The present work is motivated by two questions. (1) What should an intuitionistic epistemic logic look like? (2) How should one interpret the knowledge operator in a Kripke-model for it? In what follows we outline an answer to (2) and give a model-theoretic definition of the operator K. This will shed some light also on (1), since it turns out that K, defined as we do, fulfills the properties of a necessity operator for a normal modal logic. The interest of (...) our construction also lies in a better insight into the intuitionistic solution to Fitch's paradox, which is discussed in the third section. In particular we examine, in the light of our definition, De Vidi and Solomon's proposal of formulating the verification thesis as Φ → ¬¬KΦ. We show, as our main result, that this definition excapes the paradox, though it is validated only under restrictive conditions on the models. (shrink)

The paper attempts to give a solution to the Fitch's paradox though the strategy of the reformulation of the paradox in temporal logic, and a notion of knowledge which is a kind of ceteris paribus modality. An analogous solution has been offered in a different context to solve the problem of metaphysical determinism.

Core principles of mereology have been questioned by appealing to time travel scenarios. This paper questions the methodology of employing time travel scenarios to argue against mereology. We show some time travel scenarios are structurally equivalent to more standard ones not involving time travel; and that the three main theories about persistence through time can each solve both the time travel scenario as well as the structurally similar classical scenario. Time travel scenarios that are not similar to more standard arguments (...) are instead problematic because they are open to different, incompatible interpretations. We conclude that compared to the classical arguments against mereological principles, time travel scenarios do not add anything new. (shrink)

A group is in a state of pluralistic ignorance (PI) if, roughly speaking, every member of the group thinks that his or her belief or desire is different from the beliefs or desires of the other members of the group. PI has been invoked to explain many otherwise puzzling phenomena in social psychology. The main purpose of this article is to shed light on the nature of PI states – their structure, internal consistency and opacity – using the formal apparatus (...) of Dynamic Doxastic Logic, and also to study the sense in which such states are “fragile”, i.e. to identify plausible conditions under which a PI state cascades into a state of shared belief as the result of announcement. (shrink)

Supervaluationism holds that the future is undetermined, and as a consequence of this, statements about the future may be neither true nor false. In the present paper, we explore the novel and quite different view that the future is abundant: statements about the future do not lack truth-value, but may instead be glutty, that is both true and false. We will show that the logic resulting from this “abundance of the future” is a non-adjunctive paraconsistent formalism based on subvaluations, which (...) has the virtue that all classical laws are valid in it, while no formula like φ ∧ ¬φ is satisfiable ; The peculiar behaviour of abundant logical consequence has an illuminating analogy in probability logic; abundance preserves some important features of classical logic when it comes to express those important retrogradations of truth which are presupposed by the argument de praesenti ad praeteritum. (shrink)

Exchange of arguments in a discussion often makes individuals more radical about their initial opinion. This phenomenon is known as Group-induced Attitude Polarization. A byproduct of it are bipolarization effects, where the distance between the attitudes of two groups of individuals increases after the discussion. This paper is a first attempt to analyse the building blocks of information exchange and information update that induce polarization. I use Argumentation Frameworks as a tool for encoding the information of agents in a debate (...) relative to a given issue a. I then adapt a specific measure of the degree of acceptability of an opinion. Changes in the degree of acceptability of a, prior and posterior to information exchange, serve here as an indicator of polarization. I finally show that the way agents transmit and update information has a decisive impact on polarization and bipolarization. (shrink)

During the first months of 1887, while completing the drafts of his Mitteilungen zur Lehre vom Transfiniten, Georg Cantor maintained a continuous correspondence with Benno Kerry. Their exchange essentially concerned two main topics in the philosophy of mathematics, namely, (a) the concept of natural number and (b) the infinitesimals. Cantor's and Kerry's positions turned out to be irreconcilable, mostly because of Kerry's irremediably psychologistic outlook, according to Cantor at least. In this study, I will examine and reconstruct the main points (...) in the discussion around (a) and (b) and stress some interesting aspects of the philosophical and mathematical thought of Benno Kerry. (shrink)

Reformulation strategies for solving Fitch’s paradox of knowability date back to Edgington. Their core assumption is that the formula \, from which the paradox originates, does not correctly express the intended meaning of the verification thesis, which should concern possible knowledge of actual truths, and therefore the contradiction does not represent a logical refutation of verificationism. Supporters of these solutions claim that can be reformulated in a way that blocks the derivation of the paradox. Unfortunately, these reformulation proposals come with (...) other problems, on both the logical and the philosophical side. We claim that in order to make the reformulation idea consistent and adequate one should analyze the paradox from the point of view of a quantified modal language. An approach in this line was proposed by, among others, Kvanvig but was not fully developed in its technical details. Here we approach the paradox by means of a first order hybrid modal logic, a tool that strikes us as more adequate to express transworld reference and the rigidification needed to consistently express this idea. The outcome of our analysis is ambivalent. Given a first order formula we are able to express the fact that it is knowable in a way which is both consistent and adequate. However, one must give up the possibility of formulating as a substitution free schema of the kind \. We propose that one may instead formulate by means of a recursive translation of the initial formula, being aware that many alternative translations are possible. (shrink)

