Achille Varzi è uno dei maggiori metafisici viventi. Nel corso degli anni ha scritto testi fondamentali di logica, metafisica, mereologia, filosofia del linguaggio. Ha sconfinato nella topologia, nella geografia, nella matematica, ha ragionato di mostri e confini, percezione e buchi, viaggi nel tempo, nicchie, eventi e ciambelle; e non ha disdegnato di dialogare con gli abitanti di Flatlandia, con Neo e con Terminator. Tra le sue opere principali: Holes and Other Superficialities e Parts and Places. The Structures of Spatial Representation, (...) entrambi scritti insieme a R. Casati per MIT Press; Il mondo messo a fuoco, Laterza; e il suo libro più recente: Le tribolazioni del filosofare, con C. Calosi, per Laterza. -/- Da una giornata all’Università di Urbino nasce questa conversazione a molte voci sulla e con la filosofia di Achille C. Varzi. In un dialogo critico al quale l’Autore si presta con generosità e onestà intellettuale, Andrea Borghini, Francesco Calemi, Claudio Calosi, Elena Casetta, Valeria Giardino, Pierluigi Graziani, Patrizia Pedrini, Daniele Santoro e Giuliano Torrengo lo interrogano e mettono alla prova sui temi affrontati, nel corso degli anni, in campi diversi. Il risultato è un percorso che si snoda attraverso molti mondi, dalla logica alla metafisica, dalla filosofia del linguaggio alla filosofia della matematica, dalla mereologia alla filosofia del tempo, spingendosi in qualche caso oltre i confini del saggio filosofico. (shrink)

Fictionalism in ontology is a mixed bag. Here I focus on three main variants—which I label after the names of Pascal, Berkeley, and Hume—and consider their relative strengths and weaknesses. The first variant is just a version of the epistemic Wager, applied across the board. The second variant builds instead on the fact that ordinary language is not ontologically transparent; we speak with the vulgar, but deep down we think with the learned. Finally, on the Humean variant it’s the structure (...) of the ontological inventory, not its content, that may turn out to involve fictional elements. That is, for the Humean the fiction lies, not in the reality of common-sense ontology, but in the laws—of unity, identity, causation, etc.—in terms of which we articulate our experience of that reality. In the end, this is the kind of fictionalism that I find most interesting, sensible, and tenable. And I argue that it is even compatible with the sort of “naive” realism we have all come to appreciate in the work of Paolo Bozzi, to whom the paper is dedicated. (shrink)

Abstract. As a general theory of reasoning—and as a general theory of what holds true under every possible circumstance—logic is supposed to be ontologically neutral. It ought to have nothing to do with questions concerning what there is, or whether there is anything at all. It is for this reason that traditional Aristotelian logic, with its tacit existential presuppositions, was eventually deemed inadequate as a canon of pure logic. And it is for this reason that modern quantification theory, too, with (...) its residue of existentially loaded theorems and patterns of inference, has been claimed to suffer from a defect of logical purity. The law of non-contradiction rules out certain circumstances as impossible—circumstances in which a statement is both true and false, or perhaps circumstances where something both is and is not the case. Is this to be regarded as a further ontological bias? (shrink)

That parthood is a transitive relation is among the most basic principles of classical mereology. Alas, it is also very controversial. In a recent paper, Ingvar Johansson has put forward a novel diagnosis of the problem, along with a corresponding solution. The diagnosis is on the right track, I argue, but the solution is misleading. And once the pieces are properly put together, we end up with a reinforcement of the standard defense of transitivity on behalf of classical mereology.

I argue that Universalism (the thesis that mereological composition is unrestricted) entails Extensionalism (the thesis that sameness of composition is sufficient for identity) as long as the parthood relation is transitive and satisfies the Weak Supplementation principle (to the effect that whenever a thing has a proper part, it has another part disjoint from the first).

