Stoic work on ambiguity represents one of the most innovative, sophisticated, and rigorous contributions to philosophy and the study of language in western antiquity. This book is both the first comprehensive survey of the often difficult and scattered sources, and the first attempt to locate Stoic material in the rich array of contexts, ancient and modern, which alone can guarantee full appreciation of its subtlety, scope and complexity. The comparisons and contrasts which this book constructs will intrigue not just (...) classical scholars, and philosophers, but also logicians, theoretical linguists, communication theorists and historians of grammar and of literary theory. The Stoics on Ambiguity is designed to be intelligible to readers with no Greek or Latin. (shrink)
Daniel Ellsberg presented in Ellsberg (The Quarterly Journal of Economics 75:643–669, 1961) various examples questioning the thesis that decision making under uncertainty can be reduced to decision making under risk. These examples constitute one of the main challenges to the received view on the foundations of decision theory offered by Leonard Savage in Savage (1972). Craig Fox and Amos Tversky have, nevertheless, offered an indirect defense of Savage. They provided in Fox and Tversky (1995) an explanation of Ellsberg’s two-color problem (...) in terms of a psychological effect: ambiguity aversion . The ‘comparative ignorance’ hypothesis articulates how this effect works and explains why it is important to an understanding of the typical pattern of responses associated with Ellsberg’s two-color problem. In the first part of this article we challenge Fox and Tversky’s explanation. We present first an experiment that extends Ellsberg’s two-color problem where certain predictions of the comparative ignorance hypothesis are not confirmed. In addition the hypothesis seems unable to explain how the subjects resolve trade-offs between security and expected pay-off when vagueness is present. Ellsberg offered an explanation of the typical behavior elicited by his examples in terms of these trade-offs and in section three we offer a model of Ellsberg’s trade-offs. The model takes seriously the role of imprecise probabilities in explaining Ellsberg’s phenomenon. The so-called three-color problem was also considered in Fox and Tversky (1995). We argue that Fox and Tversky’s analysis of this case breaks a symmetry with their analysis of the two-color problem. We propose a unified treatment of both problems and we present a experiment that confirms our hypothesis. (shrink)
Experimental results on the Ellsberg paradox typically reveal behavior that is commonly interpreted as ambiguity aversion. The experiments reported in the current paper find the objective probabilities for drawing a red ball that make subjects indifferent between various risky and uncertain Ellsberg bets. They allow us to examine the predictive power of alternative principles of choice under uncertainty, including the objective maximin and Hurwicz criteria, the sure-thing principle, and the principle of insufficient reason. Contrary to our expectations, the principle (...) of insufficient reason performed substantially better than rival theories in our experiment, with ambiguity aversion appearing only as a secondary phenomenon. (shrink)
ABSTRACT: In this paper I show that, contrary to the prevalent view, in his De Interpretatione chapter 8, Aristotle is concerned with a kind of ambiguity, i.e. with homonymy; more precisely, with homonymy of linguistic expressions as it may occur in dialectical argument. The paper has two parts. In the first part, I argue that in the Sophistici Elenchi 175b39-176a5 Aristotle indubitably deals with homonymy in dialectical argument; that De Interpretatione 8 is a parallel to Sophistici Elenchi 175b39-176a5; that (...) De Interpretatione 8 is concerned with dialectical argument; that, hence, De Interpretatione 8, too, deals with homonymy in dialectical argument. In the second part I discuss objections that have been put forward against the view that De Interpretatione 8 is about homonymy and demonstrate that they do not succeed. (shrink)
This book expounds and defends a new conception of the relation between truth and meaning. Atlas argues that the sense of a sense-general sentence radically underdetermines (independently of indexicality) its truth-conditional content. He applies this linguistic analysis to illuminate old and new philosophical problems of meaning, truth, falsity, negation, existence, presupposition, and implicature. In particular, he demonstrates how the concept of ambiguity has been misused and confused with other concepts of meaning, and how the interface between semantics and pragmatics (...) has been misunderstood. The problems he tackles are common to philosophy, linguistics, cognitive psychology, and artificial intelligence, and his conclusions will be of interest to all those working in these fields. (shrink)
