Thomas Hofweber

Ontology is the philosophical discipline that tries to find out what there is: what entities make up reality, what is the stuff the world is made from? Thus, ontology is part of metaphysics, and in fact it seems to be about half of all of metaphysics. It tries to establish what (kinds of) things there are, the other half tries to find out what the (general) properties of these things are and what (general) relations they have to each other. Settling questions in ontology would bring with it major progress in metaphysics. And it would bring with it major progress in a variety of areas in philosophy outside of metaphysics as well. Many philosophical debates outside of metaphysics are quite directly influenced by how things turn out in ontology. Whether or not there are certain entities will give rise to quite different answers in various philosophical debates. I would like to very briefly describe three debates where ontological questions play a central role. These debates are either directly from metaphysics or from other areas of philosophy and they will be of central importance throughout this paper.

Ontology is the study of what there is, what kinds of things make up reality. Ontology seems to be a very difficult, rather speculative discipline. However, it is trivial to conclude that there are properties, propositions and numbers, starting from only necessarily true or analytic premises. This gives rise to a puzzle about how hard ontological questions are, and relates to a puzzle about how important they are. And it produces the ontologyobjectivity dilemma: either (certain) ontological questions can be trivially answered using only uncontroversial premises, or the uncertainties of ontology are really a threat to the truth of basically everything we say or believe. The main aim of this dissertation is to resolve these puzzles and to shed some light on the discipline of ontology. I defend a view inspired by Carnap’s internal-external distinction about what there is, but one according to which both internal and external questions are fully factual and meaningful. In particular, I argue that the trivial arguments are valid, but they do not answer any ontological questions. Furthermore, I propose an account of the function of our talk about properties, propositions and natural numbers. According to this account our talk about them has no ontological presuppositions for its literal and objective truth. This avoids the ontology-objectivity dilemma, and solves the puzzles about ontology. To do this I look at quantification and noun phrases in general, and at their relation to ontology. I argue that quantifiers are semantically underspecified in a certain respect, and play two different roles in communication. I discuss the relation between syntactic form and information structure, the function of certain non-referential, non-quantificational noun phrases, the uses of bare number determiners, and how arithmetic truths are learned and taught. The more metaphysical issues discussed include: inexpressible properties, logicism about arithmetic, nominalism, Carnap’s view about ontology, the problem of universals, the relationship between ontology and objectivity, different projects within ontology, non-existent....

This paper investigates the connection of intellectual humility to a somewhat neglected form of a limitation of human knowledge—a limitation in which facts or truths we human beings can in principle represent conceptually. I consider some arguments for such a limitation, and argue that, under standard assumptions, the sub-algebra hypothesis is the best hypothesis about how the facts we can represent relate to the ones that we can not. This hypothesis has a consequence for intellectual humility in that it supports it in metaphysics, but not in ordinary inquiry.

The semantics of noun phrases (NPs) is of crucial importance for both philosophy and linguistics. Throughout much of the history of the debate about the semantics of noun phrases there has been an implicit assumption about how they are to be understood. Basically, it is the assumption that NPs come only in two kinds. In this paper we would like to make that assumption explicit and discuss it and its status in the semantics of natural language. We will have a look at how the assumption is to be understood more precisely, what its methodological status should be, whether it has been abandoned in recent work in semantics, and whether it should be abandoned in future work. To do all this, it’s best to start with some historical context.

Cardinality arguments against regular probability measures aim to show that no matter which ordered field ℍ we select as the measures for probability, we can find some event space F of sufficiently large cardinality such that there can be no regular probability measure from F into ℍ. In particular, taking ℍ to be hyperreal numbers won't help to guarantee that probability measures can always be regular. I argue that such cardinality arguments fail, since they rely on the wrong conception of the role of numbers as measures of probability. With the proper conception of their role we can see that for any event space F, of any cardinality, there are regular hyperreal-valued probability measures.

An under-explored intermediate position between traditional materialism and traditional idealism is the view that although the spatiotemporal world is purely material, minds nonetheless have a metaphysically special place in it. One such intermediate position is that minds must exist, by metaphysical necessity, in any material world, and thus a mindless material world is impossible. This position, labeled The Subjectivity Thesis by Anton Friedrich Koch, was defended by him with an intriguing, purely metaphysical argument that is largely neglected in the contemporary debate. This paper is a critical examination of Koch’s argument, as well as of the larger position it would lead to

An under-explored intermediate position between traditional materialism and traditional idealism is the view that although the spatiotemporal world is purely material, minds nonetheless have a metaphysically special place in it. One way this can be is via a special role that subjects have in the metaphysics of material objects. Some metaphysical aspect of material objects might require the existence of subjects. This would support that minds must exist if material objects exist and thus that a mindless material world is impossible. This view, labeled the subjectivity thesis by Anton Friedrich Koch, was defended by him with an intriguing, purely metaphysical argument connected to the individuation of material objects in space and time. The present paper hopes to make progress on assessing the viability of such a position. It starts by critically examining Koch's argument for the subjectivity thesis, as well as similar arguments that give minds a central place in the metaphysics of material objects via considerations about identity and difference. It then compares these ideas to similar ones in the philosophy of time, and concludes with an outlook on whether such a position is viable and what needs to be done to fill the gaps unearthed along the way

