Ioannis G. Ntagkas

The problem of philosophical skepticism relates to the difficulty involved in underwriting the claim that we know anything of spatio-temporal reality. It is often claimed, in fact, that proper philosophical scrutiny reveals quite the opposite from what common sense suggests. Knowledge of external reality is thought to be even quite obviously denied to us as a result of the alleged fact that we all fail to know that certain skeptical scenarios do not obtain. A skeptical scenario is one in which we have neurological occurrences just like any normal situation in which we actually perceive spatio-temporal objects, but where we are deceived in some sense as a result of the manipulation of our brains from some outside source. In this work I attempt to address the problem of philosophical skepticism by claiming that most of us are able to come to know plenty about external reality, since we can come to realize that a certain philosophical theory of perception is correct. The theory I have in mind is what I call a non-cognitive theory of perception. According to this view, perceptual experience is defined by continuous, sensitive behavioral interaction with spatio-temporal objects of the appropriate size, shape, hardness, speed, etc. Knowing that this theory of perception is correct is equivalent to knowing that we know plenty about external reality. This is ultimately because by knowing that a non-cognitive theory of perception is true, we know that any skeptical scenario must fail to obtain. The structure of the work proceeds by first discussing the significance of the problem of philosophical skepticism in some detail. Chapter 1 lays out how the problem does indeed forcefully arise if it is conceded that we fail to know that the skeptical scenarios fail to obtain. Chapter 2 develops the sort of view of our epistemological situation that falls out of accepting without qualification that the problem exists. Chapter 3 examines and criticizes certain popular responses to the skeptical problem. The main goal of these first three preliminary chapters is to indicate that once it is admitted that we fail to know that the skeptical scenarios fail to obtain, the problem of philosophical skepticism forcefully presents itself. Chapter 4, however, attacks the idea that we fail to know that the skeptical scenarios fail to obtain. In this chapter I argue that this idea is wedded to the position that a certain theory of perception is correct. The theory in question is what I call a conjunctive theory of veridical experience. According to this view, normal experience of spatio-temporal objects occurs when a subject has a certain perceptual experience, and that experience also happens to match up with and/or be satisfied by what is really the case. Only when a theory of this sort is assumed, I argue, is the claim that we fail to know that the skeptical scenarios fail to obtain found to be obvious. In chapter 5 I argue that, in fact, a non-cognitive theory, rather than a conjunctive theory, is the correct view to maintain. In the final chapter 6 I develop the epistemological position that falls out of accepting a non-cognitive theory.

Perhaps the most famous proposition in the history of philosophy is Descartes' cogito 'I think, therefore I am'. Husain Sarkar claims in this provocative interpretation of Descartes that the ancient tradition of reading the cogito as an argument is mistaken. It should, he says, be read as an intuition. Through this interpretative lens, the author reconsiders key Cartesian topics: the ideal inquirer, the role of clear and distinct ideas, the relation of these to the will, memory, the nature of intuition and deduction, the nature, content and elusiveness of 'I', and the tenability of the doctrine of the creation of eternal truths. Finally, the book demonstrates how Descartes' attempt to prove the existence of God is foiled by a new Cartesian Circle.

How should we understand both the nature, and the epistemic potential, of Descartes’s Cogito? Peter Slezak’s interpretation of the Cogito’s nature sees it strictly as a selfreferential kind of denial: Descartes cannot doubt that he is doubting. And what epistemic implications flow from this interpretation of the Cogito? We find that there is a consequent lack of knowledge being described by Descartes: on Cartesian grounds, indubitability is incompatible with knowing. Even as the Cogito halts doubt, therefore, it fails to be knowledge.

Why does Descartes give some propositions, most notably cogito, a privileged epistemic status? In the first part of the paper I consider, and reject, the standard account of the indubitability of cogito championed by, among others, Hintikka, Ayer, Slezak, and Frankfurt. After examining what I call the Cartesian regress, I invoke the fiction of a self-blind individual, close to the one originally introduced by Shoemaker, to give an alternative account of the indubitability of cogito. I argue that Descartes initially needs to exempt the self-attribution of thought from the scope of Cartesian doubt, because an individual who is self-blind, and, so, cannot self-attribute thoughts, cannot treat propositions about the external world as dubitable.

