This book concerns the foundations of epistemic modality and hyperintensionality and their applications to the philosophy of mathematics. David Elohim examines the nature of epistemic modality, when the modal operator is interpreted as concerning both apriority and conceivability, as well as states of knowledge and belief. The book demonstrates how epistemic modality and hyperintensionality relate to the computational theory of mind; metaphysical modality and hyperintensionality; the types of mathematical modality and hyperintensionality; to the epistemic status of large cardinal axioms, undecidable (...) propositions, and abstraction principles in the philosophy of mathematics; to the modal and hyperintensional profiles of the logic of rational intuition; and to the types of intention, when the latter is interpreted as a hyperintensional mental state. Chapter \textbf{2} argues for a novel type of expressivism based on the duality between the categories of coalgebras and algebras, and argues that the duality permits of the reconciliation between modal and hyperintensional cognitivism and modal and hyperintensional expressivism. Elohim develops a novel, topic-sensitive truthmaker semantics for dynamic epistemic logic, and develops a novel, dynamic two-dimensional semantics grounded in two-dimensional hyperintensional Turing machines. Chapter \textbf{3} provides an abstraction principle for two-dimensional (hyper-)intensions. Chapter \textbf{4} advances a topic-sensitive two-dimensional truthmaker semantics, and provides three novel interpretations of the framework along with the epistemic and metasemantic. Chapter \textbf{5} applies the fixed points of the modal $\mu$-calculus in order to account for the iteration of epistemic states in a single agent, by contrast to availing of modal axiom 4 (i.e. the KK principle). The fixed point operators in the modal $\mu$-calculus are rendered hyperintensional, which yields the first hyperintensional construal of the modal $\mu$-calculus in the literature and the first application of the calculus to the iteration of epistemic states in a single agent instead of the common knowledge of a group of agents. Chapter \textbf{6} advances a solution to the Julius Caesar problem based on Fine's `criterial' identity conditions which incorporate conditions on essentiality and grounding. Chapter \textbf{7} provides a ground-theoretic regimentation of the proposals in the metaphysics of consciousness and examines its bearing on the two-dimensional conceivability argument against physicalism. The topic-sensitive epistemic two-dimensional truthmaker semantics developed in chapters \textbf{2} and \textbf{4} is availed of in order for epistemic states to be a guide to metaphysical states in the hyperintensional setting. -/- Chapters \textbf{8-12} provide cases demonstrating how the two-dimensional hyperintensions of hyperintensional, i.e. topic-sensitive epistemic two-dimensional truthmaker, semantics, solve the access problem in the epistemology of mathematics. Chapter \textbf{8} examines the interaction between Elohim's hyperintensional semantics and the axioms of epistemic set theory, large cardinal axioms, the Epistemic Church-Turing Thesis, the modal axioms governing the modal profile of $\Omega$-logic, Orey sentences such as the Generalized Continuum Hypothesis, and absolute decidability. These results yield inter alia the first hyperintensional Epistemic Church-Turing Thesis and hyperintensional epistemic set theories in the literature. Chapter \textbf{9} examines the modal and hyperintensional commitments of abstractionism, in particular necessitism, and epistemic hyperintensionality, epistemic utility theory, and the epistemology of abstraction. Elohim countenances a hyperintensional semantics for novel epistemic abstractionist modalities. Elohim suggests, too, that higher observational type theory can be applied to first-order abstraction principles in order to make first-order abstraction principles recursively enumerable, i.e. Turing machine computable, and that the truth of the first-order abstraction principle for two-dimensional hyperintensions is grounded in its being possibly recursively enumerable and the machine being physically implementable. Chapter \textbf{10} examines the philosophical significance of hyperintensional $\Omega$-logic in set theory and discusses the hyperintensionality of metamathematics. Chapter \textbf{11} provides a modal logic for rational intuition and provides a hyperintensional semantics. Chapter \textbf{12} avails of modal coalgebras to interpret the defining properties of indefinite extensibility, and avails of hyperintensional epistemic two-dimensional semantics in order to account for the interaction between interpretational and objective modalities and the truthmakers thereof. This yields the first hyperintensional category theory in the literature. Elohim invents a new mathematical trick in which first-order structures are treated as categories, and Vopenka's principle can be satisfied because of the elementary embeddings between the categories and generate Vopenka cardinals in the category of Set in category theory. Chapter \textbf{13} examines modal responses to the alethic paradoxes. Elohim provides a counter-example to epistemic closure for logical deduction. Chapter \textbf{14} examines, finally, the modal and hyperintensional semantics for the different types of intention and the relation of the latter to evidential decision theory. (shrink)