The spaces provided by biotechnologies of sex selection are rich with epistemological, ontological, and ethical considerations that speak to broadly held social values and epistemic frameworks. In much of the discourse about sex sehction that is not medically indicated, the figure of the "naturally" conceived (future) child is treated as a problem f or parents who want to select the sex of their child. As unknown, that child is ambiguous in terms of sex — "it" is both and neither, and (...) might be the "wrong" sex. Drawing on Beauvoirean thinking about ambiguity and desire, I cast part of the desire to select the sex of a child as bound to an ethic and epistemology of disambiguation, and urge that the space of being-unknown is one to which each person is entitled. (shrink)
In this article, ambiguity attitude is measured through the maximum price a decision maker is willing to pay to know the probability of an event. Two problems are examined in which the decision maker faces an act: in one case, buying information implies playing a lottery, while, in the other case, buying information gives also the option to avoid playing the lottery. In both decision settings, relying on the Choquet expected utility model, we study how the decision maker’s risk (...) and ambiguity attitudes affect the reservation price for ambiguity resolution. These effects are analyzed for different levels of ambiguity of the act. Operating instructions for the elicitation of the reservation price for ambiguity resolution in an experimental setting are provided at the end of the article. (shrink)
Clinical trials of novel agents often present several layers of ethical challenge. Because time and resources for ethical and safety review are limited, how investigators, IRBs, and regulators allocate attention to a trial's various safety dimensions itself represents a critical ethical question. In what follows, I use the example of a Parkinson's disease gene transfer trial to show how risks involving unknown probabilities or outcomes (ambiguity), might sometimes draw attention away from risks that involve known probabilities or outcomes. This (...) potentially undermines the goal of ‘systematic and nonarbitrary analysis of risk’ during ethical review. To counteract the possible effects of such attention biases, I propose that reviewers develop ‘cognitive aids’ like lists and, where appropriate, set aside time to discuss non-ambiguous risks. I also propose further research for addressing and understanding how attention allocation, emotion, and ambiguity influence ethical decision-making. (shrink)
The Ellsberg Paradox documented the aversion to ambiguity in the probability of winning a prize. Using an original sample of 266 business owners and managers facing risks from climate change, this paper documents the presence of departures from rationality in both directions. Both ambiguity-seeking behavior and ambiguity-averse behavior are evident. People exhibit âfearâ effects of ambiguity for small probabilities of suffering a loss and âhopeâ effects for large probabilities. Estimates of the crossover point from ambiguity (...) aversion (fear) to ambiguity seeking (hope) place this value between 0.3 and 0.7 for the risk per decade lotteries considered, with empirical estimates indicating a crossover mean risk of about 0.5. Attitudes toward the degree of ambiguity also reverse at the crossover point. (shrink)
Much has been said on the religious pluralism of John Hick but little attention has been given to a key step in his argument for religious pluralism. This key step is the observation that the universe is religiously ambiguous. Hick himself is ambiguous about what he means by ‘religious ambiguity’. In this essay I will attempt to rectify this ambiguity by analysing the notion of ‘religious ambiguity’ and arguing what interpretation of this term Hick must commit himself (...) to. (shrink)
Ambiguity associated with everyday practice of science has made it difficult to reach a consensus on how to define misconduct in science. This essay outlines some of the important ambiguities of practice such as distinguishing data from noise, deciding whether results falsify a hypothesis, and converting research into research publications. The problem of ambiguity is further compounded by the prior intellectual commitments inherent in choosing problems and in dealing with the skepticism of one's colleagues. In preparing a draft (...) code of ethics for the American Society of Biochemistry and Molecular Biology (ASBMB), an attempt was made to take into account the ambiguities of practice. Also, the draft code adopted trust as its leading principle, specifically the importance of trust as a condition necessary for there to be science. During revision of the code, the focus on trust was changed. The new orientation was on trust as a consequence of carrying out science responsibly. By addressing the obligations necessary to engender trust, the ASBMB ethics code not only sets professional standards, but also makes a clear statement of public accountability. (shrink)
This study accounts for the observed patterns of variation and ambiguity in the expression and interpretation of aspect in bare habitual statements in Polish in the framework of Bouma’s ( 2008 ) recent version of stratified bi-directional Optimality Theory (OT).
