In this paper, we consider the composition of an optimal portfolio made of two dependent risky assets. The investor is first assumed to be a risk-averse expected utility maximizer, and we recover the existing conditions under which all these investors hold at least some percentage of their portfolio in one of the assets. Then, we assume that the decision maker is not only risk-averse, but also prudent and we obtain new minimum demand conditions as well as intuitively (...) appealing interpretations for them. Finally, we consider the general case of investor’s preferences exhibiting risk apportionment of any order and we derive the corresponding minimum demand conditions. As a byproduct, we obtain conditions such that an investor holds either a positive quantity of one of the assets or a proportion greater than 50 %. (shrink)

The present note first discusses the concept of s-convex pain functions in decision theory. Then, the economic behavior of an agent with such a pain function is represented through the comparison of some recursive lotteries.

The existing literature on savings, insurance, and portfolio choices under risk has revealed that quite often comparative statics results depend, among other things, upon the values of the coefficients of relative risk aversion and relative prudence. More specifically the benchmark values for these coefficients are, respectively, one and two. Recently, several papers investigated constraints on the higher degree extensions of the coefficients of relative risk aversion and of relative prudence. The present work provides a unified (...) approach to this question based on the concept of elementary correlation increasing transformations, allowing for a better understanding of changes in risk in the multiplicative case. (shrink)

We investigate risk attitudes when the underlying domain of payoffs is finite and the payoffs are, in general, not numerical. In such cases, the traditional notions of absolute risk attitudes, that are designed for convex domains of numerical payoffs, are not applicable. We introduce comparative notions of weak and strong risk attitudes that remain applicable. We examine how they are characterized within the rank-dependent utility model, thus including expected utility as a special case. In particular, we characterize (...) strong comparative risk aversion under rank-dependent utility. This is our main result. From this and other findings, we draw two novel conclusions. First, under expected utility, weak and strong comparative risk aversion are characterized by the same condition over finite domains. By contrast, such is not the case under non-expected utility. Second, under expected utility, weak comparative risk aversion is characterized by the same condition when the utility functions have finite range and when they have convex range. By contrast, such is not the case under non-expected utility. Thus, considering comparative risk aversion over finite domains leads to a better understanding of the divide between expected and non-expected utility, more generally, the structural properties of the main models of decision-making under risk. (shrink)

Fishburn and Vickson showed that, when applied to random alternatives with an equal mean, 3rd-degree and decreasing absolute risk aversion stochastic dominances represent equivalent rules. The present paper generalizes this result to higher degrees. Specifically, higher-degree stochastic dominance rules and common preference by all decision makers with decreasing higher-order absolute risk aversion are shown to coincide under appropriate constraints on the respective moments of the random variables to be compared.

By means of minimal assumptions on the individual preferences, I show that the Willingness To Pay (WTP) for both a FSD and SSD reduction of risk is the sum of a mean effect, a pure risk effect and a wealth effect. As a result, the WTP of a risk-averse decision maker may be lower than the WTP of a risk-neutral one, for a large class of individual preferences’ representation and a large class of risks.

Research ethics committees (RECs) evaluate whether the risk-benefit ratio of a study is acceptable. Decentralized clinical trials (DCTs) are a novel approach for conducting clinical trials that potentially bring important benefits for research, including several collateral benefits. The position of collateral benefits in risk-benefit assessments is currently unclear. DCTs raise therefore questions about how these benefits should be assessed. This paper aims to reconsider the different types of research benefits, and their position in risk-benefit assessments. We (...) class='Hi'>first propose a categorization of research benefits, based on the types of benefits that can be distinguished from the literature and ethical guidelines. Secondly, we will reconsider the position of collateral benefits. We argue that these benefits are not fundamentally different from other benefits of research and can therefore be included in risk-benefit assessments of DCTs. (shrink)