It has become a veritable industry to defend Descartes against the charge of circularity and, to a lesser extent, to argue that he successfully responds to the skepticism of Sextus Empiricus. Since one of Sextus’ main skeptical ploys is to press the charge of circularity against any view, and because Descartes does reply to Sextus, it is worthwhile to criticize these efforts in the same paper. I argue that Descartes did not successfully respond to Sextus’ skeptical arguments. I argue that he is guilty of not one but of five distinct circularities in his defense of empirical knowledge, thst clearing him of such charges can only be had by rendering him naively dogmatic, and that he fails to respond to a Pyrrhonisn contraposition argument. One circle concerns divine logical voluntarism. Another concerns the semantic component of innate ideas. A third arises from his natural inability to disbelieve whatever he clearly and distinctly perceives. A fourth circularity arises in Descartes’ proof that he cannot have generated his idea of God. A final circularity concerns Descartes’ attempt to verify the reliability of his thinking nature by employing that very same thinking nature. To substantiate these claims I review the principles of Sextus’ arguments briefly and I reexamine Descartes’ texts and doctrines in detail. I also take occasion to reflect on why Descartes’ foundationalist program must have failed.

According to Lehrer’s defeasibility account of knowledge, we can understand knowledge as undefeated justified true belief. But this account faces many serious problems. One important problem is that from one’s subjective point of view, one can hardly bridge the gap between one’s personal justification and objective truth. Another important problem is that this account can hardly accommodate the externalist intuition that the epistemic status of a belief is not entirely determined by factors that are internal to the subject’s perspective. The goal of this paper is to offer an alternative account of knowledge which can successfully deal with these problems. On the basis of a Sellarsian social practice theory of justification, I argue that we can understand knowledge as objectively justified belief.

In this paper I offer a coherentist justification of induction along the lines of a Sellarsian coherence theory. On this coherence theory, a proposition is justified if we can answer all objections raised against it in our social practice of demanding justification and responding to such demands. On the basis of this theory of justification, I argue that we are justified in accepting the uniformity of nature partly because we have no alternative but to accept it for rationally pursuing our epistemic goal. In addition, my coherentist view explains which inductive inferences it is rational to accept. Furthermore, my coherentist view also explains why we can hardly determine a particular numerical value x such that we can draw the conclusion ‘it is rational to accept that p’ from the premise ‘the numerical probability of p is greater than or equal to x’.

The problem of epistemic circularity involved in justifying fundamental epistemic principles is one of the fundamental problems of epistemology. One important way out of this problem is a Sellarsian social practice theory of justification, according to which we are justified in accepting an epistemic principle if we can answer all objections raised against it in our social practice of demanding justification and responding to such demands. The main goal of this paper is to show that this social practice theory can accomplish better than its rival theories, such as Alston’s doxastic practice approach, Sosa’s reliabilist virtue epistemology, and Wright’s entitlement theory, by making comparisons with these influential theories.

The author uses a series of potential counterexamples to argue against attempts by Bergmann and Plantinga to articulate a distinction between malignant and benign epistemic circularity and, more radically, to argue that epistemic circularity per se is no fallacy, and the concept of epistemic circularity plays no role in the explanation of why some instances of epistemic circularity are irrational. The author contrasts an inferential framework, in which circularity is a problem, with an equilibrium framework, in which the concept of circularity plays no useful role and argues that defeasible reasoning can only be understood in an equilibrium, not an inferential, framework. The author uses an example of reasoning about the reliability of one’s own memory to explain how seemingly malignant epistemic circularity can be rational in an equilibrium framework. The author discusses the relevance of this conclusion to two contemporary issues: the cogency of Plantinga’s Evolutionary Argument against Naturalism and the evolutionary naturalists’ challenges to non-naturalist moral realism—and, indeed, to all forms of non-naturalist normative realism.