This response draws on Saba Mahmood's work on Muslim subjectivities in order to consider how Stalnaker's conceptualization of virtue might be applied to non-Confucian sources. I argue that when applied cross-culturally, Stalnaker's revised definition of “skillful virtue” raises normative and metaethical questions about what counts as a skill versus a mere bodily practice, the process by how skill is acquired, and how we can both allow for the ambiguity of skills and continue to make constructive arguments about them.
We report on an experiment in which subjects choose actions in strategic games with either strategic complements or substitutes against a granny, a game theorist or other subjects. The games are selected in order to test predictions on the comparative statics of equilibrium with respect to changes in strategic ambiguity. We find that subjects face higher ambiguity while playing against the granny than playing against the game theorist if we assume that subjects are ambiguity averse. Moreover, under (...) the same assumption, subjects choose more secure actions in games more prone to ambiguity which is in line with the predictions. (shrink)
This article studies the emergence of ambiguity in communication through the concept of logical irreversibility and within the framework of Shannon’s information theory. This leads us to a precise and general expression of the intuition behind Zipf’s vocabulary balance in terms of a symmetry equation between the complexities of the coding and the decoding processes that imposes an unavoidable amount of logical uncertainty in natural communication. Accordingly, the emergence of irreversible computations is required if the complexities of the coding (...) and the decoding processes are balanced in a symmetric scenario, which means that the emergence of ambiguous codes is a necessary condition for natural communication to succeed. (shrink)
In multi-armed bandit problems, information acquired from experimentation is valuable because it tells the agent whether to select a particular option again in the future. This article tests whether people undervalue this information because they are ambiguity averse, or have a distaste for uncertainty about the average quality of each alternative. It is shown that ambiguity averse agents have lower than optimal Gittins indexes, appearing to undervalue information from experimentation, but are willing to pay more than ambiguity (...) neutral agents to learn the true mean of the payoff distribution, appearing to overvalue objectively given information. This prediction is tested with a laboratory experiment that elicits a Gittins index and a willingness to pay on six two-armed bandits. Consistent with the predictions of ambiguity aversion, the Gittins indexes are significantly lower than optimal and willingnesses to pay are significantly higher than optimal. (shrink)
Complex fear learning procedures might be better suited than the common differential fear conditioning paradigm for detecting individual differences related to vulnerability for anxiety disorders. Two such procedures are the blocking procedure and the protection-from-overshadowing procedure. Their comparison allows for the examination of discriminatory fear learning under conditions of ambiguity. The present study examined the role of individual differences in such discriminatory fear learning. We hypothesized that heightened trait anxiety would be related to a deficit in discriminatory fear learning. (...) Participants gave US-expectancy ratings as an index for the threat value of individual CSs following blocking and protection-from-overshadowing training. The difference in threat value at test between the protected-from-overshadowing CS and the blocked CS was negatively correlated with scores on a self-report tension-stress scale that approximates facets of generalized anxiety disorder (DASS-S), but not with other individual difference variables. In addition, a behavioral test showed that only participants scoring high on the DASS-S avoided the protected-from-overshadowing CS. This observed deficit in discriminatory fear learning for participants with high levels of tension-stress might be an underlying mechanism for fear overgeneralization in diffuse anxiety disorders such as generalized anxiety disorder. (shrink)
This paper considers a decision-making process under ambiguity in which the decision-maker is supposed to split outcomes between familiar and unfamiliar ones. She is assumed to behave differently with respect to unfamiliar gains, unfamiliar losses and customary (familiar) outcomes. In particular, she is supposed to be pessimistic on gains, optimistic on losses and ambiguity neutral on the familiar outcomes. A generalization of the usual Choquet Integral is formalized when the decision maker holds capacities and probabilities. A characterization of (...) the decision-maker’s behavior is provided for a specific subset of capacities, in which it is shown that the decision-maker underestimates the unfamiliar outcomes while is linear in probabilities on customary ones. (shrink)
