Modal Epistemology

It has been argued that an advantage of the safety account over the sensitivity account is that the safety account preserves epistemic closure; while the sensitivity account implies epistemic closure failure. However, the argument fails to take the method-relativity of the modal conditions on knowledge, viz, sensitivity and safety, into account. In this paper, I argue that the sensitivity account and the safety account are on a par with respect to epistemic closure once the method-relativity of the modal conditions is taken into account. Therefore, epistemic closure is no longer an arbiter in the debate.

Sensitivity is a modal epistemic principle. Modal knowledge accounts are externalist in nature and claim that the knowledge yielding connection between a true belief and the truthmaker must be spelled out in modal terms. The sensitivity condition was introduced by Robert Nozick. He suggests that if S knows that p, then S’s belief that p tracks truth. Nozick argues that this truth-tracking relation can be captured by subjunctive conditionals. As a first approximation, he provides the following modal analysis of knowledge: S knows that p iff (1) p is true; (2) S believes that p; (3) if p were false, S wouldn’t believe that p and (4) if p were true, S would believe that p. The dominant terminology in the literature, also adopted here, is to call condition (3) the sensitivity condition and condition (4) the adherence condition. The sensitivity condition is intuitively appealing since it states that a subject does not know that p if she would believe that p even if p were false. Nozick used the sensitivity condition to accomplish two major tasks. First, he provided a solution to the Gettier problem by arguing that in Gettier cases subjects do not know since the sensitivity condition is violated. Second, he presented a controversial solution to the skeptical problem according to which we have external world knowledge but do not know that the skeptical hypothesis is false. This solution is available because sensitivity is not closed under known entailment. Quickly, criticism of the sensitivity condition emerged. First, most epistemologists regarded the price of abandoning knowledge closure as a price too high to pay. Second, it was noted that sensitivity leads to the counterintuitive consequence of precluding us from inductive knowledge since induction typically yields insensitive beliefs. The most dominant reaction to these problems was to replace sensitivity by the modal principle of safety, nowadays the most popular modal principle. However, sensitivity is not only important as a starting point of modal epistemology. Because of its intuitive attractiveness, many authors aimed at refining the original sensitivity account in order to avoid well-known problems. This has led to a second wave of sensitivity accounts. As of today, various sensitivity-based theories are on the market, including accounts that avoid closure failure, probabilistic interpretations of sensitivity and adherence, and contextualist approaches. There is thus a vivid and ongoing debate about the sensitivity principle in epistemology.

How do we come to know metaphysical truths? How does metaphysical inquiry work? Are metaphysical debates substantial? These are the questions which characterize metametaphysics. This book, the first systematic student introduction dedicated to metametaphysics, discusses the nature of metaphysics - its methodology, epistemology, ontology and our access to metaphysical knowledge. It provides students with a firm grounding in the basics of metametaphysics, covering a broad range of topics in metaontology such as existence, quantification, ontological commitment and ontological realism. Contemporary views are discussed along with those of Quine, Carnap and Meinong. Going beyond the metaontological debate, thorough treatment is given to novel topics in metametaphysics, including grounding, ontological dependence, fundamentality, modal epistemology, intuitions, thought experiments and the relationship between metaphysics and science. The book will be an essential resource for those studying advanced metaphysics, philosophical methodology, metametaphysics, epistemology and the philosophy of science.

These are the slides for an introductory talk about modal epistemology that I was invited to give in the context of the "What's up with …?" series at our department in Graz.
For more on this series of talks see:
http://philosophie-gewi.uni-graz.at/de/veranstaltungen/detail/cal/event/tx_cal_phpicalendar/2014/11/24/whats_up_with_modal_epistemology/

Les arguments de concevabilité sont des arguments philosophiques reposant sur le principe selon lequel tout ce qui est concevable est possible. Cette thèse se propose d’examiner et d’évaluer à un niveau général cette forme d’argumentation en s’appuyant sur des exemples historiques et contemporains. Nous examinons en particulier plusieurs candidats possibles pour préciser la notion de concevabilité et montrons que le passage de la concevabilité à la possibilité ne parvient pas à remplir tous les objectifs philosophiques que se fixe cette forme d'argumentation, en particulier lorsqu'elle vise à établir des thèses métaphysiques substantielles.