What sort of logic do we get if we adopt a supervaluational semantics for vagueness? As it turns out, the answer depends crucially on how the standard notion of validity as truth preservation is recasted. There are several ways of doing that within a supervaluational framework, the main alternative being between “global” construals (e.g., an argument is valid iff it preserves truth-under-all-precisifications) and “local” construals (an argument is valid iff, under all precisifications, it preserves truth). The former alternative is by (...) far more popular, but I argue in favor of the latter, for (i) it does not suffer from a number of serious objections, and (ii) it makes it possible to restore global validity as a defined notion. (shrink)

I focus on three mereological principles: the Extensionality of Parthood (EP), the Uniqueness of Composition (UC), and the Extensionality of Composition (EC). These principles are not equivalent. Nonetheless, they are closely related (and often equated) as they all reflect the basic nominalistic dictum, No difference without a difference maker. And each one of them—individually or collectively—has been challenged on philosophical grounds. In the first part I argue that such challenges do not quite threaten EP insofar as they are either self-defeating (...) or unsupported. In the second part I argue that they hardly undermine the tenability of EC and UC as well. (shrink)

I argue that the conjunction of perdurantism (the view that objects are temporally extended) and universalism (the thesis that any old class of things has a mereological fusion) gives rise to undesired complications when combined with certain plausible assumptions concerning the semantics of tensed statements.

One logic or many? I say—many. Or rather, I say there is one logic for each way of specifying the class of all possible circumstances, or models, i.e., all ways of interpreting a given language. But because there is no unique way of doing this, I say there is no unique logic except in a relative sense. Indeed, given any two competing logical theories T1 and T2 (in the same language) one could always consider their common core, T, and settle (...) on that theory. So, given any language L, one could settle on the minimal logic T0 corresponding to the common core shared by all competitors. That would be a way of resisting relativism, as long as one is willing to redraw the bounds of logic accordingly. However, such a minimal theory T0 may be empty if the syntax of L contains no special ingredients the interpretation of which is independent of the specification of the relevant L-models. And generally—I argue—this is indeed the case. (shrink)

Mereotopology is today regarded as a major tool for ontological analysis, and for many good reasons. There are, however, a number of open questions that call for an answer. Some are philosophical, others have direct applicative import, but all are crucial for a proper assessment of the strengths and limits of mereotopology. This paper is an attempt to put sum order in this area.

Are there any bona fide boundaries, i.e., boundaries that carve at the joints? Or is any boundary—hence any object—the result of a fiat articulation reflecting our cognitive biases and our social practices and conventions? Does the choice between these two options amount to a choice between realism and wholesome relativism?

In previous work, I introduced a complete axiomatization of classical non-tautologies based essentially on Łukasiewicz’s rejection method. The present paper provides a new, Hilbert-type axiomatization (along with related systems to axiomatize classical contradictions, non-contradictions, contingencies and non-contingencies respectively). This new system is mathematically less elegant, but the format of the inferential rules and the structure of the completeness proof possess some intrinsic interest and suggests instructive comparisons with the logic of tautologies.

In previous work I have argued that talk about negative events should not be taken at face value: typically, what we are inclined to think of as a negative event (John’s failure to go jogging) is just an ordinary, positive event (his going to the movie instead); it is a positive event under a negative description. Here I consider more closely the difficulties that arise in those cases where no positive event seems available to do the job, as with putative (...) cases of causation by omission. In particular, I elaborate on Helen Beebee’s idea that not all causal explanations are reports of causation. When we mention John’s failure to turn off the gas as an explanans of why there was an explosion, we do not say what caused the explosion. We do not mention any of the relevant causes. We just remark that one sort of event that was supposed to occur, and whose occurrence would have prevented the explosion, did not in fact occur. (shrink)

An imaginary report of Square’s plans for a journey aimed to find out whether the topology of Flatland is sphere-like or torus-like, intended as a trubute to Hans Herzberger’s uncompromising philosophical style, courage, and passion.

This is a supplement to our book "Le tribolazioni del filosofare. Comedia metaphysica ne la quale si tratta de li errori & de le pene de l’Infero". It features an entirely new canto of the poem (originally thought to be lost) along with an extensive commentary. The canto covers the first ring of the circle of the Sullen, which hosts the Adverse to the Possible, and deals with several philosophical questions concerning the metaphysics of modality.

What is money? Paraphrasing Goodman, I say that’s the wrong question to ask. The right question is, When is money? And to get the answer, Searle’s general formula for social objects (X couns as Y in context C) is fine, as long as you give it a different reading.

