PurposeThis study aimed to investigate whether oxygenated hemoglobin generated during a motor imagery task is associated with the motor learning level of the task.MethodsWe included 16 right-handed healthy participants who were trained to perform a ball rotation task. Hemodynamic brain activity was measured using near-infrared spectroscopy to monitor changes in oxy-Hb concentration during the BR MI task. The experimental protocol used a block design, and measurements were performed three times before and after the initial training of the BR task as (...) well as after the final training. The BR count during training was also measured. Furthermore, subjective vividness of MI was evaluated three times after NIRS measurement using the Visual Analog Scale.ResultsThe results showed that the number of BRs increased significantly with training. VAS scores also improved with training. Furthermore, oxy-Hb concentration and the region of interest showed a main effect. An interaction was confirmed, and it was ascertained that the change in oxy-Hb concentrations due to training was different for each ROI. The most significant predictor of subjective MI vividness was supplementary motor area oxy-Hb concentration.DiscussionHemodynamic brain activity during MI tasks may be correlated with task motor learning levels, since significant changes in oxy-Hb concentrations were observed following initial and final training in the SMA. In particular, hemodynamic brain activity in the SMA was suggested to reflect the MI vividness of participants. (shrink)

This study aimed to investigate whether the effect of mental practice can be enhanced by providing neurofeedback based on transcranial magnetic stimulation -induced motor evoked potentials. Twenty-four healthy, right-handed subjects were enrolled in this study. The subjects were randomly allocated into two groups: a group that was given correct TMS feedback and a group that was given randomized false TMS feedback. The subjects imagined pushing the switch with just timing, when the target circle overlapped a cross at the center of (...) the computer monitor. In the Real-FB group, feedback was provided to the subjects based on the MEP amplitude measured in the trial immediately preceding motor imagery. In contrast, the subjects of the Sham-FB group were provided with a feedback value that was independent of the MEP amplitude. TMS was applied when the target, moving from right to left, overlapped the cross at the center of the screen, and the MEP amplitude was measured. The MEP was recorded in the right first dorsal interosseous muscle. We evaluated the pre-mental practice and post-mental practice motor performance in both groups. As a result, a significant difference was observed in the percentage change of error values between the Real-FB group and the Sham-FB group. Furthermore, the MEP was significantly different between the groups in the 4th and 5th sets. Therefore, it was suggested that TMS-induced MEP-based neurofeedback might enhance the effect of mental practice. (shrink)

This article argues that Hume is committed to the cognitive phenomenology of believing. For Hume, beliefs have some distinctively cognitive phenomenology, which is different in kind from sensory phenomenology. I call this interpretation the “cognitive phenomenal interpretation” (“CPI”) of Hume. CPI is coherent with, and supported by, the textual evidence from A Treatise of Human Nature as well as An Enquiry Concerning Human Understanding. In both texts, Hume talks about the distinctive “manner” of believing, and CPI provides us with the (...) best explanation of Hume’s remarks on this distinctive “manner.”. (shrink)

What sort of mental state is a delusion? What causes delusions? Why are delusions pathological? This book examines these questions, which are normally considered separately, in a much-needed exploration of an important and fascinating topic, Kengo Miyazono assesses the philosophical, psychological and psychiatric literature on delusions to argue that delusions are malfunctioning beliefs. Delusions belong to the same category as beliefs but - unlike healthy irrational beliefs - fail to play the function of beliefs. Delusions and Beliefs: A Philosophical (...) Inquiry will be of great interest to students of philosophy of mind and psychology and philosophy of mental disorder, as well as those in related fields such as mental health and psychiatry. (shrink)

