Predictable polarization is everywhere: we can often predict how people’s opinions, including our own, will shift over time. Extant theories either neglect the fact that we can predict our own polarization, or explain it through irrational mechanisms. They needn’t. Empirical studies suggest that polarization is predictable when evidence is ambiguous, that is, when the rational response is not obvious. I show how Bayesians should model such ambiguity and then prove that—assuming rational updates are those which obey the value of evidence—ambiguity (...) is necessary and sufficient for the rationality of predictable polarization. The main theoretical result is that there can be a series of such updates, each of which is individually expected to make you more accurate, but which together will predictably polarize you. Polarization results from asymmetric increases in accuracy. This mechanism is not only theoretically possible, but empirically plausible. I argue that cognitive search—searching a cognitively accessible space for a particular item—often yields asymmetrically ambiguous evidence, I present an experiment supporting its polarizing effects, and I use simulations to show how it can explain two of the core causes of polarization: confirmation bias and the group polarization effect. (shrink)

Planar cell polarity, the polarization of cells within the plane of the epithelium, orthogonal to the apical‐basal axis, is essential for a growing list of developmental events, and – over the last 15 years – has evolved from a little‐studied curiosity in Drosophila to the subject of a substantial research enterprise. In that time, it has been recognized that two molecular systems are responsible for polarization of most tissues: Both the “core” Frizzled system and the “global” Fat/Dachsous/Four‐jointed system produce (...) molecular asymmetry within cells, and contribute to morphological polarization. In this review, we discuss recent findings on the molecular mechanism that links “global” directional signals with local coordinated polarity. (shrink)

Political polarization is often argued to be a major threat to democracy. This article examines whether the two different forms of polarization, ideological and affective, may risk some of the core assumptions of democratic legitimacy. The paper argues that ideological polarization is linked with increasingly radical ideological positions being accepted as legitimate contributions to democratic processes, which may lead to the erosion of the democratic culture of society. Affective polarization, in turn, presents a risk to the type of political collaboration (...) that characterizes legitimate democratic processes. The article presents some remarks on how these forms of polarization could be pre-emptively addressed in education: first, by demonstrating to students the practical consequences of neglecting the core democratic principles of toleration (Forst) and reciprocity (Rawls) in society; and second, through forms of political action that engage students’ political emotions in support of democratic principles and way of life in a nonpartisan way. (shrink)

A central question in online human sentence comprehension is, “How are linguistic relations established between different parts of a sentence?” Previous work has shown that this dependency resolution process can be computationally expensive, but the underlying reasons for this are still unclear. This article argues that dependency resolution is mediated by cue‐based retrieval, constrained by independently motivated working memory principles defined in a cognitive architecture. To demonstrate this, this article investigates an unusual instance of dependency resolution, the processing of negative (...) and positive polarity items, and confirms a surprising prediction of the cue‐based retrieval model: Partial‐cue matches—which constitute a kind of similarity‐based interference—can give rise to the intrusion of ungrammatical retrieval candidates, leading to both processing slow‐downs and even errors of judgment that take the form of illusions of grammaticality in patently ungrammatical structures. A notable achievement is that good quantitative fits are achieved without adjusting the key model parameters. (shrink)

An approximate model of a spacetime foam is presented. It is supposed that in the spacetime foam each quantum handle is like to an electric dipole and therefore the spacetime foam is similar to a dielectric. If we neglect of linear sizes of the quantum handle then it can be described with an operator containing a Grassman number and either a scalar or a spinor field. For both fields the Lagrangian is presented. For the scalar field it is the dilaton (...) gravity + electrodynamics and the dilaton field is a dielectric permeability. The spherically symmetric solution in this case give us the screening of a bare electric charge surrounded by a polarized spacetime foam and the energy of the electric field becomes finite one. In the case of the spinor field the spherically symmetric solution give us a ball of the polarized spacetime foam filled with the confined electric field. It is shown that the full energy of the electric field in the ball can be very big. (shrink)

