Hilary Putnam once suggested that “the actual existence of sets as ‘intangible objects’ suffers… from a generalization of a problem first pointed out by Paul Benacerraf… are sets a kind of function or are functions a sort of set?” Sadly, he did not elaborate; my aim, here, is to do so on his behalf. There are well-known methods for treating sets as functions and functions as sets. But these do not raise any obvious philosophical or foundational puzzles. For that, we (...) first need to provide a full-fledged function theory. I supply such a theory: it axiomatizes the iterative notion of function in exactly the same sense that ZF axiomatizes the iterative notion of set. Indeed, this function theory is synonymous with ZF. It might seem that set theory and function theory present us with rival foundations for mathematics, since they postulate different ontologies. But appearances are deceptive. Set theory and function theory provide the very same judicial foundation for mathematics. They do not supply rival metaphysical foundations; indeed, if they supply metaphysical foundations at all, then they supply the very same metaphysical foundations. (shrink)

Recent discussions in cognitive science and the philosophy of mind have defended a theory according to which we live in a virtual world akin to a computer simulation, generated by our brain. It is argued that our brain creates a model world from a variety of stimuli; this model is perceived as if it was external and perception-independent, even though it is neither of the two. The view of the mind, brain, and world, entailed by this theory has some peculiar (...) consequences which have rarely been explored in detail. This paper sets out virtual world theory and relates it to various central philosophical problems, the role of the perceiver and the problem of the existence of the external world ). The second part suggests three interpretations of virtual world theory, two familiar ones and a somewhat less familiar one. The remainder of the paper argues that the irrealist interpretation is the one we should adopt. (shrink)

According to the Dependency Theory, truth asymmetrically depends on the world, in the following sense: true propositions are true because the world makes them true. The Dependency Theory strikes many philosophers as incontrovertible, but in this paper I reject it. I begin by presenting a problem for the Dependency Theory. I then develop an alternative to the Dependency Theory which avoids that problem. This alternative is an immodest Identity Theory of Truth, and I end the paper by responding to Dodd’s (...) charge that immodest Identity Theories are incoherent. (shrink)

Putnam’s vat argument is intended to show that I am not a permanently envatted brain. The argument holds promise as a response to vat scepticism, which depends on the claim that I do not know that I am not a permanently envatted brain. However, there is a widespread idea that the vat argument cannot fulfil this promise, because to employ the argument as a response to vat scepticism I would have to make assumptions about the content of the premises and/or (...) conclusion of the argument that beg the question against the sceptic. In this paper, I show that this idea is mistaken. (shrink)

If it works, I can use Putnam’s vat argument to show that I have not always been a brain-in-a-vat. It is widely thought that the vat argument is of no use against closure scepticism – that is, scepticism motivated by arguments that appeal to a closure principle. This is because, even if I can use the vat argument to show that I have not always been a BIV, I cannot use it to show that I was not recently envatted, and (...) it is thought that the claim that I am not justified in thinking that I was not recently envatted is all that the closure sceptic requires. In this paper I first argue that scenarios in which I have been recently envatted are inadequate for the sceptic’s purposes, and so the standard argument that the vat argument is of no use against closure scepticism fails. I then argue that it is not possible to revise the standard argument to meet my objection. I conclude that, if it works, I can use the vat argument as a defence against closure scepticism. (shrink)

Metaethical realists disagree about the nature of normative properties. Naturalists think that they are ordinary natural properties: causally efficacious, a posteriori knowable, and usable in the best explanations of natural and social sciences. Non-naturalist realists, in contrast, argue that they are sui generis: causally inert, a priori knowable and not a part of the subject matter of sciences. It has been assumed so far that naturalists can explain causally how the normative predicates manage to refer to normative properties, whereas non-naturalists (...) are unable to provide equally satisfactory metasemantic explanations. This article first describes how the previous non-naturalist accounts of reference fail to tell us how the normative predicates could have come to refer to the non-natural properties rather than to the natural ones. I will then use the so-called qua-problem to show how the causal theories of reference of naturalists also fail to fix the reference of normative predicates to unique natural properties. Finally, I will suggest that, just as naturalists need to rely on the non-causal mechanism of reference magnetism to solve the previous problem, non-naturalists, too, can rely on the very same idea to respond to the pressing metasemantic challenges that they face concerning reference. (shrink)

