Ioannis G. Ntagkas

Deep disagreements concern our most basic and fundamental commitments. Such disagreements seem to be problematic because they appear to manifest epistemic incommensurability in our epistemic systems, and thereby lead to epistemic relativism. This problem is confronted via consideration of a Wittgensteinian hinge epistemology. On the face of it, this proposal exacerbates the problem of deep disagreements by granting that our most fundamental commitments are essentially arationally held. It is argued, however, that a hinge epistemology, properly understood, does not licence epistemic incommensurability or epistemic relativism at all. On the contrary, such an epistemology in fact shows us how to rationally respond to deep disagreements. It is claimed that if we can resist these consequences even from the perspective of a hinge epistemology, then we should be very suspicious of the idea that deep disagreements in general are as epistemologically problematic as has been widely supposed.

The central theme of this study is that Descartes is a teacher who develops his arguments for the different philosophical orientations of his students. Indeed, according to Cunning, so respectful is Descartes of their orientations that he actually misrepresents his own view in the Meditations on central doctrinal matters like the basis for dualism. The exegetical argument for this is the central argument of the book, though many other aspects of the Meditations are discussed in novel and interesting ways. Descartes describes himself as establishing the duality of mental and physical substances in two stages in the Meditations. It is in Meditation II, he says in the Fourth Replies, where he shows that a ..

One finds a surprising number of defenses of the legitimacy of some kinds of question-begging arguments or beliefs in the literature. Without wanting to deny the importance of dialectical analyses of begging the question, what I do here is explore the epistemic side of the issue. In particular, I want to explore the legitimacy of “epistemically circular” arguments and beliefs. My tentative conclusion is that epistemically circular arguments and beliefs are never legitimate. *Note: this is an unpublished manuscript presented at the 2011 conference of the Ontario Society for the Study of Argumentation. A copy of the manuscript is hosted at the OSSA conference archive, linked above. Some of the central ideas in this paper appear in my "Epistemic Circularity, Reliabilism, and Transmission Failure," Episteme (2014).

Can we show that our senses are reliable sources of information about the world? To show this, we need to establish that most of our perceptual judgments have been true. But we cannot determine these inductive instances without relying upon sense perception. Thus, it seems, we cannot establish the reliability of sense perception by means of an argument without falling into epistemic circularity. In this paper, I argue that this consequence is not an epistemological disaster. For this purpose, I defend a normative claim that it is reasonable to accept the general reliability of our perceptual judgments, instead of a factual claim that our perceptual judgments are generally reliable. More specifically, I offer a normative practical argument which explains why it is reasonable to accept the general reliability of our perceptual judgments, even though we cannot establish the general reliability of our perceptual judgments by means of theoretical reasoning

This paper investigates the logic of reasons. Its aim is to provide an analysis of the sentences of the form ‘p is a reason for q’ that yields a coherent account of their logical properties. The idea that we will develop is that ‘p is a reason for q’ is acceptable just in case a suitably defined relation of incompatibility obtains between p and ¬q. As we will suggest, a theory of reasons based on this idea can solve three challenging puzzles that concern, respectively, contraposing reasons, conflicting reasons, and supererogatory reasons, and opens a new perspective on some classical issues concerning non-deductive inferences.

Descartes's greatest glory was to be the first to articulate, and systematically to defend, the new scientific ideal of explanation in terms of lawfulness. For the realm of matter, lawful connections replaced anthropomorphic volitions as the model of rational explanation. Descartes's use of explanation in terms of lawfulness, inspired by Galileo's beginnings in this enterprise, was vindicated by Newton's subsequent achievement. Replacement of anthropomorphic agency, by causal mechanism, as the explanatory model, was undoubtedly the most profound of the many effects of the new science on our culture.

