This essay challenges the widely accepted principle that a person is morally responsible for what he has done only if he could have done otherwise. The author considers situations in which there are sufficient conditions for a certain choice or action to be performed by someone, So that it is impossible for the person to choose or to do otherwise, But in which these conditions do not in any way bring it about that the person chooses or acts as he (...) does. In such situations the person may well be morally responsible for what he chooses or does despite his inability to choose or to do otherwise. Finally the author considers certain suggestions for revising the principle he rejects or for replacing it with a principle of an altogether different kind. (shrink)
Since its original publication in 1979, The Possibility of Naturalism has been one of the most influential works in contemporary philosophy of science and social science. It is a cornerstone of the critical realist position, which is now widely seen as offering a viable alternative to move positivism and postmodernism. This revised edition includes a new foreword.
Jonathan Lowe argues that metaphysics should be restored to a central position in philosophy, as the most fundamental form of rational inquiry, whose findings underpin those of all other disciplines. He portrays metaphysics as charting the possibilities of existence, by idetifying the categories of being and the relations of ontological dependency between entities of different categories. He proceeds to set out a unified and original metaphysical system: he defends a substance ontology, according to which the existence of the world s (...) one world in time depends upon the existence of persisting things which retain their identity over time and through processes of qualitative change. And he contends that even necessary beings, such as the abstract objects of mathematics, depend ultimately for their existence upon there being a concrete world of enduring substances. Within his system of metaphysics Lowe seeks to answer many of the deepest and most challenging questions in philosophy. (shrink)
Jonathan Lowe argues that metaphysics should be restored to a central position in philosophy, as the most fundamental form of inquiry, whose findings underpin those of all other disciplines. He portrays metaphysics as charting the possibilities of existence, by identifying the categories of being and the relations between them. He sets out his own original metaphysical system, within which he seeks to answer many of the deepest questions in philosophy. 'a very rich book... deserves to be read carefully by anyone (...) interested in any of the many subjects he discusses.' Katherine Hawley, British Journal of the Philosophy of Science. (shrink)
Just as there are rational requirements on thought, there are rational requirements on action. This book defends a conception of ethics, and a related conception of human nature, according to which altruism is included among the basic rational requirements on desire and action. Altruism itself depends on the recognition of the reality of other persons, and on the equivalent capacity to regard oneself as merely one individual among many.
_Possible Worlds_ presents the first up-to-date and comprehensive examination of one of the most important topics in metaphysics. John Divers considers the prevalent philosophical positions, including realism, antirealism and the work of important writers on possible worlds such as David Lewis, evaluating them in detail.
The notion of the sublime, used to describe a particular kind of overwhelming or exhilarating aesthetic experience, has garnered a great deal of attention by philosophers, critical theorists and literary scholars. In the midst of this growing body of literature, Professor Jane Forsey published an article asking whether an aesthetic theory of the sublime is even possible, and argued provocatively in the negative. Claiming that efforts to explain the sublime inevitably result in theories that are either contradictory or incoherent, Forsey (...) posed a challenge to anyone who takes the sublime seriously as an aesthetic category. This volume brings together an international slate of philosophers and scholars of the sublime, who have been invited to respond to, and critically engage with, Forseys article. Unlike other monographs and anthologies that deal broadly with the sublime in aesthetics, this collection examines specific conceptual problems with the very foundations of sublime theory in a manner that is tightly focused and rigorous. It represents a variety of approaches that defend the sublime, and concludes with an original response by Professor Forsey to her critics. (shrink)
Possibility offers a new analysis of the metaphysical concepts of possibility and necessity, one that does not rely on any sort of "possible worlds." The analysis proceeds from an account of the notion of a physical object and from the positing of properties and relations. It is motivated by considerations about how we actually speak of and think of objects. Michael Jubien discusses several closely related topics, including different purported varieties of possible worlds, the doctrine of "essentialism," natural (...) kind terms and alleged examples of necessity a posteriori. The book also offers a new theory of the functioning of proper names, both actual and fictional, and the discussion of natural kind terms and necessity a posteriori depends in part on this theory. (shrink)