Wie ist es wohl, eine Fledermaus zu sein? Wäre ein rein physikalisches Duplikat von mir nur ein empfindungsloser Zombie? Muss man sich seinem Schicksal ergeben, wenn man sich unfreiwillig als lebensnotwendige Blutwaschanlage eines weltberühmten Violinisten wieder findet? Kann man sich wünschen, der König von China zu sein? Bin ich vielleicht nur ein Gehirn in einem Tank mit Nährflüssigkeit, das die Welt von einer Computersimulation vorgegaukelt bekommt? Worauf beziehen sich die Menschen auf der Zwillingserde mit ihrem Wort 'Wasser', wenn es bei (...) ihnen gar kein H2O gibt? -/- Diese und weitere seltsame Fragen sind das tägliche Brot vieler professioneller Philosophen. Die abstrusen Umstände, die dabei geschildert werden, nennt man "Gedankenexperimente". -/- Was soll die Erörterung dieser Szenarien, die sich so weit von unserem alltäglichen Leben, z.T. außerhalb der Grenzen unserer Wirklichkeit abspielen? Welche Rolle spielen diese "Gedankenexperimente" in der philosophischen Methodologie? Ist diese Rolle überhaupt berechtigt? -/- Das vorliegende Buch gibt Antworten auf diese Fragen. Es stellt sich heraus, dass diese seltsamen Gedankenexperimente nicht nur berechtigte, sondern überaus wichtige Instrumente philosophischen Forschens darstellen. (shrink)

Todd (2016) proposes an analysis of future-directed sentences, in particular sentences of the form 'will(φ)', that is based on the classic Russellian analysis of definite descriptions. Todd's analysis is supposed to vindicate the claim that the future is metaphysically open while retaining a simple Ockhamist semantics of future contingents and the principles of classical logic, i.e. bivalence and the law of excluded middle. Consequently, an open futurist can straightforwardly retain classical logic without appeal to supervaluations, determinacy operators, or any further (...) controversial semantical or metaphysical complication. In this paper, we will show that this quasi-Russellian analysis of 'will' both lacks linguistic motivation and faces a variety of significant problems. In particular, we show that the standard arguments for Russell's treatment of definite descriptions fail to apply to statements of the form 'will(φ)'. (shrink)

In this contribution, I comment on Raffaella Campaner’s defense of explanatory pluralism in psychiatry (in this volume). In her paper, Campaner focuses primarily on explanatory pluralism in contrast to explanatory reductionism. Furthermore, she distinguishes between pluralists who consider pluralism to be a temporary state on the one hand and pluralists who consider it to be a persisting state on the other hand. I suggest that it would be helpful to distinguish more than those two versions of pluralism – different understandings (...) of explanatory pluralism both within philosophy of science and psychiatry – namely moderate/temporary pluralism, anything goes pluralism, isolationist pluralism, integrative pluralism and interactive pluralism. Next, I discuss the pros and cons of these different understandings of explanatory pluralism. Finally, I raise the question of how to implement or operationalize explanatory pluralism in scientific practice; how to structure the “genuine dialogue” or shape “the pluralistic attitude” Campaner is referring to. As tentative answers, I explore a question-based framework for explanatory pluralism as well as social-epistemological procedures for interaction among competing approaches and explanations. (shrink)

