Those who model doxastic states with a set of probability functions, rather than a single function, face a pressing challenge: can they provide a plausible decision theory compatible with their view? Adam Elga and others claim that they cannot, and that the set of functions model should be rejected for this reason. This paper aims to answer this challenge. The key insight is that the set of functions model can be seen as an instance of the supervaluationist approach to vagueness (...) more generally. We can then generate our decision theory by applying the general supervaluationist semantics to decision-theoretic claims. The result: if an action is permissible according to all functions in the set, it’s determinately permissible; if impermissible according to all, determinately impermissible; and – crucially – if permissible according to some, but not all, it’s indeterminate whether it’s permissible. This proposal handles with ease some difficult cases ) on which alternative decision theories falter. One reason this view has been overlooked in the literature thus far is that all parties to the debate presuppose that an acceptable decision theory must classify each action as either permissible or impermissible. But I will argue that this thought is misguided. Seeing the set of functions model as an instance of supervaluationism provides a compelling motivation for the claim that there can be indeterminacy in the rationality of some actions. (shrink)

Traditional procedures for rational updating fail when it comes to self-locating opinions, such as your credences about where you are and what time it is. This paper develops an updating procedure for rational agents with self-locating beliefs. In short, I argue that rational updating can be factored into two steps. The first step uses information you recall from your previous self to form a hypothetical credence distribution, and the second step changes this hypothetical distribution to reflect information you have genuinely (...) learned as time has passed. While the second step resembles traditional procedures of updating by conditionalization, the first is best understood by analogy to traditional models of how agents transmit self-locating opinions through ordinary interpersonal communication. (shrink)

We know a lot about what the world is like. We know less, it seems, about what we know about what the world is like. According to a common thought, it is easier for us to come to know about the state of the world than to come to know about the state of our own knowledge. What explains this gap? An attractively simple hypothesis is that our ignorance about what we know is explained by our ignorance about the world. (...) There are things we fail to know about what we know about the world because there are things we fail to know about the world. This hypothesis is often motivated by the idea that knowledge requires a margin‐for‐error. In this paper, I'll argue that this simple hypothesis is inadequate. Not all our ignorance of our knowledge can be explained by our ignorance about the world. In this sense, at least some of our ignorance about what we know is brute. (shrink)

A widely shared intuition says moral statements like “Aborting at 150 days is permissible” seem vague. But what is the nature of such vagueness? This article proposes a novel, shifty semantic account of moral vagueness which argues: Moral vagueness is essentially a semantic phenomenon existing in our imperfect (moral) language; the referents of vague moral terms may shift under the right circumstance; our usage of vague moral terms may contribute to such shifts, but so may some factors beyond our control. (...) After the account is fleshed out, some distinctions will be drawn to differentiate it from other accounts of moral vagueness, and more importantly, efforts will be made to reconcile this account and moral realism. In conclusion, my account is by far the first (minimal) moral realism-friendly shifty semantic account of moral vagueness that successfully explains our intuitions about vague moral statements. (shrink)

This paper begins by applying a version of Timothy Williamson’s anti-luminosity argument to normative properties. This argument suggests that there must be at least some unknowable normative facts in normative Sorites sequences, or otherwise we get a contradiction given certain plausible assumptions concerning safety requirements on knowledge and our doxastic dispositions. This paper then focuses on the question of how the defenders of different forms of metaethical anti-realism (namely, error theorists, subjectivists, relativists, contextualists, expressivists, response dependence theorists, and constructivists) could (...) respond to the explanatory challenge created by the previous argument. It argues that, with two exceptions, the metaethical anti-realists need not challenge the argument itself, but rather they can find ways to explain how the unknowable normative facts can obtain. These explanations are based on the idea that our own attitudes on which the normative facts are grounded need not be transparent to us either. Reaching this conclusion also illuminates how metaethical anti-realists can make sense of instances of normative vagueness more generally. (shrink)

If there are vague propositions, then the question arises whether it is rational to care intrinsically about the vague. This paper argues—contra Bacon (2018), the most comprehensive defence of vague proposition to date—that it is. Some things, such as pain, may be rational to care intrinsically about only if precise, but some things, such as truth, are rational to care intrinsically about even if vague.

