We define here a notion of internal copy and of weak internal copy of a category. We will then determine some families of categories having an internal copy or a weak internal copy. We will consider categories of definable classes of first-order theories and we will see that the notion of internal copy is related to the notion of numerical existence property.

It is shown that functional interpretation can be used to show the existence property of intuitionistic number theory. On the basis of truth variants a comparison is then made between realisability and functional interpretation showing a structural difference between the two.

Classical first-order logic \ is commonly used to study logical connections between statements, that is sentences that in every context have an associated truth-value. Inquisitive first-order logic \ is a conservative extension of \ which captures not only connections between statements, but also between questions. In this paper we prove the disjunction and existence properties for \ relative to inquisitive disjunction Open image in new window and inquisitive existential quantifier \. Moreover we extend these results to several families of (...) theories, among which the one in the language of \. To this end, we initiate a model-theoretic approach to the study of \. In particular, we develop a toolkit of basic constructions in order to transform and combine models of \. (shrink)

Classical first-order logic \ is commonly used to study logical connections between statements, that is sentences that in every context have an associated truth-value. Inquisitive first-order logic \ is a conservative extension of \ which captures not only connections between statements, but also between questions. In this paper we prove the disjunction and existence properties for \ relative to inquisitive disjunction Open image in new window and inquisitive existential quantifier \. Moreover we extend these results to several families of (...) theories, among which the one in the language of \. To this end, we initiate a model-theoretic approach to the study of \. In particular, we develop a toolkit of basic constructions in order to transform and combine models of \. (shrink)

We systematically study several versions of the disjunction and the existence properties in modal arithmetic. First, we newly introduce three classes $\mathrm {B}$, $\Delta (\mathrm {B})$, and $\Sigma (\mathrm {B})$ of formulas of modal arithmetic and study basic properties of them. Then, we prove several implications between the properties. In particular, among other things, we prove that for any consistent recursively enumerable extension T of $\mathbf {PA}(\mathbf {K})$ with $T \nvdash \Box \bot $, the $\Sigma (\mathrm {B})$ -disjunction (...) class='Hi'>property, the $\Sigma (\mathrm {B})$ -existence property, and the $\mathrm {B}$ -existence property are pairwise equivalent. Moreover, we introduce the notion of the $\Sigma (\mathrm {B})$ -soundness of theories and prove that for any consistent recursively enumerable extension of $\mathbf {PA}(\mathbf {K4})$, the modal disjunction property is equivalent to the $\Sigma (\mathrm {B})$ -soundness. (shrink)

Aquantum logic (σ-orthocomplete orthomodular poset L with a convex, unital, and separating set Δ of states) is said to have theexistence property if the expectation functionals onlin(Δ) associated with the bounded observables of L form a vector space. Classical quantum logics as well as the Hilbert space logics of traditional quantum mechanics have this property. We show that, if a quantum logic satisfies certain conditions in addition to having property E, then the number of its blocks (maximal (...) classical subsystems) must either be one (classical logics) or uncountable (as in Hilbert space logics). (shrink)

This paper is a review of the book "Existence: Essays in Ontology" by Peter Van Inwagen.

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. 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. (shrink)

In a modal system of arithmetic, a theory S has the modal disjunction property if whenever $S \vdash \square\varphi \vee \square\psi$ , either $S \vdash \square\varphi$ or $S \vdash \square\psi. S$ has the modal numerical existence property if whenever $S \vdash \exists x\square\varphi(x)$ , there is some natural number n such that $S \vdash \square\varphi(\mathbf{n})$ . Under certain broadly applicable assumptions, these two properties are equivalent.

Constructive theories usually have interesting metamathematical properties where explicit witnesses can be extracted from proofs of existential sentences. For relational theories, probably the most natural of these is the existence property, EP, sometimes referred to as the set existence property. This states that whenever ϕϕ is provable, there is a formula χχ such that ϕ∧χϕ∧χ is provable. It has been known since the 80s that EP holds for some intuitionistic set theories and yet fails for IZF. (...) Despite this, it has remained open until now whether EP holds for the most well known constructive set theory, CZF. In this paper we show that EP fails for CZF. (shrink)

Identity, existence, predication, necessity, and truth are fundamental philosophical concerns. Colin McGinn treats them both philosophically and logically, aiming for maximum clarity and minimum pointless formalism. He contends that there are real logical properties that challenge naturalistic metaphysical outlooks. These concepts are not definable, though we can say a good deal about how they work. The aim of Logical Properties is to bring philosophy back to philosophical logic.

