ABSTRACT Our goal in this paper is to extend counterfactual accounts of scientific explanation to mathematics. Our focus, in particular, is on intra-mathematical explanations: explanations of one mathematical fact in terms of another. We offer a basic counterfactual theory of intra-mathematical explanations, before modelling the explanatory structure of a test case using counterfactual machinery. We finish by considering the application of counterpossibles to mathematical explanation, and explore a second test case along these lines.

Mathematics appears to play a genuine explanatory role in science. But how do mathematical explanations work? Recently, a counterfactual approach to mathematical explanation has been suggested. I argue that such a view fails to differentiate the explanatory uses of mathematics within science from the non-explanatory uses. I go on to offer a solution to this problem by combining elements of the counterfactual theory of explanation with elements of a unification theory of explanation. The result is a theory according to which (...) a counterfactual is explanatory when it is an instance of a generalized counterfactual scheme. (shrink)

Ultralogic as Universal? is a seminal text in non-classcial logic. Richard Routley presents a hugely ambitious program: to use an 'ultramodal' logic as a universal key, which opens, if rightly operated, all locks. It provides a canon for reasoning in every situation, including illogical, inconsistent and paradoxical ones, realized or not, possible or not. A universal logic, Routley argues, enables us to go where no other logic—especially not classical logic—can. Routley provides an expansive and singular vision of how a universal (...) logic might one day solve major problems in set theory, arithmetic, linguistics, physics, and more. It circulated in typescript in the late 1970s before appearing as the Appendix to Exploring Meinong's Jungle and Beyond. With engaging, forceful prose, unsparing criticism of entrenched institutions, and many tantalizing proof sketches, Ultralogic? has had a major influence on the development of paraconsistent and relevant logic. This new edition makes this work available for a modern audience, newly typeset and corrected, along with extensive notes, and new commentary essays. (shrink)

Lately, philosophers of mathematics have been exploring the notion of mathematical explanation within mathematics. This project is supposed to be analogous to the search for the correct analysis of scientific explanation. I argue here that given the way philosophers have been using “ explanation,” the term is not applicable to mathematics as it is in science.

According to the iterative conception of set, each set is a collection of sets formed prior to it. The notion of priority here plays an essential role in explanations of why contradiction-inducing sets, such as the Russell set, do not exist. Consequently, these explanations are successful only to the extent that a satisfactory priority relation is made out. I argue that attempts to do this have fallen short: understanding priority in a straightforwardly constructivist sense threatens the coherence of the empty (...) set and raises serious epistemological concerns; but the leading realist interpretations---ontological and modal interpretations of priority---are deeply problematic as well. I conclude that the purported explanatory virtues of the iterative conception are, at present, unfounded. (shrink)

The continental philosophy of non-classical logics is a relatively new field that seeks to determine whether any aspects of certain continental philosophers’ thinking can be characterized in terms of non-classical logics. Some of the main figures that have been examined so far are Martin Heidegger, Jacques Derrida, Gilles Deleuze, and François Laruelle. Although many of these studies are grounded in the writings of Graham Priest, who wrote some of the seminal texts in the field, Jc Beall’s work also features prominently (...) in a number of cases. After surveying this field and highlighting Beall’s influence within it, I claim that it can be substantially expanded by making further uses of Beall’s writings, especially ones that introduce non-classical logics in ways that are especially suitable for this particular field of study and also that discuss such topics as negation, subclassical logics, logical pluralism, and glutty futures. (shrink)

The advent of quantum mechanics in the early 20 th Century had profound consequences for science and mathematics, for philosophy (Schrödinger), and for logic (von Neumann). In 1968, Putnam wrote that quantum mechanics required a revolution in our understanding of logic per se. However, applications of quantum logics have been little explored outside the quantum domain. Dummett saw some implications of quantum logic for truth, but few philosophers applied similar intuitions to epistemology or ontology. Logic remained a truth-functional ’science’ of (...) correct propositional reasoning. Starting in 1935, the Franco-Romanian thinker Stéphane Lupasco described a logical system based on the inherent dialectics of energy and accordingly expressed in and applicable to complex real processes at higher levels of reality. Unfortunately, Lupasco’s fifteen major publications in French went unrecognized by mainstream logic and philosophy, and unnoticed outside a Francophone intellectual community, albeit with some translations into other Romance languages. In English, summaries of Lupasco’s logic appeared ca. 2000, but the first major treatment and extension of his system was published in 2008 (see Brenner 2008). This paper is a further attempt to establish Lupasco’s concepts as significant contributions to the history and philosophy of logic, in line with the work of Gödel, general relativity, and the ontological turn in philosophy. (shrink)