We can see mereology as a theory of parthood and topology as a theory of wholeness. How can these be combined to obtain a unified theory of parts and wholes? This paper examines various non-equivalent ways of pursuing this task, with specific reference to its relevance to spatio-temporal reasoning. In particular, three main strategies are compared: (i) mereology and topology as two independent (though mutually related) chapters; (ii) mereology as a general theory subsuming topology; (iii) topology as a general theory (...) subsuming mereology. Some more speculative strategies and directions for further research are also considered. (shrink)

An overview of the way I picture the amorphous world we live in, built around my comments and responses to nine festschrift essays by A. Borghini (on the Fedro metaphor and the art of butchery), F. Calemi (on the predication principle and metalinguistic nominalism), C. Calosi (on the argument from mereological universalism to extensonality), E. Casetta (on the role of “monsters” in the realism/antirealism debate), V. Giardino (on inductive reasoning, spatial representation, and problem solving), P. Graziani (on mereological notation), P. (...) Pedrini (on the distinction between natural and artificial boundaries), D. Santoro (on causation by omission), and G. Torrengo (on absolute vs. relational space and the problem of incongruent counterparts). (shrink)

A discussion of some philosophical themes in the Terminator film series, including: the possibility of time travel, backward causation, the difference between changing the past/future and affecting it, the difference between determinism and fatalism, and how such issues depend on the underlying philosophy of time (eternism vs. presentism vs. the growing-block theory).

There are conflicting intuitions concerning the status of a boundary separating two adjacent entities (or two parts of the same entity). The boundary cannot belong to both things, for adjacency excludes overlap; and it cannot belong to neither, for nothing lies between two adjacent things. Yet how can the dilemma be avoided without assigning the boundary to one thing or the other at random? Some philosophers regard this as a reductio of the very notion of a boundary, which should accordingly (...) be treated a mere façon de parler. In this paper I resist this temptation and examine some ways of taking the puzzle at face value within a realist perspective—treating boundaries as ontologically on a par with (albeit parasitic upon) extended parts. (shrink)

Some have argued that the vagueness exhibited by geographic names and descriptions such as ‘Albuquerque’, ‘the Outback’, or ‘Mount Everest’ is ultimately ontological: these terms are vague because they refer to vague objects, objects with fuzzy boundaries. I take the opposite stand and hold the view that geographic vagueness is exclusively semantic, or conceptual at large. There is no such thing as a vague mountain. Rather, there are many things where we conceive a mountain to be, each with its precise (...) boundary, and when we say ‘Everest’ we are just being vague as to which thing we are referring to. This paper defends this view against some plausible objections. (shrink)

I articulate and the defend the following two claims: (i) it is a mistake to think that the structure of the world should mirror the structure of the theories by which we represent it, and through which we try to decipher it, simply because those theories appear to work; (ii) among the most deplorable consequences of this mistake is the widespread tendency to think that there must be a plurality of realities, or several different and irreducible levels of a stratified (...) reality, merely because our credo includes a plurality of theories each of which appears to be as important and trustworthy as it is irreducible to (if not overtly in conflict with) the others. (shrink)

The paper investigates the link between the theory of modal occurrents (where individuals are allowed to stretch across possible worlds) and Lewis’s counterpart theory (where all individuals are world-bound but have counterparts in other worlds). First I show how to interpret modal talk extensionally within the theory of modal occurrents. Then I show that the assumption that worlds be pairwise discrete is all that is needed to reconstruct the bulk of counterpart theory (i.e., to define the concept of a counterpart (...) and to derive the standard postulates governing that concept) in terms of the theory of modal occurrents. Finally, I argue that this reconstruction allows us to view the indeterminacy of our modal intuitions as being part and parcel with the indeterminacy of our criteria for individuating modal occurrents, and that this indeterminacy is naturally explained in terms of linguistic (as opposed to ontic) vagueness. (shrink)

Are there any bona fide boundaries, i.e., boundaries that carve at the joints? Or is any boundary —hence any object—the result of a fiat articulation reflecting our cognitive biases and our so-cial practices and conventions? Does the choice between these two options amount to a choice between realism and wholesome relativism?