'There is much food for thought in McGinn's discussions and each chapter is rich with a series of considerations for thinking that the currently received views on the various topics have some serious difficulties that need confronting... For those interested in metaphysics and the philosophy of logic, this book will stimulate much further thought' -Mind 'The sweep of the book is broad and the pace is brisk... There is much material here to provide the basis for many a deep philosophical (...) discussion' -Mind 'Lucid and provocative little book... clear, direct and well argued' -Times Higher Education SupplementIdentity, existence, predication, necessity, and truth are fundamental philosophical concerns. Colin McGinn treats them both philosophically and logically, aiming for maximum clarity and minimum pointless formalism. He contends that there are real logical properties that challenge naturalistic metaphysical outlooks. These concepts are not definable, though we can say a good deal about how they work. The aim of Logical Properties is to bring philosophy back to philosophical logic. (shrink)

A metaphysical system engendered by a third order quantified modal logic S5 plus impredicative comprehension principles is used to isolate a third order predicate D, and by being able to impredicatively take a second order predicate G to hold of an individual just if the individual necessarily has all second order properties which are D we in Section 2 derive the thesis (40) that all properties are D or some individual is G. In Section 3 theorems 1 to 3 suggest (...) a sufficient kinship to Gödelian ontological arguments so as to think of thesis (40) in terms of divine property and Godly being; divine replaces positive with Gödel and others. Thesis (40), the sacred thesis, supports the ontological argument that God exists because some property is not divine. In Section 4 a fixed point analysis is used as diagnosis so that atheists may settle for the minimal fixed point. Theorem 3 shows it consistent to postulate theistic fixed points, and a monotheistic result follows if one assumes theism and that it is divine to be identical with a deity. Theorem 4 (the Monotheorem) states that if Gg and it is divine to be identical with g, then necessarily all objects which are G are identical with g. The impredicative origin of D suggests weakened Gaunilo-like objections that offer related theses for other second order properties and their associated diverse presumptive individual bearers. Nevertheless, in the last section we finesse these Gaunilo-like objections by adopting what we call an apathiatheistic opinion which suggest that the best concepts `God’ allow thorough indifference as to whether God exists or not. (shrink)

In this paper I aim to defend a version of the view that ‘exist’ expresses primarily a property of individual objects, a property that each of them has. In the first section, I will distinguish the three main types of rival conceptions concerning the semantic status of ‘exist’ that will define the subsequent discussion. In the second section it will be shown that the best explanation of our overall use of ‘exist’ in natural language requires the treatment of (...) ‘exist’ as a predicate that can be applied to individual objects. The third section will be concerned with the problem of the semantic analysis of negative singular existential sentences that contain proper names. I will briefly defend a specific solution to this problem that makes use of a single-domain free logic. In the following sections, I will try to defend this view of existence in more detail. That is, I will deal with three different specific challenges that prima facie seem to speak against the proposed view and for some rival alternatives; and I will show how these challenges can be met. (shrink)

We introduce the oak property of first order theories, which is a syntactical condition that we show to be sufficient for a theory not to have universal models in cardinality λ when certain cardinal arithmetic assumptions about λ implying the failure of GCH hold. We give two examples of theories that have the oak property and show that none of these examples satisfy SOP4, not even SOP3. This is related to the question of the connection of the (...) class='Hi'>property SOP4 to non-universality, as was raised by the earlier work of Shelah. One of our examples is the theory for which non-universality results similar to the ones we obtain are already known; hence we may view our results as an abstraction of the known results from a concrete theory to a class of theories. We show that no theory with the oak property is simple. (shrink)

Identity, existence, predication, necessity, and truth are fundamental philosophical concerns. Colin McGinn treats them both philosophically and logically, aiming for maximum clarity and minimum pointless formalism. He contends that there are real logical properties that challenge naturalistic metaphysical outlooks. These concepts are not definable, though we can say a good deal about how they work. The aim of Logical Properties is to bring philosophy back to philosophical logic.