Where is imagination in imaginative resistance? We seek to answer this question by connecting two ongoing lines of inquiry in different subfields of philosophy. In philosophy of mind, philosophers have been trying to understand imaginative attitudes’ place in cognitive architecture. In aesthetics, philosophers have been trying to understand the phenomenon of imaginative resistance. By connecting these two lines of inquiry, we hope to find mutual illumination of an attitude (or cluster of attitudes) and a phenomenon that have vexed philosophers. Our (...) strategy is to reorient the imaginative resistance literature from the perspective of cognitive architecture. Whereas existing taxonomies of positions in the imaginative resistance literature have focused on disagreements over the source and scope of the phenomenon, our taxonomy focuses on the psychological components necessary for explaining imaginative resistance. (shrink)

The two-factor theory (Davies, Coltheart, Langdon & Breen 2001; Coltheart 2007; Coltheart, Menzies & Sutton 2010) is an influential account of delusion formation. According to the theory, there are two distinct factors that are causally responsible for delusion formation. The first factor is supposed to explain the content of the delusion, while the second factor is supposed to explain why the delusion is adopted and maintained. Recently, another remarkable account of delusion formation has been proposed, in which the notion of (...) “prediction error” plays the central role (Fletcher & Frith 2009; Corlett, Krystal, Taylor & Fletcher 2009; Corlett, Taylor, Wang, Fletcher & Krystal 2010). According to this account, the prediction-error theory, delusions are formed in response to aberrant prediction-error signals, those signals that indicate a mismatch between expectation and actual experience. -/- In this chapter, we examine the relationship between the two-factor theory and the prediction-error theory in some detail. Our view is that the prediction-error theory does not have to be understood as a rival to the two-factor theory. We do not deny that there are some important differences between them. However, those differences are not as significant as they have been presented in the literature. Moreover, the core ideas of the prediction-error theory may be incorporated into the two- factor framework. For instance, the aberrant prediction-error signal that is posited by prediction-error theorists can be (or underlie) the first factor contributing to the formation of some delusions, and help explain the content of those delusions. Alternatively, the aberrant prediction-error signal can be (or underlie) the second factor, and help explain why the delusion is adopted and maintained. (shrink)

One of the most exciting debates in philosophy of imagination in recent years has been over the epistemic use of imagination where imagination epistemically contributes to justifying beliefs and acquiring knowledge. This paper defends “generationism about imagination” according to which imagination is a generative source, rather than a preservative source, of justification. In other words, imagination generates new justification above and beyond prior justification provided by other sources. After clarifying the generation/preservation distinction (Section 2), we present an argument for generationism (...) about imagination, which can be divided into two parts; the philosophical part and the empirical part. In the philosophical part of our argument (Section 3), we claim that generationism about imagination follows from what we call “INACCESSIBILITY”. According to INACCESSIBILITY, imagination is properly constrained by the imaginative constrainers (i.e., the prior representations that constrain the development of a scenario in imagination) to which non-imaginative belief-forming processes do not have access. In the empirical part of our argument (Section 4), we claim that INACCESSIBILITY is plausible in light of relevant studies and theories in the empirical literature, especially the literature on mental simulation (Section 4.1), core cognition (Section 4.2), and intuitive physics (Section 4.3). (shrink)

An introduction to how the latest psychological studies are fundamentally altering our philosophical understanding of the mind.

In discussing the famous case of Otto, a patient with Alzheimer’s disease who carries around a notebook to keep important information, Clark and Chalmers argue that some of Otto’s beliefs are physically realized in the notebook. In other words, some of Otto’s beliefs are extended into the environment. Their main argument is a functionalist one. Some of Otto’s beliefs are physically realized in the notebook because, first, some of the beliefs of Inga, a healthy person who remembers important information in (...) her head, are physically realized in her internal memory storage, and, second, there is no relevant functional difference between the role of the notebook for Otto and the role of the internal memory storage for Inga. The paper presents a new objection to this argument. I call it “the systems reply” to the functionalist argument since it is structurally analogous to the “the systems reply” to Searle’s Chinese room argument. According to the systems reply to the functionalist argument, what actually follows from their argument is not that beliefs of Otto are physically realized in the notebook but rather that the beliefs of the hybrid system consisting of Otto and his notebook are physically realized in the notebook. This paper also discusses Sprevak’s claim that the functionalist argument entails radical versions of extended mental states and shows that his argument is also vulnerable to the systems reply. (shrink)

