Luminosity

This essay provides a novel account of iterated epistemic states. The essay argues that states of epistemic determinacy might be secured by countenancing self-knowledge on the model of fixed points in monadic second-order modal logic, i.e. the modal $\mu$-calculus. Despite the epistemic indeterminacy witnessed by the invalidation of modal axiom 4 in the sorites paradox -- i.e. the KK principle: $\square$$\phi$ $\rightarrow$ $\square$$\square$$\phi$ -- an epistemic interpretation of a $\mu$-automaton permits fixed points to entrain a principled means by which to (...) account for necessary conditions on self-knowledge. (shrink)

Epistemological disjunctivists hold that perceiving subjects have “reflective access” to factive perceptual support for belief. However, little has been done to elaborate the intended notion of reflection, or introspective awareness more generally. Moreover, critics have pointed out that the disjunctivist conception of “reflective access” can seem vulnerable to varieties of Williamson’s anti-luminosity argument. In this paper I defend disjunctivism from this charge, arguing that it holds the resources for a potent defense of the claim that knowledge of perceptual states is (...) luminous. Indeed, I argue that appreciating the relation between disjunctivism and luminosity sheds critical light on how the disjunctivist conceives of perceptual support for belief. (shrink)

Recent research has identified a tension between the Safety principle that knowledge is belief without risk of error, and the Closure principle that knowledge is preserved by competent deduction. Timothy Williamson reconciles Safety and Closure by proposing that when an agent deduces a conclusion from some premises, the agent’s method for believing the conclusion includes their method for believing each premise. We argue that this theory is untenable because it implies problematically easy epistemic access to one’s methods. Several possible solutions (...) are explored and rejected. (shrink)

Stephenson (2022) has argued that Kant’s thesis that all transcendental truths are transcendentally a priori knowable leads to omniscience of all transcendental truths. His arguments depend on luminosity principles and closure principles for transcendental knowability. We will argue that one pair of a luminosity and a closure principle should not be used, because the closure principle is too strong, while the other pair of a luminosity and a closure principle should not be used, because the luminosity principle is too strong. (...) Stephenson’s argument also depends on a factivity principle for transcendental knowability, which we will argue to be false. (shrink)

Our decision-theoretic states are not luminous. We are imperfectly reliable at identifying our own credences, utilities and available acts, and thus can never be more than imperfectly reliable at identifying the prescriptions of decision theory. The lack of luminosity affords decision theory a remarkable opportunity — to issue guidance on the basis of epistemically inaccessible facts. We show how a decision theory can guarantee action in accordance with contingent truths about which an agent is arbitrarily uncertain. It may seem that (...) such advantages would require dubiously adverting to externalist facts that go beyond the internalism of traditional decision theory, but this is not so. Using only the standard repertoire of decision-theoretic tools, we show how to modify existing decision theories to take advantage of this opportunity. These improved decision theories require agents to maximize conditional expected utility — expected utility conditional upon an agent’s actual decision situation. We call such modified decision theories ‘self-confident’. These self-confident decision theories have a distinct advantage over standard decision theories: their prescriptions are better. (shrink)

David Lewis—famously—never tasted vegemite. Did he have any knowledge of what it's like to taste vegemite? Most say 'no'; I say 'yes'. I argue that knowledge of what it’s like varies along a spectrum from more exact to more approximate, and that phenomenal concepts vary along a spectrum in how precisely they characterize what it’s like to undergo their target experiences. This degreed picture contrasts with the standard all-or-nothing picture, where phenomenal concepts and phenomenal knowledge lack any such degreed structure. (...) I motivate the degreed picture by appeal to (1) limits in epistemic abilities such as recognition, imagination, and inference, and (2) the semantics of ‘knows what it’s like’ expressions. I argue that approximate phenomenal knowledge cannot be explained merely via determinable or vague phenomenal concepts. I develop a framework for systematizing approximate knowledge of phenomenal character. And I explain how my view challenges some standard assumptions about the acquisition conditions, requirements for mastery, and referential mechanisms of phenomenal concepts. (shrink)

