50 research outputs found

    Conspiracy Theories and Evidential Self-Insulation

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    What are conspiracy theories? And what, if anything, is epistemically wrong with them? I offer an account on which conspiracy theories are a unique way of holding a belief in a conspiracy. Specifically, I take conspiracy theories to be self-insulating beliefs in conspiracies. On this view, conspiracy theorists have their conspiratorial beliefs in a way that is immune to revision by counter-evidence. I argue that conspiracy theories are always irrational. Although conspiracy theories involve an expectation to encounter some seemingly disconfirming evidence (allegedly planted by the conspirators), resistance to all counter- evidence cannot be justified on these grounds

    Prejudice, generics, and resistance to evidence

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    In his book, Prejudice, Endre Begby offers a novel and engaging account of the epistemology of prejudice which challenges some of the standard assumptions that have so far guided the recent discussion on the topic. One of Begby's central arguments against the standard view of prejudice, according to which a prejudiced person necessarily displays an epistemically culpable resistance to counterevidence, is that, qua stereotype judgments, prejudices can be flexible and rationally maintained upon encountering many disconfirming instances. By expanding on Begby's analysis, I argue that, given the variety of truth conditions for true generic statements, the generic form of stereotype judgements can sometimes make prejudice extremely resistant to encounters with statistical facts about the distribution of the property among members of a certain group. At the same time, I argue that a more careful consideration of the generic form of stereotypes also allows us to recognize that evidence about how many members of the kind instantiate a property is not the only type of evidence which could disconfirm a prejudice. Evidence of no explanatory relation between a kind and a property should also have a direct effect on a prejudicial belief. For this reason, things may not look as dim for the standard view of prejudice in assessing paradigmatic instances of prejudicial beliefs as irrationally resistant to evidence.</p

    Prejudice, generics, and resistance to evidence

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    In his book, "Prejudice", Endre Begby offers a novel and engaging account of the epistemology of prejudice which challenges some of the standard assumptions that have so far guided the recent discussion on the topic. One of Begby's central arguments against the standard view of prejudice, according to which a prejudiced person necessarily displays an epistemically culpable resistance to counterevidence, is that, qua stereotype judgments, prejudices can be flexible and rationally maintained upon encountering many disconfirming instances. By expanding on Begby's analysis, I argue that, given the variety of truth conditions for true generic statements, the generic form of stereotype judgements can sometimes make prejudice extremely resistant to encounters with statistical facts about the distribution of the property among members of a certain group. At the same time, I argue that a more careful consideration of the generic form of stereotypes also allows us to recognize that evidence about how many members of the kind instantiate a property is not the only type of evidence which could disconfirm a prejudice. Evidence of no explanatory relation between a kind and a property should also have a direct effect on a prejudicial belief. For this reason, things may not look as dim for the standard view of prejudice in assessing paradigmatic instances of prejudicial beliefs as irrationally resistant to evidence

    Echo Chambers

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    What is a Conspiracy Theory?

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    In much of the current academic and public discussion, conspiracy theories are portrayed as a negative phenomenon, linked to misinformation, mistrust in experts and institutions, and political propaganda. Rather surprisingly, however, philosophers working on this topic have been reluctant to incorporate a negatively evaluative aspect when either analyzing or engineering the concept conspiracy theory. In this paper, we present empirical data on the nature of the concept conspiracy theory from five studies designed to test the existence, prevalence and exact form of an evaluative dimension to the ordinary concept conspiracy theory. These results reveal that, while there is a descriptive concept of conspiracy theory, the predominant use of conspiracy theory is deeply evaluative, encoding information about epistemic deficiency and often also derogatory and disparaging information. On the basis of these results, we present a new strategy for engineering conspiracy theory to promote theoretical investigations and institutional discussions of this phenomenon. We argue for engineering conspiracy theory to encode an epistemic evaluation, and to introduce a descriptive expression—such as ‘conspiratorial explanation’—to refer to the purely descriptive concept conspiracy theory

    CD4+ T Cell Depletion, Immune Activation and Increased Production of Regulatory T Cells in the Thymus of HIV-Infected Individuals