This paper was chosen by The Philosopher’s Annual as one of the ten best articles appearing in print in 2000. Reprinted in Volume XXIII of The Philosopher’s Annual. In his very influential book David Chalmers argues that if physicalism is true then every positive truth is a priori entailed by the full physical description – this is called “the a priori entailment thesis – but ascriptions of phenomenal consciousness are not so entailed and he concludes that Physicalism is false. As (...) he puts it, “zombies” are metaphysically possible. I attempt to show that this argument is refuted by considering an analogous argument in the mouth of a zombie. The conclusion of this argument is false so one of the premises is false. I argue at length that this shows that the original conceivability argument also has a false premise and so is invalid. (shrink)
I focus on two questions: what is knowledge, and how is knowledge possible? The latter is an example of a how-possible question. I argue that how-possible questions are obstacle-dependent and that they need to be dealt with at three different levels, the level of means, of obstacle-removal, and of enabling conditions. At the first of these levels the possibility of knowledge is accounted for by identifying means of knowing, and I argue that the identification of such means also contributes (...) to a proper understanding of what knowledge is. (shrink)
Clarifying the nature of possibility is crucial for an evaluation of the phenomenological approach to ontology. From a phenomenological perspective, it is ontological possibility, and not spatiotemporal existence, that has pre-eminent ontological status. Since the sphere of phenomenological being and the sphere of experienceability turn out to be overlapping, this makes room for two perspectives. We can confer foundational priority to the acts of consciousness over possibilities, or to pre-set possibilities over the activity of consciousness. Husserl’s position on (...) this issue seems to change over time. Ultimately, the establishment of a phenomenological perspective must involve a rejection of any hypostatization of pre-set possibilities, but not all implications of this theoretical step seem to be drawn in Husserl’s texts. This paper is devoted to an illustration of how the phenomenological notion of possibility should change when we reject the hypostatization of possibility, that is, when we reject the idea that all acts of consciousness are to be conceived as realizations of pre-set “ideal forms”. We examine this question, first, by trying to clarify the conceptual constellation of “possibility” in Husserl’s texts. This leads to an overall classification of the features of constituted possibilities. Then we distinguish such constituted possibilities from their constituting conditions, which outlines a different sense of “possibility”. In the last instance two “possibilizing” dimensions are shown to lie at the root of all ontic possibilities. This leads to a final suggestion on the nature of the relation between experience and possibility. Actual experiences create the room for possibility: they are possibilizations. In this sense, experience is to be taken as a generative sphere which goes beyond the customary boundary between epistemic and ontological. From this point of view all experience is to be conceived as emergence. (shrink)
In this lucid, deep, and entertaining book, John Perry supposes that type-identity physicalism is antecedently plausible, and that rejecting this thesis requires good reason. He aims to show that experience gap arguments, as given by Jackson, Kripke, and Chalmers, fail to provide such reason, and moreover that each failure stems from an overly restrictive conception of the content of thought.
This paper is inspired by and develops on E. J. Lowe’s work, who writes in his book The Possibility of Metaphysics that ‘metaphysical possibility is an inescapable determinant of actuality’ (1998: 9). Metaphysics deals with possibilities – metaphysical possibilities – but is not able to determine what is actual without the help of empirical research. Accordingly, a delimitation of the space of possibilities is required. The resulting – controversial – picture is that we generally need to know whether (...) something is possible before we can know whether it is actual. In order to appreciate this picture, we need to understand Lowe’s slogan: ‘essence precedes existence’ (Lowe 2008: 40). This slogan has both an ontological and an epistemic reading. The ontological reading is related to the now familiar idea that essence grounds modality, as popularised by Kit Fine. The epistemic reading suggests that we can know the essence of some entity before we know whether or not that entity exists. However, this idea is often met with puzzlement and Lowe himself sadly passed away before he had a chance to clarify this framework. I will present the framework as I understand it, develop it on my own terms, and put forward a qualified defence of it. I will also illustrate how the framework can be put to use with a case study concerning the discovery of transuranic elements. (shrink)