In the Fourth Meditation, Descartes famously treats the indifference of the will (roughly, ambivalence of reasons) as the source of error, which many read as oddly suggesting that the will judges arbitrarily. In his letter to Elisabeth dated 1st September 1645, however, he expressly takes passions to be the source of error, saying that passions move the will to judge erroneously by misrepresenting the value of objects. Although these two accounts focus on different kinds of error – theoretical and practical error, respectively – I argue that Descartes is best understood as extending the second account also to the source of theoretical error. On my reading, the first account does not imply that erroneous judgements are simply arbitrary, but it leaves out an explanation why we judge at the time we do, when we could (and should) continue to inquire insofar as we have not yet gathered sufficient evidence. The second account fills in this lacuna by giving an explanation in terms of passions. I further argue that the schematic nature of the first account is due partly to the structure of the Meditations, but mainly to the fact that Descartes has not yet systematically examined the nature of passions there.

This study credits Descartes’s Meditations with a linear central argument that can achieve its meditator’s announced goal for knowledge in prospective mathematical sciences. The argument starts from the Second Meditation’s opening argument that provides premises with an epistemic feature that enables the central argument to advance to its theist conclusion free of vicious circularity. Nevertheless, not only do standard translations obscure the Second Meditation’s opening argument. Also, the original and long-standing ‘Cartesian Circle’ Objections picture Descartes’s Meditations as a circle, but misinterpret their target passages at the Third Meditation’s start and at the Fifth Meditation’s close. These ostensible impediments to crediting the Meditations’ linear central argument each overlooks or misconstrues the technical epistemic terms the Meditations specifies, and all comply with the unchallenged current assumption that the Meditations’ central argument can be consistent with teleological religious theism.

The notion of fundamentality, as it is used in metaphysics, aims to capture the idea that there is something basic or primitive in the world. This metaphysical notion is related to the vernacular use of “fundamental”, but philosophers have also put forward various technical definitions of the notion. Among the most influential of these is the definition of absolute fundamentality in terms of ontological independence or ungroundedness. Accordingly, the notion of fundamentality is often associated with these two other technical notions.

This paper examines how new evil demon problems could arise for our access to the internal world of our own minds. I start by arguing that the internalist/externalist debate in epistemology has been widely misconstrued---we need to reconfigure the debate in order to see how it can arise about our access to the internal world. I then argue for the coherence of scenarios of radical deception about our own minds, and I use them to defend a properly formulated internalist view about our access to our minds. The overarching lesson is that general epistemology and the specialized epistemology of introspection need to talk---each has much to learn from each other.

I argue that Descartes explains physiology in terms of whole systems, and not in terms of the size, shape and motion of tiny corpuscles (corpuscular mechanics). It is a standard, entrenched view that Descartes’ proper means of explanation in the natural world is through strict reduction to corpuscular mechanics. This view is bolstered by a handful of corpuscular–mechanical explanations in Descartes’ physics, which have been taken to be representative of his treatment of all natural phenomena. However, Descartes’ explanations of the ‘principal parts’ of physiology do not follow the corpuscular–mechanical pattern. Des Chene has identified systems in Descartes’ account of physiology, but takes them ultimately to reduce down to the corpuscle level. I argue that they do not. Rather, Descartes maintains entire systems, with components selected from multiple levels of organization, in order to construct more complete explanations than corpuscular mechanics alone would allow.

In a recent paper, Barry Loewer attempts to defend Humeanism about laws of nature from a charge that Humean laws are not adequately explanatory. Central to his defense is a distinction between metaphysical and scientific explanations: even if Humeans cannot offer further metaphysical explanations of particular features of their “mosaic,” that does not preclude them from offering scientific explanations of these features. According to Marc Lange, however, Loewer’s distinction is of no avail. Defending a transitivity principle linking scientific explanantia to their metaphysical grounds, Lange argues that a charge of explanatory inadequacy resurfaces once this intuitive principle is in place. This paper surveys, on behalf of the Humean, three strategies for responding to Lange’s criticism. The ready availability of these strategies suggests that Lange’s argument may not bolster anti-Humean convictions, since the argument rests on premises that those not antecedently sharing these convictions may well reject. The three strategies also correspond to three interesting ways of thinking about relations of grounding linking Humean laws and their instances, all of which are consistent with theses of Humean supervenience, and some of which have been heretofore overlooked.

