Francesco Berto | University of St Andrews (original) (raw)

Papers by Francesco Berto

The Journal of Philosophy, 2024

We find a simple counterfactual acceptable, it is argued, to the extent that (i) our probability ... more We find a simple counterfactual acceptable, it is argued, to the extent that (i) our probability of the consequent under the thought experiment of counterfactually supposing the antecedent is high, (ii) provided the latter is on-topic with respect to the former. Counterfactual supposition is represented by Lewisian imaging. Topicality, by an algebra of subject matters. A topic-sensitive probabilistic logic is then provided, to reason about the acceptability of simple counterfactuals.

Synthese, 2024

A hyperintensional epistemic logic would take the contents which can be known or believed as more... more A hyperintensional epistemic logic would take the contents which can be known or believed as more fine-grained than sets of possible worlds. I consider one objection to the idea: Williamson's Objection from Overfitting. I propose a hyperintensional account of propositions as sets of worlds enriched with topics: what those propositions, and so the attitudes having them as contents, are about. I show that the account captures the conditions under which sentences express the same content; that it can be pervasively applied in formal and mainstream epistemology; and that it is left unscathed by the objection.

Linguistics and Philosophy, 2024

When do two sentences say the same thing, that is, express the same content? We defend two-compon... more When do two sentences say the same thing, that is, express the same content? We defend two-component (2C) semantics: the view that propositional contents comprise (at least) two irreducibly distinct constituents, (1) truth-conditions, and (2) subject-matter. We contrast 2C with one-component (1C) semantics, focusing on the view that subject-matter is reducible to truth conditions. We identify exponents of this view and argue in favor of 2C. An appendix proposes a general formal template for propositional 2C semantics.

Noûs, 2023

There is some consensus on the claim that imagination as suppositional thinking can have epistemi... more There is some consensus on the claim that imagination as suppositional thinking can have epistemic value insofar as it's constrained by a principle of minimal alteration of how we know or believe reality to be -- compatibly with the need to accommodate the supposition initiating the imaginative exercise. But in the philosophy of imagination there is no formally precise account of how exactly such minimal alteration is to work. I propose one. I focus on counterfactual imagination, arguing that this can be modeled as simulated belief revision governed by Laplacian imaging. So understood, it can be rationally justified by accuracy considerations: it minimizes expected belief inaccuracy, as measured by the Brier score.

Philosophical Studies

Sentences φ and ψ are cognitive synonyms for one when they play the same role in one's cognitive ... more Sentences φ and ψ are cognitive synonyms for one when they play the same role in one's cognitive life. The notion is pervasive (§ 1), but elusive: it is bound to be hyperintensional (§ 2), but excessive fine-graining would trivialize it and there are reasons for some coarse graining (§ 2.1). Conceptual limitations stand in the way of a natural algebra (§ 2.2), and it should be sensitive to subject matters (§ 2.3). A cognitively adequate individuation of content may be intransitive (§ 3) due to 'dead parrot' series: sequences of sentences φ1 ,... , φn where adjacent φi and φi+1 are cognitive synonyms while φ1 and φn are not (§ 3.1). Finding an intransitive account is hard: Fregean equipollence won't do (§ 3.2) and a result by Leitgeb shows that it wouldn't satisfy a minimal compositionality principle (§ 3.3). Sed contra, there are reasons for transitivity, too (§ 3.4). In § 4, we come up with a formal semantics capturing this jumble of desiderata, thereby showing that the notion is coherent. In § 5, we reassess the desiderata in its light.

Journal of Phiosophical Logic

Framing effects concern the having of different attitudes towards logically or necessarily equiva... more Framing effects concern the having of different attitudes towards logically or necessarily equivalent contents. Framing is of crucial importance for cognitive science, behavioral economics, decision theory, and the social sciences at large. We model a typical kind of framing, grounded in (i) the structural distinction between beliefs activated in working memory and beliefs left inactive in long term memory, and (ii) the topic-or subject matter-sensitivity of belief: a feature of propositional attitudes which is attracting growing research attention. We introduce a class of models featuring (i) and (ii) to represent, and reason about, agents whose belief states can be subject to framing effects. We axiomatize a logic which we prove to be sound and complete with respect to the class.