Linguistic expressions frequently make reference to the situation in which they are uttered. In fact, there are expressions whose whole point of use is to relate to their context of utterance. It is such expressions that this article is primarily about. However, rather than presenting the richness of pertinent phenomena (cf. Anderson & Keenan 1985), it concentrates on the theoretical tools provided by the (standard) two-dimensional analysis of context dependence, essentially originating with Kaplan (1989)--with a little help from Stalnaker (1978) (...) and Lewis (1979a, 1980), and various predecessors including Kamp (1971) and Vlach (1973). The current article overlaps in content with the account in Zimmermann (1991), which is however much broader (and at times deeper).. (shrink)

"Five Questions on Formal Philosophy": Like the other authors in the volume, I was asked for my reflections on the character of philosophy by answering the following five questions : 1. Why were you initially drawn to formal methods? 2. What example from your work illustrates the role formal methods can play in philosophy? 3. What is the proper role of philosophy in relation to other disciplines? 4. What do you consider the most neglected topics and/or contributions in late 20th (...) century philosophy? 5. What are the most important problems in philosophy and which are the prospects for progress? (shrink)

The paper identifies two major strands of truth theories, ontological and epistemological ones, and argues that both are of equal primacy and find their home within two-dimensional semantics. Contrary to received views, it argues further that epistemological truth theories operate on Lewisian possible worlds and ontological truth theories on Wittgensteinian possible worlds and that both are mediated by the so-called epistemic-ontic map the further specification of which is of utmost philosophical importance.

Variabilism is the view that proper names (like pronouns) are semantically represented as variables. Referential names, like referential pronouns, are assigned their referents by a contextual variable assignment (Kaplan 1989). The reference parameter (like the world of evaluation) may also be shifted by operators in the representation language. Indeed verbs that create hyperintensional contexts, like ‘think’, are treated as operators that simultaneously shift the world and assignment parameters. By contrast, metaphysical modal operators shift the world of assessment only. Names, being (...) variables, refer rigidly in the latter merely intensional contexts, but may vary their reference in hyperintensional contexts. This conforms to the intuition that the content of attitude ascriptions encapsulates referential uncertainty. Furthermore, names in hyperintensional contexts are ambiguous between de re* and de dicto* interpretations. This fact is used to account for asymmetric mistaken identity attributions (for example, Biron thinks Katherine is Rosaline, but he doesn’t think Rosaline is Katherine). -/- The variable theory compares favourably with its alternatives, including Millianism and descriptivism. Millians cannot account for the behaviour of names in hyperintensional contexts, while descriptivists cannot generate a necessary contrast between intensional and hyperintensional contexts. No other theory can capture the facts pertaining to the existentially bound use of names. (shrink)

MILLIANISM and DESCRIPTIVISM are without question the two most prominent views with respect to the semantics of proper names. However, debates between MILLIANS and DESCRIPTIVISTS have tended to focus on a fairly narrow set of linguistic data and an equally narrow set of problems, mainly how to solve with Frege's puzzle and how to guarantee rigidity. In this article, the author focuses on a set of data that has been given less attention in these debates—namely, so-called predicative uses, bound uses, (...) and shifted uses of names. The author first shows that these data points seem to favor a DESCRIPTIVIST view over a MILLIAN view, but the author then introduces an alternative view of names that not only provides a simple and elegant way of dealing with the data, but also retains rigidity without becoming subject to the problems raised by Frege's puzzle. This is the view that names are variables, also called VARIABILISM. (shrink)

This paper argues for three kinds of possible worlds: Wittgensteinian totalities of facts, Lewisian worlds or universes, concrete objects of maximal essence, and the world, a concrete object of minimal essence. It moreover explains that correspondence truth applies to Wittgensteinian totalities and pragmatic truth to Lewisian universes. And it finally argues that this conceptualization lays proper foundations to two-dimensional semantics.