In a recent article entitled “Putting Risk in its Proper Place,” Eeckhoudt and Schlesinger (2006) established a theorem linking the sign of the n-th derivative of an agent’s utility function to her preferences among pairs of simple lotteries. We characterize these lotteries and show that, in a given pair, they only differ by their moments of order greater than or equal to n. When the n-th derivative of the utility function is positive (negative) and n is odd (even), (...) the agent prefers a lottery with higher (lower) n + 2p-th moments for p belonging to the set of positive integers. This result links the preference for disaggregation of risks across states of nature to the complete structure of moments preferred by mixed risk averse agents. It can be viewed as a generalization of a proposition appearing in Ekern (1980) which focused only on the differences in the n-th moments. (shrink)

The trolley problem, first described by Foot (1967) and Thomson (The Monist, 59, 204–217, 1976), is one of the most famous and influential thought experiments in deontological ethics. The general story is that a runaway trolley is threatening the lives of five people. Doing nothing will result in the death of those persons, but acting in order to save those persons would unavoidably result in the death of another, sixth person. It appears that, depending on the situation, we (...) have different moral judgments about the permissibility of action. We will review and systematize all the proposals in the literature of the past 35 years that have attempted to grasp our moral intuitions in a simple deontological principle. In particular, seventeen proposals will be classified: six algorithmic, seven psychological, and four other invalid accounts. This review and classification sheds light on some subtle differences and clarify a few issues. (shrink)

Risk attitude is known to be a key determinant of various economic and financial choices. Behavioral studies that aim to evaluate the role of risk attitudes in contexts of this type, therefore, require tools for measuring individual risk tolerance. Recent developments in decision theory provide such tools. However, the methods available can be time consuming. As a result, some practitioners might have an incentive to prefer “fast and frugal” methods to clean but more costly methods. In this (...) article, we focus on a tractable procedure initially proposed by Holt and Laury (2002) to elicit risk attitude. We generalize this method to measure utility and risk aversion as follows. First, we allow measurement of probabilistic risk attitude through violations of expected utility due to probability weighting. Second, we use the outcome scale rather than the probability scale in the menu of choices. Third, we compare sure payoffs with lotteries instead of comparing non-degenerate lotteries. A within-subject experimental study illustrates the gains in tractability and bias minimization that can result from such an extension. (shrink)

According to the local risk-neutrality theorem an agent who has the opportunity to invest in an uncertain asset does not buy it or sell it short iff its expected value is equal to its price, independently of the agent's attitude towards risk. Contrary to that it is shown that, in the context of expected utility theory with differentiable vNM utility function, but without the assumption of stochastic constant returns to scale, nondegenerate intervals of no-trade prices may exist. With (...) a quasiconcave expected utility function they do if, and only if, the agent is risk averse of order one. (shrink)