This paper investigates the role of group identification in empathic emotion and its behavioral consequences. Our central idea is that group identification is the key to understanding the process in which empathic emotion causes helping behavior. Empathic emotion causes helping behavior because it involves group identification, which motivates helping behavior toward other members. This paper focuses on a hypothesis, which we call “self-other merging hypothesis (SMH),” according to which empathy-induced helping behavior is due to the “merging” between the helping agent (...) and the helped agent. We argue that SMH should be interpreted in terms of group identification. The group identification interpretation of SMH is both behaviorally adequate (i.e., successfully predicts and explains the helping behavior in the experimental settings) and psychologically plausible (i.e., does not posit psychologically unrealistic beliefs, desires, etc.). Empathy-induced helping behavior, according to the group identification interpretation of the SMH, does not fit comfortably into the traditional egoism/altruism dichotomy. We thus propose a new taxonomy according to which empathy-induced helping behavior is both altruistic at the individual level and egoistic at the group level. (shrink)

Delusional beliefs are typically pathological. Being pathological is clearly distinguished from being false or being irrational. Anna might falsely believe that his husband is having an affair but it might just be a simple mistake. Again, Sam might irrationally believe, without good evidence, that he is smarter than his colleagues, but it might just be a healthy self-deceptive belief. On the other hand, when a patient with brain damage caused by a car accident believes that his father was replaced by (...) an imposter or another patient with schizophrenia believes that “The Organization” painted the shops on a street in red and green to convey a message, these beliefs are not merely false or irrational. They are pathological. What makes delusions pathological? This paper explores the negative features because of which delusional beliefs are pathological. First, I critically examine the proposals according to which delusional beliefs are pathological because of (1) their strangeness, (2) their extreme irrationality, (3) their resistance to folk psychological explanations or (4) impaired responsibility-grounding capacities of people with them. I present some counterexamples as well as theoretical problems for these proposals. Then, I argue, following Wakefield’s harmful dysfunction analysis of disorder, that delusional beliefs are pathological because they involve some sorts of harmful malfunctions. In other words, they have a significant negative impact on wellbeing (=harmful) and, in addition, some psychological mechanisms, directly or indirectly related to them, fail to perform the jobs for which they were selected in the past (=malfunctioning). An objection to the proposal is that delusional beliefs might not involve any malfunctions. For example, they might be playing psychological defence functions properly. Another objection is that a harmful malfunction is not sufficient for something to be pathological. For example, false beliefs might involve some malfunctions according to teleosemantics, a popular naturalist account of mental content, but harmful false beliefs do not have to be pathological. I examine those objections in detail and show that they should be rejected after all. (shrink)

The dominant conception of delusion in psychiatry (in textbooks, research papers, diagnostic manuals, etc.) is predominantly epistemic. Delusions are almost always characterized in terms of their epistemic defects, i.e., defects with respect to evidence, reasoning, judgment, etc. However, there is an individualistic bias in the epistemic conception; the alleged epistemic defects and abnormalities in delusions relate to individualistic epistemic processes rather than social epistemic processes. We endorse the social epistemological turn in recent philosophical epistemology, and claim that a corresponding turn (...) is needed in the study of delusions. It is a turn from the (purely) individualistic conception, which characterizes delusions only by individualistic epistemic defects and abnormalities, to the (partially) social epistemic conception, which characterizes delusions by individualistic as well as social epistemic defects and abnormalities. This paper is intended as an initial step toward such a social epistemological turn. In particular, we will develop a new model of the development of delusions according to which testimonial abnormalities, including testimonial isolation and testimonial discount, are a causal factor in the development of delusions. (shrink)

1. Philosophical arguments (Schweikard & Schmid, 2013) and empirical evidence (Tomasello, Carpenter, Call, Behne, & Moll, 2005) support the idea that the capacity to engage in joint actions is a ke...