Since the linguistic turn, many have taken semantics to guide ontology. Here, I argue that semantics can, at best, serve as a partial guide to ontological commitment. If semantics were to be our guide, semantic data and semantic treatments would need to be taken seriously. Through an examination of plurals and their treatments, I argue that there can be multiple, equally semantically adequate, treatments of a natural language theory. Further, such treatments can attribute different ontological commitments to a theory. Given (...) this, I argue that semantics can fail to deliver determinate ontological commitments and determinate answers to ontological questions, more generally. (shrink)

On a widespread naturalist view, the meanings of mathematical terms are determined, and can only be determined, by the way we use mathematical language—in particular, by the basic mathematical principles we’re disposed to accept. But it’s mysterious how this can be so, since, as is well known, minimally strong first-order theories are non-categorical and so are compatible with countless non-isomorphic interpretations. As for second-order theories: though they typically enjoy categoricity results—for instance, Dedekind’s categoricity theorem for second-order PA and Zermelo’s quasi-categoricity (...) theorem for second-order ZFC—these results require full second-order logic. So appealing to these results seems only to push the problem back, since the principles of second-order logic are themselves non-categorical: those principles are compatible with restricted interpretations of the second-order quantifiers on which Dedekind’s and Zermelo’s results are no longer available. In this paper, we provide a naturalist-friendly, non-revisionary solution to an analogous but seemingly more basic problem—Carnap’s Categoricity Problem for propositional and first-order logic—and show that our solution generalizes, giving us full second-order logic and thereby securing the categoricity or quasi-categoricity of second-order mathematical theories. Briefly, the first-order quantifiers have their intended interpretation, we claim, because we’re disposed to follow the quantifier rules in an open-ended way. As we show, given this open-endedness, the interpretation of the quantifiers must be permutation-invariant and so, by a theorem recently proved by Bonnay and Westerståhl, must be the standard interpretation. Analogously for the second-order case: we prove, by generalizing Bonnay and Westerståhl’s theorem, that the permutation invariance of the interpretation of the second-order quantifiers, guaranteed once again by the open-endedness of our inferential dispositions, suffices to yield full second-order logic. (shrink)

One of Mill's primary targets, throughout his work, is intuitionism. In this paper, I distinguish two strands of intuitionism, against which Mill offers separate arguments. The first strand, a priorism, makes an epistemic claim about how we come to know norms. The second strand, ‘first principle pluralism’, makes a structural claim about how many fundamental norms there are. In this paper, I suggest that one natural reading of Mill's argument against first principle pluralism is incompatible with the naturalism that drives (...) his argument against a priorism. It must, therefore, be discarded. Such a reading, however, covertly attributes Mill realist commitments about the normative. These commitments are unnecessary. To the extent that Mill's argument against first principle pluralism is taken seriously, I suggest, it is an argument that points towards Mill as having an antirealist approach to the normative. (shrink)

The extensions of Goodman’s ‘grue’ predicate and Kripke’s ‘quus’ are constructed from the extensions of more familiar terms via a reinterpretation that permutes assignments of reference. Since this manoeuvre is at the heart of Putnam’s model-theoretic and permutation arguments against metaphysical realism (‘Putnam’s Paradox’), both Goodman’s New Riddle of Induction and the paradox about meaning that Kripke attributes to Wittgenstein are instances of Putnam’s. Evidence cannot selectively confirm the green-hypothesis and disconfirm the grue-hypothesis, because the theory of which the green-hypothesis (...) is a part has an unintended model in which the grue-hypothesis is equally confirmed; and there are no meaning-facts that determine reference, because the objects referred to by the referring terms of any language or set of intentional mental states are permutable in a way that is consistent with the truth-values of all other sentences in that language or beliefs in that set. The upshot is that the three paradoxes need to be solved in a unified way. (shrink)

Michael Dummett offered a semantic characterisation of a variety of realism-antirealism debates. This approach has fallen out of fashion. This has been to the detriment of metaphysics. This paper offers an accurate characterisation of Dummett’s view, often lacking in the literature, and then defends it against a range of attacks (from Devitt, Miller and Williamson). This understanding of realism debates is resilient, and if we take it seriously the philosophical terrain looks importantly different. In particular, the philosophy of language has (...) a foundational role with respect to metaphysics. (shrink)

It is common for contemporary ontologists to claim that they are not concerned with what exists simpliciter, but rather with what exists ’fundamentally’, or what ’really’ exists. I argue that positions of this sort cannot satisfy reasonable constraints concerning the acquisition of language. I assess and dismiss possible responses to this complaint before commenting on the prospects for a metaphysics without bespoke existence claims.