Trust in vaccination is eroding, and attitudes about vaccination have become more polarized. This is an observational study of Twitter analyzing the impact that COVID-19 had on vaccine discourse. We identify the actors, the language they use, how their language changed, and what can explain this change. First, we find that authors cluster into several large, interpretable groups, and that the discourse was greatly affected by American partisan politics. Over the course of our study, both Republicans and Democrats entered the (...) vaccine conversation in large numbers, forming coalitions with Antivaxxers and public health organizations, respectively. After the pandemic was officially declared, the interactions between these groups increased. Second, we show that the moral and non-moral language used by the various communities converged in interesting and informative ways. Finally, vector autoregression analysis indicates that differential responses to public health measures are likely part of what drove this convergence. Taken together, our results suggest that polarization around vaccination discourse in the context of COVID-19 was ultimately driven by a trust-first dynamic of political engagement. (shrink)

Polarization is a topic of intense interest among social scientists, but there is significant disagreement regarding the character of the phenomenon and little understanding of underlying mechanics. A first problem, we argue, is that polarization appears in the literature as not one concept but many. In the first part of the article, we distinguish nine phenomena that may be considered polarization, with suggestions of appropriate measures for each. In the second part of the article, we apply this analysis to evaluate (...) the types of polarization generated by the three major families of computational models proposing specific mechanisms of opinion polarization. (shrink)

Contemporary societies are often “polarized”, in the sense that sub-groups within these societies hold stably opposing beliefs, even when there is a fact of the matter. Extant models of polarization do not capture the idea that some beliefs are true and others false. Here we present a model, based on the network epistemology framework of Bala and Goyal, 784–811 1998), in which polarization emerges even though agents gather evidence about their beliefs, and true belief yields a pay-off advantage. As we (...) discuss, these results are especially relevant to polarization in scientific communities, for these reasons. The key mechanism that generates polarization involves treating evidence generated by other agents as uncertain when their beliefs are relatively different from one’s own. (shrink)

This paper uses the distribution and interpretation of antonymous adjectives in comparative constructions as an empirical basis to argue that abstract representations of measurement, or ‘degrees’, must be modeled as intervals on a scale, rather than as points, as commonly assumed. I begin by demonstrating that the facts in this domain must be accounted for in terms of the interaction of the semantics of adjectival polarity and the semantics of the comparative, rather than principles governing the (overt) expression of (...) particular types of adjectives in comparatives. I then show that a principled account of the full range of data under consideration can be constructed within a model in which degrees are formalized as intervals on a scale and adjectival polarity is characterized in terms of two structurally distinct and complementary sorts of `positive' and `negative' degrees. (shrink)

In this paper we present the results of a simulation study of credence developments in groups of communicating Bayesian agents, as they update their beliefs about a given proposition p. Based on the empirical literature, one would assume that these groups of rational agents would converge on a view over time, or at least that they would not polarize. This paper presents and discusses surprising evidence that this is not true. Our simulation study shows that these groups of Bayesian agents (...) show group polarization behavior under a broad range of circumstances. This is, we think, an unexpected result, that raises deeper questions about whether the kind of polarization in question is irrational. If one accepts Bayesian agency as the hallmark of epistemic rationality, then one should infer that the polarization we find is also rational. On the other hand, if we are inclined to think that there is something epistemically irrational about group polarization, then something must be off in the model employed in our simulation study. We discuss several possible interfering factors, including how epistemic trust is defined in the model. Ultimately, we propose that the notion of Bayesian agency is missing something in general, namely the ability to respond to higher-order evidence. (shrink)

False polarization (FP) is an interpersonal bias on judgement, the effect of which is to lead people in contexts of disagreement to overestimate the differences between their respective views. I propose to treat FP as a problem of applied social epistemology—a barrier to reliable belief-formation in certain social domains—and to ask how best one may debias for FP. This inquiry leads more generally into questions about effective debiasing strategies; on this front, considerable empirical evidence suggests that intuitively attractive strategies for (...) debiasing are not very effective, while more effective strategies are neither intuitive nor likely to be easily implemented. The supports for more effective debiasing seem either to be inherently social and cooperative, or at least to presuppose social efforts to create physical or decision-making infrastructure for mitigating bias. The upshot, I argue, is that becoming a less biased epistemic agent is a thoroughly socialized project. (shrink)

In recent epistemology, belief polarization is generally defined as a process by which a disagreement on a single proposition becomes more extreme over time. Outside of the philosophical literature, however, ‘polarization’ is often used for a different epistemic phenomenon, namely the process by which people’s beliefs on unrelated topics become increasingly correlated over time. This paper argues that the latter type of polarization, here labeled interthematic polarization, is often rational from each individual’s point of view. This suggests that belief polarization (...) is not necessarily a failure of individual rationality, but instead a failure of the social structures within which we live our epistemic lives. (shrink)