Timothy Williamson has recently proposed to undermine modal skepticism by appealing to the reducibility of modal to counterfactual logic (Reducibility). Central to Williamson’s strategy is the claim that use of the same non-deductive mode of inference (counterfactual development, or CD) whereby we typically arrive at knowledge of counterfactuals suffices for arriving at knowledge of metaphysical necessity via Reducibility. Granting Reducibility, I ask whether the use of CD plays any essential role in a Reducibility-based reply to two kinds of modal skepticism. I argue that its use is entirely dispensable, and that Reducibility makes available replies to modal skeptics which show certain propositions to be metaphysically necessary by deductive arguments from premises the modal skeptic accepts can be known.

I argue that beliefs about what appears possible are justified in much the same way as beliefs about what appears actual. I do so by chisholming, and then modalizing, the epistemic principle associated with phenomenal conservatism. The principle is tested against a number of examples, and it gives the intuitively correct results. I conclude by considering how it can be used to defend two controversial modal arguments, a Cartesian argument for dualism and an ontological argument for the existence of God.

In various arguments, Descartes relies on the principles that conceivability implies possibility and that inconceivability implies impossibility. Those principles are in tension with another Cartesian view about the source of modality, i.e. the doctrine of the free creation of eternal truths. In this paper, I develop a ‘two-modality’ interpretation of the doctrine of eternal truths which resolves the tension and I discuss how the resulting modal epistemology can still be relevant for the contemporary
discussion.

How do we know what is or is not possible? Traditionally, the answer was that whatever is conceivable is possible. However, since Saul Kripke's Naming and Necessity and Identity and Necessity, this line of thought has fallen on hard times. Modal Skepticism replaced modal rationalism. This paper explores the issue of modal epistemology, arguing that through conceiving properly, we can have some reliable modal knowledge despite incidents of modal error.

I discuss Josef Seifert, a realist phenomenologist, and David Oderberg, an Aristotelian. Both endorse essences, understood as objective quiddities. Both argue that no (a posteriori) law of nature is strongly (metaphysically) necessary: i.e. true in every possible world. But they disagree about weak necessity of laws: Seifert argues that no law is true in every possible world in which its referring expressions are non-empty, while Oderberg argues that some (indeed, any) is. I restate, relate, and review reasons of both authors for each of those theses. Seifert’s reasons include God’s ability to do miracles, conceivability of counterinstances to laws, and many others. Oderberg’s reasons include dependence of laws on particulars, depiction of laws as truths about properties necessarily connected with essences, and explanation of persistent regularities by means of that necessary connection. I argue that no reason of either Seifert or Oderberg is convincing, as its stands. But I also argue that given God and his ability to do miracles, the idea of “meaningful” but non-necessary connection between essences — an idea endorsed but insuffi ciently utilized by Seifert — is a better essentialist explanation of persistent regularities. This explanation implies that no law is necessary, be it weakly or strongly.

This is the original, longer draft for my entry on 'Hume' in the 'The Routledge Handbook of Philosophy of Imagination' (Amy Kind (ed.), London: Routledge, 2016). — Please always cite the Routledge version, unless there are passages concerned that did not make it into the Handbook for reasons of length. — This chapter overviews Hume’s thoughts on the nature and the role of imagining, with an almost exclusive focus on the first book of his Treatise of Human Nature. Over the course of this text, Hume draws and discusses three important distinctions among our conscious mental episodes (or what he calls ‘perceptions’): (i) between impressions (including perceptual experiences) and ideas (including recollections, imaginings and occurrent beliefs); (ii) between ideas of the memory and ideas of the imagination; and (iii), among the ideas of the imagination, between ideas of the judgement (i.e. occurrent beliefs) and ideas of the fancy (i.e. imaginings). I discuss each distinction in turn, also in connection to contemporary views on imagining. In addition, I briefly consider Hume’s views on the imagination as a faculty aimed at the production of ideas, as well as on the role that imagining plays in the wider context of our mental lives, notably in the acquisition of modal knowledge and in the comprehension of, and resistance to, stories and opinions that we take to be false or fictional.