Sometimes you are unreliable at fulfilling your doxastic plans: for example, if you plan to be fully confident in all truths, probably you will end up being fully confident in some falsehoods by mistake. In some cases, there is information that plays the classical role of evidence—your beliefs are perfectly discriminating with respect to some possible facts about the world—and there is a standard expected‐accuracy‐based justification for planning to conditionalize on this evidence. This planning‐oriented justification extends to some cases where (...) you do not have transparent evidence, in the sense that your beliefs are not perfectly discriminating with respect to any non‐trivial facts. In other cases, accuracy considerations do not tell you to plan to conditionalize on any information at all, but rather to plan to follow a different updating rule. Even in the absence of evidence, accuracy considerations can guide your doxastic plan. (shrink)

kk states that knowing entails knowing that one knows, and K¬K states that not knowing entails knowing that one does not know. In light of the arguments against kk and K¬K⁠, one might consider modally qualified variants of those principles. According to weak kk, knowing entails the possibility of knowing that one knows. And according to weakK¬K⁠, not knowing entails the possibility of knowing that one does not know. This paper shows that weak kk and weakK¬K are much stronger than (...) they initially appear. Jointly, they entail kk and K¬K⁠. And they are susceptible to variants of the standard arguments against kk and K¬K⁠. This has interesting implications for the debate on positive introspection and for deeper issues concerning the structure and limits of knowability. (shrink)

The Qualitative Thesis says that if you leave open P, then you are sure of if P, then Q just in case you are sure of the corresponding material conditional. We argue the Qualitative Thesis provides compelling reasons to accept a thesis that we call Conditional Locality, which says, roughly, the interpretation of an indicative conditional depends, in part, on the conditional’s local embedding environment. In the first part of the paper, we present an argument—due to Ben Holguín—showing that, without (...) Conditional Locality, the Qualitative Thesis is in tension with a margin for error principle on rational sureness. We show Conditional Locality reconciles the Qualitative Thesis with the margin for error principle. In the second part, we argue the full range of data supports what we call the Strong Qualitative Thesis. Without Conditional Locality, the Strong Qualitative Thesis has unacceptable consequences. But with Conditional Locality, it is tenable. (shrink)

This paper explores the principle that knowledge is fragile, in that whenever S knows that S doesn’t know that S knows that p, S thereby fails to know p. Fragility is motivated by the infelicity of dubious assertions, utterances which assert p while acknowledging higher-order ignorance whether p. Fragility is interestingly weaker than KK, the principle that if S knows p, then S knows that S knows p. Existing theories of knowledge which deny KK by accepting a Margin for Error (...) principle can be conservatively extended with Fragility. (shrink)

One of the central arguments for the knowledge norm of assertion appeals to the fact that it is typically legitimate to respond to an assertion with “How do you know?”, intended as a challenge to the assertion. The legitimacy of the challenge is taken as evidence in favor of the idea that permissible assertion requires knowledge. In this paper, I argue that if the legitimacy of “How do you know?” challenges supports a knowledge norm for assertion, it also supports the (...) controversial KK thesis. I further argue that data from assertion prompts likewise supports KK. This is an unwelcome consequence for many proponents of the knowledge norm of assertion who reject KK. At the same time, it constitutes new evidence from conversational patterns in favor of the KK thesis. (shrink)

Kevin Dorst has recently pointed out an apparently puzzling consequence of denying epistemic luminosity: given some natural-sounding bridging principles between knowledge, credence, and indicative conditionals, the denial of epistemic luminosity licenses the knowledge and assertability of abominable-sounding conditionals of the form ⌜If I don’t know that ϕ, then ϕ⌝. We provide a general and systematic examination of this datum by testing Dorst’s claim against various semantics for the indicative conditional in the setting of epistemic logic. Our conclusion is that, regardless (...) of whether knowledge is luminous, the knowability of these conditionals is highly sensitive to the correct semantic analysis of the indicative conditional. Moreover, standard pragmatic resources can explain away the infelicity of such assertions. As it stands, the datum does not tell against epistemic non-luminosity. (shrink)

One of the most intriguing claims in Sven Rosenkranz’s Justification as Ignorance is that Timothy Williamson’s celebrated anti-luminosity argument can be resisted when it comes to the condition ~K~KP—the condition that one is in no position to know that one is in no position to know P. In this paper, I critically assess this claim.