Recent research on thick terms like “rude” and “friendly” has revealed a polarity effect, according to which the evaluative content of positive thick terms like “friendly” and “courageous” can be more easily canceled than the evaluative content of negative terms like “rude” and “selfish”. In this paper, we study the polarity effect in greater detail. We first demonstrate that the polarity effect is insensitive to manipulations of embeddings (Study 1). Second, we show that the effect occurs not (...) only for thick terms but also for thin terms such as “good” or “bad” (Study 2). We conclude that the polarity effect indicates a pervasive asymmetry between positive and negative evaluative terms. (shrink)

Belief polarization occurs when subjects who disagree about some matter of fact are exposed to a mixed body of evidence that bears on that dispute. While we might expect mutual exposure to common evidence to mitigate disagreement, since the evidence available to subjects comes to consist increasingly of items they have in common, this is not what happens. The subjects’ initial disagreement becomes more pronounced because each person increases confidence in her antecedent belief. Kelly aims to identify the mechanisms that (...) underlie this phenomenon and assess whether these processes undermine the justification of polarized beliefs. He concludes that given evidentialism, justification is not undermined by the polarizing mechanisms. I take on board Kelly’s description of the polarizing mechanisms, but challenge his conclusion. I argue that on plausible versions of evidentialism, the beliefs that result from these routes to polarization are not justified. (shrink)

Positive polarity items (PPIs) are generally thought to have the boring property that they cannot scope below negation. The starting point of the paper is the observation that their distribution is significantly more complex; specifically, someone/something-type PPIs share properties with negative polarity items (NPIs). First, these PPIs are disallowed in the same environments that license yet type NPIs; second, adding any NPI-licenser rescues the illegitimate constellation. This leads to the conclusion that these PPIs have the combined properties of (...) yet-type and ever-type NPIs: what appears to be a prohibition is nothing but “halfway licensing”. The paper goes on to propose a unification of the analyses of rescuable PPIs, NPIs, and negative concord, and questions the grounding of polarity sensitivity in the scalar or the referential semantics of the items involved. (shrink)

"The book's major parts, one on polarity and the other on analogy, introduce the reader to the patterns of thinking that are fundamental not only to Greek philosophy but also to classical civilization as a whole. As a leading classicist in his own right, Lloyd is an impeccable guide. His sophistication in adducing anthropological parallels to Greek models of polarity and analogy broadens his perspective, making him a forerunner in the study of what we are now used to (...) calling semiotics. A striking example of Lloyd's approach is his re-examination of the dichotomy of Olympian and chthonian gods in ancient Greek world view, which surpasses the reductionist and pseudo-historical models of sky-gods and earth-goddesses that are still commonly invoked to account for polarities in Greek pantheon. "In the second part, dealing with analogy, three crucial metaphorical models for the universe turn out to be basis for a dazzlingly wide variety of scientific and philosophical perspectives. Each model is tested in the whole spectrum of Greek artistic, philosophical and scientific thought. This work is a treasure-house of insights for experts and non experts alike." --Gregory Nagy, Harvard University. (shrink)

Working in ZFC, we show that for any infinite cardinal κ and ordinal $\gamma the polarized partition relation $\[\begin{pmatrix} (2^{ → $\[\begin{pmatrix}(2^{ holds. Our proof of this relation involves the use of elementary substructures of set models of large fragments of ZFC.

We define and study the notion of quantum polarity, which is a kind of geometric Fourier transform between sets of positions and sets of momenta. Extending previous work of ours, we show that the orthogonal projections of the covariance ellipsoid of a quantum state on the configuration and momentum spaces form what we call a dual quantum pair. We thereafter show that quantum polarity allows solving the Pauli reconstruction problem for Gaussian wavefunctions. The notion of quantum polarity (...) exhibits a strong interplay between the uncertainty principle and symplectic and convex geometry and our approach could therefore pave the way for a geometric and topological version of quantum indeterminacy. We relate our results to the Blaschke–Santaló inequality and to the Mahler conjecture. We also discuss the Hardy uncertainty principle and the less-known Donoho–Stark principle from the point of view of quantum polarity. (shrink)