Synthese, 2022

Timothy Williamson has defended the claim that the semantics of the indicative 'if' is given by t... more Timothy Williamson has defended the claim that the semantics of the indicative 'if' is given by the material conditional. Putative counterexamples can be handled by better understanding the role played in our assessment of indicatives by a fallible cognitive heuristic, called the Suppositional Procedure. Williamson's Suppositional Conjecture has it that the Suppositional Procedure is humans' primary way of prospectively assessing conditionals. This paper raises some doubts on the Suppositional Procedure and Conjecture.

Philosophical Studies, 2021

We propose a new account of indicative conditionals, giving acceptability and logical closure con... more We propose a new account of indicative conditionals, giving acceptability and logical closure conditions for them. We start from Adams' Thesis: the claim that the acceptability of a simple indicative equals the corresponding conditional probability. The Thesis is widely endorsed, but arguably false and refuted by empirical research. To fix it, we submit, we need a relevance constraint: we accept a simple conditional 'If φ, then ψ' to the extent that (i) the conditional probability p(ψ|φ) is high, provided that (ii) φ is relevant for ψ. How (i) should work is well-understood. It is (ii) that holds the key to improve our understanding of conditionals. Our account has (i) a probabilistic component, using Popper functions; (ii) a relevance component, given via an algebraic structure of topics or subject matters. We present a probabilistic logic for simple indicatives, and argue that its (in)validities are both theoretically desirable and in line with empirical results on how people reason with conditionals.

Review of Symbolic Logic, 2020

We propose a dynamic hyperintensional logic of belief revision for non-omniscient agents, reducin... more We propose a dynamic hyperintensional logic of belief revision for non-omniscient agents, reducing the logical omniscience phenomena affecting standard doxastic/epistemic logic as well as AGM belief revision theory. Our agents don't know all a priori truths; their belief states are not closed under classical logical consequence; and their belief update policies are such that logically or necessarily equivalent contents can lead to different revisions. We model both plain and conditional belief, then focus on dynamic belief revision. The key idea we exploit to achieve non-omniscience focuses on topic- or subject matter-sensitivity: a feature of belief states which is gaining growing attention in the recent literature.

Review of symbolic Logic

We study imagination as reality-oriented mental simulation (ROMS): the activity of simulating non... more We study imagination as reality-oriented mental simulation (ROMS): the activity of simulating non-actual scenarios in one’s mind, to investigate what would happen if they were realized. Three connected questions concerning ROMS are: What is the logic, if there is one, of such an activity? How can we gain new knowledge via it? What is voluntary in it and what is not? We address them by building a list of core features of imagination as ROMS, drawing on research in cognitive psychology and the philosophy of mind. We then provide a logic of imagination as ROMS which models such features, combining techniques from epistemic logic, action logic, and subject matter semantics. Our logic comprises a modal propositional language with non-monotonic imagination operators, a formal semantics, and an axiomatization.

Journal of Philosophical Logic, 2019

We propose a solution to the problem of logical omniscience in what we take to be its fundamental... more We propose a solution to the problem of logical omniscience in what we take to be its fundamental version: as concerning arbitrary agents and the knowledge attitude per se. Our logic of knowledge is a spin-off from a general theory of thick content, whereby the content of a sentence has two components: (i) an intension, taking care of truth conditions; and (ii) a topic, taking care of subject matter. We present a list of plausible logical validities and invalidities for the logic of knowledge per se for arbitrary agents, and isolate three explanatory factors for them: (1) the topic-sensitivity of content; (2) the fragmentation of knowledge states; (3) the defeasibility of knowledge acquisition. We then present a novel dynamic epistemic logic that yields precisely the desired validities and invalidities, for which we provide expressivity and completeness results. We contrast this with related systems and address possible objections.

Australasian Journal of Logic, 2020

We reply to arguments by Otávio Bueno and Edward Zalta ('Object Theory and Modal Meinongianism', ... more We reply to arguments by Otávio Bueno and Edward Zalta ('Object Theory and Modal Meinongianism', Australasian Journal of Philosophy, 2017) against Modal Meinongianism, including that it presupposes, but cannot maintain, a unique denotation for names of fictional characters, and that it is not generalized to higher-order objects. We individuate the crucial difference between Modal Meinongianism and Object Theory in the for-mer's resorting to an apparatus of worlds for the representational purposes for which the latter resorts to a distinction between two kinds of predi-cation, exemplification and encoding. We argue that the distinction has fewer supporters than Bueno and Zalta want, and that there's a reason why the notion of encoding has been found baffling by some.