RESUMO Este artigo é dedicado ao argumento contra o Requisito de Existência fornecido por Takashi Yagisawa. Argumentamos que o cerne do argumento de Yagisawa – a Forte Iterabilidade – não pode ser inferido pela ideia de contingente a priori (Kripke) e é incompatível com a ideia de @-transformação (Plantinga). Assim, essas ideias, contrariamente a Yagisawa, não podem servir de base metodológica da Forte Iterabilidade. Também argumentamos que a Forte Iterabilidade é incompatível com o Princípio Constitutivo. Finalmente, mostramos que o conceito (...) de propriedades indexadas pelo mundo (o argumento de Yagisawa se fa na ideia de propriedades indexadas pelo mundo) é inconsistente e, mesmo que o defensor da Forte Iterabilidade possa resistir a esta objeção, a Forte Iterabilidade deve ser abandonada. (shrink)

The aim of this short book is to discuss the traditional topics of philosophical logic without the “formalistic fetishism and scholasticism” that McGinn associates with recent work in the field. The writing is indeed crisp, engaging, and free of formalisms. The book consists of five separate essays—one each on identity, existence, predication, necessity, and truth—loosely united by the general theme that these “logical properties” are real and irreducible. “These concepts,” McGinn says, “form a conceptual bedrock; they stand, as it (...) were, underneath all our other concepts. They have no analysis”. (shrink)

This paper is a defense of the view that existence is a property. Since the view is still a minority one, a fair amount of space is allotted to defending it against objections and counter-arguments. Positive arguments aren’t lacking, however, and emerge in the course of the discussion. Not all of the many positive or negative arguments which follow are wholly original—a fact to be expected in this context—but a fair number are, and both sorts of argument are (...) seamlessly interwoven in the warp and woof of what follows. (shrink)

The Nyāya philosopher Udayana devotes the first chapter of his Ātmatattvaviveka to refuting the Buddhist thesis of universal momentariness—the view that nothing which exists can persist through time—and to establishing the contrary view that things can and do persist. In the course of his critique of the Buddhists' "inference from existence" which purports to establish the momentariness thesis, Udayana is forced to consider the problem of how, if at all, it is possible to meaningfully and reliably think and talk (...) about things which do not exist.In this paper, I offer a close reading of this section of the ĀTV, taking seriously both the philosophical context and commitments of Udayana's work in general, and the... (shrink)

Abstract: In this paper, I examine the current case against the second-order property view of existence through a discussion of Colin McGinn's up to date statement of this case. I conclude that the second-order property view of existence remains viable.

Each of the topics mentioned in the title has its own chapter. The unifying theme is McGinn’s conception of naive common sense views of identity, existence, predication, necessity, and truth, which are argued for as being correct. McGinn thinks they should replace entrenched rival treatments of these subjects. However, some of the views McGinn takes as naive seem far from naive or in common use to this reader. This is a technical work in philosophical logic, not in the sense (...) that it is strewn with technical symbols of formal logic. It takes up and discusses topics in a sophisticated way suitable for those working in the area and is not intended primarily for novices in the subject. Having said that, it is well written and clear so that there is much that would be rewarding to nonspecialists who wish to come to the subject. There is much in the way of close and interesting argumentation. (shrink)

Revised and reprinted; originally in Dov Gabbay & Franz Guenthner (eds.), Handbook of Philosophical Logic, Volume IV. Kluwer 133-251. -- Two sorts of property theory are distinguished, those dealing with intensional contexts property abstracts (infinitive and gerundive phrases) and proposition abstracts (‘that’-clauses) and those dealing with predication (or instantiation) relations. The first is deemed to be epistemologically more primary, for “the argument from intensional logic” is perhaps the best argument for the existence of properties. This argument is (...) presented in the course of discussing generality, quantifying-in, learnability, referential semantics, nominalism, conceptualism, realism, type-freedom, the first-order/higher-order controversy, names, indexicals, descriptions, Mates’ puzzle, and the paradox of analysis. Two first-order intensional logics are then formulated. Finally, fixed-point type-free theories of predication are discussed, especially their relation to the question whether properties may be identified with propositional functions. (shrink)

Revised and reprinted in Handbook of Philosophical Logic, volume 10, Dov Gabbay and Frans Guenthner (eds.), Dordrecht: Kluwer, (2003). -- Two sorts of property theory are distinguished, those dealing with intensional contexts property abstracts (infinitive and gerundive phrases) and proposition abstracts (‘that’-clauses) and those dealing with predication (or instantiation) relations. The first is deemed to be epistemologically more primary, for “the argument from intensional logic” is perhaps the best argument for the existence of properties. This argument is (...) presented in the course of discussing generality, quantifying-in, learnability, referential semantics, nominalism, conceptualism, realism, type-freedom, the first-order/higher-order controversy, names, indexicals, descriptions, Mates’ puzzle, and the paradox of analysis. Two first-order intensional logics are then formulated. Finally, fixed-point type-free theories of predication are discussed, especially their relation to the question whether properties may be identified with propositional functions. (shrink)

