Appears to give the first model-theoretic account of both "must" and "ought" (without conflating them with one another). Some key pre-theoretic semantic and pragmatic phenomena that support a negative answer to the main title question are identified and a conclusion of some significance is drawn: a pervasive bipartisan presupposition of twentieth century ethical theory and deontic logic is false. Next, an intuitive model-theoretic framework for "must" and "ought" is hypothesized. It is then shown how this hypothesis helps to explain and (...) predict all the pre-theoretic phenomena previously observed. Next, I show that the framework hypothesized possesses additional expressive and explanatory power (e.g. derivatively predicting the existence of supererogatory and permissibly suboptimal alternatives), thus adding further confirmation that it is on the right track. (shrink)

General contrastivism holds that all claims of reasons are relative to contrast classes. This approach applies to explanation (reasons why things happen), moral philosophy (reasons for action), and epistemology (reasons for belief), and it illuminates moral dilemmas, free will, and the grue paradox. In epistemology, contrast classes point toward an account of justified belief that is compatible with reliabilism and other externalisms. Contrast classes also provide a model for Pyrrhonian scepticism based on suspending belief about which contrast class is relevant. (...) This view contrasts with contextualism, invariantism, and Schaffer's contrastivism. (shrink)

How should one understand knowledge-wh ascriptions? That is, how should one understand claims such as ‘‘I know where the car is parked,’’ which feature an interrogative complement? The received view is that knowledge-wh reduces to knowledge that p, where p happens to be the answer to the question Q denoted by the wh-clause. I will argue that knowledge-wh includes the question—to know-wh is to know that p, as the answer to Q. I will then argue that knowledge-that includes a contextually (...) implicit question. I will conclude that knowledge is a question-relative state. Knowing is knowing the answer, and whether one knows the answer depends (in part) on the question. (shrink)

All contentious moral issues--from gay marriage to abortion and affirmative action--raise difficult questions about the justification of moral beliefs. How can we be justified in holding on to our own moral beliefs while recognizing that other intelligent people feel quite differently and that many moral beliefs are distorted by self-interest and by corrupt cultures? Even when almost everyone agrees--e.g. that experimental surgery without consent is immoral--can we know that such beliefs are true? If so, how? These profound questions lead to (...) fundamental issues about the nature of morality, language, metaphysics, justification, and knowledge. They also have tremendous practical importance in handling controversial moral questions in health care ethics, politics, law, and education. Sinnott-Armstrong here provides an extensive overview of these difficult subjects, looking at a wide variety of questions, including: Are any moral beliefs true? Are any justified? What is justified belief? The second half of the book explores various moral theories that have grappled with these issues, such as naturalism, normativism, intuitionism, and coherentism, all of which are attempts to answer moral skepticism. Sinnott-Armstrong argues that all these approaches fail to rule out moral nihilism--the view that nothing is really morally wrong or right, bad or good. Then he develops his own novel theory,--"moderate Pyrrhonian moral skepticism"--which concludes that some moral beliefs can be justified out of a modest contrast class but no moral beliefs can be justified out of an extreme contrast class. While explaining this original position and criticizing alternatives, Sinnott-Armstrong provides a wide-ranging survey of the epistemology of moral beliefs. (shrink)

David Lewis (1941-2001) was Class of 1943 University Professor of Philosophy at Princeton University. His contributions spanned philosophical logic, philosophy of language, philosophy of mind, philosophy of science, metaphysics, and epistemology. In On the Plurality of Worlds, he defended his challenging metaphysical position, "modal realism." He was also the author of the books Convention, Counterfactuals, Parts of Classes, and several volumes of collected papers.