According to a rich tradition in philosophy of action, intentional action requires practical knowledge: someone who acts intentionally knows what they are doing while they are doing it. Piñeros Glasscock argues that an anti-luminosity argument, of the sort developed in Williamson, can be readily adapted to provide a reductio of an epistemic condition on intentional action. This paper undertakes a rescue mission on behalf of an epistemic condition on intentional action. We formulate and defend a version of an epistemic condition (...) that is free from any luminosity commitments. While this version of an epistemic condition escapes reductio, it comes with substantive commitments of its own. In particular, we will see that it forces us to deny the existence of any essentially intentional actions. We go on to argue that this consequence should be embraced. On the resulting picture, intentional action is not luminous. But it still entails practical knowledge. (shrink)

The externalist says that your evidence could fail to tell you what evidence you do or not do have. In that case, it could be rational for you to be uncertain about what your evidence is. This is a kind of uncertainty which orthodox Bayesian epistemology has difficulty modeling. For, if externalism is correct, then the orthodox Bayesian learning norms of conditionalization and reflection are inconsistent with each other. I recommend that an externalist Bayesian reject conditionalization. In its stead, I (...) provide a new theory of rational learning for the externalist. I defend this theory by arguing that its advice will be followed by anyone whose learning dispositions maximize expected accuracy. I then explore some of this theory’s consequences for the rationality of epistemic akrasia, peer disagreement, undercutting defeat, and uncertain evidence. (shrink)

A mental state is luminous if, whenever an agent is in that state, they are in a position to know that they are. Following Timothy Williamson's Knowledge and Its Limits, a wave of recent work has explored whether there are any non‐trivial luminous mental states. A version of Williamson's anti‐luminosity appeals to a safety‐theoretic principle connecting knowledge and confidence: if an agent knows p, then p is true in any nearby scenario where she has a similar level of confidence in (...) p. However, the relevant notion of confidence is relatively underexplored. This paper develops a precise theory of confidence: an agent's degree of confidence in p is the objective chance they will rely on p in practical reasoning. This theory of confidence is then used to critically evaluate the anti‐luminosity argument, leading to the surprising conclusion that although there are strong reasons for thinking that luminosity does not obtain, they are quite different from those the existing literature has considered. In particular, we show that once the notion of confidence is properly understood, the failure of luminosity follows from the assumption that knowledge requires high confidence, and does not require any kind of safety principle as a premise. (shrink)

The present paper argues that there is a knowledge norm for conversational implicature: one may conversationally implicate p only if one knows p. Linguistic data about the cancellation behavior of implicatures and the ways they are challenged and criticized by speakers is presented to support the thesis. The knowledge norm for implicature is then used to present a new consideration in favor of the KK thesis. It is argued that if implicature and assertion have knowledge norms, then assertion requires not (...) only knowledge but iterated knowledge: knowing that you know that you know that... you know. Such a condition on permissible assertion is argued to be plausible only if the KK thesis is true. (shrink)

According to the probabilistic relevance account of confirmation, E confirms H relative to background knowledge K just in case P(H/K&E) > P(H/K). This requires an inequality between the rational degree of belief in H determined relative to two bodies of total knowledge which are such that one (K&E) includes the other (K) as a proper part. In this paper, I argue that it is quite plausible that there are no two possible bodies of total knowledge for ideally rational agents meeting (...) this requirement. Hence, the positive relevance account may have to be rejected. (shrink)