Two-dimensional (2D) semantics is a formal framework that is used to characterize the meaning of certain linguistic expressions and the entailment relations among sentences containing them. 2D semantics has also been applied to thought contents. In contrast with standard possible worlds semantics, 2D semantics assigns extensions and truth-values to expressions relative to two possible world parameters, rather than just one. So a 2D semantic framework provides finer-grained semantic values than those available within standard possible world semantics, while using the same (...) basic model-theoretic resources. The 2D framework itself is just a formal tool. To develop a semantic theory for someone’s language, a proponent of 2D semantics must do three things: (i) explain what exactly the two possible world parameters represent, (ii) explain the rules for assigning 2D semantic values to a person’s words and sentences, and (iii) explain how 2D semantic values help in understanding the meanings of the person’s words and sentences. (shrink)

This paper deals with the semantics of de dicto , de re and de se belief reports. First, I flesh out in some detail the established, classical theories that assume syntactic distinctions between all three types of reports. I then propose a new, unified analysis, based on two ideas discarded by the classical theory. These are: (i) modeling the de re/de dicto distinction as a difference in scope, and (ii) analyzing de se as merely a special case of relational de (...) re attitudes. The resurrection of these ideas takes place in a dynamic setting. My formalization of the first idea involves a modification of the presupposition-as-anaphora resolution algorithm for DRT. The second involves treating acquaintance relations as second-order presuppositions, to be bound in the context by means of higher-order unification, or accommodated if necessary. The resulting framework requires no syntactic distinctions between different modes of attitude, with the exception of a specific subclass of de se reports characterized by special ‘ de se pronouns’ (i.e. PRO and logophors). These special pronouns are handled in syntax; everything alse is passed on to the pragmatic resolution module as it appears on the surface. The more sophisticated contextual resolution process nonetheless ensures adequate output truth conditions for a variety of classical and novel puzzles. In particular, I compare the new pragmasemantic system to the classical, syntactic analysis with respect to iterated and quantified reports, and monstrously shifted indexicals. (shrink)

Kaplan claims in Demonstratives that no operator may manipulate the context of evaluation of natural language indexicals. We show that this is not so. In fact, attitude reports always manipulate a context parameter (or, rather, a context variable). This is shown by (i) the existence of De Se readings of attitude reports in English (which Kaplan has no account for), and (ii) the existence of a variety of indexicals across languages whose point of evaluation can be shifted, but only in (...) attitude reports. We develop an alternative account within an extensional framework with overt quantification over times, worlds and contexts. Various typological facts are discussed, esp. the distinction between English, Amharic and Ewe pronouns, and that between English and Russian tenses. (shrink)

While proper names in argument positions have received a lot of attention, this cannot be said about proper names in the naming construction, as in “Call me Al”. I argue that in a number of more or less familiar languages the syntax of naming constructions is such that proper names there have to be analyzed as predicates, whose content mentions the name itself (cf. “quotation theories”). If proper names can enter syntax as predicates, then in argument positions they should have (...) a complex structure, consisting of a determiner and its restriction, like common nouns (cf. “definite description theories of proper names”). Further consideration of the compositional semantics of proper names in the naming construction also shows that they have another argument slot, that of the naming convention. As a result, we will be able to account for the indexicality of proper names in argument positions and provide compositional semantics of complex and modified proper names (e.g., the famous detective Sherlock Holmes ). (shrink)

It has been argued that most truths about macroscopic states of affairs are entailed by a (hypothetical) complete descriptionPof the world in microscopic terms. In principle, micro-reductive explanations of non-microphysical truths could be constructeda priori.Against this claim, I show that reductive explanation requires knowledge about the phenomena to be reduced which cannot bea prioriextracted from microphysical information alone. Such reductions proceed in two steps: a “reductionR0” (“role-occupant”) establishes that a macroproperty M plays a certain causal role (specified in macro-terms), while (...) a “reductionMM” (“micro-macro”) establishes that some microproperty gives rise toM. (shrink)