"Ever Since This World Began" from Love Dog (Penny-Ante Editions, 2013) by Masha Tupitsyn continent. The audio-essay you've recorded yourself reading for continent. , “Ever Since the World Began,” is a compelling entrance into your new multi-media book, Love Dog (Success and Failure) , because it speaks to the very form of the book itself: vacillating and finding the long way around the question of love by using different genres and media. In your discussion of the face, one of the (...) themes of Love Dog , I think there is something to be said about the surfaces media create and how you constantly manipulate them in your work. This seems important for thinking also about your book LACONIA: 1,200 Tweets on Film ; a book on film written in tweets, interposing already three sets of expectations and pushing the boundaries of each medium's faciality, it's surface tension. In Love Dog , is there another kind of facial interaction? Perhaps the discursive faces of approaching love as topic and love as method? If so, how did/do these intersect for you, do/did they drive the creation of this book? MASHA TUPITSYN With LACONIA and Love Dog , I wanted to pay homage to the work modernism has done on subjective time and chronological time by carrying that experiment over into the digital economy. Because LACONIA is a time-based work of cultural criticism that employs the aphorism to look at 21 st century American culture, it is also an archival work of cultural mourning and memory. And in Love Dog , which is also a work about mourning as it relates to love, I wanted to think with all my senses, and to reflect that in the writing itself by using a multi-media form. LACONIA tackled the sound bite and the promotional image--the everyday language of consumer culture--which often wants to communicate ideological agendas through the repetition of a single image or reductive phrase. I had always been interested in the approaches of artists like Barbara Kruger and Jenny Holzer and essayistic, typographical filmmakers, like Chris Marker and Godard. In both cases, I felt it was important to try to compose a book in which deep—critical—thinking happens in so-called immediate, informal, and disposable contexts. That is, in places where you are either not supposed to be serious or are not required to take things seriously. To me the most intervention is needed in every day instances of culture and representation. In order to do that, I had to utilize and interrogate the very structures I was critiquing. In other words, the writing had to materialize in that live, digital, public space. It couldn’t simply happen at home on a piece of paper or in a word document on my computer that no one could see until it was finished. It had to unfold in real time, amidst everything else. And it had to literally be surrounded by the cultural landscape I wanted to assess. In both LACONIA and Love Dog , I wanted to know how and if we can get away from what we cannot get away from? From which there is no respite. Given this, I don’t think hypertexts can really be called hypertexts anymore. Hypertexts are simply the world today. This is not only the way we read the world now. It is the way the world reads. Likewise, interfaciality, as you put it, works on a number of levels for me, both on and off the page. There is my relation to epistemological and phenomenological surfaces—the screen, the body, the face, the voice, gender; the official story. Then there is the way this dovetails formally, and to which the digital adds yet another dimension. It’s also where sound comes into Love Dog (giving the book a sound; giving tonality to the book’s ideas and feelings). As Anne Carson pointed out in her essay “The Gender of Sound,” the two are connected, and of course so are love and gender. In “Ever Since This World Began,” I wanted to think about the phenomenology of the voice, which is why I visualize the sonic in the book and why in my writing about faces, I look at the tonal aspects (the things a face voices and a voice faces) of a face. This was standard to do when images and faces were “silent” in the silent era. Those images/faces were extraordinarily audible. The greatest screen face, to me, is still Falconetti’s in Dreyer’s The Passion of Joan of Arc . We can hear her face—even though there is no actual sound on screen of her speaking. The internet is a similarly “silent” space where actual voices are lacking. So intertextuality goes with interfaciality. I’ve also talked a lot about how categorization worked when it came to the reception of my first book, Beauty Talk & Monsters . How despite the fact that Beauty Talk is a text that crisscrosses form and content in a variety of ways, not pinpointing its exact genre—choosing one genre over another—only made things worse. Fiction was the category people were most adverse to me using, even though of course there is a lot of fiction in the book. Part of how fiction works in Beauty Talk is in the reader not knowing exactly where the fiction resides. In Godard’s 1967 film, Weekend , for example, everything matters. Everything is political, whether it’s real or imaginary, film or reality. In Weekend , life is not a game and neither is the game a game. The game is really life. Either everything is important or nothing is. But many people want clear answers and demarcations so that they can decide what is important and what is not important. My use of the “I,” subjective criticism, made everything “real” in Beauty Talk . But fiction is in the construction. It is in the blending. This is why I perforate the movie screen and connect the onscreen and the offscreen; the official story and the backstory. Although I don’t think there is a difference between onscreen and offscreen anymore. Nor is there a dialectic. It’s all screen all the time now. Non-fiction, on the other hand, was more tolerated as a moniker. Unlike Love Dog , Beauty Talk wasn’t explicitly or tangibly (what is tangible is a question in all these books) working with digital forms or within this digital economy, so some people resisted the book’s hypertextuality or intertextuality because they couldn’t see its other forms, if that makes sense. It was a problem of invisibility; of how to make something appear (this is where Nietzsche, big presence in Love Dog , comes in—the nature of appearances). Something people don’t necessarily want to see. Some readers couldn’t see the way forms were interfacing in that book. On the surface, Beauty Talk was simply a text about media culture—the domination of entertainment as a mode of being and knowing—and most readers could only see that one side of the book. But as Godard puts it in Wim Wenders’ documentary about the future of cinema, Room 666 , “Films are made, images are made, when there’s no one looking. That’s what the invisible is, that which we don’t see. That’s what the incredible is, that which we don’t see. And cinema shows you that which we don’t see, the incredible.” We are living in the aftermath of narrative and temporal collapse, which means we don’t read or feel in the same way. I began to use digital forms in my writing because I don’t see us as traditional book people anymore. I would add that power also resides in the invisible, in the things we make invisible by making them