This is a critical notice of Timothy Williamson's, The Philosophy of Philosophy (Blackwell, 2007).  It focuses on criticizing the book's two main positive proposals: that we should “replace true belief by knowledge in a principle of charity constitutive of content”, and that “the epistemology of metaphysically modal thinking is tantamount to a special case of the epistemology of counterfactual thinking”.

During the last quarter of a century, a number of philosophers have become attracted to the idea that necessity can be analyzed in terms of a hyperintensional notion of essence. One challenge for proponents of this view is to give a plausible explanation of our modal knowledge. The goal of this paper is to develop a strategy for meeting this challenge. My approach rests on an account of modality that I developed in previous work, and which analyzes modal properties in terms of the notion of a metaphysical law (which is a generalization of the concept of an essential truth). I discuss what information about the metaphysical laws (including essential truths) is required for modal knowledge. Moreover, I describe two ways in which we might be able to acquire this information. The first way employs inference to the best explanation. The metaphysical laws, including the essential truths, play a crucial role in causal and grounding explanations and we can gain knowledge of these laws by abductive inferences from facts of which we have perceptual or a priori knowledge. The second way of gaining information about the metaphysical laws rests on knowledge that is partly constitutive of competence with the concepts that are needed to express the relevant information. Finally, I consider how knowledge of the metaphysical laws can be used to establish modal claims, paying special attention to the much-discussed connection between conceiving and possibility.

Corroborative evidence may be understood as having two epistemic effects: a primary effect by which it offers direct evidence for some claim, and a secondary effect by which it bolsters the appraised probative, or evidential, value of some other piece of evidence for that claim. This paper argues that the bolstering effect of corroborative evidence is epistemically legitimate because corroboration provides a reason to count the belief based on the initial evidence as sensitive to, and safe from, defeat in a way that it was not previously recognized to be. Discovering that our initial evidence tracks the truth in a way we previously didn't recognize provides a reason to positively reappraise the probative value of that evidence. The final section of the paper relates the proposed sensitivity-and safety-based account of corroboration to an explanation-based account.

In this chapter, it is suggested that our epistemic access to metaphysical modality generally involves rationalist, a priori elements. However, these a priori elements are much more subtle than ‘traditional’ modal rationalism assumes. In fact, some might even question the ‘apriority’ of these elements, but I should stress that I consider a priori and a posteriori elements especially in our modal inquiry to be so deeply intertwined that it is not easy to tell them apart. Supposed metaphysically necessary identity statements involving natural kind terms are a good example: the fact that empirical input is crucial in establishing their necessity has clouded the role and content of the a priori input, as I have previously argued (Tahko forthcoming). For instance, the supposed metaphysically necessary identity statement involving water and its microstructure can only be established with the help of a controversial a priori principle concerning the determination of chemical properties by microstructure. The Kripke-Putnam framework of modal epistemology fails precisely because it is unclear whether the required a priori element is present. My positive proposal builds on E. J. Lowe’s work. Lowe holds that our knowledge of metaphysical modality is based on our knowledge of essence. Lowe’s account strives to offer a uniform picture of modal epistemology: essence is the basis of all our modal knowledge. This is the basis of Lowe’s modal rationalism. I believe that Lowe’s proposal is on the right lines in the case of abstract objects, but I doubt that it can be successfully applied to the case of natural kinds. Accordingly, the case of natural kinds will be my main focus and I will suggest that modal rationalism, at least as it is traditionally understood, falls short of explaining modal knowledge concerning natural kinds. Yet, I think that Lowe has identified something of crucial importance for modal epistemology, namely the essentialist, a priori elements present in our modal inquiry. The upshot is that rather than moving all the way from modal rationalism to modal empiricism, a type of hybrid approach, ‘empirically-informed modal rationalism’, can be developed.

What sorts of things are the intuitions generated via thought experiment? Timothy Williamson has responded to naturalistic skeptics by arguing that thought-experiment intuitions are judgments of ordinary counterfactuals. On this view, the intuition  is naturalistically innocuous, but it has a contingent content and  could be known at best a posteriori. We suggest an alternative to Williamson’s account, according to which we apprehend  thought-experiment intuitions through our grasp on truth in fiction. On our view, intuitions like the Gettier intuition are necessarily true and knowable a priori. Our view, like Williamson’s, avoids naturalistic skepticism.

