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)

According to predictive processing, an increasingly influential paradigm in cognitive science, the function of the brain is to minimize the prediction error of its sensory input. Conceptual engineering is the practice of assessing and changing concepts or word meanings. We contribute to both strands of research by proposing the first cognitive account of conceptual engineering, using the predictive processing framework. Our model reveals a new kind of implementation problem as prediction errors are only minimized if enough agents embrace conceptual changes. (...) This problem can be overcome by emphasizing the importance ofsocial normsandconceptual pluralism. (shrink)

Conceptual engineering takes a distinctively normative and reconstructive approach to our conceptual repertoire. This approach is congenial to the ideas defended by philosophers belonging to the multifaceted tradition of American and Cambridge Pragmatism. This special issue is devoted to the investigation and development of these connections. Our introduction maps some of the historical and theoretical entanglements between the two fields and gives a short overview of the contributions to the special issue.

Conceptual engineers have made hay over the differences of their metaphilosophy from those of conceptual analysts. In this article, I argue that the differences are not as great as conceptual engineers have, perhaps rhetorically, made them seem. That is, conceptual analysts asking ‘What is X?’ questions can do much the same work that conceptual engineers can do with ‘What is X for?’ questions, at least if conceptual analysts self-understand their activity as a revisionary enterprise. I show this with a study (...) of Russell's metaphilosophy, which was just such a revisionary conception of conceptual analysis. (shrink)

This paper argues for explanatory eliminativism about topics (and cognates, such as subject matters) relative to the domain of conceptual engineering. It has become usual to think that topics serve an important explanatory role in theories of conceptual engineering, namely, to determine the limits of revision. I argue, first, that such limits can be understood either as thenormative limitspertaining to the justification of conceptual engineering, as themetaphysical limitspertaining to the identity of the concepts in question, or as theterminological limitspertaining to (...) usage of the original terminology. Second, I argue that the metaphysical reading is disputable as a theory of concepts and inconsequential for conceptual engineers, and that neither of the two leading accounts of topics that have been presented in the literature—the samesaying account and functionalism—determine the limits of revision in either of the two remaining senses. In the absence of more promising competitors, I conclude that there is no theoretical role for topics to play in theories of conceptual engineering. An upshot of my argument is that conceptual engineers should stop worrying about things like topic (dis)continuity, and instead shift their attention to the issues that really matter for justifying conceptual revisions or replacements, making terminological choices, and underpinning conceptual engineering with a theory of concepts. (shrink)

Carnap’s seminal ‘Empiricism, Semantics and Ontology’ makes important use of the notion of a framework and the related distinction between internal and external questions. But what exactly is a framework? And what role does the internal/external distinction play in Carnap’s metaontology? In an influential series of papers, Matti Eklund has recently defended a bracingly straightforward interpretation: A Carnapian framework, Eklund says, is just a natural language. To ask an internal question, then, is just to ask a question in, say, English. (...) To try to ask an external question is to try, absurdly, to ask a question in no language at all. Finding that so trivial an I/e distinction can’t help to explain Carnap’s deflationary metaontology, Eklund is led to attribute to Carnap a view he calls ontological pluralism. In this paper, I show that Eklund misreads Carnap, and I argue that this misreading obscures fundamental features of Carnap’s philosophy. I then defend an account of frameworks as what Carnap called semantical systems, and I place this account in the context of Carnap’s philosophical program of explication. Finally, I discuss the role that frameworks and the I/e distinction play in ESO, showing that ESO provides no reason to attribute the doctrine of ontological pluralism to Carnap. (shrink)