This paper investigates the relation between what James Conant has called Kantian and Cartesian varieties of skepticism. It is argued that a solution to the most prominent example of a Kantian variety of skepticism, i.e. Kripkensteinian skepticism about rule-following and meaning, can be found in the works of Wilfrid Sellars. It is then argued that, on the basis of that very same solution to the Kantian problematic of rule-following and meaning, a novel argument against external world skepticism can be formulated. (...) This argument takes the shape of a transcendental argument, which is reminiscent of Hilary Putnam’s infamous argument against the brain-in-a-vat hypothesis, but is, as is argued, superior to it in certain respects. (shrink)

Few if any distinctions are more easily recognisable and assented to than that between _objects_, that is, things which are some ways, and that which they are, that is, _ways for objects to be_ (‘ways of being’ for short). In this paper I present an argument designed to show that this distinction is indeterminate in the sense that the truth-conditions of predicational sentences leave open what should count as an object and a way of being. The bulk of the argument (...) is inspired by the celebrated permutation argument advanced by Quine, Wallace, Putnam and others. (shrink)

I present a novel anti-sceptical BIV argument by focusing on conditions on the production and use of the locative preposition ‘in’. I distinguish two uses of ‘in’—material and descriptive phenomenological—and I explain in what respect movement is central to the concept that our use of ‘in’ expresses. I go on to argue that a functionalist semantics of the intelligible use of ‘in’ demands a materialist philosophy of action in the spirit of G.E.M. Anscombe, but also why the structure of space (...) is not irrelevant either; appeal to the structure of space unsettles the causal-empirical assumptions that ground the picture of subjectivity and agency that the biv narrative assumes. Finally, I explain why a functionalist semantics demands a Naïve Realist metaphysics of perception, consistent with some of Putnam’s last writings on philosophy of perception. (shrink)

This article surveys recent literature by Parsons, McGee, Shapiro and others on the significance of categoricity arguments in the philosophy of mathematics. After discussing whether categoricity arguments are sufficient to secure reference to mathematical structures up to isomorphism, we assess what exactly is achieved by recent ‘internal’ renditions of the famous categoricity arguments for arithmetic and set theory.

Amie Thomasson and Eli Hirsch have both attempted to deflate metaphysics, by combining Carnapian ideas with an appeal to ordinary language. My main aim in this paper is to critique such deflationary appeals to ordinary language. Focussing on Thomasson, I draw two very general conclusions. First: ordinary language is a wildly complicated phenomenon. Its implicit ontological commitments can only be tackled by invoking a context principle; but this will mean that ordinary language ontology is not a trivial enterprise. Second: ordinary (...) language often points in different directions simultaneously, so that a wide variety of existence questions cannot be deflated merely by appealing to ordinary language. (shrink)

Paradigmatic cases of ontological disputes are taken to concern whether or not certain objects exist. Some theorists, however, prefer to view ontologists as really debating about what we should mean with the term “exist” (or other cognate terms). This implies interpreting ontological disputes as metalinguistic negotiations, in keeping with a recent trend to interpret other philosophical disputes along these lines (Plunkett and Sundell. Philosopher's Imprint; 2013;13:1–37). A number of issues arise from such proposal. The first is what counts as evidence (...) that an object‐level dispute is actually a metalinguistic negotiation. The second regards the dialectical relevance of considering metalinguistic negotiation as even just a possible interpretative option. The third issue concerns whether, and why, certain object‐level disputes (and especially ontological ones) should be understood as metalinguistic negotiations. (shrink)

The reliability challenge to ontology can be summarized as the complaint that no satisfying explanation is available of how one can have true ontological beliefs, given that the relevant belief-forming methods are noncausal (for example, not perception based or memory based). This paper first presents a version of the reliability challenge against realist approaches to ontology, put forward by Jared Warren. It then explores a response to the challenge on behalf of the realist that appeals to the use of abduction. (...) This response does not satisfactorily deal with the reliability challenge, though, and even leads to a further epistemic impasse. At this point, a version of ontological pluralism is presented, according to which all the competing theories in a certain ontological dispute can be true—in a sense of “true” to be articulated. The final step shows how this version of pluralism deals with the reliability challenge, especially with the complaint that we lack an explanation for our true ontological beliefs. (shrink)