In this dissertation I consider the problem of external world skepticism and attempts at providing an argument to the best explanation against it. In chapter one I consider several different ways of formulating the crucial skeptical argument, settling on an argument that centers on the question of whether we're justified in believing propositions about the external world. I then consider and reject several options for getting around this issue which I take to be inadequate. I finally conclude that the best option available to us at the moment is to argue that the antiskeptical view is the best explanation of our ordinary experiences In chapter two I argue that, if we hope to ground what counts as defending antiskepticism in common sense, there is an argument against the possibility of ever knowing one has succeeded in defending antiskepticism. After showing that common sense is no place to look in setting a goal for our antiskeptical project, I present the view that what will be crucial to settling on our antiskeptical goal is coming to a successful analysis of the nature of physical objects. I suggest some minimal criteria that must be met by a view in order to be antiskeptical based on our intuitions about core skeptical cases, but acknowledge that a fully successful response to external world skepticism will require the antiskeptic to engage in some much more difficult analysis. In chapter three I consider various views of the nature of explanation and conclude, tentatively, that explanation as it interests the antiskeptic is fundamentally causal. In chapter four I consider and reject some of the core views on which best explanation facts are so fundamental that a project of attempting to vindicate probabilistically the virtues which make explanations epistemically good. In this chapter I show that views which analyze justification in terms of best explanation factors fail. In chapter five I attempt to vindicate the various explanatory virtues probabilistically. In doing so I attempt to express or translate the various explanatory virtues in terms of probabilities in order to show that having those virtues makes a view at least prima facie more probable. In chapters six and seven I explain and evaluate the various arguments to the best explanation against skepticism present in current philosophical literature. I attempt to show that extant arguments fail to appreciate the virtues possessed by classical skeptical scenarios. In chapter eight I briefly consider some options that may be open to the antiskeptic moving forward. All routes forward contain considerable obstacles, but there are some fruitful areas of research to pursue.

Grounding is a powerful metaphysical concept; yet there is widespread scepticism about the intelligibility of the notion. In this paper, I propose an account of an entity’s nature or essence, which I then use to provide grounding conditions for that entity. I claim that an understanding of an entity’s nature, together with an account of how logically complex entities are grounded, provides all we need to understand how that entity is grounded. This approach not only allows us to say what grounds what, it also sheds light on the formal features of the grounding relation. It provides a principled argument for the orthodox view that grounding is irreflexive, asymmetrical, and transitive; but it allows that it may not be well-founded. The resulting approach gives us a powerful framework for understanding nature, grounding, and the relationship between them.

Negative facts get a bad press. One reason for this is that it is not clear what negative facts are. We provide a theory of negative facts on which they are no stranger than positive atomic facts. We show that none of the usual arguments hold water against this account. Negative facts exist in the usual sense of existence and conform to an acceptable Eleatic principle. Furthermore, there are good reasons to want them around, including their roles in causation, chance-making and truth-making, and in constituting holes and edges.

The justificatory force of empirical reasoning always depends upon the existence of some synthetic, a priori justification. The reasoner must begin with justified, substantive constraints on both the prior probability of the conclusion and certain conditional probabilities; otherwise, all possible degrees of belief in the conclusion are left open given the premises. Such constraints cannot in general be empirically justified, on pain of infinite regress. Nor does subjective Bayesianism offer a way out for the empiricist. Despite often-cited convergence theorems, subjective Bayesians cannot hold that any empirical hypothesis is ever objectively justified in the relevant sense. Rationalism is thus the only alternative to an implausible skepticism.

I consider whether a contradiction may be deducible from the proposition that God does not exist. First, I expose a candidate counterexample to a key premise in Swinburne’s argument against the deducibility of a contradiction from God’s non-existence. Second, I present two new strategies one might use to deduce a contradiction. Both strategies make use of Tarski's T-schema together with developments in other theistic arguments. One argument is a conceptualist argument from necessary truth for a necessary mind, and the other is a two-stage contingency argument for the same conclusion. The purpose of this article is not to decisively defend these arguments, but to expose new territory relevant to investigating the nature of God's necessity.

Phenomenal Conservatism is an ethics of belief that has received considerable support in recent years. One of the main arguments for it is the Self-Defeat Argument. The argument claims that the denial of Phenomenal Conservatism is self-defeating. The argument is at present highly controversial, with both supporters and critics. Critics have failed to discern the real problems with the argument: (I) that there are reasons to deny Phenomenal Conservatism that avoid the self-defeat in question and (II) the conclusion of the Self-Defeat Argument, even if true, is still compatible with our properly denying Phenomenal Conservatism. I spell out these problems in more detail here.

