Epistemic Closure Principle

Most philosophers believe that a necessary and sufficient conditions analysis of knowledge cannot be fruitful. Against this worldview, I propose a four-condition predominately externalist (PE) definition of knowledge. In addition to the traditional 'justified true belief' conditions, a 'relevancy condition' and a 'no-defeaters condition' are added. We will examine eight case studies and explain why S knows or doesn't know in various situations, including the parked car case, barn façade case, and two lottery cases. We'll respond to the skeptical argument and the 'safety' condition. A key feature of the PE theory is that it doesn't guarantee that knowledge exists. The skeptical hypothesis is accepted, and epistemic closure is rejected, so that the PE definition doesn't assure that S knows any p. The definition just states the necessary and sufficient conditions for the possibility of knowledge. Against the skeptic's impossibility conclusion, with the satisfaction of the PE conditions, knowledge is clearly possible and obtainable.

En el año 1987 se publicó una demostración de la existencia de Dios extraída de los papeles del matemático y lógico austríaco Kurt Gödel. Este argumento prosigue la línea de pensamiento de los argumentos ontológicos de San Anselmo y Gottfried Leibniz, pero utilizando lógica modal de orden superior. No obstante, dicha demostración no está exenta de problemas y explicaremos cómo, en 2014, Christopher Benzmüller y Bruno Woltzenlogel arguyeron que los axiomas y definiciones del argumento de Gödel son inconsistentes.

According to the innovative account of the structure of rational evaluation offered by Wittgenstein in his final notebooks, published as On Certainty, our rational practices necessarily presuppose arational hinge commitments. These are everyday, apparently mundane, commitments that we are optimally certain of, but which in virtue of the 'hinge' role that they play in our rational practices cannot themselves enjoy rational support. Granted that there are such hinge commitments, what is the nature of the propositional attitude in play? Many commentators have described this propositional attitude as a kind of trusting, on account of how our hinge commitments are effectively a groundless kind of presupposition. In contrast, I want to push back against this way of thinking about hinge commitments and argue instead that it is crucial to our understanding of Wittgenstein's proposal especially in terms of its implications for radical scepticism to realize that hinge commitments are not presuppositions and that the hinge propositional attitude is not one of trusting.

Zeno's arrow does not move "in the now" (Phys. 8, 239b2) or, equivalently, "in the place it is" (29 B 4). Zeno concludes from this that the arrow does not move at all. In Aristotle (ibid. 9, 239b 3 , Zeno's argument takes the form of an invalid inference from instants to periods of time. Insofar as it fails to bring out an inconsistency in Aristotle's account of motion, the paradox is thus eliminated. That instantaneous motion is a contradiction in terms belongs to the common ground Aristotle shares with Zeno. That's why information concerning Zeno's relevant argument must be sought elsewhere (see section 3). Aristotle's discussion of the Arrow pertains to the conclusions drawn from the denial of instantaneous motion. But the argument he refutes is of his own making, or so I will argue (section 2). In particular, Aristotle fails to address the presentist commitment adumbrated in his account, which would leave nothing beyond the denial of instantaneous motion for Zeno to prove. Presentism is no option in Phys. d. I will argue that Aristotle's account of the tenses in De interpretatione is prone to Zeno's argument if the (section 4).