This paper draws out and connects two neglected issues in Kant’s conception of a priori knowledge. Both concern topics that have been important to contemporary epistemology and to formal epistemology in particular: knowability and luminosity. Does Kant commit to some form of knowability principle according to which certain necessary truths are in principle knowable to beings like us? Does Kant commit to some form of luminosity principle according to which, if a subject knows a priori, then they can know that (...) they know a priori? I defend affirmative answers to both of these questions, and by considering the special kind of modality involved in Kant’s conceptions of possible experience and the essential completability of metaphysics, I argue that his combination of knowability and luminosity principles leads Kant into difficulty. (shrink)

A mental state is luminous if, whenever an agent is in that state, they are in a position to know that they are. Following Timothy Williamson’s Knowledge and Its Limits, a wave of recent work has explored whether there are any non-trivial luminous mental states. A version of Williamson’s anti-luminosity appeals to a safety- theoretic principle connecting knowledge and confidence: if an agent knows p, then p is true in any nearby scenario where she has a similar level of confidence (...) in p. However, the relevant notion of confidence is relatively underexplored. This paper develops a precise theory of confidence: an agent’s degree of confidence in p is the objective chance they will rely on p in practical reasoning. This theory of confidence is then used to critically evaluate the anti-luminosity argument, leading to the surprising conclusion that although there are strong reasons for thinking that luminosity does not obtain, they are quite different from those the existing literature has considered. In particular, we show that once the notion of confidence is properly understood, the failure of luminosity follows from the assumption that knowledge requires high confidence, and does not require any kind of safety principle as a premise. (shrink)

Rosenkranz has recently proposed a logic for propositional, non-factive, all-things-considered justification, which is based on a logic for the notion of being in a position to know, 309–338 2018). Starting from three quite weak assumptions in addition to some of the core principles that are already accepted by Rosenkranz, I prove that, if one has positive introspective and modally robust knowledge of the axioms of minimal arithmetic, then one is in a position to know that a sentence is not provable (...) in minimal arithmetic or that the negation of that sentence is not provable in minimal arithmetic. This serves as the formal background for an example that calls into question the correctness of Rosenkranz’s logic of justification. (shrink)

Many of our sources of knowledge only afford us knowledge that is inexact. When trying to see how tall something is, or to hear how far away something is, or to remember how long something lasted, we may come to know some facts about the approximate size, distance or duration of the thing in question but we don’t come to know exactly what its size, distance or duration is. In some such situations we also have some pointed knowledge of how (...) inexact our knowledge is. That is, we can knowledgeably pinpoint some exact claims that we do not know. We show that standard models of inexact knowledge leave little or no room for such pointed knowledge. We devise alternative models that are not afflicted by this shortcoming. (shrink)

I argue that no successful version of Williamson's anti‐luminosity‐argument has yet been presented, even if Srinivasan's further elaboration and defence is taken into account. There is a version invoking a coarse‐grained safety condition and one invoking a fine‐grained safety condition. A crucial step in the former version implicitly relies on the false premise that sufficient similarity is transitive. I show that some natural attempts to resolve this issue fail. Similar problems arise for the fine‐grained version. Moreover, I argue that Srinivasan's (...) defence of the more contentious fine‐grained safety condition is also unsuccessful, again for similar reasons. (shrink)

KK is the thesis that if you can know p, you can know that you can know p. Though it’s unpopular, a flurry of considerations has recently emerged in its favour. Here we add fuel to the fire: standard resources allow us to show that any failure of KK will lead to the knowability and assertability of abominable indicative conditionals of the form ‘If I don’t know it, p’. Such conditionals are manifestly not assertable—a fact that KK defenders can easily (...) explain. I survey a variety of KK-denying responses and find them wanting. Those who object to the knowability of such conditionals must either deny the possibility of harmony between knowledge and belief, or deny well-supported connections between conditional and unconditional attitudes. Meanwhile, those who grant knowability owe us an explanation of such conditionals’ unassertability—yet no successful explanations are on offer. Upshot: we have new evidence for KK. (shrink)