In this paper I want to adjudicate the dispute between those philosophers who do and those who do not think that the philosophy of language can illuminate metaphysical questions. To this end, I take the debate between Devitt and Putnam as a case study and diagnose what I take to be illuminating about their disagreement over metaphysical realism. I argue that both Putnam and Devitt are incorrect in their assessment of the significance of the model theoretic argument for realism. That, (...) whilst Devitt is entitled to claim that truth does not have anything to do with realism, Putnam’s challenge can still gain traction and seriously call into question our ability to engage in realist metaphysics. I argue that even if a completely semantically neutral conception of realism can be successfully articulated, doing so has the potential to bankrupt the methodology of metaphysical realism. Having taken this debate as a case study, I then offer some brief remarks on how to understand the philosopher who claims that realist metaphysicians should care about discussions of metasemantics and truth. Whilst I want to be cautious about generalising on the basis on this case alone, I think there are important lessons to be learned about the way in which considerations to do with language can shed light on the concerns of metametaphysics. (shrink)

Nick Bostrom considered a number of simulations and contended that the probability that we are living in one of them is high or at least nonzero. I present arguments to refute the claim that we are or might be in any one of them. -/- Here is a highly dense reasoning why we are not in the simulation: -/- Suppose Simon is in the simulation, and he entertains the idea that he is in the simulation. And he thinks about the (...) word 'apple'. But since he is always in the simulation, he has never interacted with an actual apple, which the word 'apple' refers to. -/- Then Simon must think that "if I am in the simulation, then I never interact with an actual apple, and my understanding about the word 'apple' can only be given by the simulator. And this means I never exercise my reason to gain the understanding about the word 'apple', and never exercise my reason to apply the word 'apple'. Consequently, since what I am thinking right now (namely, this entire thought within the double quotation marks) involves the word 'apple', I am not using reason to think what I am thinking." -/- By denying he is using reason to think, Simon is being incoherent in thinking the preceding thought. To avoid being incoherent, Simon must reject the idea that he is in the simulation. -/- For the similar reason, if we think we are in the simulation, we are being incoherent. More simply, to think that we are in the simulation is to be incoherent. Therefore we cannot actually think that we are in the simulation. Hence, we are not in the simulation. -/- The whole paper is to flesh out the reasoning above. (shrink)

In this essay I try to give some overall statements in order to show that new realism is to be understood as a kind of positive philosophy. Against constructivism, I argue that there is a prevalence of the objects themselves on our understanding of them because reality offers a resistance to our attempt to grasp it depending on its level of dependence from our own understanding, which is different in the case of natural objects, ideal object and social object. This (...) negativity leads to an ontological necessity of facticity. In the second part of this paper I will describe – through the exposition of three key concepts of new realism, i.e. “unamendability”, “interaction” and “affordance” – an ascending path for which the negative and the resistance turn into positivity. (shrink)

This dissertation is about human knowledge of reality. In particular, it argues that scientific knowledge is bounded by historically available instruments and theories; nevertheless, the use of several independent instruments and theories can provide access to the persistent potentialities of reality. The replicability of scientific observations and experiments allows us to obtain explorable evidence of robust entities and properties. The dissertation includes seven chapters. It also studies three cases – namely, Higgs bosons and hypothetical Ϝ-particles (section 2.4), the Ptolemaic and (...) Kepler model of the planets (section 6.7), and the special theory of relativity (chapter 7). -/- Chapter 1 is the introduction of the dissertation. Chapter 2 clarifies the notion of the real on the basis of two concepts: persistence and resistance. These concepts enable me to explain my ontological belief in the real potentialities of human-independent things and the implications of this view for the perceptual and epistemological levels of discussion. On the basis of the concept of “overlapping perspectives”, chapter 3 argues that entity realism and perspectivism are complementary. That is, an entity that manifests itself through several experimental/observational methods is something real, but our knowledge of its nature is perspectival. Critically studying the recent views of entity realism, chapter 4 extends the discussion of entity realism and provides a criterion for the reality of property tokens. Chapter 5, in contrast, develops the perspectival aspects of my view on the basis of the phenomenological-hermeneutical approaches to the philosophy of science. This chapter also elaborates my view of empirical evidence, as briefly expressed in sections 2.5 and 4.5. Chapter 6 concerns diachronic theoretical perspectives. It first explains my view of progress, according to which current perspectives are broader than past ones. Second, it argues that the successful explanations and predictions of abandoned theories can be accounted for from our currently acceptable perspectives. The case study of Ptolemaic astronomy supports the argument of this chapter. Chapter 7 serves as the conclusion of the dissertation by applying the central themes of the previous chapters to the case study of special relativity theory. I interpret frame-dependent properties, such as length and time duration, and the constancy of the speed of light according to realist perspectivism. (shrink)

