Multiarm bandit problems have been used to model the selection of competing scientific theories by boundedly rational agents. In this paper, I define a variable-arm bandit problem, which allows the set of scientific theories to vary over time. I show that Roth-Erev reinforcement learning, which solves multiarm bandit problems in the limit, cannot solve this problem in a reasonable time. However, social learning via preferential attachment combined with individual reinforcement learning which discounts the past, does.

A sentence A is epistemically less entrenched in a belief state K than a sentence B if and only if a person in belief state K who is forced to give up either A or B will give up A and hold on to B. This is the fundamental idea of epistemic entrenchment as introduced by Gärdenfors (1988) and elaborated by Gärdenfors and Makinson (1988). Another distinguishing feature of relations of epistemic entrenchment is that they permit particularly simple and elegant (...) construction recipes for minimal changes of belief states. These relations, however, are required to satisfy rather demanding conditions. In the present paper we liberalize the concept of epistemic entrenchment by removing connectivity, minimality and maximality conditions. Correspondingly, we achieve a liberalization of the concept of rational belief change that does no longer presuppose the postulates of success and rational monotony. We show that the central results of Gärdenfors and Makinson are preserved in our more flexible setting. Moreover, the generalized concept of epistemic entrenchment turns out to be applicable also to relational and iterated belief changes. (shrink)

While hedonism has been subjected to much criticism over the years, it is still a widely endorsed axiological view. One objection that appears to be generally recognised as especially troublesome to hedonists is that their central claim, that final value accrues only to experiences of pleasure gives us a narrow view of value. Much more than pleasure is valuable for its own sake. A competing theory, preferentialism, is another widespread theory about value. According to one version of preferentialism, (...) only the objects of preferences carry final value, and since not all of our preferences have pleasure as their object, preferentialists accuse hedonists of overlooking a great deal that is of value. For instance, if someone has a so-called external preference to the effect that, say, the Californian redwood forests should go on existing, then the world contains more value if the forests continue to exist.1 Given this, the possible pleasure someone would experience on learning that his preference is satisfied has nothing to do with this kind of value. Preferentialists therefore conclude that the hedonist perspective is not wide enough. In this work, it is argued that hedonists are entitled to reverse the argument. Preferentialists are restrained by not being able to recognize the object of value that is cherished by hedonists. (shrink)

Modal accounts of normality in non-monotonic reasoning traditionally have an underlying semantics based on a notion of preference amongst worlds. In this paper, we motivate and investigate an alternative semantics, based on ordered accessibility relations in Kripke frames. The underlying intuition is that some world tuples may be seen as more normal, while others may be seen as more exceptional. We show that this delivers an elegant and intuitive semantic construction, which gives a new perspective on defeasible necessity. Technically, the (...) revisited logic does not change the expressive power of our previously defined preferential modalities. This conclusion follows from an analysis of both semantic constructions via a generalisation of bisimulations to the preferential case. Reasoners based on the previous semantics therefore also suffice for reasoning over the new semantics. We complete the picture by investigating different notions of defeasible conditionals in modal logic that can also be captured within our framework. (shrink)

This paper studies the properties of eight semantic consequence relations defined from a Tarski-logic L and a preference relation ≺. They are equivalent to Shoham’s so-called preferential entailment for smooth model structures, but avoid certain problems of the latter in non-smooth configurations. Each of the logics can be characterized in terms of what we call multi-selection semantics. After discussing this type of semantics, we focus on some concrete proposals from the literature, checking a number of meta-theoretic properties and elaborating on (...) their intuitive motivation. As it turns out, many of their meta-properties only hold in case ≺ is transitive. To tackle this problem, we propose slight modifications of each of the systems, showing the resulting logics to behave better at the intuitive level and in metatheoretic terms, for arbitrary ≺. (shrink)

It is widely believed that preferential hiring practices inevitably result in hiring less qualified candidates for jobs. Indeed, this follows analytically from some definitions of preferential hiring (e.g. George Sher's). This paper describes several preferential hiring strategies that do not have this consequence. Sher's definition is thus shown to be inadequate and an alternative definition is proposed.