This work presents an overview of four different approaches to the problem of future contingency and determinism in temporal logics. All of them are bivalent, viz. they share the assumption that propositions concerning future contingent facts have a determinate truth-value. We introduce Ockhamism, Peirceanism, Actualism and T x W semantics, the four most relevant bivalent alternatives in this area, and compare them from the point of view of their expressiveness and their underlying metaphysics of time.

This paper presents two systems of temporal logic, \Lambda_{CPT} and \Lambda_{CPT@}, with ceteris paribus modalities. The principal aim is to show how this approach can be useful to give an ockhamist solution to the future contingents problem along the same lines of A. Prior. The interest of this work lies also in the fact that \Lambda_{CPT@} represents an alternative modal account of supervaluationist and post-semantics approaches to temporal reasoning.

This paper introduces a multi-agent dynamic epistemic logic for abstract argumentation. Its main motivation is to build a general framework for modelling the dynamics of a debate, which entails reasoning about goals, beliefs, as well as policies of communication and information update by the participants. After locating our proposal and introducing the relevant tools from abstract argumentation, we proceed to build a three-tiered logical approach. At the first level, we use the language of propositional logic to encode states of a (...) multi-agent debate. This language allows to specify which arguments any agent is aware of, as well as their subjective justification status. We then extend our language and semantics to that of epistemic logic, in order to model individuals’ beliefs about the state of the debate, which includes uncertainty about the information available to others. As a third step, we introduce a framework of dynamic epistemic logic and its semantics, which is essentially based on so-called event models with factual change. We provide completeness results for a number of systems and show how existing formalisms for argumentation dynamics and unquantified uncertainty can be reduced to their semantics. The resulting framework allows reasoning about subtle epistemic and argumentative updates—such as the effects of different levels of trust in a source—and more in general about the epistemic dimensions of strategic communication. (shrink)

The Compendium grammatices linguae hebraeae, one of Spinoza’s four unfinished works, was published in the Opera Posthuma of 1677. Three centuries later, there is still no critical edition and contributions towards the emendation of this work are very few and far between. This article offers a brief account of the nature, aims and chronology of Spinoza’s grammar. It also provides ample indications for a critical edition and advocates in great detail the need for numerous emendations to the text of the (...) Opera Posthuma. (shrink)

December 2008 marked the 60th anniversary of the Universal Declaration of Human Rights, arguably the single most important and influential document endorsed by the United Nations. Jacques Maritain was a primary author of the religious liberty clauses of the 1948 Declaration, and the most prominent Christian philosopher ofthe twentieth century. Maritain developed a radical critique of prevailing Westem political and social thought. A persuasive critic of secular humanism and legal positivism, Maritain sought a cultural renewal of Christian Europe by means (...) of rediscovering an integral Christian humanism. This essay explores the central ideas in Maritain's philosophical defense of universal human rights. Maritain placed the philosophical foundation of human rights in natural law, and assumed the existence of a "natural spirituality of intelligence" grasped by a connatural, pre-philosophic intuition. Yet Pope Benedict XVI challenges the central philosophical assumptions at the foundation of Maritain's defense of human rights. (shrink)

This paper studies the relation between persuasive argumentation and the speaker’s epistemic attitude. Dung-style abstract argumentation and dynamic epistemic logic provide the necessary tools to characterize the notion of persuasion. Within abstract argumentation, persuasive argumentation has been previously studied from a game-theoretic perspective. These approaches are blind to the fact that, in real-life situations, the epistemic attitude of the speaker determines which set of arguments will be disclosed by her in the context of a persuasive dialogue. This work is a (...) first step to fill this gap. For this purpose we extend one of the logics of Schwarzentruber et al. with dynamic operators, designed to capture communicative phenomena. A complete axiomatization for the new logic via reduction axioms is provided. Within the new framework, a distinction between actual persuasion and persuasion from the speaker’s perspective is made. Finally, we explore the relationship between the two notions. (shrink)

Discussion among individuals about a given issue often induces polarization and bipolarization effects, i.e. individuals radicalize their initial opinion towards either the same or opposite directions. Experimental psychologists have put forward Persuasive Arguments Theory as a clue for explaining polarization. PAT claims that adding novel and persuasive arguments pro or contra the debated issue is the major cause for polarization. Recent developments in abstract argumentation provide the tools for capturing these intuitions on a formal basis. Here Bipolar Argumentation Frameworks are (...) employed as a tool for encoding the information of agents in a debate relative to a given issue a. A probabilistic extension of BAF allows to encode the likelihood of the opinions pro or contra a before and after information exchange. It is shown, by a straightforward example, how these measures provide the basis to capture the intuitions of PAT. (shrink)