If the question is: what is to be done for philosophy?, then it calls for a political answer and I have little to say besides the obvious. If the question is: what is to be done in philosophy?, then I’m stuck. Drawing up a list of to-do’s and not-to-do’s would not, I think, be a good way to honor the general conception of philosophy that inspired Topoi throughout these years, and that I deeply share.

In a calculation involving imaginary numbers, we begin with real numbers that represent concrete measures and we end up with numbers that are equally real, but in the course of the operation we find ourselves walking “as if on a bridge that stands on no piles”. How is that possible? How does that work? And what is involved in the as-if stance that this metaphor introduces so beautifully? These are questions that bother Törless deeply. And that Törless is bothered by (...) such questions is a central question for any reader of Törless. Here I offer my interpretation, along with a reconstruction of the philosophical intuition that lies behind it all. (shrink)

There is a natural philosophical impulse (and, correspondingly, a great deal of pressure) to always ask for explanations, for example, explanations of why we act as we do. Kevin Mulligan has gone a very long way in disentangling the many different because’s, and the many senses of ‘because’, that tend to clutter our efforts to manage that impulse. This short dialogue is meant as a humble tribute to his work in this area.

It is common lore that standard, Kripke-style semantics for quantified modal logic is incompatible with the view that no individual may belong to more than one possible world, a view that seems to require a counterpart-theoretic semantics instead. Strictly speaking, however, this thought is wrong-headed. This note explains why.

I offer a diagnosis of the parallelism between the Doctrine of Potential Parts and the Doctrine of Potential Wholes and briefly examine its bearing on Johansson’s account of the Tibbles-Tib Problem.

Pojęcie niszy (otoczenia, kontekstu, siedliska, środowiska) nie cieszy się specjalnym zainteresowaniem ontologów, mimo że ma szerokie zastosowanie w rozmaitych dyscyplinach, od biologii ewolucyjnej po ekonomię. Niniejszy artykuł zawiera pierwszą teorię formalną tego pojęcia — teorię relacji pomiędzy przedmiotami a ich niszami. Teoria ta opiera się na istniejącym dorobku mereologii, topologii i teorii lokalizacji przestrzennej, które są narzędziami ontologii formalnej. Jest ona tutaj ilustrowana głównie za pomocą prostych przykładów z biologii, ale pojęcie niszy należy rozumieć — podobnie jak pojęcia części, granicy (...) i położenia — jako pojęcie strukturalne, znajdujące zastosowanie w obszernym zakresie różnych dziedzin. (shrink)

Universalist and nihilist answers to philosophical questions may be extreme, but they are clear enough. Aliquidist answers, by contrast, are typically caught between the Scylla of vagueness and indeterminacy and the Charybdis of ungroundedness and arbitrariness, and steering a proper middle course—saying exactly where in the middle one is going to settle—demands exceptional navigating powers. I myself tend to favor extreme answers precisely for this reason. Here, however, I consider one sense in which Something may claim superiority over its polar (...) competitors, Everything and Nothing, when it comes to answerting the ontological question, “What is there?”. (shrink)

A lot of work in metaphysics relies on linguistic analysis and intuitions. Do we want to know what sort of things there are or could be? Then let’s see what sort of things there must be in order for what we truthfully say to be true. Do we want to see whether x is distinct from y? Then let’s see whether there is any statement that is true of x but not of y. And so on. In this paper I (...) argue that this way of proceeding is full of traps and is bound to be pretty useless unless we already have a good idea of what sort of things there are, and of how we are going to count them. (shrink)

Quine’s desert is generally contrasted with Meinong’s jungle, as a sober ontological alternative to the exuberant luxuriance that comes with the latter. Here I focus instead on the desert as a sober metaphysical alternative to the Aristotelian garden, with its tidily organized varieties of flora and fauna neatly governed by fundamental laws that reflect the essence of things and the way they can be, or the way they must be. In the desert there are no “natural joints”; all the boundaries (...) we find are lines we have drawn, artificial fencings that merely reflect of our own demarcations, our classifications, our desperate need to ward off the flux and meet an excusable but ungrounded demand for order and stability. The desert returns a picture of reality that is radically anti-realist. And yet the picture does not amount to a form of irrealism. The desert is out there and is what it is regardless of how we feel. And it is not completely structureless. It’s just that the structure it has is very thin and does not correspond to the sort of structure that so-called metaphysical realists—and scientific realists alike—tend to attribute to it. (shrink)

Peter Simons has argued that the expression ‘the universe’ is not a genuine singular term: it can name neither a single, completely encompassing individual, nor a collection of individuals. (It is, rather, a semantically plural term standing equally for every existing object.) I offer reasons for resisting Simons’s arguments on both scores.

