This paper presents a new modal logic for ceteris paribus preferences understood in the sense of “all other things being equal”. This reading goes back to the seminal work of Von Wright in the early 1960’s and has returned in computer science in the 1990’s and in more abstract “dependency logics” today. We show how it differs from ceteris paribus as “all other things being normal”, which is used in contexts with preference defeaters. We provide a semantic analysis and several (...) completeness theorems. We show how our system links up with Von Wright’s work, and how it applies to game-theoretic solution concepts, to agenda setting in investigation, and to preference change. We finally consider its relation with infinitary modal logics. (shrink)

The expression conditional fallacy identifies a family of arguments deemed to entail odd and false consequences for notions defined in terms of counterfactuals. The antirealist notion of truth is typically defined in terms of what a rational enquirer or a community of rational enquirers would believe if they were suitably informed. This notion is deemed to entail, via the conditional fallacy, odd and false propositions, for example that there necessarily exists a rational enquirer. If these consequences do indeed follow from (...) the antirealist notion of truth, alethic antirealism should probably be rejected. In this paper we analyse the conditional fallacy from a semantic (i.e. model-theoretic) point of view. This allows us to identify with precision the philosophical commitments that ground the validity of this type of argument. We show that the conditional fallacy arguments against alethic antirealism are valid only if controversial metaphysical assumptions are accepted. We suggest that the antirealist is not committed to the conditional fallacy because she is not committed to some of these assumptions. (shrink)

It has been an open question whether or not we can define a belief revision operation that is distinct from simple belief expansion using paraconsistent logic. In this paper, we investigate the possibility of meeting the challenge of defining a belief revision operation using the resources made available by the study of dynamic epistemic logic in the presence of paraconsistent logic. We will show that it is possible to define dynamic operations of belief revision in a paraconsistent setting.

ABSTRACTDo truth tables—the ordinary sort that we use in teaching and explaining basic propositional logic—require an assumption of consistency for their construction? In this essay we show that truth tables can be built in a consistency-independent paraconsistent setting, without any appeal to classical logic. This is evidence for a more general claim—that when we write down the orthodox semantic clauses for a logic, whatever logic we presuppose in the background will be the logic that appears in the foreground. Rather than (...) any one logic being privileged, then, on this count partisans across the logical spectrum are in relatively similar dialectical positions. (shrink)

The idea of relevant logic—that irrelevant inferences are invalid—is appealing. But the standard semantics for relevant logics involve baroque metaphysics: a three-place accessibility relation, a star operator, and ‘bad’ worlds. In this article we propose that these oddities express a mismatch between non-classical object theory and classical metatheory. A uniformly relevant semantics for relevant logic is a better fit.

Standard reasoning about Kripke semantics for modal logic is almost always based on a background framework of classical logic. Can proofs for familiar definability theorems be carried out using anonclassical substructural logicas the metatheory? This article presents a semantics for positive substructural modal logic and studies the connection between frame conditions and formulas, via definability theorems. The novelty is that all the proofs are carried out with anoncontractive logicin the background. This sheds light on which modal principles are invariant under (...) changes of metalogic, and provides (further) evidence for the general viability of nonclassical mathematics. (shrink)

There was a time when 'logic' just meant classical logic. The climate is slowly changing and non-classical logic cannot be dismissed off-hand. However, a metatheory used to study the properties of non-classical logic is often classical. In this paper, we will argue that this practice of relying on classical metatheories is problematic. In particular, we will show that it is a bad practice because the metatheory that is used to study a non-classical logic often rules out the very logic it (...) is designed to study. (shrink)

In this paper we explore the relationship between norms of belief revision that may be adopted by members of a community and the resulting dynamic properties of the distribution of beliefs across that community. We show that at a qualitative level many aspects of social belief change can be obtained from a very simple model, which we call ‘threshold influence’. In particular, we focus on the question of what makes the beliefs of a community stable under various dynamical situations. We (...) also consider refinements and alternatives to the ‘threshold’ model, the most significant of which is to consider changes to plausibility judgements rather than mere beliefs. We show first that some such change is mandated by difficult problems with belief-based dynamics related to the need to decide on an order in which different beliefs are considered. Secondly, we show that the resulting plausibility-based account results in a deterministic dynamical system that is non-deterministic at the level of beliefs. (shrink)