In Beyond the Limits of Thought [2002], Graham Priest argues that logical and semantic paradoxes have the same underlying structure (which he calls the Inclosure Schema ). He also argues that, in conjunction with the Principle of Uniform Solution (same kind of paradox, same kind of solution), this is sufficient to 'sink virtually all orthodox solutions to the paradoxes', because the orthodox solutions to the paradoxes are not uniform. I argue that Priest fails to provide a non-question-begging method to 'sink (...) virtually all orthodox solutions', and that the Inclosure Schema cannot be the structure that underlies the Liar paradox. Moreover, Ramsey was right in thinking that logical and semantic paradoxes are paradoxes of different kinds. (shrink)

While the contemporary problem of the criterion raises similar epistemological issues as Agrippa’s Trilemma in ancient Pyrrhonian skepticism, the consideration of such epistemological questions has served two different purposes. On one hand, there is the purely practical purpose of Pyrrhonism, in which such questions are a means to reach suspension of judgment, and on the other hand, there is the theoretical purpose of contemporary epistemologists, in which these issues raise theoretical problems that drive the search for theoretical resolution. In classical (...) India, similar issues arise in Nāgārjuna’s Vigrahavyāvartanī, but it is not entirely clear what Nāgārjuna’s purpose is. Contrary to the theoretical interpretations of several recent scholars such as Jan Westerhoff according to which Nāgārjuna is proffering a contextualist epistemological theory, I argue that Nāgārjuna as well as the later Madhyamaka Candrakīrti, much like Pyrrhonian skeptics, employed concerns about epistemic criteria in service of purely practical purposes. There is no positive epistemological theory to be found in Nāgārjuna’s Vigrahavyāvartanī and Candrakīrti’s Prasannapadā; furthermore a putative thesis of universal emptiness is self-undermining, a conclusion which itself can be seen as part of a therapeutic program. Nonetheless, the historical persistence of these epistemological issues shows that they ought to continue to be areas of theoretical inquiry for epistemologists today. I end with reflections on the wider relevance of my conclusions, particularly with regard to demonstrating the value of philosophy. (shrink)

Recent discussions in cognitive science and the philosophy of mind have defended a theory according to which we live in a virtual world akin to a computer simulation, generated by our brain. It is argued that our brain creates a model world from a variety of stimuli; this model is perceived as if it was external and perception-independent, even though it is neither of the two. The view of the mind, brain, and world, entailed by this theory has some peculiar (...) consequences which have rarely been explored in detail. This paper sets out virtual world theory and relates it to various central philosophical problems, the role of the perceiver and the problem of the existence of the external world ). The second part suggests three interpretations of virtual world theory, two familiar ones and a somewhat less familiar one. The remainder of the paper argues that the irrealist interpretation is the one we should adopt. (shrink)

The sciences occasionally generate discoveries that undermine their own assumptions. Two such discoveries are characterized here: the discovery of apophenia by cognitive psychology and the discovery that physical systems cannot be locally bounded within quantum theory. It is shown that such discoveries have a common structure and that this common structure is an instance of Priest’s well-known Inclosure Schema. This demonstrates that science itself is dialetheic: it generates limit paradoxes. How science proceeds despite this fact is briefly discussed, as is (...) the connection between our results and the realism-antirealism debate. We conclude by suggesting a position of epistemic modesty. (shrink)

In a recent article, Emil Badici contends that the inclosure schema substantially fails as an analysis of the paradoxes of self-reference because it is question-begging. The main purpose of this note is to show that Badici's critique highlights a necessity condition for the success of dialectic about paradoxes. The inclosure argument respects this condition and remains solvent.