We present a formal semantics for epistemic logic, capturing the notion of 'knowability relative ... more We present a formal semantics for epistemic logic, capturing the notion of 'knowability relative to information' (KRI). Like Dretske, we move from the platitude that what an agent can know depends on her (empirical) information. We treat operators of the form K_AB ('B is knowable on the basis of information A') as variably strict quantifiers over worlds with a topic- or aboutness- preservation constraint. Variable strictness models the non-monotonicity of knowledge acquisition while allowing knowledge to be intrinsically stable. Aboutness-preservation models the topic-sensitivity of information, allowing us to invalidate controversial forms of epistemic closure while validating less controversial ones. Thus, unlike the standard modal framework for epistemic logic, KRI accommodates plausible approaches to the Kripke-Harman dogmatism paradox, which bear on non-monotonicity, or on topic-sensitivity. KRI also strikes a better balance between agent idealization and a non-trivial logic of knowledge ascriptions.

We present and defend the Australian Plan semantics for negation. This is a comprehensive account... more We present and defend the Australian Plan semantics for negation. This is a comprehensive account, suitable for a variety of different logics. It is based on two ideas. The first is that negation is an exclusion-expressing device: we utter negations to express incompatibilities. The second is that, because incompatibility is modal, negation is a modal operator as well. It can, then, be modelled as a quantifier over points in frames, restricted by accessibility relations representing compatibilities and incompatibilities between such points. We defuse a number of objections to this Plan, raised by supporters of the American Plan for negation, in which negation is handled via a many-valued semantics. We show that the Australian Plan has substantial advantages over the American Plan.

Erkenntnis, 2019

We present a framework for epistemic logic, modeling the logical aspects of System 1 ("fast") and... more We present a framework for epistemic logic, modeling the logical aspects of System 1 ("fast") and System 2 ("slow") cognitive processes, as per dual process theories of reasoning. The framework combines non-normal worlds semantics with the techniques of Dynamic Epistemic Logic. It models non-logically-omniscient, but moderately rational agents: their System 1 makes fast sense of incoming information by integrating it on the basis of their background knowledge and beliefs. Their System 2 allows them to slowly, step-wise unpack some of the logical consequences of such knowledge and beliefs, by paying a cognitive cost. The framework is applied to three instances of limited rationality, widely discussed in cognitive psychology: Stereotypical Thinking, the Framing Effect, and the Anchoring Effect.

Synthese, 2018

The ‘puzzle of imaginative use’ (Kind and Kung, 2016) asks: given that imagination is arbitrary e... more The ‘puzzle of imaginative use’ (Kind and Kung, 2016) asks: given that imagination is arbitrary escape from reality, how can it have any epistemic value? In particular, imagination seems to be logically anarchic, like a runabout inference ticket: one who imagines A may also imagine whatever B pops to one’s mind by free mental association. This paper argues that at least a certain kind of imaginative exercise – reality-oriented mental simulation – is not logically anarchic. Showing this is part of the task of solving the puzzle. Six plausible features of imagination, so understood, are listed. Then a formal semantics is provided, whose patterns of logical validity and invalidity model the six features.

We present a theory of truth in fiction that improves on Lewis’s [1978] ‘Analysis 2’ in two ways.... more We present a theory of truth in fiction that improves on Lewis’s [1978] ‘Analysis 2’ in two ways. First, we expand Lewis’s possible worlds apparatus by adding non-normal or impossible worlds. Second, we model truth in fiction as (make-believed) belief revision via ideas from dynamic epistemic logic. We explain the major objections raised against Lewis’s original view and show that our theory overcomes them.

I present a possible worlds semantics for a hyperintensional belief revision operator, which redu... more I present a possible worlds semantics for a hyperintensional belief revision operator, which reduces the logical idealization of cognitive agents affecting similar operators in doxastic and epistemic logics, as well as in standard AGM belief revision theory. (Revised) belief states are not closed under classical logical consequence; revising by inconsistent information does not perforce lead to trivialization; and revision can be subject to ‘framing effects’: logically or necessarily equivalent contents can lead to different revisions. Such results are obtained without resorting to non-classical logics, or to non-normal or impossible worlds semantics. The framework combines, instead, a standard semantics for propositional S5 with a simple mereology of contents.