This paper advances a reductive semantics for ‘ought’ and a naturalistic theory of normativity. It gives a unified analysis of predictive, instrumental, and categorical uses of ‘ought’: the predictive ‘ought’ is basic, and is interpreted in terms of probability. Instrumental ‘oughts’ are analyzed as predictive ‘oughts’ occurring under an ‘in order that’ modifer (the end-relational theory). The theory is then extended to categorical uses of ‘ought’: it is argued that they are special rhetorical uses of the instrumental ‘ought’. Plausible conversational (...) principles explain how this end-relational ‘ought’ can perform the expressive functions of the moral ‘ought’. The notion of an ‘ought-simpliciter’ is also discussed. (shrink)

We defend a contextualist account of deontic judgments as relativized both to (i) information and to (ii) standards or ends, against recent objections that turn on practices of moral disagreement. Kolodny & MacFarlane argue that information-relative contextualism cannot accommodate the connection between deliberation and advice; we suggest in response that they misidentify the basic concerns of deliberating agents. For pragmatic reasons, semantic assessments of normative claims sometimes are evaluations of propositions other than those asserted. Weatherson, Schroeder and others have raised (...) parallel objections to standard-relative contextualism; we argue for a parallel solution. (shrink)

In the latter half of this century, there have been two mostly separate threads within ethical theory, one on 'superogation', one on 'common-sense morality'. I bring these threads together by systematically reflecting on doing more than one has to do. A rich and coherent set of concepts at the core of common-sense morality is identified, along with various logical connections between these core concepts. Various issues in common-sense morality emerge naturally, as does a demonstrably productive definition of doing more than (...) one has to do. I then present an interpreted model-theoretic framework with the expressive power to generate truth-conditions for the core concepts, and the explanatory power to predict and explain the independently motivated logical connections between these concepts. The framework also has a certain heuristic power for 'discovering' substantive ethical theories that can derivatively generate the model-theoretic framework for the core concepts. Two theories discussed are expansions of traditional theories; two others, each giving pride of place to justice, are devised to resonate with more recent concerns. Methodologically, it is hoped that the approach within might suggest the possibility of bridging another gap: that between formal and informal studies of moral notions. (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)

It is argued that claims about personal obligation (of the form "s ought to 0") cannot be reduced to claims about impersonal obligation (of the form "it ought to be the case that p"). The most common attempts at such a reduction are shown to have unacceptable implications in cases involving a plurality of agents. It is then argued that similar problems will face any attempt to reduce personal obligation to impersonal obligation.

The existing literature treats of several investigations with a certain bearing on the question which is roughly indicated by the title “Imperatives and Logic.” Some of those investigations, however, are entirely outside the scope of the present work.Mally sets himself the task of developing a “Logik des Willens” constituting a parallel to the usual logic, the “Logik des Denkens". In order to emphasize its independence, the author also calls this “Logik des Willens” “Deontik”, and he conceives it as being based (...) on the “Wesensgesetze” of will in the same way as the usual logic is conceived as being based on the “Wesensgesetze” of thought. The author develops a formalistic deductive system on the basis of 5 axioms of demands, including the axiom that there is at least one fact which is unconditionally demanded, and through a lengthy series of theorems he arrives at the sentence that what is unconditionally demanded is identical with what is actually the case: “was sein soll, ist Tatsache”. Similarly, the author develops a system of axioms for “right” volition, including the axiom that right volition is non-contradictory. (shrink)

This paper develops an informal semantics for 'ought to be' and 'ought to be given...' and argues for its plausibility. A feature of the semantics is that it invalidates 'if a entails b, And o(a), Then o(b)' and 'if o(a) & o(b), Then o(a&b)', While validating detachment for conditional obligation.

In this paper, I apply the "conceptual role semantics" approach that I have proposed elsewhere (according to which the meaning of normative terms is given by their role in practical reasoning or deliberation) to the meaning of the term 'ought'. I argue that this approach can do three things: It can give an adequate explanation of the special connection that normative judgments have to practical reasoning and motivation for action. It can give an adequate account of why the central principles (...) of deontic logic are correct. It can give an explanation of the precise ways in which the term 'ought' is systematically context-sensitive, so that the term expresses different (but systematically related) concepts in different contexts. (shrink)