It is a commonplace of set theory to say that there is no set of all well-orderings nor a set of all sets. We are implored to accept this due to the threat of paradox and the ensuing descent into unintelligibility. In the absence of promising alternatives, we tend to take up a conservative stance and tow the line: there is no universe. In this paper, I am going to challenge this claim by taking seriously the idea that we can (...) talk about the collection of all the sets and many more collections beyond that. A method of articulating this idea is offered through an indefinitely extending hierarchy of set theories. It is argued that this approach provides a natural extension to ordinary set theory and leaves ordinary mathematical practice untouched. (shrink)

All paradoxes of self-reference seem to share some structural features. Russell in 1908 and especially Priest nowadays have advanced structural descriptions that successfully identify necessary conditions for having a paradox of this kind. I examine in this paper Priest’s description of these paradoxes, the Inclosure Scheme (IS), and consider in what sense it may help us understand and solve the problems they pose. However, I also consider the limitations of this kind of structural descriptions and give arguments against Priest’s use (...) of IS in favour of dialetheism. IS fails to identify sufficient conditions for having a paradox of self-reference. That means that, even if we identified a problem common to any reasoning satisfying IS, that problem would not explain why some of those reasonings are paradoxical and some others are not. Therefore IS cannot justify by itself the claim that some particular theory offers the best solution to the paradoxes of self-reference. We still need to consider aspects concerning the content and context of occurrence of every paradox. (shrink)

There is a phenomenon that often arises when a philosophy argues that there are limits to thought/language, and tries to justify this view by giving reasons as to why there are things about which one cannot think/talk---in the process appearing to give the lie to the claim. I will be concerned with that phenomenon. We will look at some of philosophies that fall into this camp (those of Wittgenstein, Heidegger, and Mahayana Buddhism). We will then see that Buddhist philosophy has (...) resources to address this kind of issue not present in Western traditions, namely the catuskoti and its developments. The catuskoti is a principle to the effect that claims can be true, false, both, or neither. Later developments add a fifth possibility: ineffability. Of course, one might be skeptical that such ideas can be made logically respectable. I will show how to do so with some simple tools from contemporary non-classical logic. (shrink)

In recent analytic philosophy, there is a growing interest in the project of conceptual engineering. This paper examines two ways this project might be applied to scientific research, specifically anthropological research. It argues that both of them are harmful to this research. Specifically, it argues that a reliance on the axiological standards of analytic philosophy conflicts with the goal of empirical adequacy. Section one proffers two forms that the engineering project might take when applied to the science. Section two proffers (...) a case study drawn from anthropology. Specifically, it lays out Evans-Pritchard’s Witchcraft, Oracles, and Magic Among the Azande, paying particular attention to the inconsistency he discovered in Azande witchcraft. Sections three and four argue that attempting to remove this inconsistency via the two forms of engineering disable critical features of emic research and discard empirical findings. Finally, I close by noting how the conflict between axiological standards and empirical adequacy might generalize beyond anthropology. (shrink)

I discuss two critiques of Dignāga’s epistemology, one from Candrakīrti and another from Jayarāśi. I argue that they are two versions of what I call the core problem: if the content of Dignāga’s epistemology were correct, two fundamental beliefs within this epistemological theory could not be established or known to be true, as Dignāga claims they are. In response to objections found within the classical Indian tradition as well as several plausible contemporary objections, I then argue that the core problem (...) remains a serious issue with which those sympathetic to Dignāga ought to contend. (shrink)

True contradictions are taken increasingly seriously by philosophers and logicians. Yet, the belief that contradictions are always false remains deeply intuitive. This paper confronts this belief head-on by explaining in detail how one specific contradiction is true. The contradiction in question derives from Priest's reworking of Berkeley's argument for idealism. However, technical aspects of the explanation offered here differ considerably from Priest's derivation. The explanation uses novel formal and epistemological tools to guide the reader through a valid argument with, not (...) just true, but eminently acceptable premises, to an admittedly unusual conclusion: a true contradiction. The novel formal and epistemological tools concern points of view and changes in points of view. The result is an understanding of why the contradiction is true. (shrink)