visible. Or it did for a long time. The new face of power is quickly becoming so-called transparency, which is even more corrupt because even though we now live in a behind-the-scenes culture, and see and know how the mechanisms of power and corruption operate, we still don't change. The world still doesn't change. Finally, another important thing that Godard says in Room 666 that relates to Love Dog is: “I’m here in front of the camera, and yet in my body and in my head, I’m behind it. My world is the imaginary and the imaginary is a journey between forwards and backwards.” This idea of visible/invisible, foresight and hindsight , backwards and forwards is an important dialectic in relation to time and the idea of the destinal. This is why I wanted Love Dog to travel, literally, figuratively, and discursively. You have to be open to not knowing. To epistemological, geographical, chronological, and emotional aporias. In Love Dog my story is both visible and invisible to me. Sometimes I could see where I was going. Other times I was completely in the dark existentially. Truth procedure, which love is, as bell hooks and Badiou tell us, requires expedition and openness to possibility. Unless you want a story you already know, but that is not truth procedure. So I tried to create this backwards and forwards journey in the book—this sense of travel and motion, hope and doubt—by jumping between forms, media, time; traveling to different places, texts, and emotional registers. The book’s “Time-Jump series,” which mostly takes the form of music—songs—but also a series of “green” videos that I shot, is the most obvious tribute to this idea of subjective and chronological time. continent. Your work aligns with writers that play with the form of their language, or have assumed the role of performance artist at some point: Kathy Acker, Chris Kraus, Avital Ronell, and Anne Carson to name a few representing varied approaches that show up in Love Dog . At the risk of ossifying the work, or missing the point—as these experimental modes of writing stack-up in piles of published works, do they approach a genre? MASHA As I noted in my book Life As We Show It , in Chelsea Girls the poet Eileen Myles points out, “You can’t get money without a category.” More importantly, you can’t get a category—or respect, rank—without a clear genre. This makes genre and gender an obvious pair. The two words are even linked etymologically and both genre and gender concern taxonomies of legitimacy—of sorting through what and who is valuable. So the words share common prejudices. The things one does not want to read is often synonymous with who one doesn't want to read about. Therefore a break-up of or with genre is maybe the genre or anti-genre that could be said to link these writers. Avital Ronell breaks up with philosophical tradition and modes of inquiry. Like Nietzsche, she revaluates methods of evaluation, testing out things you are not supposed to use philosophy to test (and, by the same token, testing philosophy in ways it’s not supposed to be tested), like drugs and stupidity—where philosophy fails and we fail philosophy. And Chris Kraus does something similar in her experimental fiction, using different forms to put female subjectivity “to the test,” so to speak. All these female writers and thinkers have tried to destabilize the systems that have been set up in (and against) writing. Thus missing the mark with genre, even intentionally, means that we have missed the point in some sense as writers and thinkers. And that to me is a good thing, however difficult. We’ve started at the wrong point and gone somewhere else instead. We’ve acknowledged that writing and thinking are also about failure, and that failure is always embedded in the act of writing and in our reasons for writing. So that missing the point is also the point. Derrida insisted: “We must invent a name for those ‘critical’ inventions which belong to literature while deforming its limits.” But how can you give something that resists and deforms, a name? Wouldn’t the name also be deformed? Isn't this why the aforementioned writers get hyphenated descriptors like ficto-criticism? Do we need a proper name to be able to read something carefully? I don’t think so. I don’t need it as a reader. I’ve always taken a work on its own terms. But for most people, if you don’t have an address, people don’t know how to find you. A lot of time, they won’t even know how to look. And in some cases, they’ll think you’re not even worth finding. You are not on the map because you have to literally make the map in order to exist. In her essay, “The Gender of Sound” Carson asks, “Why is female sound bad to hear?” I think for the same reason something uncategorizable (pedagogically, creatively, racially, and sexually)—Other—is hard to read. *For an audio recording of Florida , read by Masha Tupitsyn click here . continent. : We're also curious to hear know how you see the significance of 'performance' (and why the label sticks to the shoes of these authors like toilet paper) in describing this kind of writing work? MASHA I think I responded to the parenthetical portion of this question in my previous answer. As far as how performance relates to Love Dog , in Acker’s Don Quixote , which is another big presence in the book, she writes, “there is no other reality than anthropomorphism.” In Don Quixote , the dog is human and the human is dog. Which brings us to the title of Love Dog and the totemic function of the dog in the book: giving human things animal characteristics and animal things human characteristics. Rather than investing all our human love ideals into dogs, which we do constantly as a culture of dog lovers, I wanted to put the dog into love. It is the difference between the consumption of love as a patriarchal institution or status position and the essence of a type of radical and liberatory relation that would benefit humans in their bonds with other humans. So the dog in Love Dog is not simply the book’s cover or performative affect, so to speak. Love has always needed the dog, which is why the dog is the very embodiment of belief in love . Recall Argos The Great Dog and Odysseus. Argos is the only one who remembers and recognizes the ragged and old Odysseus even after his 20-year absence. So love is the high ideal and the dog, both common and dependable, is the bridge between the sacred and the profane. The dog is the house of love. And because Love Dog is a digital project, it seemed impossible to think about the post-human, technology, the virtual, or difference (which Badiou says is essential to love in In Praise of Love ) without thinking about animal-being and being-animal. Instead of simply “performing” these ideas and characteristics as literary affects, I’m interested in being-becoming. Which means the book’s tropes, leitmotifs, series, and even its titles are in service of that truth procedure. In other words, I actually want to live this way, not just write this way. And, more importantly, I want to live this way not just think this way. So Love Dog became both my totem animal and my autobiographical animal. This made the book organic, anthropomorphic—beyond literary. See the trailer to Masha Tupitsyn's new book available now from Penny Ante Editions. (shrink)