In response to the claim that certain epistemically defective inferences such as Moore’s argument lead us to the conclusion that we ought to abandon closure, Crispin Wright suggests that we can avoid doing so by distinguishing it from a stronger principle, namely transmission. Where closure says that knowledge of a proposition is a necessary condition on knowledge of anything one knows to entail it, transmission makes a stronger claim, saying that by reasoning deductively from known premises one can thereby acquire knowledge of or justification for the conclusion. Wright’s thought is that in cases such as Moore what is really going on is a failure of transmission, not a failure of closure. The problem with this claim is that it relies on an outdated formulation of closure which few nowadays would find plausible. Once we stipulate that it is the intuitive closure principle that deserves our attention, it becomes far less obvious that the project of diagnosing what is wrong with arguments such as Moore in terms of transmission failure but not closure failure can be vindicated. In order to demonstrate this claim, I consider intuitive closure of propositional justification vs. transmission of propositional justification and concede that perhaps these can come apart in the way that Wright suggests. I then argue that despite this concession, we also need an answer to the question of whether intuitive closure for doxastic justification and transmission for doxastic justification can come apart. We need an answer to this question because our ultimate interest in these issues stems from our interest in whether knowledge obeys closure, not merely whether propositional justification does. I argue that, even on the assumption that there is transmission failure of propositional justification, there is no transmission failure of doxastic justification. And if this is true, then there is no transmission failure of knowledge either. The transmission failure diagnosis of Moore’s argument and its ilk is thus in trouble.

Duncan Pritchard argues that there are two malign varieties of epistemic luck, veritic epistemic luck and reflective epistemic luck. He argues that eliminating veritic luck and meeting sceptical arguments requires an externalist, safety-based theory of knowledge, but that reflective luck is ineliminable. He raises an important challenge for internalists and externalists about knowledge alike, which is to explain how it is that ordinary beliefs can be internalistically justified. I discuss limitations that safety-based accounts have in dealing with various puzzles, and raise a worry about whether Pritchard succeeds in drawing a neat distinction between benign and malign varieties of epistemic luck. I also question Pritchard’s sceptical conclusion concerning internalist justification.

The paper is concerned with the Aristotle's solution to the three most famous Zeno's paradoxes-the Dichotomy, Achilles and the tortoise and the Arrow. His solution is compared with the contemporary, so called standard solution, which is widely accepted not only because of the way it resolves the paradoxes by itself but also because it agrees with the contemporary state of mathematics and physics. This connection with theories and ideas that were developed much later than Aristotle and now are widely accepted is an important part of the reason why the standard solution is regarded as a better solution nowadays. The aim of the paper is to show that also if we put aside these external considerations and try to look at Aristotle's solution on its own, we will see that it has counterintuitive consequences that make it unsatisfactory. With respect to Dichotomy and the Achilles and the tortoise paradoxes this counterintuitive consequence is the principle that the whole can exist independently of its parts. With respect to the Arrow paradox this counterintuitive consequence is that a physical object that is moving always occupies a portion of space larger than its size.

Wittgenstein apparently regarded G. E. Moore’s “Proof of an External World” as one of his finest pieces of philosophical work. ’ That is an important clue for anyone who wants to understand what Wittgenstein thought a satisfactory treatment of knowledge-scepticism should accomplish? I do not believe, though, that many of Moore’s modern readers would share Wittgenstein’s high regard. The greater part of the essay is devoted to exasperatingly slow ruminations on what it means to describe objects as “external”, or “outside our minds ” or “presented in space ” or “to be met with in space”. Nothing particularly consequential emerges. And the actual ‘Proof-which everyone on first reading feels blatantly begs the question-is confined to the last few pages. Here is the essence of it: Moore II Here is a hand III There is a material world (since any hand is a material object existing in space) This essay, though self-contained, returns to some of the themes in my (1985). Prior to its presenta...

I examine the nature and the structure of basic logico-mathematical knowledge. What justifies the truth of the Dedekind-Peano axioms and the validity of Modus Ponens? And is the justification we possess reflectively available? To make progress with these questions, I ultimately embed Hale's and Wright's neo-Fregeanism in a general internalistic epistemological framework. In Part I, I provide an introduction to the problems in the philosophy of mathematics to motivate the investigations to follow. I present desiderata for a fully satisfactory epistemology of mathematics and discuss relevant positions. All these positions turn out to be unsatisfactory, which motivates the abstractionist approach. I argue that abstractionism is in need of further explication when it comes to its central epistemological workings. I fill this gap by embedding neo-Fregeanism in an internalistic epistemological framework. In Part 11, I motivate, outline, and discuss the consequences of the frame- w...