When I talk about the objects of belief I do not mean, e.g., the sun to which my thought that the sun will rise tomorrow refers; I do not mean the objects we think about. I take objects rather in a general philosophical sense; they simply are the bearers of properties and the relata of relations. I am thus concerned with the objects that are related by the belief relation „_a_ believes that _p_“. In this scheme „ _a _“ represents (...) a person or an epistemic subject; but I am not going to discuss what a person is. „ _p _“ or „that _p _“ represents an object, namely the object of belief; and I am going to discuss what this is. In other words, I am interested in belief contents – to use a less neutral, narrower and equally unclear term. (shrink)

A number of puzzles about propositional attitudes in semantics and philosophy revolve around apparent referential dependencies between different attitudes within a single agent’s mental state. In a series of papers, Hans Kamp offers a general framework for describing such interconnected attitude complexes, building on DRT and dynamic semantics. I demonstrate that Kamp’s proposal cannot deal with referential dependencies between semantically conflicting attitudes, such as those in Ninan’s puzzle about de re imagination. To solve the problem I propose to replace Kamp’s (...) treatment of attitudes as context change potentials with a two-dimensional analysis. (shrink)

Putnam (1975) and Burge (1979) have made a convincing case that neither mea- nings nor beliefs are in the head. Most philosophers, it seems, have accepted their argument. Putnam explained that a subject.

In componential analysis, word meanings are (partly) decomposed into other meanings, and semantic and syntactic markers. Although a theory of word meaning based on such semantic decompositions remains compatible with the linguistic labor division thesis, it is not compatible with Kripke/Putnam-style indexical externalism. Instead of abandoning indexical externalism, a Separation Thesis is defended according to which lexical meaning need not enter the truth-conditional content of an utterance. Lexical meaning reflects beliefs about word meaning shared in a speaker community, and these (...) may rest on possibly erroneous world-level theories. It is argued that this type of lexical meaning is indispensable for explaining word composition processes and the rationality of metalinguistic disputes. (shrink)

Essentialism is, on the one hand, anchored with considerable firmness in a common sense picture of the world. On the other hand, it was dismissed for logico-philosophical reasons by a scientifically minded theorist like Quine. ``New essentialists'' like Kripke did engage in very profitable theorizing on an essentialist basis, but made no significant effort to investigate the prospects of imparting to an essentialist metaphysics a solid foundation within a scientific world view. These foundational prospects are the concern of the article. (...) – The investigation is guided by two ideas which are elaborated within a proof theoretical framework in the course of the article. First, being an essential F (where ``F'' represents a predicate) is linked with a lifelong possession of the property signified by ``F'' (but there is something more in it). Second, a special kind of necessity is involved in (true) predications of essential F-ness; it should be capable, like possibly all kinds of necessity, of being spelt out, in the final analysis, in terms of the provability of appropriate propositions in appropriate theoretical systems. In outlining the relevant axiomatic bases, the article draws on an early paper by E. Hirsch on individuation and essence. (shrink)

The paper argues that the objects of belief should not be conceived as sets of possible worlds or propositions of set of centered possible worlds or egocentric propositions (this is the propositional conception), but rather as sets of pairs consisting of a centered world and a sequence of objects (this is the intentional conception of the objects of belief). The paper explains the deep significance of this thesis for the framework of two-dimensional semantics, indeed for any framework trying to adequately (...) relate semantics and epistemology (which is here construed as what I call the Congruence Principle). I give three arguments for this thesis, two preliminary indecisive ones by way of examples, and third theoretical one alluding to a deep principle of philosophical psychology (which I call the Invariance Principle). This paper is an improved and up-dated version of my paper No. 25. It will appear in Causation, Coherence, and Concepts. A Collection of Essays of mine. (shrink)

We argue for a new mode of interpretation for attributed attitudes, what we call de translato interpretation. De translato interpretation assigns a meaning to an expression based on the interpretation given to that expression by the attitude subject rather than that standardly given by the attributor. We argue that this new mode of interpretation is distinct from but compatible with de dicto, de re and de qualitate interpretation. Formally, de translato interpretation is analyzed as introducing a modification in the language (...) used for interpretation, where the modification alters the attributor’s language in such a way as to more closely approximate the presumed language of a perspective holder. Attitude predicates are taken to introduce the perspective of their subject as a parameter of interpretation for the clause they embed. (shrink)