This thesis consists of several independent papers in population ethics. I begin in Chapter 1 by critiquing some well-known 'impossibility theorems', which purport to show there can be no intuitively satisfactory population axiology. I identify axiological vagueness as a promising way to escape or at least mitigate the effects of these theorems. In particular, in Chapter 2, I argue that certain of the impossibility theorems have little more dialectical force than sorites arguments do. From these negative arguments I move to (...) positive ones. In Chapter 3, I justify the use of a 'veil of ignorance', starting from three more basic normative principles. This leads to positive arguments for various kinds of utilitarianism - the best such arguments I know. But in general the implications of the veil depend on how one answers what I call 'the risky existential question': what is the value to an individual of a chance of non-existence? I chart out the main options, and raise some puzzles for non-comparativism, the view that life is incomparable to non-existence. Finally, in Chapter 4, I consider the consequences for population ethics of the idea that what is normatively relevant is not personal identity, but a degreed relation of psychological connectedness. In particular, I pursue a strategy based in population ethics for understanding the controversial 'time-relative interests' account of the badness of death. (shrink)

Does moral vagueness require ontic vagueness? A central challenge for nonontic treatments of moral vagueness arises from the referential stability of moral terms across small changes in how they are applied: if moral vagueness is not ontic vagueness, it’s hard to explain this referential stability. Pointing to this challenge, Miriam Schoenfield has argued that moral vagueness is ontic vagueness, at least for a moral realist. I disagree. I argue that a moral realist can use a conceptual role semantics for moral (...) terms to give a purely semantic treatment of moral vagueness. (shrink)

Miriam Schoenfield argues that moral realism and moral vagueness imply ontic vagueness. In particular, she argues that neither shifty nor rigid semantic accounts of vagueness can provide a satisfactory explanation of moral vagueness for moral realists. This paper constitutes a response. I argue that Schoenfield's argument against the shifty semantic account presupposes that moral indeterminacies can, in fact, be resolved determinately by crunching through linguistic data. I provide different reasons for rejecting this assumption. Furthermore, I argue that Schoenfield's rejection of (...) the rigid semantic account is based on a presupposition that ultimately implies the very same claim that is under dispute: the vagueness of moral predicates in imperfect languages persists in the perfect language, as well. (shrink)

This chapter discusses vagueness in ethics.

Two options are ‘incommensurate’ when neither is better than the other, but they are not equally good. Typically, we will say that one option is better in some ways, and the other in others, but neither is better ‘all things considered’. It is tempting to think that incommensurability is vagueness—that it is (perhaps) indeterminate which is better—but this ‘vagueness view’ of incommensurability has not proven popular. I set out the vagueness view and its implications in more detail, and argue that (...) it can explain most of the puzzling features of incommensurability. This argument proceeds without appeal to John Broome’s ‘collapsing principle’. (shrink)

Intuitively, there is a close link between moral status and phenomenal consciousness. Taking the link seriously can serve as the basis of a proposal that appears to have a surprising number of theoretical benefits. This proposal is the moral option, according to which moral status is partly determinative of phenomenal consciousness, and phenomenal consciousness is sufficient for possession of a moral property I refer to as “moral status.” I argue for this view on the basis of its ability to shed (...) light on the distribution problem of determining which systems are phenomenally conscious. I explicate it by drawing on a theory of attributions of phenomenal consciousness, and considering its relationship to positions on the metaphysics of consciousness. I defend it against a series of objections, including three based on previous theories of the link between phenomenal consciousness and moral status. The moral option should, in my view, be a serious contender among theories of phenomenal consciousness. (shrink)

Are moral terms semantically plastic—that is, would very slight changes in our patterns of use have shifted their meanings? This is a delicate question for moral realists. A 'yes' answer seems to conflict with the sorts of intuitions that support realism; but a 'no' answer seems to require a semantics that involves hefty metaphysical commitments. This tension can be illustrated by thinking about how standard accounts of vagueness can be applied to the case of moral terms, and also by considering (...) how realists should respond to the Moral Twin Earth problem. After presenting the puzzle, I will argue that moral realists can accept the semantic plasticity of moral expressions while accounting for contrary intuitions in a way that is nearly cost-free. (shrink)

Mark Johnston and Eric Olson have both pressed what Johnston has dubbed the personite problem. Personites, if they exist, are person-like entities whose lives extend over a continuous proper part of a person’s life. They are so person-like that they seem to have moral status if persons do. But this threatens to wreak havoc with ordinary moral thinking. For example, simple decisions to suffer some short-term hardship for long-term benefits become problematic. And ordinary punishment is always also punishment of the (...) innocent, since it punishes personites that didn’t exist when the crime was committed. An initially attractive way around the personite problem may be to simply deny that personites exist. But as I discuss in this talk, relating to contemporary discussions in metaontology, this response for principled reasons doesn’t work. The problems I discuss illustrate the significance of metaontological considerations for issues in ethics and metaethics, and generalize widely beyond the personite problem. (shrink)