In the previous discussions of irrationality in philosophy and psychology, the focus has been on irrationality at the level of individuals, such as irrational reasoning, irrational judgment, irrati...

: Sinhababu’s Humean Nature contains many interesting and important ideas, but in this short commentary I focus on the idea of vivid representations. Sinhababu inherits his idea of vivid representations from Hume’s discussions, in particular his discussion of calm and violent passions. I am sympathetic to the idea of developing Hume’s insight that has been largely neglected by philosophers. I believe that Sinhababu and Hume are on the right track. What I do in this short commentary is to raise some (...) questions about the details. The aim of asking these questions is not to challenge Sinhababu’s proposal, but rather to point at some interesting issues arising out of his proposal. The questions are about the nature of vividness, the effects of vivid representations, and Sinhababu’s account of alief cases. Keywords: Vivid Representation; Desire; Procrastination; Akrasia; Alief Le rappresentazioni vivide e i loro effetti Riassunto: Humean Nature di Neil Sinhababu contiene molte idee interessanti e importanti; tuttavia in questo breve commento intendo concentrarmi sulle rappresentazioni vivide. Sinhababu eredita l’idea di rappresentazione vivida dalle analisi di Hume, in particolare dall’analisi delle passioni calme e violente. Condivido l’intento di sviluppare questa intuizione di Hume, ampiamente trascurata dai filosofi. Credo che Sinhababu e Hume siano sulla strada giusta. Quanto intendo fare in questo breve commento è sollevare alcune questioni di dettaglio, il cui fine non è quello di mettere in discussione la proposta di Sinhababu, quanto piuttosto di indicare alcuni punti interessanti che emergono dalla sua proposta. Le mie questioni investono la natura della vividezza, gli effetti delle rappresentazioni vivide e la descrizione di Sinhababu dei casi di alief. Parole chiave: Rappresentazione vivida; Desiderio; Temporeggiare; Akrasia; Cattiva volontà. (shrink)

In this paper we address the ethics of adopting delusional beliefs and we apply consequentialist and deontological considerations to the epistemic evaluation of delusions. Delusions are characterised by their epistemic shortcomings and they are often defined as false and irrational beliefs. Despite this, when agents are overwhelmed by negative emotions due to the effects of trauma or previous adversities, or when they are subject to anxiety and stress as a result of hypersalient experience, the adoption of a delusional belief can (...) prevent a serious epistemic harm from occurring. For instance, delusions can allow agents to remain in touch with their environment overcoming the disruptive effect of negative emotions and anxiety. Moreover, agents are not blameworthy for adopting their delusions if their ability to believe otherwise is compromised. There is evidence suggesting that no evidence-related action that would counterfactually lead them to believe otherwise is typically available to them. The lack of ability to believe otherwise, together with some other conditions, implies that the agents are not blameworthy for their delusions. The examination of the epistemic status of delusions prompts us to acknowledge the complexity and contextual nature of epistemic evaluation, establish connections between consequentialist and deontological frameworks in epistemology, and introduce the notion of epistemic innocence into the vocabulary of epistemic evaluation. (shrink)

In this paper we review two debates in the current literature on clinical delusions. One debate is about what delusions are. If delusions are beliefs, why are they described as failing to play the causal roles that characterise beliefs, such as being responsive to evidence and guiding action? The other debate is about how delusions develop. What processes lead people to form delusions and maintain them in the face of challenges and counter-evidence? Do the formation and maintenance of delusions require (...) abnormal experience alone, or also reasoning biases or deficits? We hope to show that the focus on delusions has made a substantial contribution to the philosophy of the mind and continues to raise issues that are central to defining the concept of belief and gaining a better understanding of how people process information and learn about the world. (shrink)