We present four classical theories of counterpossibles that combine modalities and counterfactuals. Two theories are anti-vacuist and forbid vacuously true counterfactuals, two are quasi-vacuist and allow counterfactuals to be vacuously true when their antecedent is not only impossible, but also inconceivable. The theories vary on how they restrict the interaction of modalities and counterfactuals. We provide a logical cartography with precise acceptable boundaries, illustrating to what extent nonvacuism about counterpossibles can be reconciled with classical logic.

The semantics for counterfactuals due to David Lewis has been challenged by appealing to miracles. Miracles may skew a given similarity order in favour of those possible worlds which exhibit them. Lewis responded with a system of priorities that mitigates the significance of miracles when constructing similarity relations. We propose a prioritised ceteris paribus analysis of counterfactuals inspired by Lewis’ system of priorities. By analysing the couterfactuals with a ceteris paribus clause one forces out, in a natural manner, those possible (...) worlds which do not satisfy the requirements of the clause, thus excluding miracles. If no world can satisfy the ceteris paribus clause in its entirety, then prioritisation is triggered to select worlds that maximise agreement on those things which are favoured most. (shrink)

This paper presents a new modal logic for ceteris paribus preferences understood in the sense of "all other things being equal". This reading goes back to the seminal work of Von Wright in the early 1960's and has returned in computer science in the 1990' s and in more abstract "dependency logics" today. We show how it differs from ceteris paribus as "all other things being normal", which is used in contexts with preference defeaters. We provide a semantic analysis and (...) several completeness theorems. We show how our system links up with Von Wright's work, and how it applies to game-theoretic solution concepts, to agenda setting in investigation, and to preference change. We finally consider its relation with infinitary modal logics. (shrink)

We present a generalization of Segerberg's onion semantics for belief revision, in which the linearity of the spheres need not occur. The resulting logic is called broccoli logic. We provide a minimal relational logic, with a bi-modal neighborhood semantics. We then show that broccoli logic is a well-known conditional logic, the Burgess-Veltman minimal conditional logic.

Standard modal logic for alethic modalities analyses modalities as ranging over all possible worlds. This leaves very little room in the space of worlds to entertain impossible things. My proposal is to liberate the Leibnizian universe and reinforce the relative aspect of possibility; worlds are possible with respect to some worlds, and impossible for others. The central idea is to isolate relative possibility from conditionality. To accommodate counterpossibles, I provide a dialetheic conditional modal logic, a theory that is dialetheic at (...) every level, in the logic as well as in the set theory behind it. (shrink)

This paper is a step toward showing what is achievable using non-classical metatheory—particularly, a substructural paraconsistent framework. What standard results, or analogues thereof, from the classical metatheory of first order logic can be obtained? We reconstruct some of the originals proofs for Completeness, Löwenheim-Skolem and Compactness theorems in the context of a substructural logic with the naive comprehension schema. The main result is that paraconsistent metatheory can ‘re-capture’ versions of standard theorems, given suitable restrictions and background assumptions; but the shift (...) to non-classical logic may recast the meanings of these apparently ‘absolute’ theorems. (shrink)

This paper is about teaching elementary logic to blind or visually impaired students. The targeted audience are teachers who all of sudden have a blind or visually impaired student in their introduction to logic class, find limited help from disability centers in their institution, and have no idea what to do. We provide simple techniques that allow direct communication between a teacher and a visually impaired student. We show how the use of what is known as Polish notation simplifies communication, (...) and pedagogically is a great notation for a Braille reader. (shrink)

This volume is a collation of original contributions from the key actors of a new trend in the contemporary theory of knowledge and belief, that we call “dynamic epistemology”. It brings the works of these researchers under a single umbrella by highlighting the coherence of their current themes, and by establishing connections between topics that, up until now, have been investigated independently. It also illustrates how the new analytical toolbox unveils questions about the theory of knowledge, belief, preference, action, and (...) rationality, in a number of central axes in dynamic epistemology: temporal, social, probabilistic and even deontic dynamics. (shrink)