This article is an inquiry into how the relationship between the principle of non-contradiction and the limits of thought has been understood by thinkers as diverse as Hegel, Heidegger, Levinas, and Graham Priest. While Heidegger and Levinas focus on the question of temporality and Priest takes a formal approach, all these philosophers effectively maintain that the principle of non-contradiction imposes a restriction on thought that disables it from adequately accounting for its own limits and thus what lies beyond those limits, (...) the implication being that the violation of the principle is necessary for such an accounting to take place. However, the ultimate argument here is that, contrary to Priest’s interpretation, Hegel’s philosophy can be convincingly read as supporting the idea that the mind’s ability to go beyond any particular limit of thought can actually be said to involve an adherence to a normative demand to locate and dispel the contradictions that emerge through the very setting of determinative limits. This is a non-formal consistency that evinces a “logic” that is unknowingly followed by the Heideggerian and Levinasian phenomenological philosophies of transcendence. (shrink)

We present a strategy to dissolve semantic paradoxes which proceeds from an explanation of why paradoxical sentences or their definitions are semantically defective. This explanation is compatible with the acceptability of impredicative definitions, self-referential sentences and semantically closed languages and leaves the status of the so-called truth-teller sentence unaffected. It is based on platitudes which encode innocuous constraints on successful definition and successful expression of propositional content. We show that the construction of liar paradoxes and of certain versions of Curry’s (...) paradox rests on presuppositions that violate these innocuous constraints. Other versions of Curry’s paradox are shown not to be paradoxical at all once their presuppositions are made explicit. Part of what we say rehearses a proposal originally made by Laurence Goldstein in 1985. Like Goldstein we dispose of certain paradoxes by rejecting some of the premises from which they must be taken to proceed. However, we disagree with his more recent view that the premises to be rejected are neither true nor false. (shrink)

Chinese Chan or Zen Buddhism is renowned for its improvisational, atypical, and perplexing use of words. In particular, the tradition’s encounter dialogues, which took place between Chan masters and their interlocutors, abound in puzzling, astonishing, and paradoxical ways of speaking. In this chapter, we are concerned with Chan’s use of paradoxical language. In philosophical parlance, a linguistic paradox comprises the confluence of opposite or incongruent concepts in a way that runs counter to our common sense and ordinary rational thinking. One (...) naturally wonders about Chan masters’ rationales for their use of paradox. There are also concerns about whether the use violates the logical principle of noncontradiction to the effect that nothing can be both P and not-P all over in the same way at the same time. Chan became a viable Chinese Buddhist tradition during the Tang dynasty (618−907) and continued to develop for several centuries. The tradition had produced a huge literature; consequently, our investigation of its use of paradox cannot but be limited and selective. In the second section, I first sketch key ideas of Chan that are pertinent to our investigation and then examine the use of paradox in the sermons associated with certain Tang masters of the southern Chan. In the third section, I analyze the presence of paradoxical language in post-Tang encounter dialogues. The fourth section concludes. (shrink)

Graham Priest 2002 argues that all logical paradoxes that include set-theoretic paradoxes and semantic paradoxes share a common structure, the Inclosure Schema, so they should be treated as one family. Through a discussion of Berry's Paradox and the semantic notion ?definable?, I argue that (i) the Inclosure Schema is not fine-grained enough to capture the essential features of semantic paradoxes, and (ii) the traditional separation of the two groups of logical paradoxes should be retained.

For Jizang (549−623), a prominent philosophical exponent of Chinese Madhyamaka, all things are empty of determinate form or nature. Given anything X, no linguistic item can truly and conclusively be applied to X in the sense of positing a determinate form or nature therein. This philosophy of ontic indeterminacy is connected closely with his notion of the Way (dao), which seems to indicate a kind of ineffable principle of reality. However, Jizang also equates the Way with nonacquisition as a conscious (...) state of freedom from any attachment and definite understanding whatsoever. The issue then becomes pressing as to how we are to understand Jizang's notion of the Way. Does it indicate some metaphysical principle or reality? Is it actually a skilful expedient to lead one to the consummate state of complete spiritual freedom? How is this issue related to Jizang's conception of ontic indeterminacy? In this book chapter, I examine Jizang's key writings in an attempt to clarify his ontological position. (shrink)

