Thomas Hofweber

It is tempting to think that AI will never produce any works of art that are of significant aesthetic value, let alone ones comparable to or even surpassing the greatest works produced by humans. However, it is not so clear what precisely the reason is for this limitation of AI, which has already surpassed human performance in other areas. I discuss several possible in-principle limitations to the aesthetic value of AI-generated works and conclude that although some limits are legitimate, the overall negative stance is nonetheless unjustified. But the purely techno-optimist stance that AI will be better than humans at everything is also unjustified. The question remains how one might build an AI that specifically aims to produce works of great aesthetic value. I outline how one might do this and argue that a particular feature of aesthetic value allows for the application of reinforcement learning in the training of such an AI. Finally, I discuss some obstacles for this approach and outline what we might expect for the future of art.

Should we think that some facts or some truths are such that we human beings can’t represent them in principle in thought or language? That is, are some facts so alien to the human mind that we cannot even think whether they obtain? Chapter 7 considers a series of arguments whether this is so, and in particular how facts we can think about would relate to those that we can’t think about. The larger concern is how facts beyond what human beings can represent would affect our goal of coming to a large-scale understanding of what the world is like, and whether a version of idealism can explain why there are no ineffable facts.

The chapter argues that our human natural languages are ideal languages for metaphysics and perfectly suited to represent all the facts that metaphysics might aim to find out. It presents an argument for this conclusion from considerations about language alone, without assuming anything about what metaphysics aims to do other than that it is concerned with questions of fact, and without assuming anything about what reality in general is like. A crucial consideration in support of this argument concerns the possibility of facts ineffable for us human beings. We can see from reflecting on our own talk about facts that ineffable facts are ruled out, and thus that our languages are ideal languages for representing reality. After discussing how an argument of this kind could possibly work, the chapter outlines some larger metaphysical issues that all this is related to.

The chapter investigates the reasons that moved Schiffer to reject his position in _Remnants_ and adopt his view in _Things_ instead, in particular when it comes to the question whether that-clauses refer to propositions, and the related question whether propositions exist at all. The chapter argues that these reasons should not have moved Schiffer. It presents some problems for both the views in _Remnants_ as well as in _Things_, related to inexpressible propositions, quantification, the semantics of that-clauses, as well as semantics more generally, and argues that these problems can be solved for _Remnants_, but not for _Things_. The chapter outlines a solution to these problems, and defends the no-reference theory of that-clauses championed in _Remnants_.

How can we settle whether key metaphysical questions should properly be stated by relying on a substantial notion of metaphysical priority, like grounding or being metaphysically more fundamental than? Relatedly, how can we settle whether ontology should properly be seen as the disciple that studies either what there is or else only what there is fundamentally? Which way of thinking about ontology brings out its proper metaphysical significance? One challenge to giving notions like grounding or fundamentality key roles in metaphysics is that these notions are insufficiently clear, and that metaphysics tied to them turns into esoteric metaphysics. To make progress on these issues I propose a particular challenge—the cognitive function challenge—that needs to be met for metaphysics based on a substantial notion of priority not to turn into objectionable esoteric metaphysics. I also outline some reasons why other approaches that aim to establish such notions as legitimate for metaphysics fall short and how the cognitive function challenge might be met.

In Ontology Made Easy and elsewhere Amie Thomasson has made a proposal about the significance of easy arguments for metaphysics. Easy arguments are apparently trivial inferences from premises that seem philosophically innocent to conclusions that seem to be philosophically substantial. In this paper my focus will be on well-know easy arguments for the existence of numbers, properties, and composite objects. I critically investigate Thomasson’s proposal about how to understand easy arguments and what significance they have. In particular, I will focus on the philosophy of language in the background of these arguments, and raise various problems for Thomasson’s account. I will also discuss her critical take on the proposals that others have made about these arguments, in particular her criticism in Ontology Made Easy of my own proposal.

It seems to be impossible to draw metaphysical conclusions about the world merely from our concepts or our language alone. After all, our concepts alone only concern how we aim to represent the world, not how the world in fact is. In this paper I argue that this is mistaken. We can sometimes draw substantial metaphysical conclusions simply from thinking about how we represent the world. But by themselves such conclusions can be flawed if the concepts from which they are drawn are themselves flawed. I propose that we can overcome these limitations by focusing on a special class of concepts: inescapable concepts. Combining arguments about what the world is like from considerations about our concepts alone, together with an argument that the relevant concepts are inescapable, leads to a novel method for metaphysics, which is broadly neo-Kantian.

In their recent article ‘Resolving Frege’s other Puzzle’ Eric Snyder, Richard Samuels, and Stewart Shapiro defend a semantic type-shifting solution to Frege’s other Puzzle and criticize my own cognitive type-shifting solution. In this article I respond to their criticism and in turn point to several problems with their preferred solution. In particular, I argue that they conflate semantic function and semantic value, and that their proposal is neither based on general semantic type-shifting principles nor adequate to the data.