Evidence is one of the most fundamental notions in the field of epistemology and is emerging as a major topic across academic disciplines. The practice of every academic discipline consists largely in providing evidence for key theses and The Routledge Handbook of Philosophy of the Philosophy of Evidence, the first collection of its kind, is an outstanding reference source to the key topics, problems and debates in this exciting subject. Comprising over forty chapters by a team of international contributors the Handbook is divided into six parts: Ontology of evidence Sources of evidence Evidence and normativity Evidence and probability Social epistemology of evidence Evidence in the disciplines. Within these sections central issues, debates and problems are examined. Questions covered include: What is evidence? What is the relationship between knowledge and evidence? Is a pluralism of evidence possible? What other sources of evidence are there in addition to perception? Is what a person ought to believe completely fixed by the totality of evidence they have, or does it also depend on other factors like practical interests? Can evidential force be measured in any well-behaved way? How do socially created biases - for instance, gender biases - affect evidence-gathering? How is evidence relevant within different academic disciplines? The Routledge Handbook of Philosophy of the Philosophy of Evidence is essential reading for students and researchers in philosophy of science and epistemology and related disciplines such as law, religion, history and the social sciences.

The main goal of this chapter is to argue that accessibilism in epistemology is incompatible with vehicle externalism in philosophy of mind. As we shall see, however, there are strong arguments for both of these positions. On the one hand, there is a compelling argument for vehicle externalism: the parity argument from Clark and Chalmers 1998. On the other hand, there is a compelling argument for accessibilism: the Moorean argument from Smithies 2012. If accessibilism is incompatible with vehicle externalism, then both arguments cannot be sound. I resolve the tension by arguing that while the Moorean argument succeeds, the parity argument fails, and so vehicle externalism should be rejected on broadly epistemological grounds.

Accessibilism is a version of epistemic internalism on which justification is determined by what is accessible to the subject. I argue that misunderstandings of accessibilism have hinged on a failure to appreciate an ambiguity in the phrase ‘what is accessible to the subject’. I first show that this phrase may either refer to the very things accessible to the subject, or instead to the facts about which things are accessible to her. I then discuss Ralph Wedgwood’s (2002: 350-352) argument that accessibilism absurdly implies that an infinite regress of facts, each more complex than the last, must be accessible to the subject. I show that this regress objection only threatens the ‘very things’ disambiguation of accessibilism, not the ‘facts about’ disambiguation. After this, I discuss the relationships between the motivations for accessibilism and these two disambiguations. We will see that these motivations appear to support each disambiguation. But I will argue this appearance depends on a mistake. Just as only the ‘facts about’ disambiguation escapes the regress objection, it is also the only disambiguation which enjoys genuine support from the motivations for accessibilism. For these reasons, I recommend that future discussions of accessibilism focus on the ‘facts about’ disambiguation.

What is the role of phenomenal consciousness in grounding epistemic justification? This paper explores the prospects for a global version of phenomenal conservatism inspired by the work of Michael Huemer, according to which all epistemic justification is grounded in phenomenal seemings. I’m interested in this view because of its global ambitions: it seeks to explain all epistemic justification in terms of a single epistemic principle, which says that you have epistemic justification to believe whatever seems to you strongly enough on balance to be true. One of the attractions of phenomenal conservatism is that it offers such a simple and unified framework for explaining the epistemic role of phenomenal consciousness. I will argue, however, that the simplicity of phenomenal conservatism is not a theoretical virtue, but a theoretical vice, since it distorts the epistemological phenomena it is supposed to explain. In effect, phenomenal conservatism seeks to explain all epistemic justification on the same model as perception. But this has the predictable effect of distorting the epistemology of other domains, including introspection, inference, and a priori justification.

How are we to understand philosophical claims about sense perception being direct versus indirect? There are multiple relevant notions of perceptual directness, so I argue. Perception of external objects may be direct on some notions, while indirect on others. My interest is with the sense in which ideas count as perceptual mediators in the philosophy of Descartes and Locke. This paper has two broader aims. The first is to clarify four main notions of perceptual directness. The second is to support my contention that in the texts characterizing ideas as immediate objects of perception, Descartes and Locke are invoking the notion of directness I call ‘objectual’. This notion is modeled on the way a picture mediates perception of the pictured object. The upshot of my account is that – with respect to the objectual notion of directness – Descartes and Locke each hold an indirect theory of perception