A counterpossible conditional is a counterfactual with an impossible antecedent. Common sense del... more A counterpossible conditional is a counterfactual with an impossible antecedent. Common sense delivers the view that some such conditionals are true, and some are false. In recent publications, Timothy Williamson has defended the view that all are true. In this paper we defend the common sense view against Williamson's objections.

I present a formal theory of the logic and aboutness of imagination. Aboutness is understood as t... more I present a formal theory of the logic and aboutness of imagination. Aboutness is understood as the relation between meaningful items and what they concern, as per Yablo and Fine's works on the notion. Imagination is understood as per Chalmers' positive conceivability: the intentional state of a subject who conceives that p by imagining a situation – a configuration of objects and properties – verifying p. So far aboutness theory has been developed mainly for linguistic representation , but it is natural to extend it to intentional states. The proposed framework combines a modal semantics with a mereology of contents: imagination operators are understood as variably strict quantifiers over worlds with a content-preservation constraint.

The Journal of Philosophy, 2024

Synthese, 2024

Linguistics and Philosophy, 2024

Noûs, 2023

Philosophical Studies

Journal of Phiosophical Logic

Synthese, 2022

Philosophical Studies, 2021

Review of Symbolic Logic, 2020

Review of symbolic Logic

Journal of Philosophical Logic, 2019

Australasian Journal of Logic, 2020

Erkenntnis, 2019

Synthese, 2018

Topics of Thought. The Logic of Knowledge, Belief, Imagination, 2022

When one thinks—knows, believes, imagines—that something is the case, one’s thought has a topic: ... more When one thinks—knows, believes, imagines—that something is the case, one’s thought has a topic: it is about something, towards which one’s mind is directed. What is the logic of thought, so understood?
This book begins to explore the idea that, to answer the question, we should take topics seriously. It proposes a hyperintensional account of the propositional contents of thought, arguing that these are individuated not only by the set of possible worlds at which they are true, but also by their topic: what they are about. The book then builds epistemic, doxastic, probabilistic, and conditional logics based on this view. It applies them to issues ranging from dogmatism, scepticism, and epistemic fallibilism, to imagination and suppositional reasoning, belief revision, framing effects, and the acceptability of indicative conditionals.

We need to understand the impossible. Francesco Berto and Mark Jago start by considering what the... more We need to understand the impossible. Francesco Berto and Mark Jago start by considering what the concepts of meaning, information, knowledge, belief, fiction, conditionality, and counterfactual supposition have in common. They are all concepts which divide the world up more finely than logic does. Logically equivalent sentences may carry different meanings and information and may differ in how they're believed. Fictions can be inconsistent yet meaningful. We can suppose impossible things without collapsing into total incoherence. Yet for the leading philosophical theories of meaning, these phenomena are an unfathomable mystery. To understand these concepts, we need a metaphysical, logical, and conceptual grasp of situations that could not possibly exist: Impossible Worlds. This book discusses the metaphysics of impossible worlds and applies the concept to a range of central topics and open issues in logic, semantics, and philosophy. It considers problems in the logic of knowledge, the meaning of alternative logics, models of imagination and mental simulation, the theory of information, truth in fiction, the meaning of conditional statements, and reasoning about the impossible. In all these cases, impossible worlds have an essential role to play.

Ontology and Metaontology: A Contemporary Guide is a clear and accessible survey of ontology, foc... more Ontology and Metaontology: A Contemporary Guide is a clear and accessible survey of ontology, focussing on the most recent trends in the discipline.

Divided into parts, the first half characterizes metaontology: the discourse on the methodology of ontological inquiry, covering the main concepts, tools, and methods of the discipline, exploring the notions of being and existence, ontological commitment, paraphrase strategies, fictionalist strategies, and other metaontological questions. The second half considers a series of case studies, introducing and familiarizing the reader with concrete examples of the latest research in the field. The basic sub-fields of ontology are covered here via an accessible and captivating exposition: events, properties, universals, abstract objects, possible worlds, material beings, mereology, fictional objects.

The guide's modular structure allows for a flexible approach to the subject, making it suitable for both undergraduates and postgraduates looking to better understand and apply the exciting developments and debates taking place in ontology today.

