Given quasi-realism, the claim is that any attempt to naturalise modal epistemology would leave out absolute necessity. The reason, according to Simon Blackburn, is that we cannot offer an empirical psychological explanation for why we take any truth to be absolutely necessary, lest we lose any right to regard it as absolutely necessary. In this paper, I argue that not only can we offer such an explanation, but also that the explanation won’t come with a forfeiture of the involved necessity. (...) Using ‘squaring the circle’ as evidence, I show that, contrary to quasi-realism, absolute necessity won’t be left out in attempts to naturalise modal epistemology. (shrink)

True beliefs and truth-preserving inferences are, in some sense, good beliefs and good inferences. When an inference is valid though, it is not merely truth-preserving, but truth-preserving in all cases. This motivates my question: I consider a Modus Ponens inference, and I ask what its validity in particular contributes to the explanation of why the inference is, in any sense, a good inference. I consider the question under three different definitions of ‘case’, and hence of ‘validity’: the orthodox definition given (...) in terms of interpretations or models, a metaphysical definition given in terms of possible worlds, and a substitutional definition defended by Quine. I argue that the orthodox notion is poorly suited to explain what's good about a Modus Ponens inference. I argue that there is something good that is explained by a certain kind of truth across possible worlds, but the explanation is not provided by metaphysical validity in particular; nothing of value is explained by truth across all possible worlds. Finally, I argue that the substitutional notion of validity allows us to correctly explain what is good about a valid inference. (shrink)

We shall use Gödel’s Second Incompleteness Theorem to show that consistency is not possibility, and then argue that the argument does serious damage to some theories of modality where consistency plays a major but not exclusive role.

A natural language argument may be valid in at least two nonequivalent senses: it may be interpretationally or representationally valid (Etchemendy in The concept of logical consequence. Harvard University Press, Cambridge, 1990). Interpretational and representational validity can both be formally exhibited by classical first-order logic. However, as these two notions of informal validity differ extensionally and first-order logic fixes one determinate extension for the notion of formal validity (or consequence), some arguments must be formalized by unrelated nonequivalent formalizations in order (...) to formally account for their interpretational or representational validity, respectively. As a consequence, arguments must be formalized subject to different criteria of adequate formalization depending on which variant of informal validity is to be revealed. This paper develops different criteria that formalizations of an argument have to satisfy in order to exhibit the latter’s interpretational or representational validity. (shrink)

The epistemology of essence is a topic that has received relatively little attention, although there are signs that this is changing. The lack of literature engaging directly with the topic is probably partly due to the mystery surrounding the notion of essence itself, and partly due to the sheer difficulty of developing a plausible epistemology. The need for such an account is clear especially for those, like E.J. Lowe, who are committed to a broadly Aristotelian conception of essence, whereby essence (...) plays an important theoretical role. In this chapter, our epistemic access to essence is examined in terms of the a posteriori vs. a priori distinction. The two main accounts to be contrasted are those of David S. Oderberg and E.J. Lowe. (shrink)

Lewisian Genuine Realism about possible worlds is often deemed unable to accommodate impossible worlds and reap the benefits that these bestow to rival theories. This thesis explores two alternative extensions of GR into the terrain of impossible worlds. It is divided in six chapters. Chapter I outlines Lewis’ theory, the motivations for impossible worlds, and the central problem that such worlds present for GR: How can GR even understand the notion of an impossible world, given Lewis’ reductive theoretical framework? Since (...) the desideratum is to incorporate impossible worlds into GR without compromising Lewis’ reductive analysis of modality, Chapter II defends that analysis against objections. The rest of the thesis is devoted to incorporating impossible worlds into GR. Chapter III explores GR-friendly impossible worlds in the form of set-theoretic constructions out of genuine possibilia. Then, Chapters IV-VI venture into concrete impossible worlds. Chapter IV addresses Lewis’ objection against such worlds, to the effect that contradictions true at impossible worlds amount to true contradictions tout court. I argue that even if so, the relevant contradictions are only ever about the non-actual, and that Lewis’ argument relies on a premise that cannot be nonquestion- beggingly upheld in the face of genuine impossible worlds in any case. Chapter V proposes that Lewis’ reductive analysis can be preserved, even in the face of genuine impossibilia, if we differentiate the impossible from the possible by means of accessibility relations, understood non-modally in terms of similarity. Finally, Chapter VI counters objections to the effect that there are certain impossibilities, formulated in Lewis’ theoretical language, which genuine impossibilia should, but cannot, represent. I conclude that Genuine Realism is still very much in the running when the discussion turns to impossible worlds. (shrink)

The problem of the source of necessity is the problem of explaining what makes necessary truths necessarily true. Simon Blackburn has presented a dilemma intended to show that any reductive, realist account of the source of necessity is bound to fail. Although Blackburn's dilemma faces serious problems, reflection on the form of explanations of necessities reveals that a revised dilemma succeeds in defeating any reductive account of the source of necessity. The lesson is that necessity is metaphysically primitive and irreducible.