In the television show Deal or No Deal a contestant is endowed with a sealed box, which potentially contains a large monetary prize. In the course of the show the contestant learns more information about the distribution of possible monetary prizes inside her box. Consider two groups of contestants, who learned that the chances of their boxes containing a large prize are 20% and 80% correspondingly. Contestants in both groups receive qualitatively similar price offers for selling the content of their (...) boxes. If contestants are less risk averse when facing unlikely gains, the price offer is likely to be more frequently rejected in the first group than in the second group. However, the fraction of rejections is virtually identical across two groups. Thus, contestants appear to have identical risk attitudes over (large) gains of low and high probability. (shrink)

Various experimental procedures aimed at measuring individual risk aversion involve a list of pairs of alternative prospects. We first study the widely used method by Holt and Laury :1644–1655, 2002), for which we find that the removal of some items from the lists yields a systematic decrease in risk aversion and scrambles the ranking of individuals by risk aversion. This bias, that we call embedding bias, is quite distinct from other confounds that have (...) been previously observed in the use of the HL method. It may be related to empirical phenomena and theoretical developments where better prospects increase risk aversion. Nevertheless, we also find that the more recent elicitation method due to Abdellaoui et al., also based on lists but using only one and the same probability in the list, does not display any statistically significant bias when the corresponding items of the list are removed. Our results suggest that methods other than the popular HL one may be preferable for the measurement of risk aversion. (shrink)

For every sequence |p n } n of formulas of Peano ArithmeticPA with, every formulaA of the first-order theory diagonalizable algebras, we associate a formula 0 A, called the value ofA inPA with respect to the interpretation. We show that, ifA is true in every diagonalizable algebra, then, for every, 0 A is a theorem ofPA.