This paper aims to provide a mathematically tractable background against which to model both modal and hyperintensional cognitivism and modal and hyperintensional expressivism. I argue that epistemic modal algebras, endowed with a hyperintensional, topic-sensitive epistemic two-dimensional truthmaker semantics, comprise a materially adequate fragment of the language of thought. I demonstrate, then, how modal expressivism can be regimented by modal coalgebraic automata, to which the above epistemic modal algebras are categorically dual. I examine five methods for modeling the dynamics of conceptual (...) engineering for intensions and hyperintensions. I develop a novel topic-sensitive truthmaker semantics for dynamic epistemic logic, and develop a novel dynamic epistemic two-dimensional hyperintensional semantics. I examine then the virtues unique to the modal and hyperintensional expressivist approaches here proffered in the setting of the foundations of mathematics, by contrast to competing approaches based upon both the inferentialist approach to concept-individuation and the codification of speech acts via intensional semantics. (shrink)

In this paper, we first briefly survey the main responses to the challenge that experimental philosophy poses to the method of cases, given the common assumption that the latter is crucially based on intuitive judgments about cases. Second, we discuss two of the most popular responses in more detail: the expertise defense and the mischaracterization objection. Our take on the expertise defense is that the available empirical data do not support the claim that professional philosophers enjoy relevant expertise in their (...) intuitive judgments about cases. In contrast, the mischaracterization objection seems considerably more promising than its largely negative reception has suggested. We argue that the burden of proof is thus on philosophers who still hold that the method of cases crucially relies on intuitive judgments about cases. Finally, we discuss whether conceptual engineering provides an alternative to the method of cases in light of the challenge from experimental philosophy. We argue that this is not clearly the case, because conceptual engineering also requires descriptive information about the concepts it aims to improve. However, its primarily normative perspective on our concepts makes it largely orthogonal to the challenge from experimental philosophy, and it can also benefit from the empirical methods of the latter. (shrink)

A characterization of epistemic rationality, or epistemic justification, is typically taken to require a process of conceptual clarification, and is seen as comprising the core of a theory of (epistemic) rationality. I propose to explicate the concept of rationality. -/- It is essential, I argue, that the normativity of rationality, and the purpose, or goal, for which the particular theory of rationality is being proposed, is taken into account when explicating the concept of rationality. My position thus amounts to an (...) instrumentalist position about theories of epistemic rationality. Since there are different purposes, or goals, for which theories of rationality are proposed, the method of explication leaves room for different characterizations of rationality. I focus on two such (kinds of) purposes: first, the purpose of guiding the formation (or maintenance) of doxastic states and, second, the purpose of assessing (the formation or maintenance of) doxastic states. I conclude by outlining a pluralistic picture concerning rationality. (shrink)

Many concepts are inadequate for serious inquiry, so theorists often seek to engineer new concepts. The method of explication, which involves replacing concepts with more fruitful alternatives, is a model of this process. In this paper, I develop an account of fruitfulness, the Relevant-Goals Account of Fruitfulness. The account is in the spirit of extant proposals, but develops and extends them in important ways. In particular, while it applies to explications in general, the account allows us to derive substantive details (...) for specific explications. This is achieved through a supplementary view, Contextualism, that specifies which theoretical goals are relevant in any given case. I close by discussing how the Relevant-Goals Account fits into the dynamic nature of inquiry. (shrink)

What is the relationship between conceptual engineering and metasemantic externalism? Sally Haslanger has argued that metasemantic externalism justifies the seemingly counterintuitive consequences of her proposed conceptual revisions. But according to Herman Cappelen, metasemantic externalism makes conceptual engineering effectively impossible in practice. After raising objections to Haslanger’s and Cappelen’s views, I argue for a very different picture, on which metasemantic externalism bears very little on conceptual engineering. I argue that, while metasemantic externalism principally operates at the level of semantic-meaning, we should (...) understand conceptual engineering to operate largely at the level of speaker-meaning. This ‘Speaker-Meaning Picture’ has two key benefits. Firstly, it makes conceptual engineering often easy in practice. Secondly, it suggests a new, normative response to the well known objection that conceptual engineering serves only to change the subject. (shrink)