Negative polarity is one of the more elusive aspects of linguistics and a subject which has been gaining in importance in recent years. Written from within the well-defined theoretical framework of Generalized Quantifiers, the three main areas considered in this study are collocations, polarity items and multiple negations. In this mature piece of research, van der Wouden takes into account, not only semantic and syntactic considerations, but also to a large extent, pragmatic ones illustrating a wide array of (...) linguistic approaches. (shrink)

Polarity Items are linguistic expressions known for being a ‘lexically controlled’ phenomenon. In this paper we show how their behavior can be implemented in a deductive system. Further- more, we point out some possible directions to recast the deductive solution into a Tree Ad- joining Grammar system. In particular, we suggest to compare the proof system developed for Multimodal Categorial Grammar (Moot & Puite, 1999) with the Partial Proof Trees proposed in (Joshi & Kulick, 1997).

For two ideally rational agents, does learning a finite amount of shared evidence necessitate agreement? No. But does it at least guard against belief polarization, the case in which their opinions get further apart? No. OK, but are rational agents guaranteed to avoid polarization if they have access to an infinite, increasing stream of shared evidence? No.

The present paper is an attempt at the investigation of the nature of polarity contrast in natural languages. Truth conditions for natural language sentences are incomplete unless they include a proper definition of the conditions under which they are false. It is argued that the tertium non datur principle of classical bivalent logical systems is empirically invalid for natural languages: falsity cannot be equated with non-truth. Lacking a direct intuition about the conditions under which a sentence is false, we (...) need an independent foundation of the concept of falsity. The solution I offer is a definition of falsity in terms of the truth of a syntactic negation of the sentence. A definition of syntactic negation is proposed for English. (shrink)

An electronic poster from "Polarity from Different Perspectives," New York University, 2005. The authors present an experiment that investigated to what extent six negative polarity items (slept a wink, in ages, ever, much, at all, and yet) are licensed by 9 potential licensers.

Group polarization—roughly, the tendency of groups to incline towards more extreme positions than initially held by their individual members— has been rigorously studied by social psychol- ogists, though in a way that has overlooked important philosophical questions about this phenomenon which remain unexplored. Two such salient questions are metaphysical and epistemological, respectively. From a metaphysical point of view, can group polarization, understood as an epistemic feature of a group, be reduced to epistemic features of its individual members? Relatedly, from an (...) epistemological point of view, is group polarization best understood as a kind of cognitive bias or rather in terms of intellectual vice? This book taxonomizes this possibility space by comparing four models which combine potential answers to the metaphysical and epistemological questions. The models we consider are: group polarization as a collective bias, a summation of individual epistemic vices; a summation of individual biases; and a collective epistemic vice. We defend a collective vice model of group polarization over the competing alternatives. (shrink)

The dissociation between the domains of knowledge continues to perpetuate the fragmentation of people’s health and healing experiences. Of particular significance are the polarities that have been created between the objective, subjective and spiritual dimensions of knowledge and human experience. This paper offers a consideration of how faith might serve as a pragmatic avenue towards assuaging the polarities between knowledges and enhancing nurses’ ability to attend to the complex and mulitdimensional nature of health and healing processes.

What is the communicative value of negative polarity? That is, why do so many languages maintain a stock of special indefinites that occur only in a proper subset of the contexts in which ordinary indefinites can appear? Previous answers include: marking the validity of downward inferences; marking the invalidity of veridical inferences; or triggering strengthening implications. My starting point for exploring a new answer is the fact that an NPI must always take narrow scope with respect to its licensing (...) context. In contrast, ordinary indefinites are notorious for taking wide scope. So whatever other functions NPIs may have, they at least serve as an utterly reliable signal that an indefinite is taking narrow scope. As also proposed in recent work of Kusumoto and Tancredi, I will show that NPIs are only licensed in contexts in which the wide scope construal of an indefinite fails to entail the narrow scope. In other words, weak NPIs occur only in contexts in which taking narrow scope matters for interpretation. Thus one part of the explanation for the ubiquity and robust stability of negative polarity is that it signals scope relations. (shrink)

We generalize the intuitionistic Hyland–Ong games to a notion of polarized games allowing games with plays starting by proponent moves. The usual constructions on games are adjusted to fit this setting yielding game models for both Intuitionistic Linear Logic and Polarized Linear Logic. We prove a definability result for this polarized model and this gives complete game models for various classical systems: , λμ-calculus, … for both call-by-name and call-by-value evaluations.