There is a long tradition of philosophical arguments seeking to prove substantial metaphysical theses starting from epistemic premises. In particular, in order to prove that something is possible, in an interesting metaphysical sense, some philosophers start from what is conceivable (in some sense to be determined). The aim of this paper is to distinguish and evaluate the differents ways one can reject the metaphysical conclusion of a conceivability argument while accepting its epistemic premise. To do so, I will focus on a particular conceivability argument, namely the zombie argument attributed to David Chalmers (1996). However, the conclusions are intended to be generalizable to any conceivability argument.
Suppose that A submits a zombie argument to B. Suppose that B accept the premise that zombies are concevable. Our question is : how can B consistently accept that and the conclusion that zombies are possible?
The paper presents three arguments designed to show that three different options are available to B. If we generalize of other kinds of conceivability arguments, there are at least three ways to refuse the possibility-conclusion while accepting the conceivability-premise of a conceivability argument.

How do we know what’s (metaphysically) possible and impossible? Arguments from Kripke and Putnam suggest that possibility is not merely a matter of (coherent) conceivability/imaginability. For example, we can coherently imagine that Hesperus and Phosphorus are distinct objects even though they are not possibly distinct. Despite this apparent problem, we suggest, nevertheless, that imagination plays an important role in an adequate modal epistemology. When we discover what is possible or what is impossible, we generally exploit important connections between what is possible and what we can coherently imagine. We can often come to knowledge of metaphysical modality a priori.

Much mainstream analytic epistemology is built around a sceptical treatment of modality which descends from Hume. The roots of this scepticism are argued to lie in Hume’s (nominalist) theory of perception, which is excavated, studied and compared with the very different (realist) theory of perception developed by Peirce. It is argued that Peirce’s theory not only enables a considerably more nuanced and effective epistemology, it also (unlike Hume’s theory) does justice to what happens when we appreciate a proof in mathematics.

These are some rough ideas about a phenomenological account of possibility and necessity, which I was asked to present at the University of Vienna in January 2013. The following remarks on these issues are work in progress. So, any comments are very welcome.
[email protected]

The negative zombie argument concludes that physicalism is false from the premises that p ∧¬q is ideally negatively conceivable and that what is ideally negatively conceivable is possible, where p is the conjunction of the fundamental physical truths and laws and q is a phenomenal truth (Chalmers 2002; 2010). A sentence φ is ideally negatively conceivable iff φ is not ruled out a priori on ideal rational reflection. In this paper, I argue that the negative zombie argument is neither a priori nor conclusive. First, I argue that the premises of the argument are true only if there exists an adequate finite ideal reasoner that believes ◊(p ∧ ¬q) on the basis of not believing p → q on a priori basis. Roughly, a finite reasoner is a reasoner with cognitive limitations (e.g. finite memory). I argue that is finite only if reasons nonmonotonically and only approach ideal reflection at the limit of a reasoning sequence. This would render the argument nonconclusive. Finally, I argue that, for some q, does not believe ◊(p ∧ ¬q) on the basis of not believing p → q on a priori basis (e.g. for q ='something is conscious'). This would render the choice of an adequate q dependent on empirical information (and the argument a posteriori). I conclude that the negative zombie argument (and, maybe, all zombie arguments) is neither a priori nor conclusive.

In his " Access Denied to Zombies " , Gualtiero Piccinini argues that the possibility of zombies does not entail the falsity of physicalism, since the accessibility relation can be understood so that even in S5 system for modal logic worlds inaccessible from our world are allowed (in the case in which the accessibility relation is understood as an equivalence rather than as universal accessibility). According to Piccinini, whether the zombie world is accessible from our world depends on whether physicalism is true in our world, which is something that cannot be answered in a non-question-begging way. In order to show this, he recalls a well known strategy of making a parody of the zombie argument. After pointing out that Piccinini's strategy of parodying the zombie argument renders his former strategy, based on the distinguishing between the two notions of accessibility , redundant, I recall the two ways of handling parodies of the zombie argument. In addition, I argue that persisting on the distinction between accessibility understood as an equivalence and universal accessibility in dealing with the zombie argument relies upon accepting modal dualism (a view that there are two spaces of possibilities rather than one), which is something usually dismissed for methodological reasons (simplicity in particular). Given that Piccinini has not provided new arguments neither in favour of modal dualism nor in favour of parodying the zombie argument, the conclusion he infers remains unsupported by the premises he uses. KEYWORDS: the zombie argument, the accessibility relation, modal dualism, parody.