On the one hand they seem to be quite obviously truth conditionally equivalent, but on the other hand they seem to be about different things. Whereas (1) is about Jupiter and its moons, (2) is about numbers. In particular, the word ‘four’ appears in (1) in the position of an adjective or determiner, whereas it seems to be a name for a number in (2). Furthermore, (2) appears to be an identity statement claiming that what two number terms stand for is the same thing. Several authors have proposed answers to this puzzle, including Frege, by either pinning the issue on the nature of numbers, pretense, fictionalism, or the nature of reference, but all these proposals agreed that (2) is an identity statement and that in it ‘four’ is a name for an object. In [Hofweber, 2007] I argued that (2) is not an identity statement and that ‘four’ in (2) is not a name for an object. The argument for it was this: When we look at what role (2) has in actual communication we can see that (2) has a focus effect on a discourse that arises from the syntax without special intonation

Many significant problems in metaphysics are tied to ontological questions, but ontology and its relation to larger questions in metaphysics give rise to a series of puzzles that suggest that we don't fully understand what ontology is supposed to do, nor what ambitions metaphysics can have for finding out about what the world is like. Thomas Hofweber aims to solve these puzzles about ontology and consequently to make progress on four metaphysical debates tied to ontology: the philosophy of arithmetic, the metaphysics of ordinary objects, the problem of universals, and the question of whether the fact-like aspect of reality is independent of us. Crucial parts of the proposed solution involve considerations about quantification and its relationship to ontology, the place of reference in natural languages, the relationship between syntactic form and focus, whether there could be any ineffable facts, and others.

Everyone working on metaphysical questions about properties or propositions knows the reaction that many non-philosophers, even nonmetaphysicians, have to such questions. Even though they agree that Fido is a dog and thus has the property (or feature or characteristic) of being a dog, it seems weird, suspicious, or confused to them to now ask what that thing, the property of being a dog, is. The same reservations do not carry over to asking what this thing, Fido, is. There is a substantial and legitimate project to find out more about Fido, but is there a similar substantial and legitimate project to find out more about the property of being a dog? Metaphysicians know that there is a straightforward way to motivate such a project, and much of the contemporary debate in the metaphysics of properties is in the ballpark of carrying it out. If we agree that Fido has the property of being a dog, then there is something that is a property and that Fido has. Thus we can ask about what this thing is that he has. How does it relate to Fido? Is it concrete or abstract? Is it fully present in each object that has it? And so on and so forth. Maybe the nonphilosophers are merely not used to asking such questions about unusual entities such as properties, but they are equally legitimate for them as they are for any other thing. However, even metaphysicians sometimes have the nagging feeling that something has gone wrong in the metaphysics of properties, and that a substantial metaphysical investigation into their..

In “Tense and Reality”, Kit Fine () proposed a novel way to think about realism about tense in the metaphysics of time. In particular, he explored two non-standard forms of realism about tense, arguing that they are to be preferred over standard forms of realism. In the process of defending his own preferred view, fragmentalism, he proposed a fragmentalist interpretation of the special theory of relativity, which will be our focus in this paper. After presenting Fine's position, we will raise a problem for his fragmentalist interpretation of STR. We will argue that Fine's view is in tension with the proper explanation of why various facts obtain. We will then consider whether similar considerations also speak against fragmentalism in domains other than STR, notably fragmentalism about tense.

Every fifteen years or so Stephen Schiffer writes a state of the art book on the philosophy of language, with special emphasis on belief ascriptions, meaning, and propositions. The latest is his terrific new book The Things we Mean. It is again full of ideas, insights, arguments, expositions, and theories. For us, however, who believe that that-clauses are first and foremost clauses, not referring expressions, and that they thus do not refer to propositions or anything else, The Things we Mean brings home the news that our champion, the author of Remnants of Meaning, has, alas, crossed over to the dark side. Although Schiffer’s earlier book defended one of the best versions of the no-reference theory, and brought up many of the issues that need to be addressed to defend such a theory, he now has recanted and switched sides. His new theory holds that propositions do exist after all, and that-clauses do refer to them. However, some of the motivation for the no-reference theory is incorporated into his new theory. In Remnants of Meaning one of the main reasons for rejecting the reference of that-clauses was the apparent impossibility to compositionally assign that-clauses their referents, and thus to give a compositional semantics for natural language. In The Things we Mean Schiffer still finds fault with any way to compositionally determine what things propositions are. But now the conclusion is not that they are not things, but that they are things that are not reducible to certain other things: they are sui generis entities. But they are not just any kind of sui generis entities, they are pleonastic entities. The use of the term ”pleonastic” might be slightly confusing, though, since propositions according to the new theory are neither pleonastic in the sense of redundant, nor pleonastic in the sense of the pleonastic it, which suggests a no-reference theory. Rather they are pleonastic in a certain technical sense. Simply put, pleonastic entities are the ones that i) can be introduced by 1 something-from-nothing transformations, and ii) the statement that there are such entities doesn’t imply anything about other entities that wasn’t implied before..