This article discusses the polarization of information and knowledge, a phenomenon that is increasingly relevant in different spheres of the contemporary socioeconomic dynamics. According to this notion, founded mainly on the works of Karl Marx, information and knowledge are central elements in the contradictions between capital and labour, as well as in the internal contradictions of the working class. The idea of polarization of information and knowledge offers a critical point of view against the authors who, while trying to grasp (...) the socioeconomic dynamics of our times, are captured by the enchantment of the techno-scientific progress. The article also adopts the Marxian concepts of universal labour and general intellect to argue that information, knowledge, and science are social constructions built collectively and should be treated as common goods. However, currently, the emancipatory perspective of the general intellect envisioned by Marx has been replaced by an opposite tendency: the private appropriation of the general intellect. (shrink)

Polarization simplifies and deforms language, ideas, and people and reduces social life into an oppositional binary based on harmful “us versus them” narratives. What can we do to bring about a transformation away from polarity to peace? What are the polarities obscuring the path to peace? Is it a question of belief versus belief? Does it make sense to appeal to reason, discourse, and compromise in a polarized climate? What is the difference between harmful and helpful polarities? In the (...) pursuit of peace and justice, the authors in this volume answer these and other questions relating to polarity and politics. (shrink)

The main claim of this paper is that a general theory of negative concord (NC) should allow for the possibility of NC involving scoping of a universal quantifier above negation. I propose that Greek NC instantiates this option. Greek n-words will be analyzed as polarity sensitive universal quantifiers which need negation in order to be licensed, but must raise above negation in order to yield the scoping ∀¬. This gives the correct interpretation of NC structures as general negative statements. (...) The effect is achieved by application of QR, and the account is fully compositional, as only sentence negation is the vehicle of logical negation ¬. Greek n-words are also compared to nwords in Romance, Slavic, and Hungarian. This analysis, if correct, has two important.. (shrink)

This article is concerned with how we make decisions based on how problems are presented to us and the effect that the framing of the problem might have on our choices. Current philosophical and psychological accounts of the framing effect in experiments such as the Asian Disease Problem concern reference points and domains. We question the importance of reference points and domains. Instead, we adopt a linguistic perspective focussing on the role of the evaluative polarity evoked by the words (...) - negativeand positive - used to describe the options in the decision problem. We show that the evaluative polarity of the different wordings in the ADP better explain participants’ behaviour than reference points and domains. We propose two models in which the values given to evaluative polarity words directly influence the strength of framing. The results indicate that linguistic considerations regarding evaluative polarity have to be considered in relation to the ADP. The account resembles Fuzzy-Trace-Theory but allows for thestrength of evaluative polarity to directly affect behaviour. In the discussion, we also assess how evaluative polarity relates to negation, antonyms and the communicative frame within which the choices are presented. (shrink)

Notch is a mechanosensitive receptor that requires direct cell–cell contact for its activation. Both the strength and the range of notch signaling depend on the size and geometry of the contact sites between cells. These properties of cell–cell contacts in turn depend on cell shape and polarity. At the molecular level, the E3 ubiquitin ligase Neuralized links receptor activation with epithelial cell remodeling. Neur regulates the endocytosis of the Notch ligand Delta, hence Notch activation. It also targets the apical (...) polarity protein Stardust to promote the endocytosis of the Crumbs complex, thereby contributing to epithelium remodeling. Here, we review the interplay between Notch signaling and cell polarity and discuss the possible significance of linking Notch signaling with epithelial cell polarity via a common regulator. Notch receptor activation depends on direct cell–cell contacts that in turn depends on cell shape and cellular polarity. The size and geometry of cell–cell contacts have an impact on the strength and range of signaling. The E3 ubiquitin ligase Neuralized regulates the endocytosis and signaling activity of Delta. The activity of Neuralized is tightly regulated during development. Neuralized also modulates epithelial cell polarity by targeting the apical polarity protein Stardust and by promoting the endocytosis of Crumbs. Thus, the cell-specific expression of Neuralized couples Notch receptor activation with cell polarity regulation in epithelia. (shrink)

We dub the kyaa in (2a) polar kyaa, which we distinguish from the homophonous thematic kyaa ‘what’. in (3). In (3), kyaa is the theme argument of the verb diyaa ‘gave’. The same has been argued for the scope marking construction, at least under the indirect dependency approach (Dayal 1994 among others). The preverbal position has been argued to be the unmarked position for wh-words in Hindi-Urdu (Kidwai 2000, among others).