A prominent philosophical debate concerns whether we should accept causal decision theory or evidential decision theory as our best theory of rational choice. However, instead of accepting one of these theories at the expense of the other, an alternative would be to accept that both theories play a partial role in the true account of rational choice. In this paper, I defend a pluralist account of this sort. In particular, I argue that rational permissibility is an indeterminate notion, with EDT (...) and CDT each corresponding to one sharpening of this notion. (shrink)

Theories that posit metaphysical structure are able to do much work in philosophy. Some, however, find the notion of ‘metaphysical structure’ unintelligible. In this paper, I argue that their charge of unintelligibility fails. There is nothing distinctively problematic about the notion. At best, their charge of unintelligibility is a mere reiteration of previous complaints made toward similar notions. In developing their charge, I clarify several important concepts, including primitiveness, intelligibility, and the Armstrong-inspired “ontologism” view of the world. I argue that, (...) ultimately, their charge is best understood as an objection whose central premise is that the notion of ‘structure’ runs contrary to an important presupposition of contemporary metaphysics. But that central premise is, on closer inspection, implausible. I respond to the objection by identifying three popular metaphysical theories that violate the alleged presupposition but are still generally regarded as intelligible. The objection thus fails to show that a theory that posits metaphysical structure is unintelligible. (shrink)

A problem of the many Fs arises in cases where intuitively there is precisely one F (in the region you are talking about), but when you look closely you find many candidates for being that F, each one apparently as well-qualified as the next. Imagine an apparently solitary cloud in an otherwise blue sky. Look closer, and you'll see lots of water vapor molecules, with no one collection of them more eligible than the others to count as the cloud. Many (...) things are like this when you look closely enough. The problem arises for mundane things like rocks, houses and coins. It also arises for entities that present special philosophical challenges, like persons and experiencers. In this essay, I present a new argument that the problem of the many experiencers is an especially hard problem of the many, and property dualism—the view that properties that there is something it is like to instantiate are irreducible—may be the best way to solve it. (shrink)

It is notoriously difficult to find an intuitively satisfactory rule for evaluating populations based on the welfare of the people in them. Standard examples, like total utilitarianism, either entail the Repugnant Conclusion or in some other way contradict common intuitions about the relative value of populations. Several philosophers have presented formal arguments that seem to show that this happens of necessity: our core intuitions stand in contradiction. This paper assesses the state of play, focusing on the most powerful of these (...) ‘impossibility theorems’, as developed by Gustaf Arrhenius. I highlight two ways in which these theorems fall short of their goal: some appeal to a supposedly egalitarian condition which, however, does not properly reflect egalitarian intuitions; the others rely on a background assumption about the structure of welfare which cannot be taken for granted. Nonetheless, the theorems remain important: they give insight into the difficulty, if not perhaps the impossibility, of constructing a satisfactory population axiology. We should aim for reflective equilibrium between intuitions and more theoretical considerations. I conclude by highlighting one possible ingredient in this equilibrium, which, I argue, leaves open a still wider range of acceptable theories: the possibility of vague or otherwise indeterminate value relations. (shrink)

ABSTRACT I consider paradoxical spectrum arguments involving transitive relations like ‘better than’. I argue that, despite being formally different from sorites arguments, at least some spectrum arguments arise from vagueness, and that vagueness might often be the most natural diagnosis.

This paper looks at the phenomenon of ethical vagueness by asking the question, how ought one to reason about what to do when confronted with a case of ethical vagueness? I begin by arguing that we must confront this question, since ethical vagueness is inescapable. I then outline one attractive answer to the question: we ought to maximize expected moral value when confronted with ethical vagueness. This idea yields determinate results for what one rationally ought to do in cases of (...) ethical vagueness. But what it recommends is dependent on which substantive theory of vagueness is true; one can't draw conclusions about how to reason about vagueness in ethics in the absence of concrete assumptions about the nature of vagueness. (shrink)

This essay defends an epistemicist response to the phenomenon of vagueness concerning moral terms. I outline a traditional model of - and then two novel approaches to - epistemicism about moral predicates, and I demonstrate how the foregoing are able to provide robust explanations of the source of moral, as epistemic, indeterminacy. The first approach to moral epistemicism concerns the extensions of moral predicates, as witnessed by the non-transitivity of a value-theoretic sorites paradox. The second approach to moral epistemicism is (...) induced by the status of moral dilemmas in the epistemic interpretation of two-dimensional semantics. I examine the philosophical significance of the foregoing, and compare the proposal to those of ethical expressivism, constructivism, and scalar act-consequentialism. Finally, I examine the status of moral relativism in light of the epistemicist models of moral vagueness developed in the paper. (shrink)