Akama et al. [1] systematically studied an arithmetical hierarchy of the law of excluded middle and related principles in the context of first-order arithmetic. In that paper, they first provide a prenex normal form theorem as a justification of their semi-classical principles restricted to prenex formulas. However, there are some errors in their proof. In this paper, we provide a simple counterexample of their prenex normal form theorem [1, Theorem 2.7], then modify it in an appropriate way which still serves (...) to largely justify the arithmetical hierarchy. In addition, we characterize a variety of prenex normal form theorems by logical principles in the arithmetical hierarchy. The characterization results reveal that our prenex normal form theorems are optimal. For the characterization results, we establish a new conservation theorem on semi-classical arithmetic. The theorem generalizes a well-known fact that classical arithmetic is $\Pi _2$ -conservative over intuitionistic arithmetic. (shrink)

Libertarian paternalism is a weak form of paternalism that recommends nudges rather than bans, restrictions, or other strong interventions. Nudges influence people’s choice by modifying contextual factors (the “choice architecture”). This paper explores the possibility of an epistemic analogue of libertarian paternalism. What I call “epistemic libertarian paternalism” is a weak form of epistemic paternalism that recommends “epistemic nudges” rather than stronger paternalistic interventions. Epistemic nudges influence people’s beliefs and judgments by modifying contextual factors (the “epistemic choice architecture”). The main (...) aim of this paper is to defend epistemic libertarian paternalism from the “irrationality problem”, which I take to be the most urgent problem for epistemic libertarian paternalism; given how epistemic nudges work (i.e. they typically co-opt psychological biases), nudged beliefs are irrational. In response to the irrationality problem, I admit that nudged beliefs are often (not always, though) irrational, but insist that there are conditions in which epistemic nudging can be justifiable nonetheless. I will propose two conditions that are jointly sufficient for justifiable epistemic nudging: “Veridicality Condition” (which says that nudged beliefs are more likely to be true than non-nudged beliefs) and “Not-More-Irrationality Condition” (which says that nudged beliefs are not more likely to be irrational than non-nudged beliefs). (shrink)

Imaginings are often characterized in terms of vividness. However, there is little agreement in the philosophical literature as to what it amounts to and how to even investigate it. In this paper, we propose a natural kind methodology to study vividness and suggest treating it as a homeostatic property cluster with an underlying nature that explains the correlation of properties in that cluster. This approach relies on the empirical research on the vividness of mental imagery and contrasts with those accounts (...) that treat vividness as an explanatory primitive and with those that attempt to provide a definition. We apply the natural kind methodology to make several substantive claims about the vividness of mental imagery. First, we will argue that it forms a homeostatic property cluster, in that it is reliably correlated with, but not defined by, some properties, such as the level of detail, clarity, perception-likeness and intensity. In arguing for this claim, we also show how the cluster can be modified in the light of empirical research by complementing it with a correlation between vividness and familiarity. Second, we will argue that these correlations can be explained by an underlying property at the architectural level; i.e., the availability of stored sensory information for the elaboration of a mental image. (shrink)

The article Social epistemological conception of delusion, written by Kengo Miyazon and Alessandro Salice, was originally published electronically on the publisher’s internet portal on 17 September 2020 without open access.

The central hypothesis of this book, Delusions and Beliefs: A Philosophical Inquiry (Routledge, 2019), is that delusions are malfunctional beliefs (Chapter 1); they belong to the category of belief (Chapter 2) but, unlike mundane false or irrational beliefs, they fail to perform some functions of belief (Chapter 3). More precisely, delusions directly or indirectly involve some malfunctioning cognitive mechanisms, which is empirically supported by the two-factor account of delusion formation (Chapter 4).