For Humean atomists, cosmic contents supervene on a spatiotemporal mosaic of modally insulated, freely recombinable local qualities. One piecemeal subspecies of Humean atomism promises more than global supervenience—somehow or other—on a separable base; it constrains how exactly elemental inputs yield everything else. Roughly, the distribution of basic local qualities across elements in one part of our cosmos metaphysically suffices for the complete local physical state of that part: anything sharing this part’s basic elemental decoration should share its more complete contents, regardless of what may be happening elsewhere. On a non-piecemeal alternative, derivative contents can be recognizably local to, or manifest within, one part of our cosmos while reflecting some more global elemental base. To develop this alternative, non-piecemeal Humeans can borrow inspiration from some critics of Humean supervenience, who already distinguish a broader notion of locality from strict Humean intrinsicality.

I argue that Schaffer fails to provide a non-question-begging argument for priority monism. Despite his suggestion to the contrary, Humean pluralists need not, and plausibly do not, endorse his tiling constraint on metaphysically basic objects. Moreover, the distinction between supervenience—of the sort at issue in Humean doctrine—and metaphysical necessitation—of the sort at issue in Schaffer’s tiling constraint—points toward an alternative treatment of the phenomena initially inspiring Schafferian monism. There is an important possibility, one that Humeans can or should embrace, that Schaffer overlooks when drawing his monistic conclusion.

The GRW dynamics propose a novel, relevantly “observer”-independent replacement for orthodox “measurement”-induced collapse. Yet the tails problem shows that this dynamical innovation is not enough: a principled alternative to the orthodox account demands some corresponding ontological advancement as well. In fact, there are three rival fundamental ontologies on offer for the GRW dynamics. Debate about the relative merits of these candidates is a microcosm of broader disagreement about the role of ontology in our physical theorizing. According to imprimitivists, the GRW dynamics directly describe (only) some (element’s) undulation in an unfamiliar high-dimensional physical field. Primitivists resist this GRW0 proposal on the grounds that it fails to secure comprehensible contact with our data about macroscopic objects in ordinary lowdimensional space-time. They expect an adequate fundamental ontology to include at least some spatiotemporally localized entities—intuitively, concrete constituents of our familiar macroscopic landscape. The most compelling case goes by way of distributional basing: minimally, primitivists expect a theory’s predictions immediately about spatiotemporal distributions of fundamental entities to provide a supervenience base for data about configurations of macroscopic objects. But while the background intuition is familiar, the distributional model is surprisingly subtle. Lack of clarity about its details generates serious confusion for both sides of our debate.

For Humeans, many facts—even ones intuitively “about” particular, localized macroscopic parts of the world—turn out to depend on surprisingly global fundamental bases. We investigate some counterintuitive consequences of this picture. Many counterfactuals whose antecedents describe intuitively localized, non-actual states of affairs nevertheless end up involving wide-ranging implications for the global, embedding Humean mosaic. The case of self-undermining chances is a familiar example of this. We examine that example in detail and argue that popular existing strategies such as “holding the laws fixed as laws” or “holding the laws fixed as true” are of no help. Interestingly, we show how a new proposal that draws on the resources of the Mentaculus can yield the right results—but only on the assumption that the Humean can make cross-world identifications. We go on to argue that the Humean cannot make such identifications. We conclude that the root of this trouble is deeper, and its reach broader, than the familiar cases suggest. We think it is very much an open question whether the Humean has sufficient resources to properly conceptualize macroscopic objects or to analyze these “local” counterfactuals.

