This encyclopedia entry urges what it takes to be correctives to common (mis)understandings concerning the phenomenon of incommensurability and incomparability and briefly outlines some of their philosophical upshots.

Orthodox Bayesian decision theory requires an agent’s beliefs representable by a real-valued function, ideally a probability function. Many theorists have argued this is too restrictive; it can be perfectly reasonable to have indeterminate degrees of belief. So doxastic states are ideally representable by a set of probability functions. One consequence of this is that the expected value of a gamble will be imprecise. This paper looks at the attempts to extend Bayesian decision theory to deal with such cases, and concludes (...) that all proposals advanced thus far have been incoherent. A more modest, but coherent, alternative is proposed. Keywords: Imprecise probabilities, Arrow’s theorem. (shrink)

Many have claimed that unspecific evidence sometimes demands unsharp, indeterminate, imprecise, vague, or interval-valued probabilities. Against this, a variant of the diachronic Dutch Book argument shows that perfectly rational agents always have perfectly sharp probabilities.

How should we make decisions when we're uncertain about what we ought, morally, to do? Decision-making in the face of fundamental moral uncertainty is underexplored terrain: MacAskill, Bykvist, and Ord argue that there are distinctive norms by which it is governed, and which depend on the nature of one's moral beliefs.

In the growing literature on decision-making under moral uncertainty, a number of skeptics have argued that there is an insuperable barrier to rational "hedging" for the risk of moral error, namely the apparent incomparability of moral reasons given by rival theories like Kantianism and utilitarianism. Various general theories of intertheoretic value comparison have been proposed to meet this objection, but each suffers from apparently fatal flaws. In this paper, I propose a more modest approach that aims to identify classes of (...) moral theories that share common principles strong enough to establish bases for intertheoretic comparison. I show that, contra the claims of skeptics, there are often rationally perspicuous grounds for precise, quantitative value comparisons within such classes. In light of this fact, I argue, the existence of some apparent incomparabilities between widely divergent moral theories cannot serve as a general argument against hedging for one's moral uncertainties. (shrink)

Abstract: This paper defends a constraint that any satisfactory decision theory must satisfy. I show how this constraint is violated by all of the decision theories that have been endorsed in the literature that are designed to deal with cases in which opinions or values are represented by a set of functions rather than a single one. Such a decision theory is necessary to account for the existence of what Ruth Chang has called “parity” (as well as for cases in (...) which agents have incomplete preferences or imprecise credences). The problem with the all of the decision theories that have been defended to account for parity is that they are committed to a claim I call unanimity: when all of the functions in the set agree that an agent ought to do A, then an agent ought to do A. A decision theory committed to unanimity violates the constraint I defend in this paper. Thus, if parity exists, a new approach to decision theory is necessary. (shrink)

One of the perennial challenges of ethical theory has been to provide an answer to a number of views that appear to undermine the importance of ethical questions. We may refer to such views collectively as “deflationary ethical theories.” These include theories, such as nihilism, according to which no action is better than any other, as well as relativistic theories according to which no ethical theory is better than any other. In this article I present a new response to such (...) deflationary ethical views. Drawing a distinction between acceptance and rejection, on the one hand, and belief and disbelief, on the other, I argue that we have strong reason to reject these theories, even if we do not have reason to disbelieve them. In Section I, I clarify the question of what ethical theory we should accept, and I argue for the central importance of this question. In Section II, I discuss what I call “absolutely deflationary” ethical theories. These are theories according to which it matters not at all what we do or not at all what ethical theory we accept. I argue that it is generally rational to reject any theory of this kind. In Section III, I discuss what I call “relatively deflationary” ethical theories. These are theories according to which it matters little what we do or what ethical theory we accept. I argue that we have strong pro tanto reason to reject theories of this kind. And then, in Sections IV and V, I reply to some common objections to my arguments. Throughout, I will be arguing not that deflationary ethical theories are false but only that we should reject them from the practical point of view as a basis for guiding our actions. (shrink)

Decision theory and folk psychology both purport to represent the same phenomena: our belief-like and desire- and preference-like states. They also purport to do the same work with these representations: explain and predict our actions. But they do so with different sets of concepts. There's much at stake in whether one of these two sets of concepts can be accounted for with the other. Without such an account, we'd have two competing representations and systems of prediction and explanation, a dubious (...) dualism. Folk psychology structures our daily lives and has proven fruitful in the study of mind and ethics, while decision theory is pervasive in various disciplines, including the quantitative social sciences, especially economics, and philosophy. My interest is in accounting for folk psychology with decision theory -- in particular, for believe and wanting, which decision theory omits. Many have attempted this task for belief. (The Lockean Thesis says that there is such an account.) I take up the parallel task for wanting, which has received far less attention. I propose necessary and sufficient conditions, stated in terms of decision theory, for when you're truly said to want; I give an analogue of the Lockean Thesis for wanting. My account is an alternative to orthodox accounts that link wanting to preference (e.g. Stalnaker (1984), Lewis (1986)), which I argue are false. I argue further that want ascriptions are context-sensitive. My account explains this context-sensitivity, makes sense of conflicting desires, and accommodates phenomena that motivate traditional theses on which 'want' has multiple senses (e.g. all-things-considered vs. pro tanto). (shrink)

Some philosophers have recently argued that decision-makers ought to take normative uncertainty into account in their decisionmaking. These philosophers argue that, just as it is plausible that we should maximize expected value under empirical uncertainty, it is plausible that we should maximize expected choice-worthiness under normative uncertainty. However, such an approach faces two serious problems: how to deal with merely ordinal theories, which do not give sense to the idea of magnitudes of choice-worthiness; and how, even when theories do give (...) sense to magnitudes of choice-worthiness, to compare magnitudes of choice-worthiness across different theories. Some critics have suggested that these problems are fatal to the project of developing a normative account of decision-making under normative uncertainty. The primary purpose of this article is to show that this is not the case. To this end, I develop an analogy between decision-making under normative uncertainty and the problem of social choice, and then argue that the Borda Rule provides the best way of making decisions in the face of merely ordinal theories and intertheoretic incomparability. (shrink)