Suppose that we want to frame a conception of reasons that isn't relativized to the inclinations of particular agents. That is, we want to identify particular things that count as reasons for acting simpliciter and not merely as reasons for some agents rather than others, depending on their inclinations. One way to frame such a conception is to name some features that an action can have and to say that they count as reasons for someone whether or not he is (...) inclined to care about them. The problem with the resulting conception, as we have seen, is that it entails the normative judgment that one ought to be inclined to care about the specified features, on pain of irrationality, and this normative judgment requires justification. The advantage of internalism is that it avoids these normative commitments. It says that things count as reasons for someone only if he is inclined to care about them, and so it leaves the normative question of whether to care about them entirely open. Yet if we try to leave this question open, by defining things as reasons only for those inclined to care about them, we'll end up with a definition that's relativized to the inclinations of particular agents—won't we? Not necessarily. For suppose that all reasons for acting are features of a single kind, whose influence depends on a single inclination. And suppose that the inclination on which the influence of reasons depends is, not an inclination that distinguishes some agents from others, but rather an inclination that distinguishes agents from nonagents. In that case, to say that these features count as reasons only for those who are inclined to care about them will be to say that they count as reasons only for agents—which will be to say no less than that they are reasons for acting, period, since applying only to agents is already part of the concept of reasons for acting. The restriction on the application of reasons will drop away from our definition, since it restricts their application, not to some proper subset of agents, but rather to the set of all agents, which is simply the universe of application for reasons to act. (shrink)
This article includes a basic overview of possible world semantics and a relatively comprehensive overview of three central philosophical conceptions of possible worlds: Concretism (represented chiefly by Lewis), Abstractionism (represented chiefly by Plantinga), and Combinatorialism (represented chiefly by Armstrong).
David Lewis holds that a single possible world can provide more than one way things could be. But what are possible worlds good for if they come apart from ways things could be? We can make sense of this if we go in for a metaphysical understanding of what the world is. The world does not include everything that is the case—only the genuine facts. Understood this way, Lewis's “cheap haecceitism” amounts to a kind of metaphysical anti-haecceitism: it says there (...) aren't any genuine facts about individuals over and above their qualitative roles. (shrink)
In this chapter, I survey what I call Lewisian approaches to modality: approaches that analyze modality in terms of concrete possible worlds and their parts. I take the following four theses to be characteristic of Lewisian approaches to modality. (1) There is no primitive modality. (2) There exists a plurality of concrete possible worlds. (3) Actuality is an indexical concept. (4) Modality de re is to be analyzed in terms of counterparts, not transworld identity. After an introductory section in which (...) I motivate analyzing modality in terms of possible worlds, I devote one section to each of these four theses. For each thesis, I take Lewis’s interpretation and defense as my starting point. I then consider and endorse alternative ways of accepting the thesis, some of which disagree substantially with Lewis’s interpretation or defense. There is more than one way to be a Lewisian about modality. (shrink)
God is traditionally taken to be a perfect being, and the creator and sustainer of all that is. So, if theism is true, what sort of world should we expect? To answer this question, we need an account of the array of possible worlds from which God is said to choose. It seems that either there is (a) exactly one best possible world; or (b) more than one unsurpassable world; or (c) an infinite hierarchy of increasingly better worlds. Influential arguments (...) for atheism have been advanced on each hierarchy, and these jointly comprise a daunting trilemma for theism. In this paper, I argue that if theism is true, we should expect the actual world to be a multiverse comprised of all and only those universes which are worthy of creation and sustenance. I further argue that this multiverse is the unique best of all possible worlds. Finally, I explain how his unconventional view bears on the trilemma for theism. (shrink)
In this paper I argue against the stronger of the two views concerning the right and wrong kind of reasons for belief, i.e. the view that the only genuine normative reasons for belief are evidential. The project in this paper is primarily negative, but with an ultimately positive aim. That aim is to leave room for the possibility that there are genuine pragmatic reasons for belief. Work is required to make room for this view, because evidentialism of a strict (...) variety remains the default view in much of the debate concerning normative reasons for belief. Strict versions of evidentialism are inconsistent with the view that there are genuine pragmatic reasons for belief. (shrink)
Gordon Belot investigates the distinctive notion of geometric possibility that relationalists rely upon. He examines the prospects for adapting to the geometric case the standard philosophical accounts of the related notion of physical possibility, with particular emphasis on Humean, primitivist, and necessitarian accounts of physical and geometric possibility. This contribution to the debate concerning the nature of space will be of interest not only to philosophers and metaphysicians concerned with space and time, but also to those interested (...) in laws of nature, modal notions, or more general issues in ontology. (shrink)
Meno's Paradox from Socrates to Sextus Gail Fine. sense that they consider the issues it raises; and they argue, against its conclusion, that inquiry is possible. Like Plato and Aristotle, they also explain what makes inquiry possible; and they do ...
