic account can do it justice. (shrink)

Gilbert Harman’s famous principle of Clutter Avoidance commands that “one should not clutter one’s mind with trivialities". Many epistemologists have been inclined to accept Harman’s principle, or something like it. This is significant because the principle appears to have robust implications for our overall picture of epistemic normativity. Jane Friedman (2018) has recently argued that one potential implication is that there are no genuine purely evidential norms on belief revision. In this paper, we present some new objections to a suitably (...) formulated version of the clutter principle qua norm on belief revision. Moreover, we argue that the clutter principle is best understood as a norm on non-doxastic stages of inquiry. In our view, it is a norm of asking and considering questions rather than a norm of settling on an answer to a question by forming a belief. (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.

It is through our actions that we affect the way the world goes. Whenever we face a choice of what to do, we also face a choice of which of various possible worlds to actualize. Moreover, whenever we act intentionally, we act with the aim of making the world go a certain way. It is only natural, then, to suppose that an agent's reasons for action are a function of her reasons for preferring some of these possible worlds to others, (...) such that what she has most reason to do is to bring about the possible world which, of all those available to her, is the one that she has most reason to want to obtain. This is what is known as the `teleological conception of practical reasons'. Whether this is the correct conception of practical reasons is important not only in its own right, but also in virtue of its potential implications for what sort of moral theory we should accept. Below, I argue that the teleological conception is indeed the correct conception of practical reasons. (shrink)

The ability to compare possibilities and designate some as ‘better’ than others is a fundamental aspect of our use of modals and propositional attitude verbs. This article aims to support a proposal by Sloman that certain modal expressions, in particular, ought, in fact have a more pronounced comparative backbone than others . The connection between ‘ought’ and ‘better’ is supported by linguistic data and a proposal is advanced for modeling ideals in a way that makes room for non-comparative, strong, priority-type (...) necessity. (shrink)

On the traditional deontic framework, what is required (what morality demands) and what is optimal (what morality recommends) can't be distinguished and hence they can't both be represented. Although the morally optional can be represented, the supererogatory (exceeding morality's demands), one of its proper subclasses, cannot be. The morally indifferent, another proper subclass of the optional-one obviously disjoint from the supererogatory-is also not representable. Ditto for the permissibly suboptimal and the morally significant. Finally, the minimum that morality allows finds no (...) place in the traditional scheme. With a focus on the question, What would constitute a hospitable logical neighborhood for the concept of supererogation?, I present and motivate an enriched logical and semantic framework for representing all these concepts of common sense morality. (shrink)

Motivational judgement internalists hold that there is a necessary connection between moral judgments and motivation. There is, though, an important lack of clarity in the literature about the types of moral evaluation the theory is supposed to cover. It is rarely made clear whether the theory is intended to cover all moral judgements or whether the claim covers only a subset of such judgements. In this paper I will investigate which moral judgements internalists should hold their theory to apply to. (...) I will argue that the possibility of the supererogation amoralist, someone who makes genuine supererogation judgements but remains unmotivated by them, makes it implausible to be an internalist about moral goodness. As a result, internalists should restrict their claim to moral requirement judgements. I will then argue that this creates an explanatory burden for Internalism. In order for their view to be plausible they must explain why some moral judgements and not others are necessarily connected to motivation. (shrink)

In "Doing Well Enough: Toward a Logic for Common Sense Morality", Paul McNamara sets out a semantics for a deontic logic which contains the operator It is supererogatory that. As well as having a binary accessibility relation on worlds, that semantics contains a relative ordering relation, . For worlds u, v and w, we say that u w v when v is at least as good as u according to the standards of w. In this paper we axiomatize logics complete (...) over three versions of the semantics. We call the strongest of these logics DWE for Doing Well Enough. (shrink)