This thesis investigates the conceptual relationship between laws of nature and free will. In order to clarify the discussion, I begin by distinguishing several questions with respect to the nature of a law: i) do the laws of nature cover everything that happens? ii) are they deterministic? iii) can there be exceptions to universal and deterministic laws? iv) do the laws of nature govern everything in the world? In order to answer these questions I look at three widely endorsed accounts (...) of laws: "Humean" regularity accounts, laws as relations among universals, and the dispositional essentialist account. I argue that there is nothing in the very nature of a law - in any of the accounts surveyed - that implies a positive answer to questions (i) and (ii). I show that this has important consequences for the free will problem. I then turn to the compatibility of free will and determinism. I focus on the Humean view and the dispositional essentialist account of laws. And the bulk of this discussion concerns the consequence argument, especially the question of whether the laws of nature are "up to us". I show that, on the dispositional conception of laws, there is no sense in which the laws of nature are up to us, contrary to the Humean view. However, this does not mean that there is no room for free will on the dispositional account. I argue that free will requires the laws of nature to be limited in scope, rather than being indeterministic. I conclude by showing that this allows one to resist the claim that indeterminism rules out free will. (shrink)

Scott Sehon argues that the conception of determinism employed in the Consequence Argument is implausible because it rules out the logical possibility of the laws of nature being violated. Sehon says, for instance, that determinism is incompatible with the logical possibility of an interventionist God. His objection to the Consequence Argument boils down to a way of reading the box in what is implied by van Inwagen's conception of determinism. Sehon reads the box as logical necessity, and this clearly precludes (...) the logical possibility of the laws of nature being violated. However, I argue that determinism as employed in the argument is not implausible. First, I try to show that it is legitimate to read the box of □ as either metaphysical or logical necessity depending on the account of laws that one assumes. If one accepts a fully Humean account of laws, then the box should be read as logical necessity. Nevertheless, I argue that this is not a problem for the Humean. On the other hand, if one reads the box as metaphysical necessity, which is mainly motivated by the dispositional account of laws and might be motivated by Armstrong's account, then determinism is compatible with the logical possibility of the laws being violated. (shrink)

Logical pluralism is the view according to which there is more than one relation of logical consequence, even within a given language. A recent articulation of this view has been developed in terms of quantification over different cases: classical logic emerges from consistent and complete cases; constructive logic from consistent and incomplete cases, and paraconsistent logic from inconsistent and complete cases. We argue that this formulation causes pluralism to collapse into either logical nihilism or logical universalism. In its place, we (...) propose a modalist account of logical pluralism that is independently well motivated and that avoids these collapses. (shrink)

En este artículo, analizo las principales respuestas que se han dado al argumento finitista de Etchemendy, y muestro que ninguna de ellas es exitosa. Primero, describo y critico las propuestas que intentan resolverlo apelando a consideraciones modales. Estas soluciones fallan porque presuponen un finitismo demasiado débil, donde se acepta la existencia de infinitos conjuntos o de mundos posibles con infinitos objetos. Pero hay versiones más fuertes del finitismo que reintroducen el problema. Luego considero las soluciones que apelan a categorías semánticas. (...) Una de ellas categoriza incorrectamente este problema como un desacuerdo sobre el significado de los cuantificadores. La otra solución falla porque, si fuera tomada en serio, tendría efectos muy nocivos para la lógica en general. Finalmente argumento que la mejor solución es morder la bala y aceptar que la lógica no debería ser fuertemente independiente de algunos asuntos que tradicionalmente fueron considerados como 'extralógicos'. In this paper, I analyze the main replies that have been given to Etchemendy's finitist argument, and I show that none of them is successful. First, I describe and criticize the proposals that try to solve the problem by appealing to modal considerations. These solutions fail because they presuppose a very weak finitism, where the existence of infinitely many sets, or possible words with infinitely many objects, is accepted. But there are stronger versions of finitism that reintroduce the problem. Then I consider the solutions which appeal to semantical categories. One of them incorrectly categorizes the problem as a disagreement in the meaning of the quantifiers. The other fails because, if taken seriously, it would have harmful effects on logic in general. Finally I argue that the best solution is to bite the bullet and accept that logic shouldn't be strongly independent from some issues which were traditionally considered as 'extra-logical'. (shrink)

According to modalism, modality is primitive. In this paper, we examine the implications of this view for modal epistemology, and articulate a modalist account of modal knowledge. First, we discuss a theoretical utility argument used by David Lewis in support of his claim that there is a plurality of concrete worlds. We reject this argument, and show how to dispense with possible worlds altogether. We proceed to account for modal knowledge in modalist terms.

This paper responds to criticism of the Kripkean account of logical truth in first-order modal logic. The criticism, largely ignored in the literature, claims that when the box and diamond are interpreted as the logical modality operators, the Kripkean account is extensionally incorrect because it fails to reflect the fact that all sentences stating truths about what is logically possible are themselves logically necessary. I defend the Kripkean account by arguing that some true sentences about logical possibility are not logically (...) necessary. (shrink)

David Lewis’s genuine modal realism is a controversial thesis in modal metaphysics. Charles Chihara and Ross Cameron have each argued that Lewis’s defence of his thesis involves his committing serious methodological errors; in particular, that his replies to two well-known and important objections are question-begging. Scott Shalkowski has further argued that Lewis’s attempt to analyse modal talk in non-modal terms is viciously circular. This paper considers the methodology which Lewis uses to argue for his thesis, and the paper tries to (...) show that it is guilty of no methodological errors. (shrink)