A logic is called 'paraconsistent' if it rejects the rule called 'ex contradictione quodlibet', a... more A logic is called 'paraconsistent' if it rejects the rule called 'ex contradictione quodlibet', according to which any conclusion follows from inconsistent premises. While logicians have proposed many technically developed paraconsistent logical systems and contemporary philosophers like Graham Priest have advanced the view that some contradictions can be true, and advocated a paraconsistent logic to deal with them, until recent times these systems have been little understood by philosophers. This book presents a comprehensive overview on paraconsistent logical systems to change this situation.
The book includes almost every major author currently working in the field. The papers are on the cutting edge of the literature some of which discuss current debates and others present important new ideas. The editors have avoided papers about technical details of paraconsistent logic, but instead concentrated upon works that discuss more "big picture" ideas. Different treatments of paradoxes takes centre stage in many of the papers, but also there are several papers on how to interpret paraconistent logic and some on how it can be applied to philosophy of mathematics, the philosophy of language, and metaphysics.

This book is both an introduction to and a research work on Meinongianism. “Meinongianism” is tak... more This book is both an introduction to and a research work on Meinongianism. “Meinongianism” is taken here, in accordance with the common philosophical jargon, as a general label for a set of theories of existence – probably the most basic notion of ontology. As an introduction, the book provides the first comprehensive survey and guide to Meinongianism and non-standard theories of existence in all their main forms. As a research work, the book exposes and develops the most up-to-date Meinongian theory (called modal Meinongianism), applies it to specific fields, and discusses its open problems. The unifying focus of the work is a single, basic philosophical notion: the notion of existence. Each main theory of the notion available in philosophy is introduced via a detailed, self-contained exposition, and critically evaluated, with the original research emerging in the final Chapters. Part I of the book provides a historical introduction to, and critical discussion of, the dominant philosophical view of existence: the “Kantian-Fregean-Quinean” perspective. Part II is the full-fledged introduction to the Meinongian theories of existence as a real property of individuals: after starting with the so-called naïve Meinongian conception and its problems, it provides a self-contained presentation of the main neo-Meinongian proposals, and a detailed discussion of their strengths and weaknesses. Part III develops a specific neo-Meinongian theory of existence employing a model-theoretic semantic framework. It discusses its application to the ontology and semantics of fictional objects, and its open problems. The methodology of the book follows the most recent trends in analytic ontology. In particular, the meta-ontological point of view is largely privileged

There is a principle in things, about which we cannot be deceived, but must always, on the contra... more There is a principle in things, about which we cannot be deceived, but must always, on the contrary, recognize the truth – viz. that the same thing cannot at one and the same time be and not be": with these words of the Metaphysics, Aristotle introduced the Law of Non-Contradiction, which was to become the most authoritative principle in the history of Western thought. However, things have recently changed, and nowadays various philosophers, called dialetheists, claim that this Law does not hold unrestrictedly – that in peculiar circumstances the same thing may at the same time be and not be, and contradictions may obtain in the world. This book opens with an examination of the famous logical paradoxes that appear to speak on behalf of contradictions (e.g., the Liar paradox, the set-theoretic paradoxes such as Cantor’s and Russell’s), and of the reasons for the failure of the standard attempts to solve them. It provides, then, an introduction to paraconsistent logics – non-classical logics in which the admission of contradictions does not lead to logical chaos –, and their astonishing applications, going from inconsistent data base management to contradictory arithmetics capable of circumventing Gödel’s celebrated Incompleteness Theorem. The final part of the book discusses the philosophical motivations and difficulties of dialetheism, and shows how to extract from Aristotle’s ancient words a possible reply to the dialetheic challenge. How to Sell a Contradiction will appeal to anyone interested in non-classical logics, analytic metaphysics, and philosophy of mathematics, and especially to those who consider challenging our most entrenched beliefs the main duty of philosophical inquiry.