This anthology of the very latest research on truth features the work of recognized luminaries in the field, put together following a rigorous refereeing process. Along with an introduction outlining the central issues in the field, it provides a unique and unrivaled view of contemporary work on the nature of truth, with papers selected from key conferences in 2011 such as Truth Be Told, Truth at Work, Paradoxes of Truth and Denotation and Axiomatic Theories of Truth. Studying the nature of (...) the concept of ‘truth’ has always been a core role of philosophy, but recent years have been a boom time in the topic. With a wealth of recent conferences examining the subject from various angles, this collection of essays recognizes the pressing need for a volume that brings scholars up to date on the arguments. Offering academics and graduate students alike a much-needed repository of today’s cutting-edge work in this vital topic of philosophy, the volume is required reading for anyone needing to keep abreast of developments, and is certain to act as a catalyst for further innovation and research. (shrink)

We use a mechanized verification system, PVS, to examine the argument from Anselm’s Proslogion Chapter III, the so-called “Modal Ontological Argument.” We consider several published formalizations for the argument and show they are all essentially similar. Furthermore, we show that the argument is trivial once the modal axioms are taken into account. This work is an illustration of Computational Philiosophy and, in addition, shows how these methods can help detect and rectify errors in modal reasoning.

The starting point of this paper is a claim defended most famously by Graham Priest: that given certain observed similarities between the set-theoretic and the semantic paradoxes, we should be looking for a ‘uniform solution’ to the members of both families. Despite its indisputable surface attractiveness, I argue that this claim hinges on a problematic reasoning move. This is seen most clearly, I suggest, when the claim and its underlying assumptions are examined by the lights of a novel, quite general (...) and, I contend, promising take on inter-theoretic analogy. The ensuing discussion is intended to serve as both a possible case study and a first step towards the broader aim of the paper: namely, to initiate a wider conversation on the methodology of paradox-solving on the one hand, and the use of inter-theoretic analogies on the other. (shrink)

In this issue, Constance Kassor describes Gorampa's attitude to contradictions as they occur in various contexts of Buddhist pursuit. We agree with much of what she says; with some things we do not.First, some preliminary comments, and a fundamental disagreement. Kassor says:Based on . . . [the assumption that Nāgārjuna has a coherent system of thought] one must resolve apparent contradictions in Nāgārjuna's texts in order to maintain the coherency of his logic. The problem with contradictions is that if they (...) are introduced into a classical logical system, that entire system can break down. This is because of the law of explosion—the principle that everything can follow [DGP: does follow] from a contradiction.One .. (shrink)

Infinite idealizations appear in our best scientific explanations of phase transitions. This is thought by some to be paradoxical. In this paper I connect the existing literature on the phase transition paradox to work on the concept of indispensability, which arises in discussions of realism and anti-realism within the philosophy of science and the philosophy of mathematics. I formulate a version of the phase transition paradox based on the idea that infinite idealizations are explanatorily indispensable to our best science, and (...) so ought to attract a realist attitude. I go on to offer a solution to the paradox by drawing a distinction between two types of indispensability: constructive and substantive indispensability. I argue that infinite idealizations are constructively indispensable to explanations of phase transitions, but not substantively indispensable. This helps to resolve the paradox, I maintain, since realist commitment tracks substantive, and not constructive, indispensability. (shrink)

The article proposes an analogue of conceptual change in the context of comprehensive or deep emotional change and growth, and explores some aspects of its logic in that context. This is not to reduce emotions to concepts, but to say that concepts express the sense that is already inherent in experience and reality. When emotional states change so thoroughly that their applicable concepts become completely different, they shift from one logical structure to another. At the moment or phase when one (...) conceptual structure transforms into another, two logically incompatible descriptions both apply to the same state at the same time. As a result, the correct description of this moment and its development involves conceptual confusion, non sequitur, and logical contradiction. In these contexts, the sense itself of the emotional experience and process is partly characterized by what are otherwise violations of sense. Failure of sense is part of how these experiences make sense. The article explores some of the consequences of this paradox of sense for the nature and experience of deep emotional change and for the meaning of change itself in this context. (shrink)