The article discusses Saul Kripke’s influential theories of a posteriori necessary truths and natural kinds. With respect to the statements of identity involving proper names, it is argued that although their truth is a posteriori and necessary in the specific sense of counterfactual invariance, this is of no significance for substantial philosophical issues beyond the philosophy of language, because this counterfactual invariance is a trivial consequence of the use of proper names as rigid designators. The case is made that the expansion of the realm of necessary a posteriori truths to the statements of theoretical identity that involve “natural kind terms”, as well as the Kripkean essentialist theory of natural kinds, has no weighty argumentative support and fits badly both with science and language practice. This sets the stage for the development of an appropriately sophisticated «descriptivist» account of meaning and reference that would be better suited for a widened range of Kripke-Putnam style thought experiments. The general outlines of such a descriptivist account are provided.

It is argued in this paper that modal rationalism can be reconciled with logical pluralism together with the metaphysical foundation of logic. Namely, ideal conceivability is extensionally more akin to metaphysical modality than to logical modality, given that the space of conceivable worlds (scenarios) is (like the space of metaphysically possible worlds) narrower than the space of logically possible worlds, which opens room for the claim that the space of conceivable scenarios and the space of metaphysically possible worlds are coextensive. These considerations corroborate the claim that even if it turns out that modal monism (a view that logical modality and metaphysical modality are extensionally equivalent) is false, modal rationalism might still be true. At the end of this paper, I address pluralism in geometry (according to which there is more than one correct system of geometry) to show that modal rationalism is compatible with that view either.

... semantic contents of the claims that use of the modal operators enables us to make. ... (On a de re modalist view there can be necessary truths in which de re modality is ... will concern abstract entities or they will be inferential principles for reasoning with de re modal notions.) Thus ...

(2018) Pacific Philosophical Quarterly. Vogel, Sosa, and Huemer have all argued that sensitivity is incompatible with knowing that you do not believe falsely, therefore the sensitivity condition must be false. I show that this objection misses its mark because it fails to take account of the basis of belief. Moreover, if the objection is modified to account for the basis of belief then it collapses into the more familiar objection that sensitivity is incompatible with closure. (But that is an objection which sensitivity theorists are already prepared to meet, one way or another.)

This book in the epistemology of religion discusses a wide spectr of sources in um analytic, scholastic and apologetic philosophy and theology in order to argue nondeductively for the following thesis: Apart from religious experience, it cannot be evident (in a defined sense of psychological impossibility) that the Trinity doctrine is logically possible. Hence, this conclusion is drawn deductively: Apart from religious experience, it cannot be evident that Christianity or the Trinity doctrine have nonminimal logical probability. As the author points out, however, they still may be justified, well argued, plausibly logically probable, and probable in other than the logical sense. The book will be of interest to philosophers of religion, analytic theologians, and researchers in analytic scholasticism.

This paper evaluates whether and to what extent modal constraints on knowledge or the semantics of ‘knows’, which make essential reference to what goes on in other possible worlds, can be considered non-epistemic factors with epistemic significance. This is best understood as the question whether modal factors are non-truth-relevant factors that make the difference between true belief and knowledge, or to whether a true belief falls under the extension of ‘knowledge’ in a context, where a factor is truth-relevant with respect to S’s belief that P iff it bears on the probability that P is true. To the extent that these factors are non-epistemic, epistemologies that endorse them—modal epistemologies—stand in conflict with intellectualism. I focus on three modal epistemologies: safety, sensitivity, and David Lewis’s epistemic contextualism. I argue that prima facie, safety and sensitivity allow that non-epistemic changes in a context can shift the closeness ordering on worlds, and in so doing make a difference to whether S knows P, while Lewis’s contextualism allows that non-epistemic changes in a context can shift the relevant domain of not-P possibilities that must be eliminated for ‘S knows P’ to be true in that context. Then to make her theory compatible with intellectualism, the modal epistemologist must say much more about the notion of probability at play in the definition of ‘truth-relevant’. I suggest that either accepting or rejecting that modal epistemologies are intellectualist has significance consequences for debates between pragmatists and purists, which radiate into wider contemporary epistemology.