We report the results of an experiment which investigates the impact of the manner in which likelihood information is presented to decision-makers on valuations assigned to lotteries. We find that subjects who observe representative sequences of outcomes attach higher valuations to lotteries than those who are given only a verbal description of a probability distribution. We interpret this in terms of a reduction in ambiguity about the possible lottery outcomes. These findings suggest that ambiguity aversion may be a (...) confounding factor in reported experimental violations of expected utility theory based on verbal descriptions of probability distributions. (shrink)
This article deals with the impact of governmental assistance on insurance demand under ambiguity, i.e., in situations where probabilities are uncertain. First, using a model of insurance demand under ambiguity, we derive theoretical predictions about the impact of several governmental assistance programmes on optimal insurance demand. For example, governmental assistance through a fixed public support scheme implies that partial insurance is always optimal under fair insurance with ambiguity. Second, we present the results of an experiment designed to (...) test these predictions. We find support for several of our theoretical predictions. For example, the presence of governmental assistance through a fixed public support scheme decreases individuals’ willingness to pay to be fully insured. Finally, we compare these results with those obtained for a risk situation. We find that, regardless of the form of governmental assistance, participants in the ambiguity context are consistently willing to pay more to be fully insured than participants in the risk situation. (shrink)
This article presents the results of a survey designed to test, with economically sophisticated participants, Ellsberg’s ambiguity aversion hypothesis, and Smithson’s conflict aversion hypothesis. Based on an original sample of 78 professional actuaries (all members of the French Institute of Actuaries), this article provides empirical evidence that ambiguity (i.e. uncertainty about the probability) affect insurers’ decision on pricing insurance. It first reveals that premiums are significantly higher for risks when there is ambiguity regarding the probability of the (...) loss. Second, it shows that insurers are sensitive to sources of ambiguity. The participants indeed, charged a higher premium when ambiguity came from conflict and disagreement regarding the probability of the loss than when ambiguity came from imprecision (imprecise forecast about the probability of the loss). This research thus documents the presence of both ambiguity aversion and conflict aversion in the field of insurance, and discuses economic and psychological rationales for the observed behaviours. (shrink)
We use the multiple price list method and a recursive expected utility theory of smooth ambiguity to separate out attitude towards risk from that towards ambiguity. Based on this separation, we investigate if there are differences in agent behaviour under uncertainty over gain amounts vis-a-vis uncertainty over loss amounts. On an aggregate level, we find that (i) subjects are risk averse over gains and risk seeking over losses, displaying a “reflection effect” and (ii) they are ambiguity neutral (...) over gains and are mildly ambiguity seeking over losses. Further analysis shows that on an individual level, and with respect to both risky and ambiguous prospects, there is limited incidence of a reflection effect where subjects are risk/ambiguity averse (seeking) in gains and seeking (averse) in losses, though this incidence is higher for ambiguous prospects. A very high proportion of such cases of reflection exhibit risk (ambiguity) aversion in gains and risk (ambiguity) seeking in losses, with the reverse effect being significantly present in the case of risk but almost absent in case of ambiguity. Our results suggest that reflection across gains and losses is not a stable individual characteristic, but depends upon whether the form of uncertainty is precise or ambiguous, since we rarely find an individual who exhibits reflection in both risky and ambiguous prospects. We also find that correlations between attitudes towards risk and ambiguity were domain dependent. (shrink)
This paper continues a study of event ambiguity as a primitive concept. Axioms are described for a comparative ambiguity relation on an arbitrary event set that are necessary and sufficient for a representation of the relation by a functional that is nonnegative, vanishes at the empty event, and satisfies complementary equality and submodularity. Uniqueness characteristics of representing functionals are discussed. The theory is extended to multifactor events, where marginal ambiguity and additive representations arise.