This paper argues that two widely accepted principles about the indicative conditional jointly presuppose the falsity of one of the most prominent arguments against epistemological iteration principles. The first principle about the indicative conditional, which has close ties both to the Ramsey test and the “or‐to‐if” inference, says that knowing a material conditional suffices for knowing the corresponding indicative. The second principle says that conditional contradictions cannot be true when their antecedents are epistemically possible. Taken together, these principles entail that (...) it is impossible to be in a certain kind of epistemic state: namely, a state of ignorance about which of two partially overlapping bodies of knowledge corresponds to one's actual one. However, some of the more popular “margin for error” style arguments against epistemological iteration principles suggest that such states are not only possible, but commonplace. I argue that the tension between these views runs deep, arising just as much for non‐factive attitudes like belief, presupposition, and certainty. I also argue that this is worse news for those who accept the principles about the indicative conditional than it is for those who reject epistemological iteration principles. (shrink)

The early literature on epistemic logic in philosophy focused on reasoning about the knowledge or belief of a single agent, especially on controversies about "introspection axioms" such as the 4 and 5 axioms. By contrast, the later literature on epistemic logic in computer science and game theory has focused on multi-agent epistemic reasoning, with the single-agent 4 and 5 axioms largely taken for granted. In the relevant multi-agent scenarios, it is often important to reason about what agent A believes about (...) what agent B believes about what agent A believes; but it is rarely important to reason just about what agent A believes about what agent A believes. This raises the question of the extent to which single-agent introspection axioms actually matter for multi-agent epistemic reasoning. In this paper, we formalize and answer this question. To formalize the question, we first define a set of multi-agent formulas that we call agent-alternating formulas, including formulas like Box_a Box_b Box_a p but not formulas like Box_a Box_a p. We then prove, for the case of belief, that if one starts with multi-agent K or KD, then adding both the 4 and 5 axioms (or adding the B axiom) does not allow the derivation of any new agent-alternating formulas—in this sense, introspection axioms do not matter. By contrast, we show that such conservativity results fail for knowledge and multi-agent KT, though they hold with respect to a smaller class of agent-nonrepeating formulas. (shrink)

We long to love and to be loved. We also fear love because we risk betrayal by those we love, or we betray them. Predrag Cicovacki's charming book, Luminosity of Love, uses the extraordinary love story of the great unconventional Serbian poet Laza Kostić and the vivacious aristocratic young woman, Lenka Dundjerski, as a starting point for a wide-ranging discussion of the nature of love, its importance in the Western philosophical tradition, and its relevance for living a meaningful life in (...) our high-tech materialistic world of the 21st century. By combining real love stories and philosophical reflections on them, the author focuses on the moments of betrayal that bring us to a crossroads at which point we may choose to retreat from loving, and instead satisfy ourselves with substitutes for love. Alternatively, we may realize that our fear and sense of betrayal need not get the last word when it comes to love, and that we can aspire to transform ourselves into more caring and radiating personalities. Our struggle to realize this aspiration is a love story--the ultimate love story that should concern us. This book is a superb philosophical essay about the transformative power of love. (shrink)

Williamson’s “anti-luminosity” argument aims to establish that there are no significant luminous conditions. “Far from forming a cognitive home”, luminous conditions are mere “curiosities”. Even supposing Williamson’s argument succeeds in showing that there are no significant luminous states his conclusion has not thereby been established. When it comes to determining what is luminous, mental events and processes are among the best candidates. It is events and processes, after all, which constitute the stream of consciousness. Judgment, for instance, is plausibly self-conscious. (...) If I am judging then plausibly I must know that I am. Similarly, deliberation is plausibly self-conscious. To be deliberating about some matter I plausibly must know that I am. That one is judging and that one is deliberating are thus plausibly luminous conditions. Furthermore, I argue, Williamson’s anti-luminosity argument fails to speak against this suggestion. This reveals that Williamson’s argument is more limited in scope than has been thought—something likely missed due to a misplaced focus on mental states in the luminosity debate as well as in epistemology and the philosophy of mind more generally. For all Williamson shows, there may be luminous events and processes of a sort apt to constitute a cognitive home. I conclude by considering how the anti-luminosity argument might be reinstated in the judgment case and argue that the natural way to do so fails. (shrink)