La guida completa al Teorema di incompletezza. …, Jan 1, 2008

«Esiste negli esseri un principio rispetto al quale è necessario che si sia sempre nel vero: è qu... more «Esiste negli esseri un principio rispetto al quale è necessario che si sia sempre nel vero: è questo il principio che afferma che non è possibile che la medesima cosa in un unico e medesimo tempo sia e non sia»: così, nella Metafisica di Aristotele, viene presentato il Principio di Non-Contraddizione, destinato a diventare la legge più autorevole nella storia dell'intero pensiero occidentale. Oggi, tuttavia, diversi filosofi sostengono che questa legge non ha validità universale, che vi sono situazioni in cui una stessa cosa può insieme essere e non essere, e l'assurdo si realizza nel mondo. In questo volume, Francesco Berto esamina il vasto dibattito sulla contraddizione in corso nella comunità filosofica internazionale; introduce le più moderne strategie logico-filosofiche per descrivere mondi abitati da contraddizioni; e mostra come proprio nell'antica parola di Aristotele il Principio trovi risposte ai suoi critici attuali. Che ci si schieri dall'una o dall'altra parte, si esce dalla lettura di queste pagine con la convinzione che il regno dell'assurdo non sia un buco nero del pensiero, ma un affascinante terreno d'esplorazione filosofica.

Ho scritto questo libro per me stesso (ossia, per diventare ricco e famoso), ma non avrei potuto ... more Ho scritto questo libro per me stesso (ossia, per diventare ricco e famoso), ma non avrei potuto farlo da un lato senza l'affetto, e dall'altro senza la competenza, delle persone e degli studiosi che hanno influito su di me.

Epistemic Uses of Imagination, 2021

One sense of 'imagination' that matters in epistemology has the word mean 'reality-oriented menta... more One sense of 'imagination' that matters in epistemology has the word mean 'reality-oriented mental simulation' (ROMS): we suppose that something is the case; develop the supposition by importing background knowledge and beliefs; and check what is true in the imagined scenario.
What is the logic of ROMS? Imagination has a reputation for being logically anarchic. In particular, it's hyperintensional: we can imagine A without imagining a necessarily equivalent B. This work considers a Principle of Equivalence in Imagination which, if accepted, will limit the anarchy: when A and B are equivalent in imagination, one will imagine the same things after supposing either in ROMS.
What is equivalence in imagination? It is suggested that it's cognitive equivalence. A and B are cognitively equivalent for one when they play the same role in one's cognitive life: whatever one understands, concludes, etc., given either, one does, given the other. ROMS is logically modelled via variably strict modals. Two formal semantics are proposed for them: one uses possible worlds plus an algebra of topics; the other resorts to impossible worlds. The two deal with equivalence in imagination in subtly different ways.

THe Logica Yearbook 2018, 2019

A Topic-Sensitive Intentional Modal (TSIM) is a two-place, variably strict modal with an aboutnes... more A Topic-Sensitive Intentional Modal (TSIM) is a two-place, variably strict modal with an aboutness or topicality constraint, of the form ‘X^φψ’ (read: ‘Given φ, the agent X’s that ψ’, X being some mental state or act). TSIMs do nice things for mainstream and formal epistemology, belief revision theory, and mental simulation theory. I present a basic formal semantics for TSIMs and explore three readings of ‘X^φψ’ one gets by imposing different constraints on their truth conditions: (1) as expressing knowability relative to information (‘Given total information φ, one is in the position to know that ψ’), inspired by Dretske’s view that what one can know depends on the available (empirical) information; (2) as a mental simulation operator (‘In mental simulation starting with input φ, one imagines that ψ’) capturing features of mainstream mental simulation theories, like that of Nichols and Stich; (3) as a hyperintensional belief revision operator (‘After (statically) revising by φ, one believes that ψ’), reducing the idealization of cognitive agents one finds in standard doxastic logics and AGM. I close by mentioning developments of TSIM theory currently in progress.

Tractatus 4.024 inspired the dominant semantics of our time: truth-conditional semantics. Such se... more Tractatus 4.024 inspired the dominant semantics of our time: truth-conditional semantics. Such semantics is focused on possible worlds: the content of p is the set of worlds where p is true. It has become increasingly clear that such an account is, at best, defective: we need an ‘independent factor in meaning, constrained but not determined by truth-conditions’ (Yablo 2014, p. 2), because sentences can be differently true at the same possible worlds. I suggest a missing comment which, had it been included in the Tractatus, would have helped semantics get this right from the start. This is my 4.0241: ‘Knowing what is the case if a sentence is true is knowing its ways of being true’: knowing a sentence’s truth possibilities and what we now call its topic, or subject matter. I show that the famous ‘fundamental thought’ that ‘the “logical constants” do not represent’ (4.0312) can be understood in terms of ways-based views of meaning. Such views also help with puzzling claims like 5.122: ‘If p follows from q, the sense of “p” is contained in the that of “q”’, which are compatible with a conception of entailment combining truth-preservation with the preservation of topicality, or of ways of being true.