Back in thirteenth-century Europe, in the early years of the great universities, learning was spiced with the danger of mob violence and a terrifyingly repressive religious censorship. Roger Bacon, a humble and devout English friar, seems an unlikely figure to challenge the orthodoxy of his day - yet he risked his life to establish the basis for true knowledge. Born c.1220, Bacon was passionately interested in the natural world and how things worked. Such dangerous topics were vetoed by his (...) class='Hi'>Order, and it was only when a new Pope proved sympathetic that he began compiling his encyclopaedia on everything from optics to alchemy - the synopsis took a year and ran to 800,000 words and he was never to complete the work itself. Sadly, the enlightened Pope died, and Bacon was tried as a magician and incarcerated for ten years. Legend transformed Bacon into a sorcerer, 'Doctor Mirabilis', yet he taught that all magic was based on fraud, and his books were the first flowering of the scientific thinking that would transform our world. He advanced the understanding of optics, made geographical breakthroughs later used by Columbus, predicted everything from horseless carriages to the telescope, and stressed the importance of mathematics to science, a significance ignored for 400 years. His biggest contribution was to insist that a study of the natural world by observation and exact measurement was the surest foundation for truth. Clegg uncovers the realities of life in a medieval university and friary, setting out the shadowy facts of Bacon's life alongside his writings. The result is both a fascinating biography and a picture of the age. (shrink)

I focus my discussion on the well-known Ellsberg paradox. I find good normative reasons for incorporating non-precise belief, as represented by sets of probabilities, in an Ellsberg decision model. This amounts to forgoing the completeness axiom of expected utility theory. Provided that probability sets are interpreted as genuinely indeterminate belief, such a model can moreover make the “Ellsberg choices” rationally permissible. Without some further element to the story, however, the model does not explain how an agent may come to have (...) unique preferences for each of the Ellsberg options. Levi holds that the extra element amounts to innocuous secondary “risk” or security considerations that are used to break ties when more than one option is rationally permissible. While I think a lexical choice rule of this kind is very plausible, I argue that it involves a greater break with xpected utility theory than mere violation of the ordering axiom. (shrink)

European Journal of Political Theory, Volume 21, Issue 3, Page 608-614, July 2022. In The Shifting Border, Ayelet Shachar argues that the exercise of sovereign power through border regimes no longer tracks territorial boundaries. In my commentary, I first argue that Shachar’s analysis implicitly calls into question the legitimacy of the international order. I then raise the worry that the logic which severs the link between the exercise of sovereignty and territory is the same logic that can be (...) used to justify injustice and atrocity such as ethnic cleansing. Shachar’s normative proposals do not sufficiently recognize or guard against this risk. (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)

Diagnostic tests allow better informed medical decisions when there is uncertainty about a patient’s health status and, therefore, about the desirability to undertake treatment. This paper studies the relation between the expected value of diagnostic information and a patient's risk aversion. We show that the ex ante value of diagnostic information increases with risk aversion for diseases with low prevalence, but decreases with risk aversion for diseases with high prevalence. On the other hand, the (...) ex post value of diagnostic information always increases with the patient's degree of risk aversion. (shrink)

In The Shifting Border, Ayelet Shachar argues that the exercise of sovereign power through border regimes no longer tracks territorial boundaries. In my commentary, I first argue that Shachar’s analysis implicitly calls into question the legitimacy of the international order. I then raise the worry that the logic which severs the link between the exercise of sovereignty and territory is the same logic that can be used to justify injustice and atrocity such as ethnic cleansing. Shachar’s normative proposals (...) do not sufficiently recognize or guard against this risk. (shrink)