An online game of chess against a human opponent appears to be indistinguishable from a game against a machine: both happen on the screen. Yet, people prefer to play chess against other people despite the fact that machines surpass people in skill. When the philosophers of 1970’s and 1980’s argued that computers will never surpass us in chess, perhaps their intuitions were rather saying “Computers will never be favored as opponents”? In this paper we analyse through the introduced concepts of (...) psychological affordances and psychological interplay, what are the mechanisms that make a human-human interaction more meaningful than a human-computer interaction. We claim that an HH chess game consists of two intertwined, but independent simultaneous games—only one of which is retained in the HC game. To help with the analysis we introduce the thought experiment of a Preferential Engagement Test which is inspired by, but non-equivalent to, the Standard Turing Test. We also explore how the PET can illuminate, and be illuminated by, various philosophies of mind reading: Theory Theory, Simulation Theory and Mind Minding. We propose that our analysis along with the concept of PET could illuminate in a new way the conditions and challenges a machine must face before it can replace humans in a given occupation. (shrink)

We introduce Information Bearing Relation Systems (IBRS) as an abstraction of many logical systems. These are networks with arrows recursively leading to other arrows etc. We then define a general semantics for IBRS, and show that a special case of IBRS generalizes in a very natural way preferential semantics and solves open representation problems for weak logical systems. This is possible, as we can the strong coherence properties of preferential structures by higher arrows, that is, arrows, which do not go (...) to points, but to arrows themselves. (shrink)

I argue that there is an important sense in which God’s love is partial or preferential. In developing this argument, I appeal to Thomas Aquinas’s claim that God’s love for persons has the character of friendship. By its nature, friendship exhibits a considerable degree of partiality. For whether a person prefers to be united to another in friendship depends on whether the latter reciprocates the former’s affection and endorses those commitments conducive to fellowship. If God’s love is expressive of friendship, (...) then the sort of partiality some may wish to deny of his love may be one of its salient features. (shrink)

Handling exceptions in a knowledge-based system is an important issue in many application domains, such as medical domain. Recently, there is an increasing interest in nonmonotonic extension of description logics to handle exceptions in ontologies. In this paper, we propose three preferential semantics for plausible subsumption to deal with exceptions in description logic-based knowledge bases. Our preferential semantics are defined in the framework of possibility theory, which is an uncertainty theory devoted to handling incomplete information. We consider the properties of (...) these semantics and their relationships. We also discuss the relationship between two of our preferential semantics and two existing preferential semantics. We extend a description logic-based knowledge base by adding preferential subsumptions. Entailment of plausible subsumptions relative to an extended knowledge base is defined. Properties of the preferential subsumption relations relative to an extended description logic-based knowledge base are discussed. Finally, we show that our semantics for plausible subsumption can be reduced to standard semantics of an expressive description logic. Thus, the problem of plausible subsumption checking under our semantics can be reduced to the problem of subsumption checking under the classical semantics. (shrink)

The preferential option for the poor is a concept and set of ideas in Catholic social teaching that is highly relevant to bioethics scholarship and practice. The option for the poor is mentioned frequently in the bioethics literature but with little specification of its history and implications for ethical and theological analysis. This article examines the origins and implications of the preferential option; compares it to critical race theory, which dominates current debates about discrimination and oppression; and proposes a set (...) of principles for further application in bioethical scholarship and discussion. (shrink)

I consider the question of the possibility of the coexistence of neighborly love (love for strangers) and preferential love (love for persons because of or despite their attributes). This question has long perplexed interpreters of Kierkegaard. I make a threefold intervention into this interpretive debate. First, I aim to show that we shouldn’t privilege preferential love over neighborly love. Second, I reformulate preferential and neighborly love on a ‘topological’ model, so as to get a better grip on them. And third, (...) I argue that preferential love can coexist with neighborly love insofar as the latter is granted primacy over the former. (shrink)

