In “Proof-Theoretic Justification of Logic”, building on work by Dummett and Prawitz, I show how to construct use-based meaning-theories for the logical constants. The assertability-conditional meaning-theory takes the meaning of the logical constants to be given by their introduction rules; the consequence-conditional meaning-theory takes the meaning of the logical constants to be given by their elimination rules. I then consider the question: given a set of introduction rules \, what are the strongest elimination rules that are validated by an assertability (...) conditional meaning-theory based on \? I prove that the intuitionistic introduction rules are the strongest rules that are validated by the intuitionistic elimination rules. I then prove that intuitionistic logic is the strongest logic that can be given either an assertability-conditional or consequence-conditional meaning-theory. In “Grounding Grounding” I discuss the notion of grounding. My discussion revolves around the problem of iterated grounding-claims. Suppose that \ grounds \; what grounds that \ grounds that \? I argue that unless we can get a satisfactory answer to this question the notion of grounding will be useless. I discuss and reject some proposed accounts of iterated grounding claims. I then develop a new way of expressing grounding, propose an account of iterated grounding-claims and show how we can develop logics for grounding. In “Is the Vagueness Argument Valid?” I argue that the Vagueness Argument in favor of unrestricted composition isn’t valid. However, if the premisses of the argument are true and the conclusion false, mereological facts fail to supervene on non-mereological facts. I argue that this failure of supervenience is an artifact of the interplay between the necessity and determinacy operators and that it does not mean that mereological facts fail to depend on non-mereological facts. I sketch a deflationary view of ontology to establish this. (shrink)

When some objects are the parts of another object, they compose that object and that object is composite. This article is intended as an introduction to the central questions about composition and a highly selective overview of various answers to those questions. In §1, we review some formal features of parthood that are important for understanding the nature of composition. In §2, we consider some answers to the question: which pluralities of objects together compose something? As we will see, the (...) dominant answers are all of them and none of them. In §§3-4, we examine one of the main arguments that has driven philosophers to these extreme answers: the argument from vagueness. In §5, we turn to the question of whether composition is unique: is it sometimes the case that some things compose more than one thing? Finally, in §6, we turn from the question of which composites exist to the question of which composites exist fundamentally. (shrink)

How does vagueness interact with metaphysical modality and with restrictions of it, such as nomological modality? In particular, how do definiteness, necessity (understood as restricted in some way or not), and actuality interact? This paper proposes a model-theoretic framework for investigating the logic and semantics of that interaction. The framework is put forward in an ecumenical spirit: it is intended to be applicable to all theories of vagueness that express vagueness using a definiteness (or: determinacy) operator. We will show how (...) epistemicists, supervaluationists, and theorists of metaphysical vagueness like Barnes and Williams (2010) can interpret the framework.  We will also present a complete axiomatization of the logic we recommend to both epistemicists and local supervaluationists. . (shrink)

Words, languages, symphonies, fictional characters, games, and recipes are plausibly abstract artifacts— entities that have no spatial location and that are deliberately brought into existence as a result of creative acts. Many accept that composition is unrestricted: for every plurality of material objects, there is a material object that is the sum of those objects. These two views may seem entirely unrelated. I will argue that the most influential argument against restricted composition—the vagueness argument—doubles as an argument that there can (...) be no abstract artifacts. There is no way to resist the vagueness argument against abstract artifacts that does not also undermine the vagueness argument against restricted composition. (shrink)

Mereological nihilism is the view that no objects have proper parts. Despite how counter‐intuitive it is, it is taken quite seriously, largely because it solves a number of puzzles in the metaphysics of material objects – or so its proponents claim. In this article, I show that for every puzzle that mereological nihilism solves, there is a similar puzzle that (a) it doesn’t solve, and (b) every other solution to the original puzzle does solve. Since the solutions to the new (...) puzzles apply just as well to the old puzzles, the old puzzles provide no motivation to be a mereological nihilist. (shrink)

Composition as Identity is the view that an object is identical to its parts taken collectively. I elaborate and defend a theory based on this idea: composition is a kind of identity. Since this claim is best presented within a plural logic, I develop a formal system of plural logic. The principles of this system differ from the standard views on plural logic because one of my central claims is that identity is a relation which comes in a variety of (...) forms and only one of them obeys substitution unrestrictedly. I justify this departure from orthodoxy by showing some problems which result from attempts to avoid inconsistencies within plural logic by means of postulating other non-singular terms besides plural terms. Thereby, some of the main criticisms raised against Composition as Identity can be addressed. Further, I argue that the way objects are arranged is relevant with respect to the question which object they compose, i.e. to which object they are identical to. This helps to meet a second group of arguments against Composition as Identity. These arguments aim to show that identifying composite objects on the basis of the identity of their parts entails, contrary to our common sense view, that rearranging the parts of a composite object does not leave us with a different object. Moreover, it allows us to carve out the intensional aspects of Composition as Identity and to defend mereological universalism, the claim that any objects compose some object. Much of the pressure put on the latter view can be avoided by distinguishing the question whether some objects compose an object from the question what object they compose. Eventually, I conclude that Composition as Identity is a coherent and plausible position, as long as we take identity to be a more complex relation than commonly assumed. (shrink)