How is knowledge of the external world possible? How is knowledge of other minds possible? How is a priori knowledge possible? These are all examples of how-possible questions in epistemology. In this highly original book Quassim Cassam explains how such questions arise and how they should be answered.
The book also sheds new light on the nature of metaphysical theorizing by exploring the interaction of semantic and metaphysical issues, the connections between different metaphysical issues, and the nature of ontological commitment.
“There are no gaps in logical space,” David Lewis writes, giving voice to sentiment shared by many philosophers. But different natural ways of trying to make this sentiment precise turn out to conflict with one another. One is a *pattern* idea: “Any pattern of instantiation is metaphysically possible.” Another is a *cut and paste* idea: “For any objects in any worlds, there exists a world that contains any number of duplicates of all of those objects.” We use resources from model (...) theory to show the inconsistency of certain packages of combinatorial principles and the consistency of others. (shrink)
We provide a new perspective on the relation between the space of description of an object and the appearance of novelties. One of the aims of this perspective is to facilitate the interaction between mathematics and historical sciences. The definition of novelties is paradoxical: if one can define in advance the possibles, then they are not genuinely new. By analyzing the situation in set theory, we show that defining generic (i.e., shared) and specific (i.e., individual) properties of elements of a (...) set are radically different notions. As a result, generic and specific definitions of possibilities cannot be conflated. We argue that genuinely stating possibilities requires that their meaning has to be made explicit. For example, in physics, properties playing theoretical roles are generic; then, generic reasoning is sufficient to define possibilities. By contrast, in music, we argue that specific properties matter, and generic definitions become insufficient. Then, the notion of new possibilities becomes relevant and irreducible. In biology, among other examples, the generic definition of the space of DNA sequences is insufficient to state phenotypic possibilities even if we assume complete genetic determinism. The generic properties of this space are relevant for sequencing or DNA duplication, but they are inadequate to understand phenotypes. We develop a strong concept of biological novelties which justifies the notion of new possibilities and is more robust than the notion of changing description spaces. These biological novelties are not generic outcomes from an initial situation. They are specific and this specificity is associated with biological functions, that is to say, with a specific causal structure. Thus, we think that in contrast with physics, the concept of new possibilities is necessary for biology. (shrink)
Many epistemologists call themselves ‘fallibilists’. But many philosophers of language hold that the meaning of epistemic usages of ‘possible’ ensures a close knowledge- possibility link : a subject’s utterance of ‘it’s possible that not-p’ is true only if the subject does not know that p. This seems to suggest that whatever the core insight behind fallibilism is, it can’t be that a subject could have knowledge which is, for them, possibly false. I argue that, on the contrary, subjects can (...) have such possibly false knowledge. My ultimate aim, then, is to vindicate a very robust form of fallibilism. Uniquely, however, the account I offer does this while also allowing that concessive knowledge attributions – sentences of the form “I know that p, but it’s possible that not-p” – are not only infelicitous but actually false whenever uttered. The account predicts this result without conceding KPL. I argue that my account has the resources to explain some related cases for which the KPL account yields the wrong predictions. Taken as a whole, the linguistic data not only do not support the proposal that subjects cannot have possibly false knowledge, but indeed positively favor the proposal that they can. (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)
In the history of modern philosophy systematic connections were assumed to hold between the modal concepts of logical possibility and necessity and the concept of conceivability. However, in the eyes of many contemporary philosophers, insuperable objections face any attempt to analyze the modal concepts in terms of conceivability. It is important to keep in mind that a philosophical explanation of modality does not have to take the form of a reductive analysis. In this paper I attempt to provide a (...) response-dependent account of the modal concepts in terms of conceivability along the lines of a nonreductive model of explanation. (shrink)