Thought insertion is a common delusion in schizophrenia. People affected by it report that there are thoughts in their heads that have been inserted by a third party. These thoughts are self-generated but subjec-tively experienced as alien (hereafter, we shall call them alien thoughts for convenience). In chapter 5 of Transparent Minds, Jordi Fernández convincingly argues that the phenomenon of thought insertion can be accounted for as a pathology of self-knowledge. In particular, he argues that the application of the bypass (...) model of self-knowledge can shed light on what is amiss in people with thought insertion. In this brief commentary, we examine the proposal by Fernández, highlight some of its strengths, and raise one main objection to it. In mainstream philosophical accounts of thought insertion, people who report the delusion are thought to have ownership of the alien thoughts, but to lack a sense of agency with respect to such thoughts, and this is supposed to explain why they ascribe the thoughts to some-one else. Fernández correctly identifies the limitations of mainstream accounts of thought insertion. First, to claim that people with the delu-sion of thought insertion own the alien thoughts does not sit well with the phenomenology of thought insertion as it is reflected in people’s self-reports. Second, people do not need to experience a sense of agency with respect to a thought in order to ascribe the thought to themselves. Sense of agency is too demanding a condition for self-ascription. Fernández puts forward a novel account of thought insertion, at-tempting to solve the problems identified with mainstream accounts. He defends the view that thought insertion is a failure of self-knowledge that consists in the person failing to ascribe one of her be-liefs to herself. Similar accounts to the one Fernández develops in the chapter have been defended by Bortolotti and Broome (2009) and Pickard (2010). For Fernández, the failure in self-ascription is due to the fact that the person with thought insertion does not feel pressured to endorse the content of a belief that she has [Fernández (2013), p. 142]. Fernández explains this phenomenon in detail by reference to the bypass model of self-knowledge. When Fernández develops his own proposal, he relies on the claim that the alien thought is a belief. We challenge this claim.We agree with Fernández that, in thought insertion, the person does not ascribe the alien thought to herself and does not commit to the content of the thought being true, in spite of the thought being self-generated. Such considerations powerfully suggest to us that the alien thought is not a belief. Given the elusive nature of mental states in general and beliefs in particular, this may seem just a terminological issue. But in the present context, whether the alien thought is a belief is important in order to offer a characterisation of thought insertion that makes jus-tice to the first-person reports and other behavioural manifestations of people with the delusion. One may also argue that, as the model of self-knowledge Fernández applies to alien thoughts, that is, the bypass model, is a model of self-knowledge for beliefs, such a model could only feature in the explanation of thought insertion if alien thoughts were beliefs. But we do not think this is necessarily the case, as in the book Fernández successfully applies his bypass model to other types of mental states, such as desires. (shrink)

Genetically modified cassava is currently being developed to address problems of diseases that threaten the food security of farmers in developing countries. The technologies are aimed at smallholder farmers, in hopes of reducing the vulnerability of cassava production to these diseases. In this paper we examine barriers to farmers’ voice in the development of GM cassava. We also examine the role of a translational research process to enhance farmers’ voice, to understand the sources of vulnerability farmers in a group in (...) Kenya’s Coast face, and to determine if their concerns are consistent with those of the scientists in agriculture addressing farmers’ needs. A two-way communication participatory process provided insights into the complex vulnerability context of farmers, their primary concerns with processing and markets of cassava in order to improve livelihoods, the lack of networks with two way communication flows, and the lack of information on GM technologies. The translational research engaged farmers and scientists in an iterative process where scientists are learning what farmers need, and farmers are learning about the potential benefits and risks from GM technologies, while at the same time expressing their concerns. (shrink)

SULLIVAN-BISSETTEMA, BRADLEYHELEN, AND NOORDHOFPAUL oup. 2017. pp. 272. £50.