Fred Dretske notoriously claimed that knowledge closure sometimes fails. Crispin Wright agrees that warrant does not transmit in the relevant cases, but only because the agent must already be warranted in believing the conclusion in order to acquire her warrant for the premise. So the agent ends up being warranted in believing, and so knowing, the conclusion in those cases too: closure is preserved. Wright’s argument requires that the conclusion’s having to be warranted beforehand explains transmission failure. I argue that it doesn’t, and that the correct explanation does not imply that the agent will end up warranted in believing the conclusion when transmission fails. Those who agree that transmission does fail in those cases, therefore, might as well follow Dretske in denying knowledge closure too. 3 Wright Back to Dretske, or

Let Entitlement Epistemology be the theory of knowledge which says that entitlement—a special kind of unearned warrant to accept or believe—can help us successfully address a range of sceptical arguments. Prominent versions of this theory urge that epistemology should not be concerned with knowledge (and similar externalist states) but rather with justification, warrant, and entitlement (at least insofar as these are conceived of as internalist states). Knowledge does not come first, half-way, or even last in epistemological theorizing—rather, it ought to come nowhere. In this chapter Wright-style entitlement epistemology is explored in depth. Four types of Wright-style entitlement epistemology are formulated. Three types are overly concessive to scepticism, undermining the goal of entitlement epistemology. Type II avoids these concessions, seeing knowledge as minimal, and places knowledge in a weakly internalist framework.

Since the invention of possible world semantics, modal logic applications have increased by developing logics alethic, tense, epistemic, doxastic, and so on. However, many logicians also recognize that a modal logic that only considers one kind of modality is quite restricted. Multi-modal logics raise intending to consider the most ambits involved in the validity of inferences, such as time, place, knowledge, belief, obligations, and so on. In this master thesis, I develop multi-modal logics utilizing alethic, epistemic, and doxastic logics using tableaux systems. In chapter 1, I review alethic, epistemic, and doxastic logic, both semantical and axiomatically. In chapter 2, I present the axiomatic system of the multi-modal logic based on alethic T, epistemic T, and doxastic D, along with the axiom that knowledge entails believe and give to it fusion semantics. In chapter 3, I develop the tableaux for the system in chapter 2 and give two examples of their application. In chapter 4, I use the machinery to evaluate Spinoza’s statements on modality, for he believed this is merely an error of our cognition. In chapter 5, I give a temporalization of the basic multi-modal system and expose how this came as a modification of an alethic-temporal logic. In chapter 6, I develop systems based on S5 and utilize them to discuss the invalidity of a version of the closure for knowledge and belief through the distinction between absolute and relative knowledge. In chapter 7, I develop conditional epistemic-doxastic logics and utilize them to evaluate some skeptic issues. In chapter 8, I develop the non-normal version of the basic multi-modal logic, discuss the omniscience problem –both material and strict– and give two proposals of solutions. In chapter 9, I develop epistemic-doxastic logics based on intuitionistic logic and utilize them to criticize some statements relative to negation; properly, I review the failure of inferring epistemic possibilities due to ignorance. In chapter 10, I develop the first-order version of the basic multi-modal logic, and I develop its relation to de re and de dicto modality. In chapter 11, I develop the meta-theorems of the tableaux systems shown in the thesis: the soundness and completeness proofs.

Introduction - John Greco Part One. Varieties of Skepticism and Skeptical Arguments 1. The Pyrrhonian Problematic- Markus Lammenranta 2. The Problem of the Criterion- Richard Fumerton 3. Cartesian Skepticism: Arguments and Antecedents- Jose Luis Bermudez 4. Hume's Skepticism- Michael Williams 5. Skepticism about the External World- John Greco 6. Skepticism about Induction- Weintraub 7. Skepticism about A Priori Justification: Self-evidence, Defeasibility, and Cogito Propositions- Robert Audi 8. Moral Realism, Quasi-Realism and Skepticism- Terence Cuneo 9. Religious Skepticism - Paul K. Moser 10. Live Skeptical Hypotheses - Bryan Frances Part Two. Responses to Skepticism 11. Berkeley's Treatment of Skepticism - George Pappas 12. Kant's Response to Skepticism- Robert Stern 13. Reid's Response to Skepticism- James Van Cleve 14. Peirce and Skepticism - Christopher Hookway 15. Moore's Common Sense Response- Noah Lemos 16. Austin's Way with Skepticism - Mark Kaplan...