Is it possible to gain knowledge about the real world based solely on experiences in virtual reality? According to one influential theory of knowledge, you cannot. Robert Nozick's truth-tracking theory requires that, in addition to a belief being true, it must also be sensitive to the truth. Yet beliefs formed in virtual reality are not sensitive: in the nearest possible world where P is false, you would have continued to believe that P. This is problematic because there is increasing awareness from philosophers and technologists that virtual reality is an important way in which we can arrive at beliefs and knowledge about the world. Here I argue that a suitably modified version of Nozick's sensitivity condition is able to account for knowledge from virtual reality.

Many metaphysical controversies can be understood as debates over whether some alleged entities are metaphysically possible. (Examples: Are zombies possible? Is atomless gunk possible? Are extended simples possible? etc.) No doubt, with regard to these matters, we may have opinions or theories, commonsensical or sophisticated. But do we have knowledge of them? Can we really know that something is metaphysically possible, and if so, how? Several different answers have been offered in the literature, intending to illustrate how we may have knowledge of metaphysical modality. In this paper, I concentrate on a proposal by Timothy Williamson (2007). On this account, our alleged knowledge of metaphysical modality is justified by and grounded in our capacity to handle ordinary mundane counterfactual conditionals. However, I argue that Williamson’s account fails, mainly because the modality involved in ordinary mundane counterfactuals is causal, and thus our capacity to handle them still falls short of giving us any knowledge of metaphysical modality. In the end of the paper, I also provide my own answer to the question. My answer is a sceptical one: we do not really have knowledge of metaphysical modality. But such ignorance is harmless, or so I argue.

In this article, I defend the view that we can acquire factual knowledge – that is, contingent propositional knowledge about certain (perceivable) aspects of reality – on the basis of imaginative experience. More specifically, I argue that, under suitable circumstances, imaginative experiences can rationally determine the propositional content of knowledge-constituting beliefs – though not their attitude of belief – in roughly the same way as perceptual experiences do in the case of perceptual knowledge. I also highlight some philosophical consequences of this conclusion, especially for the issue of whether imagination can help us to learn something from fictions.

This paper challenges the Kripkean interpretation of a posteriori necessities. It will be demonstrated, by an analysis of classic examples, that the modal content of supposed a posteriori necessities is more complicated than the Kripkean line suggests. We will see that further research is needed concerning the a priori principles underlying all a posteriori necessities. In the course of this analysis it will emerge that the modal content of a posteriori necessities can be best described in terms of a Finean conception of modality – by giving essences priority over modality. The upshot of this is that we might be able to establish the necessity of certain supposed a posteriori necessities by a priori means.

SUMMARY: The article argues against attempts to combine ontological realism about modality with the rejection of modal rationalism and it suggests that modal realism requires (at least a weak form of) modal rationalism. KEY WORDS: modal realism, epistemology, a priori, empiricism, intuition RESUMEN: El artículo da argumentos en contra de que se intente combinar el rea-lismo ontológico sobre la modalidad con el rechazo del racionalismo modal y sugiere que el realismo modal exige (por lo menos una forma débil de) racionalismo modal.

Corroborative evidence may be understood as having two epistemic effects: a primary effect by which it offers direct evidence for some claim, and a secondary effect by which it bolsters the appraised probative, or evidential, value of some other piece of evidence for that claim. This paper argues that the bolstering effect of corroborative evidence is epistemically legitimate because corroboration provides a reason to count the belief based on the initial evidence as sensitive to, and safe from, defeat in a way that it was not previously recognized to be. Discovering that our initial evidence tracks the truth in a way we previously didn't recognize provides a reason to positively reappraise the probative value of that evidence. The final section of the paper relates the proposed sensitivity-and safety-based account of corroboration to an explanation-based account.