This article explores “Inner Speech Account of Introspection”, according to which inner speech is the source of our introspective self-knowledge. The view hypothesizes that we come to know that we are thinking that p by being aware of the sentence of inner speech “p” accompanying the thought. I argue for Inner Speech Account by showing that it explains six explananda imposed for the philosophical theories of introspection; peculiar access, privileged access, detection condition, the lack of phenomenology, occurent/dispositional distinction, and content/attitude (...) distinction. (shrink)

Declan Smithies’ The Epistemic Role of Consciousness is a defense of “Phenomenal Mentalism” according to which, necessarily, which propositions X has epistemic justification to believe at any given time is determined solely by X’s phenomenally individuated mental states at that time. Smithies offers two kinds of arguments for Phenomenal Mentalism: the ones that appeal to particular cases such as blindsight and the ones that appeal to general epistemic principles such as the JJ principle. My focus is on the former. More (...) precisely, I focus on a particular argument from below in Chapter 3, which I call “Argument from Blindsight”. According to this argument, the cases of blindsight show that consciousness is necessary for perceptual justification. In response, I raise two worries about Argument from Blindsight: first, it is difficult to find a plausible interpretation of “full rationality” according to which the premises are true and, second, the argument oscillates between empirical and stipulative discussions of blindsight in a potentially problematic manner. (shrink)

Previous studies have found that serum lipid levels independently associate with mental health problems in adulthood. However, little is known about the association between serum lipid levels and positive aspects of mental health such as resilience and self-esteem, which develop in adolescence. The aim of this study is to examine the association between serum lipid levels and resilience and self-esteem in Japanese adolescents. Data were pooled data from the Adachi Child Health Impact of Living Difficulty study in 2016 and 2018, (...) a school-based, cross-sectional study in Adachi City, Tokyo, Japan. Resilience of the child was assessed by caregivers, and self-esteem was self-identified via questionnaires. Serum lipid levels [total cholesterol, low-density lipoproteins, and high-density lipoproteins ] were assessed in school health checkup, in addition to height and weight measurements. Multiple linear regression was applied to investigate the association between standardized serum lipid levels and resilience and self-esteem. LDL showed inverse association with resilience [β = −1.26, 95% confidence interval = −2.39 to −0.14] after adjusting for child’s BMI, month of birth, sex, absence of parent, household income, caregiver’s mental health, and lifestyle. We also found an inverse association of total cholesterol and higher LDL cholesterol with self-esteem. HDL cholesterol was not associated with resilience and self-esteem. Among Japanese adolescent, total and LDL cholesterol may be biomarkers of resilience and self-esteem. (shrink)

We provide a fine‐grained analysis on the relation between König's lemma, weak König's lemma, and the decidable fan theorem in the context of constructive reverse mathematics. In particular, we show that double negated variants of König's lemma and weak König's lemma are equivalent to double negated variants of the general decidable fan theorem and the binary decidable fan theorem, respectively, over a nearly intuitionistic system containing a weak countable choice only. This implies that the general decidable fan theorem is not (...) equivalent to the binary decidable fan theorem in the absence of a strong countable choice. In addition, we introduce a principle which fills the gap between König's lemma and weak König's lemma, and show that König's lemma is equivalent to weak König's lemma plus this principle. We also solve several problems arising from the investigation. (shrink)

This paper offers an account of collective epistemic vices, which we call the “group identification account”. The group identification account attributes collective epistemic vices to the groups that are constituted by “group identification”, which is a primitive and non-doxastic self-understanding as a group member (Turner, 1982; Brewer, 1991; Brewer & Gardner, 1996; Pacherie, 2013; Salice & Miyazono, 2020). The distinctive feature of the group identification account is that it enables us to attribute epistemic vices not just to established social groups (...) (e.g. committees, research teams, juries) but also to loose social groups (e.g. loosely connected people in an echo chamber) when they are constituted by group identification. The group identification account is contrasted with Fricker’s (2010, 2020) influential account, the “joint commitment account”, which focuses on established social groups, and has difficulty in making sense of collective epistemic vices of loose social groups. The group identification account is motivated by the fact that collective epistemic vices can be useful to diagnose not only the epistemic performance of established groups but also that of loose groups in real-life cases, such as echo chamber (Nguyen, 2020), implicit bias (Holroyd, 2020), group polarization (Broncano-Berrocal & Carter, 2021), etc. (shrink)