Against the mainstream Quinean meta-ontology, Meinongians claim: “There are things that do not ex... more Against the mainstream Quinean meta-ontology, Meinongians claim: “There are things that do not exist”. It is sometimes said that the “there are” in that sentence expresses “Meinongian quantification”. I consider two supposedly knock-down meta-ontological objections to Meinongianism from the literature: (1) an objection from equivocation, to the effect that the view displays a conceptual or semantic misunderstanding, probably of quantificational expressions; and (2) an objection from analyticity, to the effect that that sentence is Frege-analytically false i.e., it is synonymous with a logical falsity. Objection (1) is countered via a development of Williamson’s argument against epistemic conceptions of analyticity. Objection (2), which points at alleged linguistic evidence, is countered by resorting to linguistic counter-evidence. The upshot is a set-up of the debate between Quineans and Meinongians, in which the two parties disagree on substantive matters concerning de re the property of existence, taken as a natural property in the Lewis-Sider sense; and in which quick alleged refutations, such as objections from meaning-variance or analytic falsehood, rarely achieve their expected results.

While the term "metaontology" may well have been used before, one can take 1998 as the year it of... more While the term "metaontology" may well have been used before, one can take 1998 as the year it officially entered the lexicon of analytic philosophy. That year, Peter van Inwagen published an essay having that word as its title (see ). Quine taught us that the fundamental question of ontology is "What is there?" Van Inwagen asked about the meaning of that very question, and wondered how we should address it-what is the correct methodology of ontology. This was for him the subject of metaontology. His "meta" prefix pointed at a higher level of inquiry: "meta-X" as the investigation of the basic notions and techniques of discipline X.

The Logica Yearbook 2011, 2012

World semantics for relevant logics include so-called non-normal or impossible worlds providing m... more World semantics for relevant logics include so-called non-normal or impossible worlds providing model-theoretic counterexamples to such irrelevant entailments as (A ∧ ¬A) → B, A → (B∨¬B), or A → (B → B). Some well-known views interpret non-normal worlds as information states. If so, they can plausibly model our ability of conceiving or representing logical impossibilities. The phenomenon is explored by combining a formal setting with philosophical discussion. I take Priest’s basic relevant logic N4 and extend it, on the syntactic side, with a representation operator, (R), and on the semantic side, with particularly anarchic non-normal worlds. This combination easily invalidates unwelcome “logical omniscience” inferences of standard epistemic logic, such as belief-consistency and closure under entailment. Some open questions are then raised on the best strategies to regiment (R) in order to express more vertebrate kinds of conceivability.

Existence and Nature: New Perspectives, Oct 1, 2012

Stanford Encyclopedia of Philosophy, 2021

A hyperintensional concept draws a distinction between necessarily equivalent contents. If the co... more A hyperintensional concept draws a distinction between necessarily equivalent contents. If the concept is expressed by an operator, , then is hyperintensional insofar as and can differ in truth value in spite of and 's being necessarily equivalent. Necessary equivalence of claims is standardly understood in terms of possible worlds (ways things could have been): and are necessarily equivalent when they are true at the same worlds. This is sometimes put in terms of sentences sharing an intension. An extensional operator (e.g., Boolean negation) allows substitution salva veritate of sentences with the same extension, that is, truth value: if has the same truth value as , then also has the same truth value as. An intensional operator (e.g., the box of necessity) allows substitution salva veritate of sentences that express necessary equivalents: if is necessarily equivalent to , then has the same truth value as. The expression "hyperintensional" is thus for an that defies substitution salva veritate even of expressions with the same intension. Cresswell (1975) introduced the expression "hyperintensional" to pick out a position in a sentence where substitution fails for logical equivalents. Nowadays the term is used more broadly, with unrestrictedly necessary equivalence replacing logical equivalence. Candidates for unrestricted necessity often include, besides the logical, mathematical and metaphysical necessity. We don't discuss whether one of these is reducible to the others-e.g., the mathematical to the logical, as claimed by logicists.