Adams’s Thesis, the claim that the probabilities of indicative conditionals equal the conditional probabilities of their consequents given their antecedents, has proven impossible to accommodate within orthodox possible-world semantics. This essay proposes a modification to the orthodoxy that removes this impossibility. The starting point is a proposal by Jeffrey and Stalnaker that conditionals take semantic values in the unit interval, interpreting these (à la McGee) as their expected truth-values at a world. Their theories imply a false principle, namely, that the (...) probability of a conditional is independent of any proposition inconsistent with its antecedent. But they also point to something important, namely, that our uncertainty about conditionals is not confined to uncertainty about the facts (what the actual world is like) but also expresses uncertainty about the counterfacts (what the world would be like if one or another supposition were true). To capture this observation, this essay proposes that the semantic contents of conditionals be treated as sets of vectors of possible worlds, not singleton worlds, with the coordinates of each specifying the world that is or would be true under the supposition that it represents. The probabilities of truth for conditionals will then depend on the joint probabilities of the facts and counterfacts, the latter in turn depending on the mode of supposition. The implication of this treatment is that the probabilities of conditionals are conditional probabilities whenever the mode of supposition is evidential. (shrink)
Andrew Chignell recently proposed an original reconstruction of Kant's ‘Only Possible Argument’ for the existence of God. Chignell claims that what motivates the ‘Grounding Premise’ of Kant's proof, ‘real possibility must be grounded in actuality’, is the requirement that the predicates of a really possible thing must be ‘really harmonious’, i.e. compatible in an extra-logical or metaphysical sense. I take issue with Chignell's reconstruction. First, the pre-Critical Kant does not present ‘real harmony’ as a general condition of real (...) class='Hi'>possibility. Second, the real harmony requirement is not what motivates the ‘Grounding Premise’ of the proof. Instead, this premise is sufficiently motivated by what Chignell labels the ‘content’ requirement. Finally, Kant's downgrading of the proof in his Critical period is not based on a concern regarding the real harmony of the predicates of God, but on his Critical restrictions on cognition in general and modal cognition in particular. (shrink)
The new …eld of judgment aggregation aims to …nd collective judgments on logically interconnected propositions. Recent impossibility results establish limitations on the possibility to vote independently on the propositions. I show that, fortunately, the impossibility results do not apply to a wide class of realistic agendas once propositions like “if a then b” are adequately modelled, namely as subjunctive implications rather than material implications. For these agendas, consistent and complete collective judgments can be reached through appropriate quota rules (which (...) decide propositions using acceptance thresholds). I characterise the class of these quota rules. I also prove an abstract result that characterises consistent aggregation for arbitrary agendas in a general logic. (shrink)
In traditional semantics for classical logic and its extensions, such as modal logic, propositions are interpreted as subsets of a set, as in discrete duality, or as clopen sets of a Stone space, as in topological duality. A point in such a set can be viewed as a "possible world," with the key property of a world being primeness—a world makes a disjunction true only if it makes one of the disjuncts true—which classically implies totality—for each proposition, a world either (...) makes the proposition true or makes its negation true. This chapter surveys a more general approach to logical semantics, known as possibility semantics, which replaces possible worlds with possibly partial "possibilities." In classical possibility semantics, propositions are interpreted as regular open sets of a poset, as in set-theoretic forcing, or as compact regular open sets of an upper Vietoris space, as in the recent theory of "choice-free Stone duality." The elements of these sets, viewed as possibilities, may be partial in the sense of making a disjunction true without settling which disjunct is true. We explain how possibilities may be used in semantics for classical logic and modal logics and generalized to semantics for intuitionistic logics. The goals are to overcome or deepen incompleteness results for traditional semantics, to avoid the nonconstructivity of traditional semantics, and to provide richer structures for the interpretation of new languages. (shrink)
The recent literature on economic models has rejected the traditional requirement that their epistemic value necessary depended on them offering actual explanations of phenomena. Contributors to that literature have argued that many models do not aim at providing how-actually explanations, but instead how-possibly explanations. However, how to assess the epistemic value of HPEs remains an open question. We present a programmatic approach to answering it. We first introduce a conceptual framework that distinguishes how-actually explanations from how-possibly explanations and that further (...) differentiates between epistemic and objective how-possibly explanations. Secondly, we show how that framework can be used for methodological appraisal as well as for understanding methodological controversies. (shrink)
Jennifer Church presents a new account of perception, which shows how imagining alternative perspectives and possibilities plays a key role in creating and validating experiences of self-evident objectivity. She explores the nature of moral perception and aesthetic perception, and argues that perception can be both literal and substantive.