Traditional views on philosophical methodology characterize our primary philosophical goal as production of a successful conceptual analysis. The notion of conceptual analysis, however, faces several challenges—from experimental philosophy to more traditional worries such as the paradox of analysis. This paper explores an alternate approach, commonly called conceptual engineering, which aims at recommending conceptual revisions. An important question for the conceptual engineer is as follows: what counts as a case of successful conceptual engineering? What sorts of revisions are permitted, and what (...) sorts are too revisionary? In this paper I examine ‘functional’ approaches to conceptual engineering, ultimately arguing for a ‘radical’ functionalism according to which even revisions which ‘change the subject’ are permitted, and successful re-engineering is constrained only by the requirement that continuity in needed functions of a pre-engineering concept be maintained somewhere in the postengineering conceptual scheme. I further argue that this approach suggests a heightened role, in metaphilosophical discourse, for a neglected epistemic goal—conceptual efficacy. (shrink)

According to Herman Cappelen’s Austerity Framework, conceptual engineering doesn’t involve concepts, and barely involves engineering. I begin by raising two objections to the Austerity Framework as it stands: the framework cannot account for important normative aspects of conceptual engineering; and it doesn’t give us an adequate response to Strawson-style objections that conceptual engineering serves only to change the subject. I then supplement the Austerity Framework with an account of semantic normativity, which builds on the speaker/semantic meaning distinction, and show that (...) so-supplemented the Austerity Framework successfully overcomes the two objections. I tentatively conclude that semantic normativity should play a key role in how we understand conceptual engineering. (shrink)

This paper argues for explanatory eliminativism about topics (and cognates, such as subject matters) relative to the domain of conceptual engineering. It has become usual to think that topics serve an important explanatory role in theories of conceptual engineering, namely, to determine the limits of revision. I argue, first, that such limits can be understood either as thenormative limitspertaining to the justification of conceptual engineering, as themetaphysical limitspertaining to the identity of the concepts in question, or as theterminological limitspertaining to (...) usage of the original terminology. Second, I argue that the metaphysical reading is disputable as a theory of concepts and inconsequential for conceptual engineers, and that neither of the two leading accounts of topics that have been presented in the literature—the samesaying account and functionalism—determine the limits of revision in either of the two remaining senses. In the absence of more promising competitors, I conclude that there is no theoretical role for topics to play in theories of conceptual engineering. An upshot of my argument is that conceptual engineers should stop worrying about things like topic (dis)continuity, and instead shift their attention to the issues that really matter for justifying conceptual revisions or replacements, making terminological choices, and underpinning conceptual engineering with a theory of concepts. (shrink)

Conceptual analysis aims to uncover the basic criteria of concepts that underwrite categorizing members via the method of cases. However, conceptual analysis has not been very successful and experimental philosophy has increasingly detailed this lack of success. This essay reviews Thinking Off Your Feet: How Empirical Psychology Vindicates Armchair Philosophy by Michael Strevens, which attempts a novel defence of conceptual analysis. It is a strategic intervention that seems to preserve a relatively traditional picture of philosophical inquiry. I concentrate on several (...) assumptions in this intervention that might be questioned and conclude there are good reasons to continue an interrogation of how we understand the philosophical enterprise. Ideally, this might encourage us to rebuild our picture of what philosophy is. (shrink)

Kevin Scharp’s influential work on the alethic paradoxes combines an extensively developed inconsistency theory with a substantial conceptual engineering project. I argue that Scharp’s inconsistency theory is in tension with his conceptual engineering project: the inconsistency theory includes an account of concepts that implies that the conceptual engineering project will fail. I recommend that Scharp revises his account of concepts, and show how doing so allows him to resolve the tension. The discussion is important for ongoing work on conceptual engineering. (...) Firstly, it is important to get clear on whether Scharp’s conceptual engineering project is—or could be—successful. Secondly, the issues discussed herein may generalise to other conceptual engineering projects, such as explication and ameliorative projects. In particular, the discussion has implications for how conceptual engineers can think about concepts and their relation to how we use words. (shrink)

This encyclopedia article provides a procedural account of explication outlining each step that is part of the overall explicative effort (2). It is prefaced by a summary of the historical development of the method (1). The latter part of the article includes a rough structural theory of explication (3) and a detailed presentation of an examplary explication taken from the history of philosophy and the foundations of mathematics (4).