O argumento zumbi negativo parte das premissas de que p ∧ ¬q é idealmente negativamente concebível, de que o que é idealmente negativamente concebível é possível e de que o fisicalismo é incompatível com a possibilidade de p ∧ ¬q para concluir que o fisicalismo é falso. No argumento, p é a conjunção das verdades e leis físicas fundamentais e q é uma verdade fenomenal qualquer. Uma sentença φ é idealmente negativamente concebível sse um raciocinador ideal não acredita que ¬φ em reflexão priori. Uma versão da tese da escrutabilidade pressuposta pelo argumento afirma que, para todo φ que sobrevém em p, o raciocinador ideal acredita que p → φ em reflexão a priori. Nesse artigo, argumento que, dado algumas interpretações relevantes da noção de probabilidade (pr(.)), o raciocinador ideal acredita verdadeiramente, para todo φ, que p → pr(φ) = x em reflexão a priori. Mas então, dependendo do valor de pr(q) e das correlações entre q e outras sentenças, o raciocinador ideal também acredita (provavelmente, verdadeiramente) que p → q em reflexão a priori. Então, para alguns qs relevantes, p ∧ ¬q não é idealmente negativamente concebível e o argumento zumbi tem uma premissa falsa. A escolha de um q adequado dependeria de informação empírica, o que faria o argumento zumbi não ser nem conclusivo, nem a priori.

The negative zombie argument has as premises that p∧¬q is ideally negatively conceivable, that what is ideally negatively conceivable is possible, and that Physicalism is incompatible with p∧¬q being possible and as conclusion that Physicalism is false. In the argument, p is the conjunction of the fundamental physical truths and laws and q is an arbitrary phenomenal truth. A sentence φ is ideally negatively conceivable if and only if an ideal reasoner does not believe that ¬φ on a priori reflection. The argument presupposes a version of the scrutability thesis stating that, for all φ that supervene on p, the ideal reasoner believes that p → φ on a priori reflection. In this paper, I argue that, given relevant interpretation of probabilities, the ideal reasoner believes truly, for all φ, that p → pr(φ) = x on a priori reflection. But then, depending on the value of pr(q) and the correlations between q and other sentences, the ideal reasoner also believes (probably, truly) that p → q on a priori reflection. For some relevant qs, p∧¬q is not ideally negatively conceivable and the zombie argument has a false premise. The choice of an adequate q depends on empirical information, what makes the zombie argument neither conclusive nor a priori.

Accounting for our knowledge of de re modalities is probably the main reason why the proponents of modal empiricism think that their view should be preferred to modal rationalism. In this paper, I address Sonia Roca-Royes' account, which is tak-en to be a representative modal empiricist view, in order to show that modal empiricism faces serious problems even in explaining our knowledge of possibility de re, something which seems to be the easiest thing to explain on this view. I argue that Roca-Royes' account does not prove what she claims it does, that it can hardly be articulated in a non-redundant way, and that her account of our knowledge of possibility de re can hardly be reconciled with the essentiality of origin principle, to which modal empiricists sometimes appeal while criticizing the modal rationalist account. KEYWORDS: De re modal knowledge – modal empiricism – modal epistemology – modal rationalism. 1. Modal rationalism and our knowledge of modality de re Modal epistemology examines possibilities and boundaries of our modal knowledge. One of the most intriguing questions in this philosophical discipline is related to the knowledge of unrealized possibilities, that is, the knowledge that something is possible even if it is not realized in the actual world (or at least we do not know whether it is realized or not; see Van In

Modal knowledge accounts that are based on standards possible-worlds semantics face well-known problems when it comes to knowledge of necessities. Beliefs in necessities are trivially sensitive and safe and, therefore, trivially constitute knowledge according to these accounts. In this paper, I will first argue that existing solutions to this necessity problem, which accept standard possible-worlds semantics, are unsatisfactory. In order to solve the necessity problem, I will utilize an unorthodox account of counterfactuals, as proposed by Nolan (Notre Dame J Formal Logic 38:535–572, 1997), on which we also consider impossible worlds. Nolan’s account for counterpossibles delivers the intuitively correct result for sensitivity i.e. S’s belief is sensitive in intuitive cases of knowledge of necessities and insensitive in intuitive cases of knowledge failure. However, we acquire the same plausible result for safety only if we reject his strangeness of impossibility condition and accept...