In the late 20th century theorists within the radical feminist tradition such as Haraway highlighted the impossibility of separating knowledge from knowers, grounding firmly the idea that embodied bias can and does make its way into argument. Along a similar vein, Moulton exposed a gendered theme within critical thinking that casts the feminine as toxic ‘unreason’ and the ideal knower as distinctly masculine; framing critical thinking as a method of masculine knowers fighting off feminine ‘unreason’. Theorists such as Burrow have (...) picked up upon this tradition, exploring the ways in which this theme of overly masculine, or ‘adversarial’, argumentation is both unnecessary and serves as an ineffective base for obtaining truth. Rooney further highlighted how this unnecessarily gendered context results in argumentative double binds for women, undermining their authority and stifling much-needed diversity within philosophy as a discipline.These are damning charges that warrant a response within critical thinking frameworks. We suggest that the broader critical thinking literature, primarily that found within contexts of critical pedagogy and dispositional schools, can and should be harnessed within the critical thinking literature to bridge the gap between classical and feminist thinkers. We highlight several methods by which philosophy can retain the functionality of critical thinking while mitigating the obstacles presented by feminist critics and highlight how the adoption of such methods not only improves critical thinking, but is also beneficial to philosophy, philosophers and feminists alike. (shrink)

Ceteris Paribus clauses in reasoning are used to allow for defeaters of norms, rules or laws, such as in von Wright’s example “I prefer my raincoat over my umbrella, everything else being equal”. In earlier work, a logical analysis is offered in which sets of formulas Γ, embedded in modal operators, provide necessary and sufficient conditions for things to be equal in ceteris paribus clauses. For most laws, the set of things allowed to vary is small, often finite, and so (...) Γ is typically infinite. Yet the axiomatisation they provide is restricted to the special and atypical case in which Γ is finite. We address this problem by being more flexible about ceteris paribus conditions, in two ways. The first is to offer an alternative, slightly more general semantics, in which the set of formulas only give necessary but not sufficient conditions. This permits a simple axiomatisation. (shrink)

Editors' Introduction and List of Contributors.

Linear logic, introduced by Girard, is a refinement of classical logic with a natural, intrinsic accounting of resources. This accounting is made possible by removing the ‘structural’ rules of contraction and weakening, adding a modal operator and adding finer versions of the propositional connectives. Linear logic has fundamental logical interest and applications to computer science, particularly to Petri nets, concurrency, storage allocation, garbage collection and the control structure of logic programs. In addition, there is a direct correspondence between polynomial-time (...) computation and proof normalization in a bounded form of linear logic. In this paper we show that unlike most other propositional logics, full propositional linear logic is undecidable. Further, we prove that without the modal storage operator, which indicates unboundedness of resources, the decision problem becomes PSPACE-complete. We also establish membership in NP for the multiplicative fragment, NP-completeness for the multiplicative fragment extended with unrestricted weakening, and undecidability for fragments of noncommutative propositional linear logic. (shrink)

Greimas’s conception of narrative is based on a causality linked to basic paradigms establishing the deep meaning of a story; Girard’s conception of narrative is rooted in a universal mimetic desire which leads the “lynchers” to justify exclusion by producing mythical narratives demonstrating that the excluded was evil; Kymlicka’s perspective on cultural relationships is based on the necessity to create a socio-political framework helping people to cooperate in order to invent a better world. These three important thinkers analyze stories (...) people tell themselves or believe in in order to organize a controlled and safer way of life for themselves. We compare the theoretical perspectives of these three thinkers in order to understand in what way contemporary writers of the Americas structure their narratives and explore encounters while aiming at fostering a vision of the world oriented towards multi and transculturalism. (shrink)

This book explores the nature and implications of positive, creative, and loving mimesis and brings together the interdisciplinary fields of Girardian studies and creativity studies in new and original ways. Scientists, philosophers, psychologists, theologians and ancient thinkers are brought into thought provoking and insightful dialogue with Girardian conceptions of mimetic desire, scapegoating, and hominization.