I argue that absolutism, the view that absolutely unrestricted quantification is possible, is to blame for both the paradoxes that arise in naive set theory and variants of these paradoxes that arise in plural logic and in semantics. The solution is restrictivism, the view that absolutely unrestricted quantification is not possible. -/- It is generally thought that absolutism is true and that restrictivism is not only false, but inexpressible. As a result, the paradoxes are blamed, not on illicit quantification, but (...) on the logical conception of set which motivates naive set theory. The accepted solution is to replace this with the iterative conception of set. -/- I show that this picture is doubly mistaken. After a close examination of the paradoxes in chapters 2--3, I argue in chapters 4 and 5 that it is possible to rescue naive set theory by restricting quantification over sets and that the resulting restrictivist set theory is expressible. In chapters 6 and 7, I argue that it is the iterative conception of set and the thesis of absolutism that should be rejected. (shrink)

RESUMO: A presente investigação questiona a essência teo-lógica dos futuros contingentes. Para o efeito, analisa-se, primeiramente, a argumentação segundo a qual, sob certas condições lógicas, teológicas, ontológicas e cosmológicas antinecessitantes, detetadas por G. W. Leibniz, a abertura contingente do futuro parece ser compatível com o regime das "verdades contingentes pré-determinadas", regime enquadrado teologicamente pelo princípio do "futuro melhor" ou do "único futuro verdadeiro". No entanto, os futuros contingentes incitam, com e contra Aristóteles, ao desenvolvimento de uma lógica temporal e plurivalente, (...) ao modo de J. Łukasiewicz ou A. Prior. Essa lógica garante a abertura do futuro sem o oneroso custo metafísico da adesão a uma teo-lógica omnideterminante. A crítica do determinismo lógico, daí resultante, afigura-se mais coadunável com as condições pós-metafísicas inerentes à episteme agnósticacontemporânea, mas, nesse caso, a abertura do futuro implicaria uma profunda redefinição das próprias ideias e funções de "Deus", "matéria", "história" e "verdade". ABSTRACT: This paper investigates the theological essence of contingent futures. First, it analyses the argument according to which, under certain logical, theological, ontological, and cosmological conditions detected by Leibniz, the contingent openness of the future may be compatible with the regime of "pre- determined contingent truths", theologically grounded in the principle of an "optimal future" or a "single true future". However, the examination of contingent futures has also fostered, both for and against Aristotle's position, the development of a many-valued and temporal logic as proposed by J. Łukasiewicz or A. Prior. This logic safeguards the openness of future without the metaphysically expensive cost of adhering to an all-determining theo-logic. It hence follows that the critique of logical determinism seems to be more appropriate to express the post-metaphysical conditions of our present agnostic mentality. In this case, however, the openness of the future would entail a profound redefinition of the very ideas and functions of "God", "matter", "history", and "truth". (shrink)

Jamie Tappenden was one of the first authors to entertain the possibility of a common treatment for the Liar and the Sorites paradoxes. In order to deal with these two paradoxes he proposed using the Strong Kleene semantic scheme. This strategy left unexplained our tendency to regard as true certain sentences which, according to this semantic scheme, should lack truth value. Tappenden tried to solve this problem by using a new speech act, articulation. Unlike assertion, which implies truth, articulation only (...) implies non-falsity. In this paper I argue that Tappenden’s strategy cannot be successfully applied to truth and the Liar. (shrink)

The Analytic Tradition in Philosophy is an excellent successor to an excellent book : It is a fine an example of the necromantic style in the history of philosophy where the object of the exercise is to resurrect the mighty dead in order to get into an argument with them, either because we think them importantly right or instructively wrong. However what was a pardonable a simplification and a reasonable omission in the earlier book has now metamorphosed into a sin (...) of omission and an oversimplification in its successor—the book lacks is an adequate discussion of the Ramified Theory of Types and Russell’s reasons for adopting it. I conclude with a brief meditation on Open Question Arguments and the threats that they pose to some of the analyses proposed by Russell and Moore themselves. (shrink)