A simple argument proposes a direct link between realism about quantum mechanics and one kind of metaphysical holism: if elementary quantum theory is at least approximately true, then there are entangled systems with intrinsic whole states for which the intrinsic properties and spatiotemporal arrangements of salient subsystem parts do not suffice. Initially, the proposal is compelling: we can find variations on such reasoning throughout influential discussions of entanglement. Upon further consideration, though, this simple argument proves a bit too simple. To get such metaphysically robust consequences out, we need to put more than minimal realism in. This paper offers a diagnosis: our simple argument seems so compelling thanks to an equivocation. The predictions of textbook quantum theory already resonate with familiar holistic slogans; for realists, then, any underlying reality, conforming to such predictions, also counts as holistic in some sense or other, if only by association. Such associated holism, though, does not establish the sort of specific, robust supervenience failure claimed by our simple argument. While it may be natural to slide to this stronger conclusion, facilitating the slide is not minimal realism per se but an additional explanatory assumption about how and why reality behaves in accordance with our theory: roughly, quantum theory accurately captures patterns in the features and behaviors of physical reality because some underlying metaphysical structure constrains reality to exhibit these patterns. Along with the diagnosis comes a recommendation: we can and should understand one traditional disagreement about the metaphysics of entanglement as another manifestation of a familiar and more general conflict between reductive and non-reductive conceptions of metaphysical theorizing. Such reframing makes clearer what resources reductionists have for resisting the simple argument’s challenge from quantum holism. It also has an important moral for their opponents. Traditional focus on whole-part supervenience failure distracts from a root disagreement about metaphysical structure and its role in our theorizing. Non-reductionists fond of our simple argument would be better off tackling this root directly.

Abstract This paper develops an explanationist treatment of the problem of the criterion. Explanationism is the view that all justified reasoning is justified in virtue of the explanatory virtues: simplicity, fruitfulness, testability, scope, and conservativeness. A crucial part of the explanationist framework is achieving wide reflective equilibrium. I argue that explanationism offers a plausible solution to the problem of the criterion. Furthermore, I argue that a key feature of explanationism is the plasticity of epistemic judgments and epistemic methods. The explanationist does not offer any fixed judgments or methods to guide epistemic conduct; even the explanatory virtues themselves are subject to change. This feature of explanationism gives it an advantage over non-explanationist views that offer fixed epistemic judgments and epistemic methods. The final section of this paper responds to objections to explanationism

This chapter examines the status of inference to the best explanation in naturalistic metaphysics. The methodology of inference to the best explanation in metaphysics is studied from the perspective of contemporary views on scientific explanation and explanatory inferences in the history and philosophy of science. This reveals serious shortcomings in prevalent attempts to vindicate metaphysical "explanationism" by reference to similarities between science and naturalistic metaphysics. This critique is brought out by considering a common gambit of methodological unity: (1) Both metaphysics and science employ inference to the best explanation. (2) One has no reason to think that if explanationism is truth-conducive in science, it is not so in metaphysics. (3) One has a positive reason to think that if explanationism is truth-conducive in science, it is also so in metaphysics.

Traditional epistemological interpretations have portrayed Hegel as offering a coherentist solution to the problem of the criterion in the introduction to The Phenomenology of Spirit. In this paper, I criticize the coherentist interpretation and present an alternative reading that emphasizes the central role of conscious experience in Hegel's argument. In the first part of the paper, I show how the passages commonly used to support the coherentist interpretation ultimately fail to do so and argue that coherence by itself cannot be the lynchpin for an adequate solution to the problem of the criterion. In the second part, I then develop a novel interpretation of Hegel's argument by drawing attention to the fact that Hegel formulates both the problem of the criterion and his solution to it in terms of consciousness.

The author argues that Descartes is not trapped inside the Cartesian circle. The essay rehearses Descartes’ argument against the “evil demon” hypothesis. The so-called Cartesian circle is described and some of the most prominent discussions of the problem are evaluated. Such arguments tend either to leave Descartes in the circle, or themselves depend upon distinctions that in the end lead to Descartes claiming something less than metaphysical certainty for his system. The author argues that Descartes’ real Archimedian point is the light of nature, and that his project is to extend the certainty of the light of nature to those ideas which are clear and distinct. Using this interpretation of Descartes, the author returns to the accounts of the critics to account for their mischaracterization of Descartes’ reasoning as circular.