The paper introduces a probabilistic semantics for the paraconsistent temporal logic Ab presented by the authors in a previous work on future contingents. Probabilistic concepts help framing two possible interpretations of the logic in question - a `subjective' and an `objective' one - and explaining the rationale behind both of them. We also sketch a proof-method for Ab and address some considerations regarding the conceptual appeal of our proposal and its possible future developments.

This paper aims at presenting the work of Dutch architecture Hans van der Laan through a comparison with the Renaissance architect Leon Battista Alberti by stating the similarity of the role assigned to proportion in architectural design by both architects. In particular, the study will show how both Van der Laan and Alberti understood proportion and the perceptive and aesthetic values of proportioned forms as the result of an intellectual appreciation.

Group polarization occurs when an initial attitude or belief of individuals becomes more radical after group discussion. Polarization often leads subgroups towards opposite directions. Since the 1960s this effect has been observed and repeatedly confirmed in lab experiments by social psychologists. Persuasive Arguments Theory emerged as the most convincing explanation for this phenomenon. This paper is a first attempt to frame the PAT explanation more formally by means of Bipolar Argumentation Frameworks. In particular, I show that polarization may emerge in (...) a BAF by simple and rational belief updates by participants. (shrink)

This remarkably lucid and original book presents a powerful case for the rationality of induction, a defense beginning with a “nomological-explanatory solution” and concluding with a “theological-explanatory solution.” Foster’s arguments range from his opening defense of the rationality of the methods of inductive and inferential reasoning, that is, the reasoning at the foundation of modern scientific discoveries about the natural world, to his conclusion linking the existence of universal and necessary laws of nature to the existence of a personal creator (...) God as the ultimate source of those laws. (shrink)

This early work by Derrida, his 1953/ 54 dissertation, introduced the philosophy of Husserl to French intellectuals. Derrida’s professed goal in this work is to “arrange for access to and complete intelligibility of a historical movement: that of Husserlian phenomenology”. According to Derrida, Husserl began with the intention of undertaking a philosophical revolution, but in the end remained “the prisoner of a great classical tradition: the one that reduces human finitude to an accident of history, to an ‘essence of man’ (...) that understands temporality against a background of possible or actual eternity in which it has or could have participated”. Derrida announces with these opening comments that he does not share in this “great classical tradition,” which so clearly served as the inspiration for Husserl’s turn toward philosophy and his lifelong search, which was a search for philosophic certitude and a search for meaning. (shrink)

Despite several criticisms surrounding the DSM classification in psychiatry, a significant bulk of research on mental conditions still operates according to two core assumptions: a) homogeneity, that is the idea that mental conditions are sufficiently homogeneous to justify generalization; b) additive comorbidity, that is the idea that the coexistence of multiple conditions in the same individual can be interpreted as additive. In this paper we take autism research as a case study to show that, despite a plethora of criticism, psychiatric (...) research often continues to operate in accordance with this model. Then we argue that such a model runs into problems once facts about comorbidity are taken into account. Finally, we offer some suggestions on how to tackle the challenge raised by comorbidity and its impact on heterogeneity. To do so, we explore transdiagnostic stratification accounts and network models to show that combining these approaches can move us in the right direction. (shrink)

Several theories propose that one of the core functions of inner speech (IS) is to support subjects in the completion of cognitively effortful tasks, especially those involving executive functions (EF). In this paper we focus on two populations who notoriously encounter difficulties in performing EF tasks, namely, people diagnosed with schizophrenia who experience auditory verbal hallucinations (Sz-AVH) and people within the Autism Spectrum Conditions (ASC). We focus on these two populations because they represent two different ways in which IS can (...) fail to help in EF tasks, which can be illustrative for other mental conditions. First, we review the main components of EF (Section 1). Then we explain the functions that IS is taken to perform in the domain of EF (Section 2) and review the evidence concerning problems about EF in the two populations of our study: Sz-AVH (Section 3) and ASC (Section 4). After this we further detail our account about what a properly functioning IS can do for both populations and how different IS profiles may impact EF performance: in the case of Sz-AVH, the uncontrolled and intrusive character of IS negatively affects EF performance, whereas in ASC, EF is not sufficiently supported by IS, given the tendency in this population to present a diminished use of IS (Section 5). We finally briefly discuss Attention Deficit/Hyperactivity Disorder (ADHD) and Developmental Language Disorders (DLD). (shrink)