Profoundly important ethical and political controversies turn on the question of whether biological life is an essential aspect of a human person, or only an extrinsic instrument. Lee and George argue that human beings are physical, animal organisms - albeit essentially rational and free - and examine the implications of this understanding of human beings for some of the most controversial issues in contemporary ethics and politics. The authors argue that human beings are animal organisms and that their personal identity (...) across time consists in the persistence of the animal organisms they are; they also argue that human beings are essentially rational and free and that there is a radical difference between human beings and other animals; criticize hedonism and hedonistic drug-taking; present detailed defenses of the prolife positions on abortion and euthanasia; and defend the traditional moral position on marriage and sexual acts. (shrink)

Conspiracy theories are rather a popular topic these days, and a lot has been written on things like the meaning of _conspiracy theory_, whether it’s ever rational to believe conspiracy theories, and on the psychology and demographics of people who believe conspiracy theories. But very little has been said about why people might be led to posit conspiracy theories in the first place. This paper aims to fill this lacuna. In particular, I shall argue that, in open democratic societies, citizens (...) justifiably presuppose that the epistemic authorities—journalists, academics, scientists, and so on—are engaged in a good faith pursuit of the truth. This presupposition generates certain normative expectations on the behaviors of the epistemic authorities—they ought to be open to new evidence, possess a healthy degree of skepticism, be willing to engage with opponents, and so on. So, when an epistemic authority is presented with some putatively anomalous data or an alternative hypothesis for some event or phenomena, people expect the epistemic authority to respond in a way that is consonant with these norms. In some instances, however, the epistemic authorities do not respond in this way and instead are dogmatic, dismissive, and engage in _ad hominem_. From the point of view of the citizen, there’s a tension here between how the epistemic authorities ought to behave and how they have, in fact, behaved which is best resolved either by taking the epistemic authorities less seriously or by positing a conspiracy theory. Put another way, the failure of the epistemic authorities to adhere to the norms by which we take them to be governed when presented with apparent anomalies or alternative hypotheses is one reason for which one might initially posit a conspiracy theory. (shrink)

In §2-4, I survey three extant ways of making sense of indeterminate truth and find each of them wanting. All the later sections of the paper are concerned with showing that the most promising way of making sense of indeterminate truth is via either a theory of truthmaker gaps or via a theory of truthmaking gaps. The first intimations of a truthmaker–truthmaking gap theory of indeterminacy are to be found in Quine (1981). In §5, we see how Quine proposes to (...) solve Unger’s problem of the many via positing the possibility of groundless truth. In §6, I elaborate the truthmaker gap model of indeterminacy first sketched by Sorensen (2001, ch.11) and use it to give a reductive analysis of indeterminate truth. In §7, I briefly assess what kind of formal framework can best express the possibility of truthmaker gaps. In §8, I contrast what I dub ‘the ordinary conception of worldly indeterminacy’ with Williamson’s conception of worldly indeterminacy. In §9, I show how one can distinguish linguistic from worldly indeterminacy on a truthmaker gap conception. In §10, I briefly sketch the relationship between truthmaker gaps and ignorance. In §11, I assess whether a truthmaker gap conception of vagueness is really just a form of epistemicism. In §12, I propose that truthmaker gaps can yield a plausible model of (semantic) presupposition failure. In §13, in response to the worry that a truthmaker gap conception of indeterminacy is both parochial and controversial—since it commits us to an implausibly strong theory of truthmaking—I set forth a truthmaking gap conception of indeterminacy. In §14, I answer the worry that groundless truths, of whatever species, are just unacceptably queer. A key part of this answer is that a truthmaker–truthmaking gap model of indeterminacy turns out to be considerably less queer than any model of indeterminacy which gives up on Tarski’s T-schema for truth (and cognate schemas). (shrink)