Dialetheism, 2018

A dialetheia is a sentence, A, such that both it and its negation, ¬A, are true (we shall talk of... more A dialetheia is a sentence, A, such that both it and its negation, ¬A, are true (we shall talk of sentences throughout this entry; but one could run the definition in terms of propositions, statements, or whatever one takes as her favourite truth-bearer: this would make little difference in the context). Assuming the fairly uncontroversial view that falsity just is the truth of negation, it can equally be claimed that a dialetheia is a sentence which is both true and false...

"It is a venerable slogan due to David Hume, and inherited by the empiricist tradition, that the ... more "It is a venerable slogan due to David Hume, and inherited by the empiricist tradition, that the impossible cannot be believed, or even conceived. In Positivismus und Realismus, Moritz Schlick claimed that, while the merely practically impossible is still conceivable, the logically impossible, such as an explicit inconsistency, is simply unthinkable.

An opposite philosophical tradition, however, maintains that inconsistencies and logical impossibilities are thinkable, and sometimes believable, too. In the Science of Logic, Hegel already complained against “one of the fundamental prejudices of logic as hitherto understood”, namely that “the contradictory cannot be imagined or thought” (Hegel 1931: 430). Our representational capabilities are not limited to the possible, for we appear to be able to imagine and describe also impossibilities — perhaps without being aware that they are impossible.

Such impossibilities and inconsistencies are what this entry is about..."

Cellular automata (henceforth: CA) are discrete, abstract computational systems that have proved ... more Cellular automata (henceforth: CA) are discrete, abstract computational systems that have proved useful both as general models of complexity and as more specific representations of non-linear dynamics in a variety of scientific fields. Firstly, CA are (typically) spatially and temporally discrete: they are composed of a finite or denumerable set of homogenous, simple units, the atoms or cells. At each time unit, the cells instantiate one of a finite set of states. They evolve in parallel at discrete time steps, following state update functions or dynamical transition rules: the update of a cell state obtains by taking into account the states of cells in its local neighborhood (there are, therefore, no actions at a distance). Secondly, CA are abstract: they can be specified in purely mathematical terms and physical structures can implement them. Thirdly, CA are computational systems: they can compute functions and solve algorithmic problems. Despite functioning in a different way from traditional, Turing machine- like devices, CA with suitable rules can emulate a universal Turing machine (see entry), and therefore compute, given Turing’s thesis (see entry on Church-Turing thesis), anything computable...

The Reasoner, 2019

October 2019 update on the Logic of Conceivability project outcomes.

EU Research, 2019

The human imagination is enormously powerful, allowing us to conceive of far-fetched scenarios th... more The human imagination is enormously powerful, allowing us to conceive of far-fetched scenarios that go far beyond our individual experience. Yet imagination is useful for everyday practical reasoning as well. Researchers in the Logic of Conceivability project are using mathematical tools to investigate the logic of the human imagination, as Dr Peter Hawke explains

Questo è un articolo per la Festschrift in onore di Vero Tarca.

"Riuscirà il lato oscuro della filosofia de noantri a sottrarsi per sempre al referaggio anonimo?... more "Riuscirà il lato oscuro della filosofia de noantri a sottrarsi per sempre al referaggio anonimo? Spero di no. Sottrarsi è inaccettabile e sospetto che alcuni di coloro che lo fanno siano in malafede."

Questo post è stato originariamente pubblicato nel blog di filosofia dell'Università di Urbino:

http://filosofia.uniurb.it/i-referaggi-e-il-lato-oscuro-della-filosofia-italiana/

This is a 2016 interview on my research work.

Carocci

Profili, bacheche, post virali ed epic fail, like e dislike, ci introducono alla logica senza che... more Profili, bacheche, post virali ed epic fail, like e dislike, ci introducono alla logica senza che ce ne accorgiamo.

'La mia posizione filosofica in relazione al pensiero di Emanuele Severino.' -- Un piccolo interv... more 'La mia posizione filosofica in relazione al pensiero di Emanuele Severino.' -- Un piccolo intervento (Festschrift per Severino, in uscita in una collettanea).

This is a paper to to appear in "Graham Priest on Dialetheism and Paraconsistency", a volume dedi... more This is a paper to to appear in "Graham Priest on Dialetheism and Paraconsistency", a volume dedicated to GP, edited by Can Başkent, and Thomas M. Ferguson.