The paper studies the impact of informational ambiguity on behalf of informed traders on history-dependent price behaviour in a model of sequential trading in financial markets. Following Chateauneuf et al. (J Econ Theory 137:538–567, 2008), we use neo-additive capacities to model ambiguity. Such ambiguity and attitudes to it can engender herd and contrarian behaviour, and also cause the market to break down. The latter, herd and contrarian behaviour, can be reduced by the existence of a bid-ask spread.
We survey the literature that has explored the implications of decision-making under ambiguity for financial market outcomes, such as portfolio choice and equilibrium asset prices. This ambiguity literature has led to a number of significant advances in our ability to rationalize empirical features of asset returns and portfolio decisions, such as the failure of the two-fund separation theorem in portfolio decisions, the modest exposure to risky securities observed for a majority of investors, the home equity preference in international (...) portfolio diversification, the excess volatility of asset returns, the equity premium and the risk-free rate puzzles, and the occurrence of trading break-downs. (shrink)
Competence has recently been proposed as an explanation for the degree of ambiguity aversion. Using general knowledge questions we presented subjects with simple lotteries in which they could bet on an event and against the same event. We show that the sum of certainty equivalents for both bets depends on the judged knowledge of the class of events. We also elicited the decision weights for events and complementary events. We found a similar effect of knowledge on the sum of (...) decision weights. (shrink)
In a recent article, Machina (Am Econ Rev forthcoming, 2008) suggested choice problems in the spirit of Ellsberg (Q J Econ 75:643–669, 1961), which challenge tail-separability, an implication of Choquet expected utility (CEU), to a similar extent as the Ellsberg paradox challenged the sure-thing principle implied by subjective expected utility (SEU). We have tested choice behavior for bets on one of Machina’s choice problems, the reflection example. Our results indicate that tail-separability is violated by a large majority of subjects (over (...) 70% of the sample). These empirical findings complement the theoretical analysis of Machina (Am Econ Rev forthcoming, 2008) and, together, they confirm the need for new approaches in the analysis of ambiguity for decision making. (shrink)
In this paper I discuss the interrelated topics of stereotype threat and attributional ambiguity as they relate to gender and gender identity. The former has become an emerging topic in feminist philosophy and has spawned a tremendous amount of research in social psychology and elsewhere. But the discussion, at least in how it connects to gender, is incomplete: the focus is only on cisgender women and their experiences. By considering trans women’s experiences of stereotype threat and attributional ambiguity, (...) we gain a deeper understanding of the phenomena, and their problematic effects. (shrink)
In this essay, I explore the ways that Beauvoir’s description of philosophical novels reveals her understanding of consciousness as a particular sort of ambiguity: that which not only gives the world meaning, but which also, necessarily, finds meaning in the world through the values, ideas, and objects given to it by others. It is through the philosophical (metaphysical) novel that Beauvoir finds a medium for the philosophical communication of ambiguity – that is, a medium for writing human being. (...) More specifically, I consider the metaphysical stance Beauvoir is able to describe because of her commitment to philosophical literature. In writing, and in reading, fiction, what is manifest is both found and given, discovered and created; and the metaphysics of the novel offers a way to read philosophy as poeisis, poetry in the sense of bringing-forth or revealing worldly meaning, in ways that are ambiguously particular and universal. (shrink)
This paper discusses Jean-Yves Jaffray’s ideas on ambiguity and the views underlying his ideas. His models, developed 20 years ago, provide the most tractable separation of risk attitudes, ambiguity attitudes, and ambiguity beliefs available in the literature today.