Suppose you’d like to believe that p, whether or not it’s true. What can you do to help? A natural initial thought is that you could engage in Intentionally Biased Inquiry : you could look into whether p, but do so in a way that you expect to predominantly yield evidence in favour of p. This paper hopes to do two things. The first is to argue that this initial thought is mistaken: intentionally biased inquiry is impossible. The second is (...) to show that reflections on intentionally biased inquiry strongly support a controversial ‘access’ principle which states that, for all p, if p is part of our evidence, then that p is part of our evidence is itself part of our evidence. (shrink)

In in this paper, I make use of an “doxastic planning model” of epistemic evaluation to argue for a form of epistemic internalism. In doing so, I begin by responding to a recent argument of Schoenfield’s against my previous attempt to develop such an argument. In doing so, I distinguish a variety of ways that argument might be understood, and discuss how both internalists and externalists might make use of the ideas within it. Then I argue that, despite these complexities, (...) the doxastic planning model continues to support a modest form of epistemic internalism. I conclude by showing that, far from conflicting with “anti-luminosity” arguments in epistemology, this form of internalism is best understood as a natural reaction to these arguments. (shrink)

This article aims to show that Williamson's anti-luminosity argument does not succeed if we presuppose a constitutive connection between the phenomenal and the doxastic. In contrast to other luminists, however, my strategy is not to critically focus on the refined safety condition in terms of degrees of confidence that anti-luminists typically use in this context. Instead, I will argue that, given a certain conception of what Chalmers calls ‘direct phenomenal concepts,’ luminosity is guaranteed even if the refined safety condition in (...) terms of degrees of confidence is taken for granted. (shrink)

Discusses the journey of Buddhist ideas on awareness and personhood from India to China. Encounters of Mind explores a crucial step in the philosophical journey of Buddhism from India to China, and what influence this step, once taken, had on Chinese thought in a broader scope. The relationship of concepts of mind, or awareness, to the constitution of personhood in Chinese traditions of reflection was to change profoundly after the Cognition School of Buddhism made its way to China during the (...) sixth century. India’s Buddhist philosophers had formulated the idea that, in order for human beings to achieve perfect enlightenment, they had to produce a state of awareness through practice that they described as “luminous.” However, once introduced to the Chinese tradition, the concept of the “luminous mind” was to become a condition already found within human nature for the possibility of achieving human ideals. This notion of the luminous mind was to have far-reaching significance both for Chinese Buddhism and for medieval Confucianism. Douglas L. Berger follows the transforming path of conceptions of the luminosity of consciousness and the perfectibility of personhood in order to bring into clearer relief the history of Indian and Chinese philosophical dialogue, as well as in the hope that such dialogue will be reignited. (shrink)

The Gettier Problem and Moore’s Paradox are related in a way that is unappreciated by philosophers. If one is in a Gettier situation, then one is also in a Moorean situation. The fact that S is in a Gettier situation (the fact that S is “Gettiered”), like the fact that S is in a Moorean situation (the fact that S is “Moored”), cannot (in the logical sense of “cannot”) be known by S while S is in that situation. The paper (...) starts the job of mapping what can be said about this feature of Gettier situations. The goal is to stimulate further exploration into this yet uncharted territory. (shrink)

In this paper I present a more refined analysis of the principles of deductive closure and positive introspection. This analysis uses the expressive resources of logics for different types of group knowledge, and discriminates between aspects of closure and computation that are often conflated. The resulting model also yields a more fine-grained distinction between implicit and explicit knowledge, and places Hintikka’s original argument for positive introspection in a new perspective.