Typically, nudging is a technique for steering the choices of people without giving reasons or using enforcement. In benevolent cases, it is used when people are insufficiently responsive to reason. The nudger triggers automatic cognitive mechanisms—sometimes even biases—in smart ways in order to push irrational people in the right direction. Interestingly, this technique can also be applied to doxastic attitudes. Someone who is doxastically unresponsive to evidence can be nudged into forming true beliefs or doxastic attitudes that are propositionally justified. (...) When doxastic nudging uses non-rational mechanisms, the worry is that nudging cannot result in justified beliefs or knowledge, as the resulting doxastic attitudes lack the right kind of basis. In this paper, I will argue that given the right background views about knowledge, justified beliefs and the relevant processes, epistemic nudging is possible even in these cases. That is, all kinds of nudging can—in appropriate circumstances—produce justified beliefs or knowledge in the nudgee. (shrink)
An epistemological how-possible question asks how knowledge, or knowledge of some specific kind, is possible. Familiar epistemological how-possible questions include ‘How is knowledge of the external world possible?’, ‘How is knowledge of other minds possible?’ and ‘How is a priori knowledge possible?’ These are the three questions that I tackle in my book. In each case, I explain how and why the question arises and propose a way of answering it. The main negative claim of the book is that transcendental (...) arguments are of little use in answering how-possible questions. A transcendental demonstration of the necessity of a certain kind of knowledge does not amount to an explanation of its possibility. The main positive claim is that such questions call for what I describe as a multi-levels response. I give an account of the multi-levels approach and put it to use in explaining how various kinds of knowledge are possible.Epistemological how-possible questions are not directly concerned with whether knowledge is possible, but if we cannot explain how a certain kind of knowledge is possible then the reality of that kind of knowledge is called into question. How-possible questions are obstacle-dependent. We ask how knowledge …. (shrink)
Extensively classroom-tested, Possibilities and Paradox provides an accessible and carefully structured introduction to modal and many-valued logic. The authors cover the basic formal frameworks, enlivening the discussion of these different systems of logic by considering their philosophical motivations and implications. Easily accessible to students with no background in the subject, the text features innovative learning aids in each chapter, including exercises that provide hands-on experience, examples that demonstrate the application of concepts, and guides to further reading.
Drawing on the so-called “doctrinal paradox”, List and Pettit (2002) have shown that, given an unrestricted domain condition, there exists no procedure for aggregating individual sets of judgments over multiple interconnected propositions into corresponding collective ones, where the procedure satisfies some minimal conditions similar to the conditions of Arrow’s theorem. I prove that we can avoid the paradox and the associated impossibility result by introducing an appropriate domain restriction: a structure condition, called unidimensional alignment, is shown to open up a (...)possibility result, similar in spirit to Black’s median voter theorem. Specifically, I prove that, given unidimensional alignment, propositionwise majority voting is the unique procedure for aggregating individual sets of judgments into collective ones in accordance with the above mentioned minimal conditions. (shrink)
This article gives two arguments for believing that our society is unknowingly guilty of serious, large-scale wrongdoing. First is an inductive argument: most other societies, in history and in the world today, have been unknowingly guilty of serious wrongdoing, so ours probably is too. Second is a disjunctive argument: there are a large number of distinct ways in which our practices could turn out to be horribly wrong, so even if no particular hypothesized moral mistake strikes us as very likely, (...) the disjunction of all such mistakes should receive significant credence. The article then discusses what our society should do in light of the likelihood that we are doing something seriously wrong: we should regard intellectual progress, of the sort that will allow us to find and correct our moral mistakes as soon as possible, as an urgent moral priority rather than as a mere luxury; and we should also consider it important to save resources and cultivate flexibility, so that when the time comes to change our policies we will be able to do so quickly and smoothly. (shrink)