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    Mechanisms by which HIV affects the thymus are multiple and only partially known, and the role of thymic dysfunction in HIV/AIDS immunopathogenesis remains poorly understood. To evaluate the effects of HIV infection on intra-thymic precursors of T cells in HIV-infected adults, we conducted a detailed immunophenotypic study of thymic tissue isolated from 7 HIV-infected and 10 HIV-negative adults who were to undergo heart surgery. We found that thymuses of HIV-infected individuals were characterized by a relative depletion of CD4+ single positive T cells and a corresponding enrichment of CD8+ single positive T cells. In addition, thymocytes derived from HIV-infected subjects showed increased levels of activated and proliferating cells. Our analysis also revealed a decreased expression of interleukin-7 receptor in early thymocytes from HIV-infected individuals, along with an increase in this same expression in mature double- and single-positive cells. Frequency of regulatory T cells (CD25+FoxP3+) was significantly increased in HIV-infected thymuses, particularly in priorly-committed CD4 single positive cells. Our data suggest that HIV infection is associated with a complex set of changes in the immunophenotype of thymocytes, including a reduction of intrathymic CD4+ T cell precursors, increased expression of activation markers, changes in the expression pattern of IL-7R and enrichment of T regulatory cells generation

    Increased Bone Marrow Interleukin-7 (IL-7)/IL-7R Levels but Reduced IL-7 Responsiveness in HIV-Positive Patients Lacking CD4+ Gain on Antiviral Therapy

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    Background: The bone marrow (BM) cytokine milieu might substantially affect T-lymphocyte homeostasis in HIV-positive individuals. Interleukin-7 (IL-7) is a bone marrow-derived cytokine regulating T-cell homeostasis through a CD4+-driven feedback loop. CD4+ T-lymphopenia is associated with increased free IL-7 levels and reduced IL-7R expression/function, which are only partially reverted by highly active antiretroviral therapy (HAART). We investigated the BM production, peripheral expression and signaling (pStat5+ and Bcl-2+ CD4+/CD8+ T cells) of IL-7/IL-7Ra in 30 HAART-treated HIV-positive patients who did not experience CD4+ recovery (CD4+ #200/ml) and who had different levels of HIV viremia; these patients included 18 immunological nonresponders (INRs; HIV-RNA#50), 12 complete failures (CFs; HIV-RNA.1000), and 23 HIVseronegative subjects. Methods: We studied plasma IL-7 levels, IL-7Ra+CD4+/CD8+ T-cell proportions, IL-7Ra mRNA expression in PBMCs, spontaneous IL-7 production by BM mononuclear cells (BMMCs), and IL-7 mRNA/IL-7Ra mRNA in BMMC-derived stromal cells (SCs). We also studied T-cell responsiveness to IL-7 by measuring the proportions of pStat5+ and Bcl-2+ CD4+/CD8+ T cells. Results: Compared to HIV-seronegative controls, CFs and INRs presented elevated plasma IL-7 levels and lower IL-7Ra CD4+/CD8+ cell-surface expression and peripheral blood production, confirming the most relevant IL-7/IL-7R disruption. Interestingly, BM investigation revealed a trend of higher spontaneous IL-7 production in INRs (p = .09 vs. CFs) with a nonsignificant trend toward higher IL-7-Ra mRNA levels in BMMC-derived stromal cells. However, upon IL-7 stimulation, the proportion of pStat5+CD4+ T cells did not increase in INRs despite higher constitutive levels (p = .06); INRs also displayed lower Bcl-2+CD8+ T-cell proportions than controls (p = .04). Conclusions: Despite severe CD4+ T-lymphopenia and a disrupted IL-7/IL-7R profile in the periphery, INRs display elevated BM IL-7/IL-7Ra expression but impaired T-cell responsiveness to IL-7, suggesting the activity of a central compensatory pathway targeted to replenish the CD4+ compartment, which is nevertheless inappropriate to compensate the dysfunctional signaling through IL-7 receptor

    The open abdomen in trauma and non-trauma patients : WSES guidelines

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    Damage control resuscitation may lead to postoperative intra-abdominal hypertension or abdominal compartment syndrome. These conditions may result in a vicious, self-perpetuating cycle leading to severe physiologic derangements and multiorgan failure unless interrupted by abdominal (surgical or other) decompression. Further, in some clinical situations, the abdomen cannot be closed due to the visceral edema, the inability to control the compelling source of infection or the necessity to re-explore (as a "planned second-look" laparotomy) or complete previously initiated damage control procedures or in cases of abdominal wall disruption. The open abdomen in trauma and non-trauma patients has been proposed to be effective in preventing or treating deranged physiology in patients with severe injuries or critical illness when no other perceived options exist. Its use, however, remains controversial as it is resource consuming and represents a non-anatomic situation with the potential for severe adverse effects. Its use, therefore, should only be considered in patients who would most benefit from it. Abdominal fascia-to-fascia closure should be done as soon as the patient can physiologically tolerate it. All precautions to minimize complications should be implemented.Peer reviewe
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