An open question in the semantics of modality is what relations there are among different modal flavours. In this article, we consider the thorny issue of whether ascribing to an agent the obligation to φ implies that it is possible for the agent to φ. Traditionally, this issue has been interpreted as whether ‘ought’ implies ‘can’. But another linguistic interpretation is available as well, namely, whether ‘must’ implies ‘can’ (MIC). We show that ‘must’ does imply ‘can’ via a convergent argument. (...) The first strand of the argument is theoretical: it consists in proving MIC from a well-established theory of modality in natural language, i.e., that proposed by Kratzer. The second strand is empirical: we present novel acceptability judgment studies showing that MIC predicts and explains the linguistic behaviour of native English speakers. (shrink)

Ethically permissible clinical trials must not expose subjects to risks that are unreasonable in relation to anticipated benefits. In the research ethics literature, this moral requirement is typically understood in one of two different ways: as requiring the existence of a state of clinical equipoise, meaning a state of honest, professional disagreement among the community of experts about the preferred treatment; or as requiring an equilibrium between individual and collective ethics. It has been maintained that this second interpretation makes it (...) mandatory to minimize the number of patients receiving the treatment that will eventually be shown to be inferior by the trial. This requirement has led to the development of adaptive trials, i.e., trials in which treatment allocation is determined by data accumulated during interim analysis. Many statisticians argue that in some circumstances—typically with potentially high benefits, as in the much discussed ECMO trial—adaptive design is the only ethically permissible experimental design. Nevertheless, some proponents of clinical equipoise argue that adaptive trials are neither ethically required nor permissible. More specifically, they argue that clinical trials using adaptive designs fail to meet the moral requirement of clinical equipoise, since these trials presuppose an epistemic state that is incompatible with a physician’s duty of care to her subjects. This paper emphasizes that the debate is to a large extent resting on an epistemological confusion. Specifically, I argue that this response conflates two different conceptions of statistical evidence, and that recognizing this distinction elucidates an epistemological framework in which adaptive trials are both consistent with and recommended by the moral requirement of clinical equipoise. (shrink)

Reasons-based accounts of our normative conclusions face difficulties in distinguishing between what ought to be done and what is required. This article addresses this problem from a formal perspective. I introduce a rudimentary formalization of a reasons-based account and demonstrate that that the model faces difficulties in accounting for the distinction between oughts and requirements. I briefly critique attempts to distinguish between oughts and requirements by appealing to a difference in strength or weight of reasons. I then present a formalized (...) reasons-based account of permissions, oughts and requirements. The model exploits Joshua Gert (2004; 2007) and Patricia Greenspan’s (2005; 2007; 2010) suggestion that some reasons perform a purely justificatory function. I show that the model preserves the standard entailment relationships between requirements, oughts and permissions. (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)

I recast the DWE ("Doing Well Enough") deontic framework as an Andersonian-Kangerian modal framework and explore its metatheory systematically.

Methodological individualists often claim that any social phenomenon can ultimately be explained in terms of the actions and interactions of individuals. Any Nagelian version of methodological individualism requires that there be bridge laws that translate social statements into individualistic ones. We show that Nagelian individualism can be put to logical scrutiny by making the relevant social and individualistic languages fully explicit and mathematically precise. In particular, we prove that the social statement that a group of (at least two) agents performs (...) a deontically admissible group action cannot be expressed in a well-established deontic logic of agency that models every combination of actions, omissions, abilities, and obligations of finitely many individual agents. (shrink)

Weak ontic necessity is the ontic necessity expressed by “should” or “ought to”. An example of it is “I should be dead by now”. A feature of this necessity is that whether it holds is irrelevant to whether its underlying proposition holds. This necessity essentially involves time. This paper presents a logic for conditional weak ontic necessity in branching time. The logic’s language includes the next instant operator, the last instant operator, and the operator for conditional weak ontic necessity. Formulas (...) are evaluated at tuples consisting of a tree-based model, a context, a timeline, and an instant. A context is a set of ordered ontic laws determining expected timelines. When evaluating conditional weak ontic necessity, we first update the context with the antecedent, then check whether the consequent holds with respect to the updated context. We discuss some consequences of the formalization and compare it to some related work. We study the logic’s expressivity and axiomatize a special validity of it. (shrink)

(2013). Conversation and responsibility. Canadian Journal of Philosophy: Vol. 43, No. 2, pp. 267-286.