We are often uncertain how to behave morally in complex situations. In this controversial study, Ted Lockhart contends that moral philosophy has failed to address how we make such moral decisions. Adapting decision theory to the task of decision-making under moral uncertainly, he proposes that we should not always act how we feel we ought to act, and that sometimes we should act against what we feel to be morally right. Lockhart also discusses abortion extensively and proposes new ways to (...) deal with the ethical and moral issues which surround it. (shrink)

We typically have to act under uncertainty. We can be uncertain about the relevant descriptive facts, but also about the relevant normative facts. However, the search for a theory of decision-making under normative uncertainty is doomed to failure. First, the most natural proposal for what to do given normative uncertainty faces two devastating problems. Second, the motivations for wanting a theory of what to do given descriptive uncertainty do not carry over to normative uncertainty. Descriptive facts may be inaccessible even (...) in principle, and ignorance of them excuses one from blame, but normative facts are in principle accessible, and ignorance of them arguably is no excuse. Normative facts differ from descriptive facts: normative facts affect what we ought to do no matter what, while descriptive facts affect what we ought to do only insofar as we are aware of them. (shrink)

(No abstract is available for this citation).

Non-moral ignorance can exculpate: if Anne spoons cyanide into Bill's coffee, but thinks she is spooning sugar, then Anne may be blameless for poisoning Bill. Gideon Rosen argues that moral ignorance can also exculpate: if one does not believe that one's action is wrong, and one has not mismanaged one's beliefs, then one is blameless for acting wrongly. On his view, many apparently blameworthy actions are blameless. I discuss several objections to Rosen. I then propose an alternative view on which (...) many agents who act wrongly are blameworthy despite believing they are acting morally permissibly, and despite not having mismanaged their moral beliefs.1. (shrink)

Let’s say that you regard two things as on a par when you don’t prefer one to other and aren’t indifferent between them. What does rationality require of you when choosing between risky options whose outcomes you regard as on a par? According to Prospectism, you are required to choose the option with the best prospects, where an option’s prospects is a probability-distribution over its potential outcomes. In this paper, I argue that Prospectism violates a dominance principle—which I call The (...) Principle of Predominance—because it sometimes requires you to do something that’s no better than the alternatives and might be worse. I argue that this undermines the strongest argument that’s been given in favor of Prospectism. (shrink)

I argue that any plausible decision theory for agents with incomplete preferences which obeys the Never Worse Principle will violate Transitivity. The Never Worse Principle says that if one option never does worse than another, you shouldn’t disprefer it. Transitivity says that if you prefer X to Y and you prefer Y to Z, then you should prefer X to Z. Violating Transitivity allows one to be money pumped. Although agents with incomplete preferences are already, in virtue of having incomplete (...) preferences, vulnerable to being money pumped, I argue that the money pump argument for Transitivity is more serious than the one for Completeness. (shrink)

We are often unsure about what we ought to do. This can be because we lack empirical knowledge, such as the extent to which future generations will be harmed by climate change. It can also be because we lack normative knowledge, such as the relative moral importance of the interests of present people and the interests of future people. However, though the question of how one ought to act under empirical uncertainty has been addressed extensively by both economists and philosophers---with (...) expected utility theory providing the standard formal framework---the question of how one ought to act under normative uncertainty is comparatively neglected. My thesis attempts to address this gap. -/- In my thesis I develop a view that I call metanormativism: that there are second-order norms that govern action that are relative to a decision-maker's uncertainty about first-order norms. -/- In the first part of the thesis, I defend one specific metanormative view: that under normative uncertainty decision-makers should maximise expected choice-worthiness, treating normative uncertainty analogously with empirical uncertainty. Drawing on the analogy between decision-making under normative uncertainty and social choice theory, I defend this view at length in response to the problem of merely ordinal theories and the problem of intertheoretic value comparisons. -/- In the second part of the thesis, I explore the implications of metanormativism for other philosophical issues. I argue that it has important consequences regarding the theory of rational action in the face of incomparable values, the causal/evidential debate in decision-theory, and our assessment of the value of moral philosophy. (shrink)

Moral dilemmas can arise from uncertainty, including uncertainty of the real values involved. One interesting example of this is that of experimentation on human embryos and foetuses, If these have a moral stauts similar to that of human persons then there will be server constraitns on what may be done to them. If embryous have a moral status similar to that of other small clusters of cells, then constraints will be motivated largely by consideration for the persons into whom the (...) embryos may develop. If the truth lies somewhere between these two extremes, the embryo having neither the full moral weight of persons, nor a completely negligible moral weight, then different kinds of constraints will be appropriate. On the face of it, in order to know what kinds of experiements, if any, we are morally justified in performing on embryos we have to know what the moral weight of the embryo is. But then an impasse threatens, for it seems implausible that we can settle with certainty the exact moral status of the human embryo. It is the purpose of this paper to show that moral uncertainty need not make rational moral justification impossible. I develop a framework which distinguishes between what is morally right/wrong, and what is morally justified/unjustified, and applies standard decision theoretic tools to the case of moral uncertainties. (This was the first published account of what has subsequently become known as Expected Moral Value Theory. An earlier version of the paper, "A decision theoretic argument against human embryo experimentation", was published in M. Fricke (ed.), Essays in honor of Bob Durrant. (University of Otago Press, 1986) 111-27.). (shrink)