The special composition question is the question, ‘When do some things compose something?’ The answers to this question in the literature have largely been at odds with common sense, either by allowing that any two things compose something, or by denying the existence of most ordinary composite objects. I propose a new ‘series-style’ answer to the special composition question that accords much more closely with common sense, and I defend this answer from van Inwagen's objections. Specifically, I will argue that (...) the proposed answer entails the transitivity of parthood, that it is non-circular, and that it casts some light on the ancient puzzle about the Ship of Theseus. (shrink)

David Lewis (1986) criticizes moderate views of composition on the grounds that a restriction on composition must be vague, and vague composition leads, via a precisificational theory of vagueness, to an absurd vagueness of existence. I show how to resist this argument. Unlike the usual resistance, however, I do not jettison precisificational views of vagueness. Instead, I blur the connection between composition and existence that Lewis assumes. On the resulting view, in troublesome cases of vague composition, there is an object, (...) which definitely exists, about which it is vague whether the relevant borderline parts compose it. (shrink)

One of the most influential arguments in favour of perdurantism is the Argument from Vagueness. The argument proceeds in three stages: The first aims to establish atemporal universalism. The second presents a parallel argument in favour of universalism in the context of temporalized parthood. The third argues that diachronic universalism entails perdurantism. I offer a novel objection to the argument. I show that on the correct way of formulating diachronic universalism the principle does not entail perdurantism. On the other hand, (...) if diachronic universalism is formulated as Sider proposes, the argument fails to establish his principle, and thus perdurantism. (shrink)

This paper consists of two parts. The first concerns the logic of vagueness. The second concerns a prominent debate in metaphysics. One of the most widely accepted principles governing the ‘definitely’ operator is the principle of Distribution: if ‘p’ and ‘if p then q’ are both definite, then so is ‘q’. I argue however, that epistemicists about vagueness should reject this principle. The discussion also helps to shed light on the elusive question of what, on this framework, it takes for (...) a sentence to be borderline or definite. In the second part of the paper, I apply this result to a prominent debate in metaphysics. One of the most influential arguments in favour of Universalism about composition is the Lewis-Sider argument from vagueness. An interesting question, however, is whether epistemicists have any particular reasons to resist the argument. I show that there is no obvious reason why epistemicists should resist the argument but there is a non-obvious one: the rejection of Distribution argued for in the first part of the paper provides epistemicists with a unique way of resisting the argument from vagueness. (shrink)

On the standard view for something to exist is for one thing to exist: in slogan form, to be is to be countable. E.J. Lowe argues something can exist without being countable as one, however. His primary example is homogenous “stuff,” i.e., qualitatively uniform and infinitely divisible matter. Lacking nonarbitrary boundaries and being everywhere the same, homogenous stuff lacks a principle of individuation that would yield countably distinct constituents. So, for Lowe, homogenous stuff is strongly uncountable. Olson rejects Lowe’s view (...) and defends the orthodox connection between existence and number. He argues that if there is any stuff, there is a number of portions of stuff. Sider also rejects a stuff ontology, claiming it is incompatible with his preferred view that the familiar quantifiers of predicate logic carve at nature’s joints. Against these arguments, I defend the uncountability of stuff and the possibility of existence without countability. If to be is to be countable, more is needed than the arguments that Olson and Sider provide. (shrink)

One of the central debates in contemporary metaphysics has been the debate between endurantism and perdurantism about persistence. In this paper I argue that much of this debate has been misconstrued: most of the arguments in the debate crucially rely on theses which are strictly orthogonal to the endurantism/perdurantism debate. To show this, I note that the arguments in the endurantism/perdurantism debate typically take the following form: one presents a challenge that endurantists allegedly have some trouble addressing, and to which (...) perdurantism apparently has a straightforward response. I argue, however, that in each case, there are versions of endurantism that can offer precisely the same response to the challenge, and thus the ability to provide this particular solution does not directly tell in favour of one the two views. In §1, I elaborate two views which will be particularly prominent in the discussion: liberal endurantism and restrictive perdurantism. In §2–6 I discuss in turn the central pro-perdurantism arguments: the argument from anthropocentricism, the argument from vagueness, the argument from recombination, the argument from temporary intrinsics, and the argument from coincidence. In §7–8, I discuss the main pro-endurantism arguments: the arguments from motion, and the argument from permanent coincidence. Finally, in §9, I discuss what conclusion can be drawn from this discussion. (shrink)

It has been argued by some that the argument from vagueness is one of the strongest arguments in favor of the theory of temporal parts. I will neither support nor dispute this claim here. Rather, I will present a version of the argument from vagueness, which – if successful – commits one to the existence of modal parts. I argue that a commitment to the soundness of the argument from vagueness for temporal parts compels one to commit to the soundness (...) of the argument from vagueness for modal parts. I say compels, but not entails; an objection to one of the arguments highlights analogous ways to reject the other, making it difficult to endorse one and reject the other. This would be a significant conclusion, if true, since there are far fewer who currently commit themselves to modal parts than the many who currently commit themselves to temporal parts. (shrink)