There has been increasing attention in sociology and internet studies to the topic of ‘digital remains’: the artefacts users of social network services (SNS) and other online services leave behind when they die. But these artefacts also pose philosophical questions regarding what impact, if any, these artefacts have on the ontological and ethical status of the dead. One increasingly pertinent question concerns whether these artefacts should be preserved, and whether deletion counts as a harm to the deceased user and therefore (...) provides pro tanto reasons against deletion. In this paper, I build on previous work invoking a distinction between persons and selves to argue that SNS offer a particularly significant material instantiation of persons. The experiential transparency of the SNS medium allows for genuine co-presence of SNS users, and also assists in allowing persons (but not selves) to persist as ethical patients in our lifeworld after biological death. Using Blustein’s “rescue from insignificance” argument for duties of remembrance, I argue that this persistence function supplies a nontrivial (if defeasible) obligation not to delete these artefacts. Drawing on Luciano Floridi’s account of “constitutive” information, I further argue that the “digital remains” metaphor is surprisingly apt: these artefacts in fact enjoy a claim to moral regard akin to that of corpses. (shrink)

Abstract: There is no such thing as ‘the’ hylemorphic account of personal identity. There are several views that count as hylemorphic, and these views can be grouped into two main families—the corruptionist view, and the survivalist view. The differentiating factor is that the corruptionist view holds that the persistence of the soul is not sufficient for the persistence of the person, while the survivalist view holds that the persistence of the soul is sufficient for the persistence of the person. In (...) this paper, I argue that hylemorphists should prefer the corruptionist view. This project ought to be of interest to anyone working on issues of personal identity, not only because hylemorphic views are historically important, but also because they are currently receiving significant attention in the personal identity literature. (shrink)

In 1988, Nadine Dormoy conducted a series of interviews with Rene Girard after a number of books and conferences had situated his work in a new context of research on self-organizing systems. In these interviews, Girard discusses the intellectual activity that followed the 1982 Stanford University conference, Disorder and Order. Girard also discusses Theater of Envy, his book on Shakespeare, as well as corrects several misunderstandings of his mimetic hypothesis.

Tens of thousands of students have learned to be more discerning at constructing and evaluating arguments with the help of Patrick J. Hurley. Hurley’s lucid, friendly, yet thorough presentation has made A CONCISE INTRODUCTION TO LOGIC the most widely used logic text in North America. In addition, the book’s accompanying technological resources, such as CengageNOW and Learning Logic, include interactive exercises as well as video and audio clips to reinforce what you read in the book and hear in class. (...) In short, you’ll have all the assistance you need to become a more logical thinker and communicator. Important Notice: Media content referenced within the product description or the product text may not be available in the ebook version. (shrink)

Since St. Thomas Aquinas holds that death is a substantial change, a popular current interpretation of his anthropology must be mistaken. According to that interpretation – the ‘survivalist’ view – St. Thomas holds that we human beings survive our deaths, constituted solely by our souls in the interim between death and resurrection. This paper argues that St. Thomas must have held the ‘corruptionist’ view: the view that human beings cease to exist at their deaths. Certain objections to the corruptionist view (...) are also met. (shrink)

Presents an historical analysis of social contract theory by considering the works of prominent philosophers.

Quantum mechanical entangled configurations of particles that do not satisfy Bell’s inequalities, or equivalently, do not have a joint probability distribution, are familiar in the foundational literature of quantum mechanics. Nonexistence of a joint probability measure for the correlations predicted by quantum mechanics is itself equivalent to the nonexistence of local hidden variables that account for the correlations (for a proof of this equivalence, see Suppes and Zanotti, 1981). From a philosophical standpoint it is natural to ask what sort of (...) concept can be used to provide a “joint” analysis of such quantum correlations. In other areas of application of probability, similar but different problems arise. A typical example is the introduction of upper and lower probabilities in the theory of belief. A person may feel uncomfortable assigning a precise probability to the occurrence of rain tomorrow, but feel comfortable saying the probability should be greater than ½ and less than ⅞. Rather extensive statistical developments have occurred for this framework. A thorough treatment can be found in Walley (1991) and an earlier measurement-oriented development in Suppes (1974). It is important to note that this focus on beliefs, or related Bayesian ideas, is not concerned, as we are here, with the nonexistence of joint probability distributions. Yet earlier work with no relation to quantum mechanics, but focused on conditions for existence has been published by many people. For some of our own work on this topic, see Suppes and Zanotti (1989). Still, this earlier work naturally suggested the question of whether or not upper and lower measures could be used in quantum mechanics, as a generalization of.. (shrink)