The ‘no-difference problem’ challenges us to explain in which way the occurrence of an aggregate effect gives us reason to act in a specific way, although our individual actions make no difference to the effect’s occurrence. When discussing this problem, philosophers usually distinguish between so-called ‘triggering cases’, where the aggregate effect in question is brought about upon reaching a precise threshold, and ‘non-triggering cases’, in which no such precise threshold exists. However, despite their relevant differences, it is widely assumed not (...) only that both categories of cases confront us with the same moral problem, but also that this problem should be solved in the same way no matter which category we are considering. In this paper, I argue that this assumption is mistaken by showing that non-triggering cases pose very different moral problems than triggering cases unless very specific and, arguably, unlikely assumptions in neighbouring debates about causation and decision-making under indeterminacy hold. (shrink)

How should we make choices where the values we subscribe to give conflicting recommendations? I will be defending a reduction of decision making under conflict to decision making under indeterminacy, in the spirit of Broome. To defend this, I set out and endorse the basic features of decision making under conflict that Ruth Chang identifies. I show that we find exactly those features in cases of decision making under indeterminacy not involving conflicting values. Further, my theory of decision making under (...) indeterminacy predicts and explains these features. Particular attention will be paid to the aspect that Chang emphasizes as the decisive problem for the Broomean reduction: the resolutional residue, or angst, that decision making under conflict evinces. (shrink)

How should deontologists concerned with the ethics of killing apply their moral theory when we don’t know all the facts relevant to the permissibility of our action? Though the stakes couldn’t be higher, and uncertainty is endemic where killing is concerned, few deontologists have an answer to this question. In this paper I canvass two possibilities: that we should apply a threshold standard, equivalent to the ‘beyond a reasonable doubt’ standard applied for criminal punishment; and that we should fit our (...) deontological ethical theory into the apparatus of decision theory. I show that the first approach faces insurmountable obstacles, while the second holds much more promise for deontologists than they might first have assumed. (shrink)

This thesis will utilise the literature on the distinction between doing harm and allowing harm to develop a novel system of moral sequencing that can be applied to general moral problems to decide if, when, and how an agent should intervene to prevent harm from occurring to another agent. Off the back of this discussion, this thesis will offer a way of determining the responsibility of certain agents for their actions within a moral sequence. These motivations will be at the (...) centre of the discussions in this thesis and will be accomplished by ultimately updating the system of moral sequencing so that it makes sense of practical cases of inner-agent change, which itself provides a justification for intervening earlier, and potentially diminishing the responsibility for agents who have experienced an inner-agent change, in a moral sequence. (shrink)

This paper develops and defends the view that substantively normative uses of words like “good”, “right” and “ought” are irresolvably indeterminate: any single case of application is like a borderline case for a vague or indeterminate term, in that the meaning-fixing facts, together with the non-linguistic facts, fail to determine a truth-value for the target sentence in context. Normative claims, like vague or indeterminate borderline claims, are not meaningless, though. By making them, the speaker communicates information about the precisifications that (...) s/he accepts. The analogy with vague/indeterminate language, I argue, lays out a new and interesting foundation for a subjectivist approach to normativity. (shrink)

How should deontologists approach decision-making under uncertainty, for an iterated decision problem? In this paper I explore the shortcomings of a simple expected value approach, using a novel example to raise questions about attitudes to risk, the moral significance of tiny probabilities, the independent moral reasons against imposing risks, the morality of sunk costs, and the role of agent-relativity in iterated decision problems.

:Self-ownership theorists argue that many of our most morally urgent and enforceable rights stem from the fact that we own ourselves. Critics of self-ownership argue that the claim that people own their bodies commits self-ownership theorists to several implausible conclusions because self-ownership theory relies on several vague moral predicates, and any precisification of the required predicates is seemingly too permissive or too restrictive. I argue that this line of criticism does not undermine the case for self-ownership theory because self-ownership theory (...) does not require precisification of each moral concept that it is based on and, even if it did, the theory’s alleged extensional inadequacy does not undermine its justification. (shrink)

Various people have claimed that some cases involve indeterminate permissibility. However, it’s unclear what guidance one can take away from this fact: are indeterminately permissible options choiceworthy and if so when? In this paper, I present a counterexample that undermines two existing responses to this question and I then present two alternative solutions that avoid this counterexample.