Should objects count as necessarily having certain properties, despite their not having those properties when they do not exist? For example, should a cat that passes out of existence, and so no longer is a cat, nonetheless count as necessarily being a cat? In this essay I examine different ways of adapting Aldo Bressan’s MLν so that it can accommodate an affirmative answer to these questions. Anil Gupta, in The Logic of Common Nouns, creates a number of languages that (...) have a kinship with Bressan’s MLν , three of which are also tailored to affirmatively answering these questions. After comparing their languages, I argue that metaphysicians and philosophers of language should prefer MLν to Gupta’s languages in most applications because it can accommodate essential properties, like being a cat, while being more uniform and less cumbersome. (shrink)

We discuss relationships among the existence property, the disjunction property, and their weak variants in the setting of intermediate predicate logics. We deal with the weak and sentential existence properties, and the Z-normality, which is a weak variant of the disjunction property. These weak variants were presented in the author’s previous paper [16]. In the present paper, the Kripke sheaf semantics is used.

This paper presents Integrated Information Theory (IIT) 4.0. IIT aims to account for the properties of experience in physical (operational) terms. It identifies the essential properties of experience (axioms), infers the necessary and sufficient properties that its substrate must satisfy (postulates), and expresses them in mathematical terms. In principle, the postulates can be applied to any system of units in a state to determine whether it is conscious, to what degree, and in what way. IIT offers a parsimonious explanation of (...) empirical evidence, makes testable predictions, and permits inferences and extrapolations. IIT 4.0 incorporates several developments of the past ten years, including a more accurate translation of axioms into postulates and mathematical expressions, the introduction of a unique measure of intrinsic information that is consistent with the postulates, and an explicit assessment of causal relations. By fully unfolding a system's irreducible cause-effect power, the distinctions and relations specified by a substrate can account for the quality of experience. (shrink)

The notion of existence is a very puzzling one philosophically. Often philosophers have appealed to linguistic properties of sentences stating existence. However, the appeal to linguistic intuitions has generally not been systematic and without serious regard of relevant issues in linguistic semantics. This paper has two aims. On the one hand, it will look at statements of existence from a systematic linguistic point of view, in order to try to clarify what the actual semantics of such statements (...) in fact is. On the other hand, it will explore what sort of ontology such statements reflect. The first aim is one of linguistic semantics; the second aim is one of descriptive metaphysics. Philosophically, existence statements appear to reflect the distinction between endurance and perdurance as well as particular notions of abstract states and of kinds. Linguistically, statements of existence involve a particular way of drawing the distinction between eventive and stative verbs and between individual-level and stage-level predicates as well as a particular approach to the semantics of bare plurals and mass nouns. (shrink)

According to Essentialism, an object’s properties divide into those that are essential and those that are accidental. While being human is commonly thought to be essential to Socrates, being a philosopher plausibly is not. We can motivate the distinction by appealing—as we just did—to examples. However, it is not obvious how best to characterize the notion of essential property, nor is it easy to give conclusive arguments for the essentiality of a given property. In this paper, I elaborate (...) on these issues and explore the way in which essential properties behave in relation to other related properties, like sufficient-for-existence properties and individual essences. (shrink)

Are properties universal or particular? According to Universalism, properties are universals because there is a certain fundamental tie that makes properties capable of being shareable by more than one thing. On the opposing side, Particularism is the view that properties are particulars due to the existence of a fundamental tie that makes properties incapable of being shared. My aim in this paper is to critically examine the connections between the notions of the fundamental tie and universality and particularity. I (...) argue, first, that universality and particularity can characterize a property if and only if there is a universalist or a particularist fundamental tie, and, second, that it is unclear that these should be the fundamental ties that connect ordinary and scientific properties to their respective bearers. Then I develop an alternative approach to properties and the fundamental tie, which is neutralist because it dispenses with universality and particularity as features of properties, and naturalist because it naturalizes the possession of properties by replacing metaphysical fundamental ties with a scientific one, in particular, a physical process. I show how this approach improves our understanding of properties and instantiation. (shrink)

I first show how one might argue for a mind-independent conception of beauty and artistic merit. I then discuss whether this makes aesthetic judgements suitable to undermine skeptical worries about the existence of mind-independent moral value and categorical reasons.