Optimal protective responses to long-term risks depend on rational perceptions of ambiguous risks and uncertain time horizons. Our study examined the joint influence of uncertain delay and risk in an original sample of business owners and managers. We found that many subjects disliked uncertainty in the timing of an outcome, a reaction we term ``lottery timing risk aversion.'' Such aversion to uncertain timing was positively related to aversion to ambiguous probabilities for lotteries involving storm damage risks. This association suggests that (...) uncertainty may be processed similarly in both the risk and time dimensions. (shrink)
An argument can be superficially valid and rhetorically effective even if what is plausibly meant, what is derived from what, and how it is derived is not at all clear. An example of such an argument is provided by Socrates’s famous refutation of Euthyphro’s second definition of holy, which is generally regarded as clearly valid and successful. This paper provides a stricter logical analysis than the ones in the literature. In particular, it is shown that the argument contains a syntactically (...) ambiguous expression, a passage that needs to be read charitably, and a previously unnoticed but crucial shift between two notions of unholy. Different analyses may be provided, depending on how these interpretation problems are solved. The conditions under which the refutation is valid and successful are far from obvious, and are here explicitly specified. (shrink)
In this particularly well written volume Graeme Hirst presents a theoretically motivated foundation for semantic interpretation (conceptual analysis) by computer, and shows how this framework facilitates the resolution of both lexical and syntactic ambiguities.
The distinction between constitutive and regulative rules is applied to rules for critical discussion that have to do with the use of ambiguous expressions. This leads to a distinction between rule violating fallacies, by which one abandons a critical discussion, and norm violating fallacies, which are in a way admissible within a critical discussion. According to the formal model for critical discussion, proposed in this paper, fallacies of the norm violating type arc not prohibited. Instead, it provides discussants with devices (...) to discuss fallacies and fallacy criticisms. (shrink)
In his book Frederic Schick develops his challenge to standard decision theory. He argues that talk of the beliefs and desires of an agent is not sufficient to explain choices. To account for a given choice we need to take into consideration how the agent understands the problem, how he sees in a selective way the options open to him. The author applies his new logic to a host of common human predicaments. Why do people in choice experiments act so (...) often against expectations? Why do people cooperate in situations where textbook logic predicts that they won't? What exactly is weakness of will? What are people reporting when they say their lives have no meaning for them? This book questions the foundations of technical and philosophical decision theory and will appeal to all those who work in that field, be they philosophers, economists or psychologists. (shrink)
the first full length study of Beauvoir's political philosophy, this book both locates Beauvoir in her own intellectual and political context and demonstrates the continuing significance of her thinking. Beauvoir still speaks, in a unique voice, to many pressing questions concerning politics. These include, among others, the values and dangers of liberal humanism; how oppressed groups become complicit in their own oppression; how social identities are perpetuated; the limits to rationalism and the difficulties of political judgment; and the place of (...) emotions, such as the desire for revenge, in politics. (shrink)
Teachers are often placed in a space of tensionbetween responding to students as persons andresponding to students through theirinstitutionally-defined roles. Particularlywith respect to eros, which has becomeincreasingly the subject of strictinstitutional legislation and regulation,teachers have little recourse to a language ofresponsibility outside an institutional frame. By studying the significance of communicativeambiguity for responsibility, this paperexplores what is ethically at stake forteachers in erotic forms of communication. Specifically, it is Levinas's own ambiguousunderstanding of the ethical significance oferos, and what we have (...) to learn from it, thatoffers a way of reading the place of eros inresponsibility. I conclude my discussion withsome thoughts on what a renewed understandingof responsibility might mean at the personaland institutional levels. (shrink)
This paper is an exploration of the Cartesian paradigms of clarity and univocity and how these inform contemporary educational theory and practice. Phenomenology is discussed as a way of disrupting Descartes' visions of clarity and distinctness as paradigms of knowledge and as a return of inquiry to life as it is actually lived. Analogical discourse is examined as a way of giving a voice to this sort of inquiry. Heidegger's notions of inquiry as obedience and thanksgiving are discussed.