Although higher-order metaphysics seems prima facie to be a promising new approach to metaphysics, it is nonetheless based on a mistake. This mistake is tied to a misuse of formal languages in metaphysics in general, not just to the use of higher-order rather than lower-order languages. I hope to highlight the mistake by discussing a popular recent example of higher- order metaphysics: the argument that reality is not structured using reasoning inspired by the Russell-Myhill paradox. A key issue will be the relationship between higher-order quantification in formal languages and quantification in English, in particular the questions whether such quantifiers are already to be found in English, and whether they could simply be added to English if not in order to gain expressive strength. I will conclude that little of metaphysical significance follows from this Russell-Myhill inspired argument against structure. The reason why the results of higher-order logic show little of metaphysical significance generalizes to other uses of higher-order logic in metaphysical theorizing, and with it supports that higher-order metaphysics is a flawed research program. I end with some reflections on what positive role formal tools like higher-order logic can have in metaphysics, and what the fundamental mistake is on which higher-order metaphysics is based.

Do human beings have a special and distinguished place in reality? In Idealism and the Harmony of Thought and Reality Thomas Hofweber contends that they do. We are special since there is an intimate connection between our human minds and reality itself. This book defends a form of idealism which holds that our human minds constrain, but do not construct, reality as the totality of facts. Reality as the totality of facts is thus not independent of our minds, and our minds play a metaphysically special role in all of reality. But reality as the totality of things is taken to be completely independent of us. Hofweber's proposed form of conceptual idealism is formulated via the notion of a harmony between our minds and reality. This harmony is defended through considerations in the philosophy of language. How can one possibly defend a metaphysical thesis like idealism from considerations about our own representation? A key step in the book's argument is to consider a special class of concepts--inescapable concepts--which we cannot rationally replace with different ones. This leads to a new approach for making progress in metaphysics--immanent metaphysics--which is broadly neo-Kantian in spirit.

Although higher-order metaphysics seems prima facie to be a promising new approach to metaphysics, it is nonetheless based on a mistake. This mistake is tied to a misuse of formal languages in metaphysics in general, not just to the use of higher-order rather than lower-order languages. I hope to highlight the mistake by discussing a popular recent example of higher- order metaphysics: the argument that reality is not structured using reasoning inspired by the Russell-Myhill paradox. A key issue will be the relationship between higher-order quantification in formal languages and quantification in English, in particular the questions whether such quantifiers are already to be found in English, and whether they could simply be added to English if not in order to gain expressive strength. I will conclude that little of metaphysical significance follows from this Russell-Myhill inspired argument against structure. The reason why the results of higher-order logic show little of metaphysical significance generalizes to other uses of higher-order logic in metaphysical theorizing, and with it supports that higher-order metaphysics is a flawed research program. I end with some reflections on what positive role formal tools like higher-order logic can have in metaphysics, and what the fundamental mistake is on which higher-order metaphysics is based.

Can it ever be rational to revise one's own logic by one's own lights? In this paper I argue that logic is never rationally revisable, even if one's own logic gives rise to paradoxes and allows one to derive any conclusion whatsoever. Instead of revising logic, we need to revise a certain widely held position in the philosophy of logic, one tied to the standard conception of validity and to the alleged monotonicity of deductive reasoning. I develop the alternative conception of validity and of deductive reasoning, which explains why we are generally entitled to the conclusions of deductive reasoning, even though we rationally do not accept them in certain circumstances tied to paradoxes.

Nominalists, who believe that everything there is is concrete and nothing is abstract, seem to have a problem with mathematics. Mathematics says that there are lots of prime numbers, and prime numbers don’t seem to be concrete. What should a nominalist do with mathematics? In the last few decades several programs in the philosophy of mathematics have been formulated which are, more or less explicitly, accounts of what a nominalist can say about mathematics. These programs, and the criticism of them, make up a substantial part of the literature in the philosophy of mathematics during this time. Usually such a program involves two parts. One is purely philosophical. It deals with the motivation for nominalism, and argues why certain technical results would show that nominalists have an account of mathematics. The other part is to provide the technical results needed in the program.

Although idealism was widely defended in the history of philosophy, it is nowadays almost universally considered a non-starter. This holds in particular for a strong form of idealism, which asserts that not just minds or the mental in general, but our human minds in particular are metaphysically central to reality. Such a view seems to be excessively anthropocentric and contrary to what we by now know about our place in the universe. Nonetheless, there is reason to think that such a strong form of idealism is indeed correct. In this paper, I will present an argument for idealism of this kind through considerations about a harmony between our thought and reality. The central argument in favour of idealism will come from a possibly unexpected source: we can see that a strong form of idealism is true simply from considerations about our language alone. I shall argue that thinking about how we represent reality allows us to conclude that idealism is true, and thus that reality must be a certain way. But no argument of this kind seems to allow for a metaphysical conclusion like idealism, since considerations about our language alone only show how we represent reality, not how reality is. And thus idealism can’t possibly follow, since it concerns how reality is, not just how we represent it to be. A good part of the second half of the paper is devoted to showing how such an argument is possible after all, and that it really does establish idealism.

The terms `endurance' and `perdurance' are commonly thought to denote distinct ways for an object to persist, but it is surprisingly hard to say what these are. The common approach, defining them in terms of temporal parts, is mistaken, because it does not lead to two coherent philosophical alternatives: endurance so understood becomes conceptually incoherent, while perdurance becomes not just true but a conceptual truth. Instead, we propose a different way to articulate the distinction, in terms of identity rather than temporal parts: an object endures if its identity is determined at every moment at which it exists. We make precise what it means for the identity of an object to be determined at a moment. We also discuss what role the endurance / perdurance distinction, so understood, should play in the debates about time, material objects and personal identity