Catholic health care has long been focused on the needs of the poor, yet its primary interaction with the poor is in the delivery of health care and not within leadership. The preferential option for the poor is one tool that leads to greater participation. Especially important is the hermeneutic element that Pope Francis emphasizes. While some government programs already include those who are poor in leadership, Catholic health care is only starting to grapple with the Pope’s challenge. This essay (...) explores inclusion of the poor in governance and strategic planning, revealing a better way to engage with those who are poor and give a better witness to the Gospel mandate for Catholic health care. (shrink)

Complex systems can be characterized by classes of equivalency of their elements defined according to system specific rules. We propose a generalized preferential attachment model to describe the class size distribution. The model postulates preferential growth of the existing classes and the steady influx of new classes. According to the model, the distribution changes from a pure exponential form for zero influx of new classes to a power law with an exponential cut-off form when the influx of new classes is (...) substantial. Predictions of the model are tested through the analysis of a unique industrial database, which covers both elementary units (products) and classes (markets, firms) in a given industry (pharmaceuticals), covering the entire size distribution. The model's predictions are in good agreement with the data. The paper sheds light on the emergence of the exponent tau approximately 2 observed as a universal feature of many biological, social and economic problems. (shrink)

In this article, we redefine classical notions of theory reduction in such a way that model-theoretic preferential semantics becomes part of a realist depiction of this aspect of science. We offer a model-theoretic reconstruction of science in which theory succession or reduction is often better - or at a finer level of analysis - interpreted as the result of model succession or reduction. This analysis leads to 'defeasible reduction', defined as follows: The conjunction of the assumptions of a reducing theory (...) T with the definitions translating the vocabulary of a reduced theory T' to the vocabulary of T, defeasibly entails the assumptions of reduced T'. This relation of defeasible reduction offers, in the context of additional knowledge becoming available, articulation of a more flexible kind of reduction in theory development than in the classical case. Also, defeasible reduction is shown to solve the problems of entailment that classical homogeneous reduction encounters. Reduction in the defeasible sense is a practical device for studying the processes of science, since it is about highlighting different aspects of the same theory at different times of application, rather than about naive dreams concerning a metaphysical unity of science. (shrink)

Female-biased parental investment is unusual but not unknown in human societies. Relevant explanatory models include Fisher’s principle, the Trivers-Willard model, local mate and resource competition and enhancement, and economic rational actor models. Possible evidence of female-biased parental investment includes sex ratios, mortality rates, parents’ stated preferences for offspring of one sex, and direct and indirect measurements of actual parental behavior. Possible examples of female-biased parental investment include the Mukogodo of Kenya, the Ifalukese of Micronesia, the Cheyenne of North America, the (...) Herero of southern Africa, the Kanjar of south Asia, the Mundugumor of New Guinea, contemporary North America, and historical Germany, Portugal, and the United States. (shrink)

This paper is concerned with removing the identity schema from the axiomatic basis of deontic conditionals. This is in order to allow a stipulated ideal to be contrary or opposite in nature to the fact it is predicated upon. It is desirable, or so it is argued, to retain the order-theoretic orientation of preferential semantics towards the analysis of deontic conditionals, more specifically of maximality semantics in the tradition from Bengt Hansson. So understood, the problem involves abstracting away the settledness (...) assumption that is built in to maximality semantics. This is the assumption that what is optimal given ϕ is that which all the best ϕ-states have in common, notably ϕ itself. We propose a solution based on a strict and finite preference relation over which deontic conditionals are evaluated by letting ϕ-states evolve freely, as fate or fortune would have it, into different possibly ensuing optima that may but need not be ϕ-states themselves. The result is a deontic conditional that does not have identity. This new conditional is shown to be a proper generalization of the Hansson conditional. Hansson’s conditional can be recovered in the new idiom as a special case. Indeed, the new semantics is general enough to cover several apparently very different conceptions of deontic conditionality. For instance, the input/output logic known as basic output is a sublogic of the new system. This is somewhat surprising and suggests that there may yet be unity to be had in the field of deontic logic. (shrink)