The Ecclesiastical History of Orderic Vitalis has been called `the greatest of all medieval chronicles'. Written in Normandy between 1114 and 1141, it is a detailed history of the Norman people and their conquests, full of vivid, often penetrating portraits of the lives and characters of kings and queens, lords and bishops, simple knights, and humble villagers. The chronicle gives a unique, authentic picture of feudal society during a period of rapid change in church and state which saw the emergence (...) of the Anglo-Norman realm, the spread of new forms of monasticism, and the launching of the Crusades. Published in 1968, volume II of Marjorie Chibnall's six-volume edition of the Ecclesiastical History is now available for the first time in paperback. `a superbly edited Latin text and a unique English translation of the work of a major historian' American Historical Review `Mrs Chibnall is giving us... her edition of a classical medieval text which will itself become a classic of medieval scholarship.' Times Literary Supplement. (shrink)

This article argues that Lara Buchak’s risk-weighted expected utility (REU) theory fails to offer a true alternative to expected utility theory. Under commonly held assumptions about dynamic choice and the framing of decision problems, rational agents are guided by their attitudes to temporally extended courses of action. If so, REU theory makes approximately the same recommendations as expected utility theory. Being more permissive about dynamic choice or framing, however, undermines the theory’s claim to capturing a steady choice disposition in (...) the face of risk. I argue that this poses a challenge to alternatives to expected utility theory more generally. (shrink)

Heath and Tversky (1991, Journal of Risk and Uncertainty 4:5–28) posed that reaction to ambiguity is driven by perceived competence. Competence effects may be inconsistent with ambiguity aversion if betting on own judgement is preferred to betting on a chance event, because judgemental probabilities are more ambiguous than chance events. This laboratory experiment analyses whether ambiguity affects prices and volumes in a double auction market, and contrasts ambiguity aversion to competence effects. In order to test for (...) the presence of competence effects, in the experiment uncertainty is tied to the realisation of events about which the decision maker is more or less knowledgeable. Two experiments are presented: in the first, knowledge is exogenous, whereas in the second the knowledge judgement is endogenous. Market prices provide evidence in favour of the competence hypothesis only when competence is self-assessed. Comparable volumes are observed in both experiments. (shrink)

The undecidability of the first-order theory of diagonalizable algebras is shown here.

A central point of debate over environmental policies concerns how future costs and benefits should be assessed. The most commonly used method for assessing the value of future costs and benefits is economic discounting. One often-cited justification for discounting is uncertainty. More specifically, it is risk aversion coupled with the expectation that future prospects are more risky. In this paper I argue that there are at least two reasons for disputing the use of risk aversion as (...) a justification for discounting when dealing with longterm decisions, one technical and one ethical. Firstly, I argue that technically, it implies an inconsistency between theory and practice. And secondly, I argue that discounting for uncertainty relies on a form of individualism which, while reasonable in standard microeconomic theory where an agent chooses how to spread her own consumption over her own lifetime, is inappropriate in the context of intergenerational social decisions. (shrink)

_Postures of the Mind _was first published in 1985. Minnesota Archive Editions uses digital technology to make long-unavailable books once again accessible, and are published unaltered from the original University of Minnesota Press editions. Annette Baier develops, in these essays, a posture in philosophy of mind and in ethics that grows out of her reading of Hume and the later Wittgenstein, and that challenges several Kantian or analytic articles of faith. She questions the assumption that intellect has authority over (...) all human feelings and traditions; that to recognize order we must recognize universal laws—descriptive or prescriptive; that the essential mental activity is representing; and that mental acts can be analyzed into discrete basic elements, combined according to statable rules of synthesis. In the first group of essays—"Varieties of Mental Postures"—Baier evaluates the positions taken by philosophers ranging from Descartes to Dennett and Davidson. Among her topics are remembering, intending, realizing, caring, representing, changing one's mind, justifying one's actions and feelings, and having conflicting reasons for them. The second group of essays—"Varieties of Moral Postures" - explores the sort of morality we get when all of these capacities become reflective and self-corrective. Some deal with particular moral issues—our treatment of animals, our policies regarding risk to human life, our contractual obligations; others, with more general questions on the role of moral philosophers and the place of moral theory. These essays respond to the theories of Hobbes, Kant, Rawls, and MacIntyre, but Baier's most positive reaction is to David Hume; _Postures of the Mind _ affirms and cultivates his version of a moral reflection that employs feeling and tradition as well as reason. (shrink)

We extend first-order logic to include variadic function symbols, and prove a substitution lemma. Two applications are given: one to bounded quantifier elimination and one to the definability of certain Borel sets.