Among the key factors that play a crucial role in the acquisition of knowledge, Buddhist philosophers list (i) the testimony of sense experience, (ii) introspective awareness (iii) inferences drawn from these directs modes of acquaintance, and (iv) some version of coherentism, so as guarantee that truth claims remains consistent across a diverse philosophical corpus. This paper argues that when Buddhists employ reason, they do so primarily in order to advance a range of empirical and introspective claims. As a result, reasoning, (...) in particular inductive reasoning on the testimony of perception, is based on a theory of causation. (shrink)

A joint modelling of objective worlds and subjective perceptions within two-dimensional semantics eliminates the margin for error principle and solves the epistemic sorites paradox. Two objective knowledge modalities can be defined in two-dimensional frames accounting for subjective perceptions: “necessary knowledge” (NK) and “possible knowledge” (PK), the latter being better suited to the interpretation of knowledge utterances. Two-dimensional semantics can in some cases be reduced to one-dimensional ones, by defining accessibility relations between objective worlds that reflect subjective perceptions: NK and PK (...) are respectively equivalent to ${\square \square }$ and ${\lozenge \square }$ in some one-dimensional frame, and to ${\square }$ and another modality in some other. (shrink)

Since its appearance over a decade ago, Timothy Williamson's anti-luminosity argument has come under sustained attack. Defenders of the luminous overwhelmingly object to the argument's use of a certain margin-for-error premise. Williamson himself claims that the premise follows easily from a safety condition on knowledge together with his description of the thought experiment. But luminists argue that this is not so: the margin-for-error premise either requires an implausible interpretation of the safety requirement on knowledge, or it requires other equally implausible (...) assumptions. In this paper I bolster the margin-for-error premise against these attacks by recasting Williamson's own two-part defence, the first part intended to work on the assumption that there is no constitutive connection between the phenomenal and the doxastic, and the second intended to work without this assumption. Pace various luminists, I argue that the appeals to safety needed for Williamson's two-part defence are plausible. I also argue that all that is needed to generate the margin-for-error premise from these safety conditions is an empirical assumption about the kinds of creatures we are: that is, creatures whose beliefs are structured by certain dispositions. By recasting the anti-luminosity argument in this way, we can understand what is really at stake in the debate about luminosity: that is, whether we are luminous. (shrink)

Recently, Timothy Williamson has argued that considerations about margins of errors can generate a new class of cases where agents have justified true beliefs without knowledge. I think this is a great argument, and it has a number of interesting philosophical conclusions. In this note I’m going to go over the assumptions of Williamson’s argument. I’m going to argue that the assumptions which generate the justification without knowledge are true. I’m then going to go over some of the recent arguments (...) in epistemology that are refuted by Williamson’s work. And I’m going to end with an admittedly inconclusive discussion of what we can know when using an imperfect measuring device. (shrink)

The paper discusses some ways in which the phenomenon of borderline cases may be thought to bear on the traditional philosophical idea that certain domains of facts are fully open to our view. The discussion focusses on a very influential argument (due to Tim Williamson) to the effect that, roughly, no such domains of luminous facts exist. Many commentators have felt that the vagueness unavoidably inherent in the description of the facts that are best candidates for being luminous plays an (...) illicit role in the argument. The paper investigates this issue by centring around the idea that vagueness brings with itself borderline cases, and that these in turn generate absence of a fact of the matter and hence epistemically benign lack of knowledge. It is argued that, given the possibility of absence of a fact of the matter, the idea of luminosity should be reformulated using the notion of determinacy, and that the resulting reformulation is not immediately subject to the original anti-luminosity argument. However, it is shown that the specific understanding of determinacy required by this strategy validates a new argument against the reformulated version of luminosity. Moreover, reflection on the connection between mistake and absence of a fact of the matter offers another argument against such version, with the surprising upshot that, granting the soundness of the original anti-luminosity argument, not even the determinacy of a certain fact would guarantee its knowability. (shrink)