David Lewis proposed to deal with the semantics of sentences that state what is possible for an individual in terms of possible individuals that are in ways the first individual might have been, so called counterparts of the individual. In this book, I defend counterpart semantics as an approach to the semantics of modality and natural language semantics in particular. Counterpart semantics has a rival, the standard Kripkean semantics that deals with the same sentences in terms of an accessibility relation (...) between possible worlds. While counterpart semantics appears to be more flexible and carries less metaphysical presuppositions (it does not presuppose that I myself exist in various possible worlds, e.g.), Kripkean semantics has some advantages of its own. Most importantly, it incorporates the core assumptions of what may be called standard possible-worlds semantics; i.e. the core assumptions of the most successful framework within linguistic semantics. Counterpart semantics, on the other hand, does not conform to these assumptions, or so I will argue. In this book I opt for a synthesis of these two approaches that allows to combine their advantages. In Chap.1 I introduce the basic idea of counterpart semantics. I defend counterparts against the charge, made by Kripke, that counterparts are irrelevant for the analysis of modality. In Chap. 2 I present the classical version of counterpart semantics, i.e. David Lewis's translation of the language of quantified modal logic into counterpart theory. I discuss some well-known problems and opt for a revision of that translation that is able to solve the problems. Lewis's translation indirectly defines semantical values for expressions of quantified modal logic. In Chap.3 I evaluate counterpart semantics with respect to basic features of possible-worlds semantics. I conclude that the semantical values indirectly assigned to sentences by Lewis's translation are not sets of possible worlds, and that they do not meet certain intuitive demands on notions of meaning and content. (The revisions proposed in Chap.2 do not change this.) In Chap.4 I discuss various versions of a combination of counterpart semantics with Kripkean semantics found in the literature. But I conclude that here, the benefits of the latter are achieved by forfeiting the advantages of the former. Chap.5 finally contains my own proposal how to combine the two approaches in a more satisfactory way. The core semantical notion is truth according to a maximal complete representation, where representations now play the role of worlds. It is an important feature of the counterpart relation that it is qualitative, i.e. a relation in which things stand in virtue how they are. In Chap.1 I point out why it is qualitative, and why it ought to be. In Chap.6 I show how to make the notion of a qualitative property or relation precise. Finally, in Chap.7 I show how to extend this and related notions to predicates and propositions. For counterpart semantics to work at all we have to assume that everything that can be said at all can in principle be expressed in a language with qualitative predicates only (and perhaps, additionally, names, treated directly referentially). In Chap.7 I show how this assumption allows to maintain that the representations of our semantics deserve their name. (shrink)

The paper analyzes the meaning of color terms within the framework of Kaplan's character theory (which, when generalized to a treatment of hidden indexicality or dependence on the context world, can perfectly accommodate Kripke's notions of apriority and of (metaphysical) necessity). It explains this framework and why it might be fruitfully applied to color terms. Then it defends six theses: that (1) the predicate "is red" and (2) even the relation "appears red to" are hidden indexicals (i.e., have, as used (...) in English, different extensions in different context worlds), that (3) the phenomenal, the comparative, and the epistemic reading of "appears red to" are not three different readings, but reflect the context world dependence of this term, that (4) the statement "x is red iff x would appear red to most English-speaking people under normal conditions" is a priori in English, but analytic only in one reading and not in another, and that these observations account well for the epistemology of color terms and allow us to be metaphysically conservative by claiming that our context world is presumably such that (5) the statement "x appears red to y iff x (appropriately) causes y to be in a certain (disjunctive) neural state N" is necessarily true and (6) the statement "x is red iff the reflectance spectrum of the surface of x is of some (disjunctive) kind R" is necessarily true as well. (shrink)