With the growing success of right-wing populism, there has been an explosion of debates on polarization and social cohesion. In part, social cohesion is seen as being disrupted by right-wing populists and those who blame migration for this alleged disruption of cohesion. The developing polarization is not only social, but also political, so that in some cases there is already talk of a new cleavage. On the one hand, there are right-wing populists, people who do not want any major changes (...) or who have problems with globalization; on the other hand, there are those who want to push through a transformation towards a ‘truly’ pluralistic society. Two issues in particular serve as bridges for this polarization: Muslim migration and the expansion of sexual and gender diversity. Positions on these two issues mark the content that facilitates the consolidation of opposing group identities. As a result, debates about values and identity dominate, leading to a polarization that reaches far into society. (shrink)

We study the effective and proof-theoretic content of the polarized Ramsey’s theorem, a variant of Ramsey’s theorem obtained by relaxing the definition of homogeneous set. Our investigation yields a new characterization of Ramsey’s theorem in all exponents, and produces several combinatorial principles which, modulo bounding for ${\Sigma^0_2}$ formulas, lie (possibly not strictly) between Ramsey’s theorem for pairs and the stable Ramsey’s theorem for pairs.

Public discussions of political and social issues are often characterized by deep and persistent polarization. In social psychology, it’s standard to treat belief polarization as the product of epistemic irrationality. In contrast, we argue that the persistent disagreement that grounds political and social polarization can be produced by epistemically rational agents, when those agents have limited cognitive resources. Using an agent-based model of group deliberation, we show that groups of deliberating agents using coherence-based strategies for managing their limited resources tend (...) to polarize into different subgroups. We argue that using that strategy is epistemically rational for limited agents. So even though group polarization looks like it must be the product of human irrationality, polarization can be the result of fully rational deliberation with natural human limitations. (shrink)

We show that if κ is a weakly compact cardinal, then $\left( \matrix \kappa ^{+} \\ \kappa\endmatrix \right)\rightarrow \left(\left( \matrix \alpha \\ \kappa \endmatrix \right)_{m}\left( \matrix \kappa ^{n} \\ \kappa \endmatrix \right)_{\mu}\right)^{1,1}$ for any ordinals α < κ⁺ and µ < κ, and any finite ordinals m and n. This polarized partition relation represents the statement that for any partition $\kappa \times \kappa ^{+}=\underset i<m\to{\bigcup }K_{i}\cup \underset j<\mu \to{\bigcup }L_{j}$ of κ × κ⁺ into m + µ pieces either there (...) are A ∈ [κ]κ, B ∈ [κ⁺]α, and i < m with A × B ⊆ Ki or there are C ∈ [κ]κ, D ∈ [κ⁺]α, and j < μ with C × D ⊆ Lj. Related results for measurable and almost measurable κ are also investigated. Our proofs of these relations involve the use of elementary substructures of set models of large fragments of ZFC. (shrink)

The dissociation between the domains of knowledge continues to perpetuate the fragmentation of people’s health and healing experiences. Of particular significance are the polarities that have been created between the objective, subjective and spiritual dimensions of knowledge and human experience. This paper offers a consideration of how faith might serve as a pragmatic avenue towards assuaging the polarities between knowledges and enhancing nurses’ ability to attend to the complex and mulitdimensional nature of health and healing processes.

Discussion among individuals about a given issue often induces polarization and bipolarization effects, i.e. individuals radicalize their initial opinion towards either the same or opposite directions. Experimental psychologists have put forward Persuasive Arguments Theory as a clue for explaining polarization. PAT claims that adding novel and persuasive arguments pro or contra the debated issue is the major cause for polarization. Recent developments in abstract argumentation provide the tools for capturing these intuitions on a formal basis. Here Bipolar Argumentation Frameworks are (...) employed as a tool for encoding the information of agents in a debate relative to a given issue a. A probabilistic extension of BAF allows to encode the likelihood of the opinions pro or contra a before and after information exchange. It is shown, by a straightforward example, how these measures provide the basis to capture the intuitions of PAT. (shrink)