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.

According to a standard view, paradoxes are arguments with plausible premises that entail an implausible conclusion. This is false. In many paradoxes the premises are not plausible precisely because they entail an implausible conclusion. Obvious responses to this problem—including that the premises are individually plausible and that they are plausible setting aside the fact that they entail an implausible conclusion—are shown to be inadequate. A very different view of paradox is then introduced. This is a functionalist view according to which paradoxes are the kinds of things that puzzle people in characteristic ways. It is claimed that this view, too, fails and for the very same reason. The result is a new puzzle about the nature of paradoxes.

This paper identifies two distinct dimensions of what might be called testimonial strength: first, in the case of testimony from more than one speaker, testimony can be said to be stronger to the extent that a greater proportion of the speakers give identical testimony; second, in both single-speaker and multi-speaker testimony, testimony can be said to the stronger to the extent that each speaker expresses greater conviction in the relevant proposition. These two notions of testimonial strength have received scant attention in the philosophical literature so far, presumably because it has been thought that whatever lessons we learn from thinking about testimony as a binary phenomenon will apply mutatis mutandis to varying strengths of testimony. This paper shows that this will not work for either of the two aforementioned dimensions of testimonial strength, roughly because less testimony can provide more justification in a way that can only be explained by appealing to the (non-binary) strength of the testimony itself. The paper also argues that this result undermines some influential versions of non-reductionism about testimonial justification.

The aim of this paper is to evaluate a family of responses to Cartesian scepticism whose common point is to rely on the non-contextualist restriction of one or more epistemic principles; more precisely, principles asserting the closure of knowledge under various logical operations. I will attempt to show that one cannot respond to closure-based scepticism without considering other applications of closure principles than that which is usually the exclusive subject of discussion in the contemporary literature. Those other applications of closure principles give rise to different sceptical arguments, and I will argue that if one takes those other closure-based arguments into account (and understands the challenge raised by the sceptic in a minimally internalist and rational sense) then one is faced with serious difficulties, for it seems that no theoretical solution can be found unless one settles for some questionable dialectical misbehaviour, such as begging the question against the sceptic, most notably. In particular, I will defend the view that any solution relying on the Wittgensteinian idea of ‘hinge’ falls prey to those problems, if it is interpreted in such a way that it lends to a special kind of propositional attitude, distinct from ordinary belief.

De acordo com Jennifer Lackey (2007), deve-se asserir que p somente se (i) é razoável acreditar que p e (ii) se alguém asseriu que p, afirmaria que p pelo menos em parte porque é razoável acreditar que p. Como dados para essa norma de asserção, Lackey apela à intuição de que, nos casos de afirmação altruísta, os agentes afirmam com propriedade epistêmica algo que não acreditam. Se essa norma de afirmação fosse verdadeira, então ela explicaria por que as afirmações altruístas são epistemicamente apropriadas. Neste trabalho, oferecemos uma reductio ad absurdum desse ponto de vista. O resultado é que os asserções altruístas não são epistemicamente apropriados.

In this paper, I defend an epistemic requirement on fitting hopes and worries: it is fitting to hope or to worry that p only if one’s epistemic position makes it rational to suspend judgment as to whether p. This view, unlike prominent alternatives, is ecumenical; it retains its plausibility against a variety of different background views of epistemology. It also has other important theoretical virtues: it is illuminating, elegant, and extensionally adequate. Fallibilists about knowledge have special reason to be friendly to my view; it can help them explain why it can be unfitting to hold on to hope and worry in the face of overwhelming evidence, and it can also help them explain the sense in which knowledge that p and hope that –p are in tension with one another.