In this article, I have two aims. Firstly, I argue that Hilary Putnam's model theoretic indeterminacy argument against external realism and Saul Kripke's so-called Kripkensteinian argument against semantic realism have the same dialectical structure and the same conclusion---both force the opponent to face the same dilemma. Namely: either adopt meaning minimalism or postulate unobservable semantic facts. Secondly, I analyze more closely the first horn of the dilemma---meaning minimalism. This is the position according to which there are no truth conditions for (...) meaning-ascriptions. It has been suggested that this position is incoherent. However, I argue that there is a coherent option available for the meaning minimalist. As Crispin Wright has proposed, a coherent meaning minimalist has to adopt a structured truth-predicate with at least two levels: one is a minimal or a deflationary truth-predicate for a semantic discourse and the other, more substantial or objective truth-predicate for discourses like natural sciences. Subsequently, this leads to a position close to Huw Price's global expressivism. Thus, the ultimate dilemma that Putnam's and the Kripkensteinian argument establish is the following choice: either meaning minimalism with a structured two-level truth-predicate or robust realism regarding meaning. (shrink)

I consider a new, non-disjunctive strategy for ‘relational’ or ‘naïve realist’ theories to respond to arguments from ‘perfect’ (causally matching) hallucinations. The strategy, in a nutshell, is to treat such hypothetical cases as instances of perception rather than hallucination. After clarifying the form and dialectic of such arguments, I consider three objections to the strategy. I provide answers to the first two objections but concede that the third — based on the possibility of ‘chaotic’ (uncaused) perfect hallucinations — cannot obviously (...) be dealt with by the proposed strategy. However, such ‘chaotic’ scenarios are also problematic for standard representational accounts of experience. Thus I conclude that perfect hallucinations pose no more of a threat to the relational theory than to its main representational rival. (shrink)

In this article I am interpreting Friedrich Nietzsche's piece of writing "How the "True World" finally became a fable - The History of an Error" in the context of 20th-century analytical philosophy of language. In particular, I am going to argue that the main theme in this text - the issue of abolishing "the true world" - can be interpreted as Hilary Putnam's model-theoretic arguments against external realism and Saul Kripke's Wittgensteinian arguments against truth-conditional meaning theories. Interpreting this Nietzsche's text (...) with the help of these arguments gives rise to two options determining Nietzsche's own position. The perspective of Putnam's argument seems to push Nietzsche to the quietist camp - the view that significant metaphysical debate between external realism and its opposite is impossible or inexpressible. On the other hand, the Kripkensteinian perspective gives us reasons to interpret Nietzsche as an adherer of the pragmatic account of semantics, which explains meaning through the use of language. (shrink)

It is often claimed that anti-realism is a form of transcendental idealism or that Kant is an anti-realist. It is also often claimed that anti-realists are committed to some form of knowability principle and that such principles have problematic consequences. It is therefore natural to ask whether Kant is so committed, and if he is, whether this leads him into difficulties. I argue that a standard reading of Kant does indeed have him committed to the claim that all empirical truths (...) are knowable and that this claim entails that there is no empirical truth that is never known. I extend the result to a priori truths and draw some general philosophical lessons from this extension. However, I then propose a re-examination of Kant’s notion of experience according to which he carefully eschews any commitment to empirical knowability. Finally I respond to a remaining problem that stems from a weaker, justified believability principle. (shrink)

Putnam’s semantic argument against the BIV hypothesis and Sosa’s argument against dream skepticism based on the imagination model of dreaming share some important structural features. In both cases the skeptical option is supposed to be excluded because preconditions of its intelligibility are not fulfilled (affirmation and belief in the dream scenario, thought and reference in the BIV scenario). Putnam’s reasoning is usually interpreted differently, as a classic case of deception, but this feature is not essential. I propose to interpret BIV’s (...) utterances as cases of reference failure best captured by truth-value gaps. Both anti-skeptical strategies are then vulnerable to the same type of objections (how do we know what state we are in or how do we know what kind of language do we speak). (shrink)