In this essay it will be argued that if preferential treatment for individuals who have suffered from past discrimination is permissible in any context, it should be extended to the allocation of scarce medical resources. This contention will be based on two facts: one, that health care, in particular certain life-saving operations, constitutes a scarce social good similar to but more important than other social goods such as desirable jobs and positions in desirable professional schools; secondly, that a claim can (...) plausibly be made that the greater incidence of death due to heart disease among blacks is a result of the effect of past discrimination. In addition, an argument to the effect that preferential treatment is indeed permissible will be sketched that is based upon a critique of the decision in the Bakke case. (shrink)

In Volume I of Works of Love, Kierkegaard condemns preferential, “earthly” love and extols the virtues of impartial, “Christian” love. Yet he claims that his vision of Christianity leaves room for earthly relationships in their full richness. Controversy over this claim is longstanding, but a number of contemporary scholars have come to Kierkegaard’s defense. In what follows, I attempt to counter this trend. I do so by criticizing a scholar who I take to be one of Kierkegaard’s most persuasive apologists (...) – Jamie Ferreira. Drawing on recent work by Harry Frankfurt, I argue that essential to human love-relationships is their generation of preferential moral commitments. Ferreira’s defense of Kierkegaard is therefore inadequate; it shows only how Kierkegaardian Christianity leaves room for attention to distinct individuals, not how such distinctness can become morally relevant. Indeed, Kierkegaard’s ethic of selflessness specifically precludes this possibility, since partiality, he claims, is necessarily selfish. This claim I also dispute. If my argument succeeds, then, I will have shown not only that Kierkegaardian Christianity eliminates the possibility of loving earthly relationships, but also that it does so on inadequate grounds. I will conclude by briefly discussing the possibility of revising Kierkegaard’s account, taking as my example the amendments recently proposed by Sharon Krishek. (shrink)

Next SectionBackground: Publication bias and discrimination are increasingly recognised in medicine. A survey was conducted to determine if medical journals were more likely to publish research reports from members of their own than a rival journal’s editorial board. Methods: A retrospective review was conducted of all research reports published in 2006 in the four competing medical journals within five medical specialties. Only three journals were willing to divulge the authorship of reports that had been rejected. Results: Overall, 4460 research reports (...) were published in 2006 by the 20 journals from five subspecialties (mean 223 (SD = 164) reports per journal; median 176; interquartile range 108–238). On average, 17.2 (7.7%) reports were from a journal’s own editorial board (SD = 10.7; median 15; interquartile range 10–23; n = 20), and 6.3 (2.8%) reports were from a member of the editorial board of one of the three rival journals within the specialty (SD = 7.3; median 3.5; interquartile range 1–8; n = 60). There was a statistically significant excess of publications from the journal’s own editorial board in 14 of the 20 journals (p<0.05). Journals were almost three times more likely to publish reports from their own editorial board than from one of the three rivals within their subspecialty (p<0.0001; median difference 11; Mann–Whitney U test; power for 5% significance >99.99%). Conclusions: There was a significant excess of publications from medical journals’ own editorial boards, although it is not possible to determine whether this is due to bias in the peer review process or selective submission by editors. (shrink)

The present study provides evidence that the activation strength produced by emotional stimuli must pass a threshold level in order to be consciously perceived, contrary to the assumption of continuous quality of representation. An analysis of receiver operating characteristics for attentional blink performance was used to distinguish between two models of emotion perception by inspecting two different ROC’s shapes. Across all conditions, the results showed that performance in the attentional blink task was better described by the two-limbs ROC predicted by (...) the Krantz threshold model than by the curvilinear ROC implied by the signal-detection theory. (shrink)

Medical tourism is the practice of traveling across international borders with the intention of accessing medical care, paid for out-of-pocket. This practice has implications for preferential access to medical care for Canadians both through inbound and outbound medical tourism. In this paper, we identify four patterns of medical tourism with implications for preferential access to care by Canadians: Inbound medical tourism to Canada’s public hospitals; Inbound medical tourism to a First Nations reserve; Canadian patients opting to go abroad for medical (...) tourism; and Canadian patients traveling abroad with a Canadian surgeon. These patterns of medical tourism affect preferential access to health care by Canadians by circumventing domestic regulation of care, creating jurisdictional tensions over the provision of health care, and undermining solidarity with the Canadian health system. (shrink)