Assuming that events form a genuine ontological category, shall we say that a good inventory of the world ought to include “negative” events—failures, omissions, things that didn’t happen—along with positive ones? I argue that we shouldn’t. Talk of non-occurring events is like talk of non-existing objects and should not be taken at face value. We often speak as though there were such things, but deep down we want our words to be interpreted in such a way as to avoid serious (...) ontological commitment. (shrink)

This is a revised and extended version of the formal theory of holes outlined in the Appendix to the book "Holes and Other Superficialities". The first part summarizes the basic framework (ontology, mereology, topology, morphology). The second part emphasizes its relevance to spatial reasoning and to the semantics of spatial prepositions in natural language. In particular, I discuss the semantics of ‘in’ and provide an account of such fallacious arguments as “There is a hole in the sheet. The sheet is (...) in the drawer. Ergo *there is a hole in the drawer”. (shrink)

According to a popular line of reasoning, diachronic vagueness creates a problem for the endurantist conception of persistence. Some authors have replied that this line of reasoning is inconclusive, since the endurantist can subscribe to a principle of Diachronic Unrestricted Composition (DUC) that is perfectly parallel to the principle required by the perdurantist’s semantic account. I object that the endurantist should better avoid DUC. And I argue that even DUC, if accepted, would fail to provide the endurantist with the necessary (...) resources for explaining diachronic vagueness in familiar semantic terms. (shrink)

This paper focuses on the semantics of statements of the form ‘x is P at t’ vis-à-vis its metaphysical underpinnings. I begin by considering four main readings, corresponding to the four basic parsings of the temporal modifier ‘at t’: (1) at-t x is P, (2) x-at-t is P, (3) x is-at-t P, and (4) x is P-at-t. Each of these readings—which correspond to different metaphysical conceptions of the nature of temporal change—is found inadequate or otherwise problematic. In the second part (...) of the paper I therefore consider a fifth account whose advantages over (1)–(4), I argue, exceed its revisionary costs. This fifth account is based on a conception of objects as entia successiva held together by a nexus of temporal counterparthood and reads ‘x is P at t’ as ‘the t-counterpart of x is P’. (shrink)

The semantics of our event talk is a complex affair. What is it that we are talking about when we speak of Brutus’s stabbing of Caesar? Exactly where and when did it take place? Was it the same event as the killing of Caesar? Some take questions such as these to be metaphysical questions. I think they are questions of semantics—questions about the way we talk and about what we mean. And I think that this conflict between metaphysic and semantic (...) concerns is indicative of a “deep indeterminacy” (Bennett’s phrase) in our event concept. We do talk about events; but what events a statement is about is not something that can be inferred from the event names we use; it depends heavily (more heavily than with ordinary material objects) on local context and unprincipled intuitions. This paper illustrates this view in connection with two examples: the phenomenon of vagueness and the dispute over identity statements. (shrink)

A compact overview of the main formal theories of parthood and of their mutual relationships, up to Classical Extensional Mereology. Written as an Appendix to the other essays included in the volume.

Since its first appearance in 1966, the notion of a supervaluation has been regarded by many as a powerful tool for dealing with semantic gaps. Only recently, however, applications to semantic gluts have also been considered. In previous work I proposed a general framework exploiting the intrinsic gap/glut duality. Here I also examine an alternative account where gaps and gluts are treated on a par: although they reflect opposite situations, the semantic upshot is the same in both cases--the value of (...) some expressions is not uniquely defined. Other strategies for generalizing supervaluations are considered and some comparative facts are discussed. (shrink)

In ‘Towards a Solution to the Sorites Paradox’, Graham Priest gives us a new account of the sorites based on fuzzy logic. The novelty lies in the suggestion that truth-value assignments should themselves be treated as fuzzy objects, i.e., objects about which we can make fuzzy identity statements. I argue that Priest’s solution does not have the explanatory force that Priest advocates. That is, it does not explain why we find the existence of a cut-off point counter-intuitive. I also argue (...) that this sort of explanation calls for a general theory that goes beyond the special case of linguistic vagueness, for the phenomenon is at bottom not linguistic. (shrink)