Many properties of compacta have “textbook” definitions which are phrased in lattice-theoretic terms that, ostensibly, apply only to the full closed-set lattice of a space. We provide a simple criterion for identifying such definitions that may be paraphrased in terms that apply to all lattice bases of the space, thereby making model-theoretic tools available to study the defined properties. In this note we are primarily interested in properties of continua related to unicoherence; i.e., properties that speak to the existence of (...) “holes” in a continuum and in certain of its subcontinua. (shrink)

In a recent paper, Montagna proved the undecidability of the first-order theory of diagonalisable algebras. This result is here refined — the set of finitely refutable sentences is shown effectively inseparable from the set of theorems. The proof is quite simple.

We show that infinite sets whose power-sets are Dedekind-finite can only carry N₀-categorical first order structures. We identify other subclasses of this class of Dedekind-finite sets, and discuss their possible first order structures.

The aim of this paper is to introduce a formal system STW of self-referential truth, which extends the classical first-order theory of pure combinators with a truth predicate and certain approximation axioms. STW naturally embodies the mechanisms of general predicate application/abstraction on a par with function application/abstraction; in addition, it allows non-trivial constructions, inspired by generalized recursion theory. As a consequence, STW provides a smooth inner model for Myhill's systems with levels of implication.

In the age of big data, machine learning models are globally used to execute default risk prediction. Imbalanced datasets and redundant features are two main problems that can reduce the performance of machine learning models. To address these issues, this study conducts an analysis from the viewpoint of different balance ratios as well as the selection order of feature selection. Accordingly, we first use data rebalancing and feature selection to obtain 32 derived datasets with varying ratios of (...) balance and feature combinations for each dataset. Second, we propose a comprehensive metric model based on multimachine learning algorithms to select the best-derived dataset with the optimal balance ratio and feature combination. Finally, the convolutional neural network is trained on the selected derived dataset to evaluate the performance of our approach in terms of type-II error, accuracy, G-mean, and AUC. There are two contributions in this study. First, the optimal balance ratio is found through the classification accuracy, which changes the deficiency of the existing research that samples are imbalanced or the balance ratio is 1 : 1 and ensures the accuracy of the classification model. Second, a comprehensive metric model based on the machine learning algorithm is proposed, which can simultaneously find the best balance ratio and the optimal feature selection. The experimental results show that our method can noticeably improve the performance of CNN, and CNN outperforms the other four commonly used machine learning models in the task of default risk prediction on four benchmark datasets. (shrink)

Ernest Gellner's final book, first published in 1998, is a synoptic interpretation of the thought of Wittgenstein and Malinowski.

This essay argues that the Chinese Mental Health Act of 2013 is overly individualistic and fails to give proper moral weight to the role of Chinese families in directing the process of decision-making for hospitalizing and treating the mentally ill patients. We present three types of reactions within the medical community to the Act, each illustrated with a case and discussion. In the first two types of cases, we argue that these reactions are problematic either because they comply with (...) the law but undermine the patient’s interests by refusing the family’s request to have the patient hospitalized, or violate the law by hospitalizing patients in response to the real concerns of their families. In the third type of situation, psychiatrists inappropriately encourage families to produce evidence of the patient’s behavior that is harmful to self or others in order legally to commit the patient. Each of these problems, we conclude, should be tackled by supplementing Article 30 of the Act with the stipulation that a psychiatrist may authorize the involuntary hospitalization of a patient, who is not at risk of causing physical harm to self or others, with the consent of all major family members. Drawing on the deeply culturally embedded moral traditions of Confucian medical familism, this proposal would facilitate the proper treatment of a significant number of Chinese mentally ill patients under the care of their families. (shrink)