In this paper I show that a variety of Cartesian Conceptions of the mental are unworkable. In particular, I offer a much weaker conception of limited discrimination than the one advanced by Williamson (2000) and show that this weaker conception, together with some plausible background assumptions, is not only able to undermine the claim that our core mental states are luminous (roughly: if one is in such a state then one is in a position to know that one is) but (...) also the claim that introspection is infallible with respect to our core mental states (where a belief that C obtains is infallible just in case if one believes that C obtains then C obtains). The upshot is a broader and much more powerful case against the Cartesian conception of the mental than has been advanced hitherto. (shrink)

Questions about the transparency of evidence are central to debates between factive and non-factive versions of mentalism about evidence. If all evidence is transparent, then factive mentalism is false, since no factive mental states are transparent. However, Timothy Williamson has argued that transparency is a myth and that no conditions are transparent except trivial ones. This paper responds by drawing a distinction between doxastic and epistemic notions of transparency. Williamson's argument may show that no conditions are doxastically transparent, but it (...) fails to show that no conditions are epistemically transparent. Moreover, this reinstates the argument from the transparency of evidence against factive mentalism. (shrink)

The paper discusses some ways in which vagueness and its phenomena may be thought to impose certain limits on our knowledge and, more specifically, may be thought to bear on the traditional philosophical idea that certain domains of facts are luminous, i.e., roughly, fully open to our view. The discussion focuses on a very influential argument to the effect that almost no such interesting domains exist. Many commentators have felt that the vagueness unavoidably inherent in the description of the facts (...) that are best candidates for being luminous plays an illicit role in such argument. The paper centres around the idea that vagueness brings with itself the prima facie plausibility of soritical principles. Using the diagnostics of sharpenings, it is first pointed out that, despite certain considerations to the contrary, the margin‐for‐error principle required by the anti‐luminosity argument may well derive all of its plausibility from an underlying soritical principle. The notion of confidence that is relevant to the argument is then isolated and sharply distinguished from the notion of subjective probability. Against this background, it is argued that the reasoning about confidence involved in the argument in favour of the problematic margin‐for‐error principle is fallacious in the same way in which sorites reasoning is. This reveals the possibility of having reliable knowledge even at the penumbral limit with falsity, a possibility for which a concrete formal model is constructed. The model in turn permits a deeper appreciation of the role played in the dialectic by the distinction between confidence and subjective probability as well as by confidence requirements on knowledge. It is concluded that careful heeding of vagueness and its phenomena, far from forcing new and surprising limits on our knowledge, actually removes one of the main barriers – unreliability – often thought to stand in its way. (shrink)

Timothy Williamson’s anti luminosity argument has received considerable attention. Escaping unnoticed, though, is a strikingly similar argument from David Hume. This paper highlights some of the arresting parallels between Williamson’s reasoning and Hume’s that will allow us to appreciate more deeply the plausibility of Williamson’s reasoning and to understand how, following Hume, we can extend this reasoning to undermine the “luminosity” of simple necessary truths. More broadly the parallels help us to identify a common skeptical predicament underlying both arguments, which (...) we shall call “the quarantine problem”. The quarantine problem expresses a deep skepticism about achieving any exalted epistemic state. Further, the perspective gained by the quarantine problem allows us to easily categorize existing responses to Williamson’s anti luminosity argument and to observe the deficiencies of those responses. In sum, the quarantine problem reveals the deeply fallibilistic nature of whatever knowledge we may possess. (shrink)

This paper supersedes an ealier version, entitled "A Non-Standard Semantics for Inexact Knowledge with Introspection", which appeared in the Proceedings of "Rationality and Knowledge". The definition of token semantics, in particular, has been modified, both for the single- and the multi-agent case.