Belief polarization (BP) is widely seen to threaten havoc on our shared political lives. It is often assumed that BP is the product of epistemically irrational behaviors at the individual level. After distinguishing between BP as it occurs in intra-group and inter-group settings, this paper argues that neither process necessarily reflects individual epistemic irrationality. It is true that these processes can work in tandem to produce so-called “echo chambers.” But while echo chambers are often problematic from the point of view (...) of collective rationality, it doesn't follow that individuals are doing anything wrong, epistemically speaking, in seeking them out. In non-ideal socio-epistemic contexts, echo chamber construction might provide one's best defense against systematic misinformation and deception. (shrink)

People are manifestly polarized. On many topics, extreme perspectives are much easier to find than ‘reasonable’, ‘moderate’ perspectives. A natural reaction to this situation is that something epistemically irrational is afoot. Here, I question this natural reaction. I argue that often polarization is epistemically innocuous. In particular, I argue that certain mechanisms that underlie polarization are rational, and polarized beliefs are often fully justified. Additionally, even reflective subjects, who recognize themselves as in a polarized or polarizing situation shouldn’t necessarily reduce (...) confidence in the relevant beliefs. Finally, I draw attention to some often overlooked epistemic _benefits_ associated with polarization. A fuller understanding of the epistemology of polarization requires incorporating both the potential costs and the potential benefits, and being more precise about exactly what is—and is not—epistemically objectionable in these situations. (shrink)

We have evaluated analytically the vacuum polarization in a Coulomb field using the relativistic Dirac-Coulomb wave functions by a new method. The result is made finite by an appropriate choice of contour integrations and gives the standard result in the lowest order of iteration. We used the formalism of self-field quantum electrodynamics in the evaluation of the vacuum polarization which needs neither field quantization nor renormalization. There are no infrared or ultraviolet divergences.

This paper discusses the behavior of three lexically distinct Greek expressions which appear to be the counterparts of English even: akomi ke, oute, and esto. The behavior of these three expressions is examined in positive and negative sentences, and it is demonstrated that they all are polarity sensitive. The distributional constraints of the three even-items, crucially, are shown to follow from their distinct scalar associations. In particular, the low-scalar likelihood of positive even (akomi ke) remains problematic with negation as (...) well as affirmation, a fact supporting the polarity approach to even and the lexical ambiguity that is associated with it. In further support of this conclusion, negative bias in questions is shown to arise not with negative polarity oute (which is ungrammatical in questions) or positive akomi ke (which is fine but creates no bias), but with esto— a low scalar item defined on a context-dependent scale. This finding strengthens Kay's 1990 and Horn's 1989 observation that likelihood alone is not sufficient for capturing the scalar properties of even. (shrink)

In the 4 1/2 to 5 days between fertilization and implantation, the mouse conceptus must gain the abilities to implant and produce an embryo. Each of these is the sole developmental responsibility of one of two cell types forming the blastocyst, trophectoderm and inner cell mass (ICM), respectively. Trophectoderm is a polarized transporting epithelium while the ICM is an aggregate of non‐epithelial pluripotent stem cells. These two cell types originate from the division of polar blastomeres when their cleavage furrows parallel (...) their apical surfaces. Blastomeres polarize in response to asymmetric cell–cell contact, and understanding the mechanism of this induction is regarded as the key to understanding the origin of trophectoderm and ICM. Here we propose a model based on transcellular ion current loops for the induction of cell polarity during the development of the first epithelium, trophectoderm. (shrink)

RNA localization is a powerful strategy used by cells to localize proteins to subcellular domains and to control protein synthesis regionally. In germ cells, RNA targeting has profound implications for development, setting up polarities in genetic information that drive cell fate during embryogenesis. The frog oocyte offers a useful system for studying the mechanism of RNA localization. Here, we discuss critically the process of RNA localization during frog oogenesis. Three major pathways have been identified that are temporally and spatially separated (...) in oogenesis. Each pathway uses a different mechanism to effect RNA localization. In some cases, localization elements within the 3' untranslated region have been identified and have provided unique insights into the localization process. This important field is still in its infancy, however, and much remains to be learned. BioEssays 21:546–557, 1999. © 1999 John Wiley & Sons, Inc. (shrink)

Several types of polarized partition relations are considered. In particular we deal with partitions defined on cartesian products of more than two factors. MSC: 03E05.