There are two ways of understanding the notion of a contradiction: as a conjunction of a statement and its negation, or as a pair of statements one of which is the negation of the other. Correspondingly, there are two ways of understanding the Law of Non-Contradiction (LNC), i.e., the law that says that no contradictions can be true. In this paper I offer some arguments to the effect that on the first (collective) reading LNC is non-negotiable, but on the second (...) (distributive) reading it is perfectly plausible to suppose that LNC may, in some rather special and perhaps undesirable circumstances, fail to hold. (shrink)

Las universidades de hoy son grandes sistemas de control autoritario, estandarización, gradación, contabilidad, clasificación, créditos y sanciones. Necesitamos descolonizar los sistemas de acceso y gestión en la medida en que han convertido la educación superior en un producto comercializable, clasificado, comprado y vendido por unidades estándar, medido, contado y reducido a equivalencia básica mediante pruebas mecánicas y, por lo tanto, fácilmente sujetas a consistencia estadística, con estándares y unidades numéricas. Tenemos que descolonizar esto porque disuade a estudiantes y profesores de (...) una libre búsqueda del conocimiento. (shrink)

A critical survey of the main metaphysical theories concerning the nature of material objects (substratum theories, bundle theories, substance theories, stuff theories) and their identity conditions, both synchronic (monist vs. pluralist theories) and diachronic (three-dimensionalism, four-dimensionalism, sequentialism).

Some philosophers have argued that the vagueness exhibited by names and descriptions such as ‘Mount Everest’, ‘Downtown Manhattan’, or ‘that cloud in the sky’ is ultimately ontological: they are vague because they refer to vague objects, objects with fuzzy boundaries. I take the opposite stand and argue for the view that all vagueness is semantic. There is no such thing as a vague mountain. Rather, there are many things where we conceive the mountain to be, each with its precise boundary, (...) and when we say ‘Everest’ we are just being vague as to which thing we are referring to. This paper defends this view against some plausible objections. (shrink)

This work gives an extended presentation of the treatment of variable-binding operators adumbrated in [3:1993d]. Illustrative examples include elementary languages with quantifiers and lambda-equipped categorial languages. Some remarks are also offered to illustrate the philosophical import of the resulting picture. Particularly, a certain conception of logic emerges from the account: the view that logics are true theories in the model-theoretic sense, i.e. the result of selecting a certain class of models as the only “admissible” interpretation structures (for a given language).

It is shown that a complete axiomatization of classical non-tautologies can be obtained by taking F (falsehood) as the sole axiom along with the two inference rules: (i) if A is a substitution instance of B, then A |– B; and (ii) if A is obtained from B by replacement of equivalent sentences, then A |– B (counting as equivalent the pairs {T, ~F}, {F, F&F}, {F, F&T}, {F, T&F}, {T, T&T}). Since the set of tautologies is also specifiable by (...) purely syntactic means, the resulting picture gives an improved syntactic account of classical sentential logic. The picture can then be completed by considering related systems that prove adequate to specify the set of contradictions, the set of non-contradictions, and the set of contingencies respectively. (shrink)

The theory according to which most ordinary objects are mere “entia successiva”—sequences of distinct mereological aggregates, whose unity resides exclusively in our minds—is a variant of the standard, three-dimensional conception of objects. For the aggregates are, at bottom, endurants, i.e., entities that persist through time by being fully present at any time at which they exist. In this paper I compare this theory with the so-called “stage view”, according to which ordinary objects—indeed, all objects—are sequences of momentary entities that cannot (...) truly be said to persist through time. Both theories face a number of intuitive difficulties but the stage view, I argue, has a lot more to offer in return. (shrink)

This is a sequel to my paper "Il denaro è un’opera d’arte", focusing on the metaphysics of those peculiar social objects that play an increasingly central role in the financial world—derivatives. On the analysis I offer, they appear to run afoul of Searle’s theory of social objects (or of the theory outlined in my earlier paper), and I put forward some suggestions on where to look for the necessary adjustments.