This book tackles the issues that arise in connection with intensional logic -- a formal system for representing and explaining the apparent failures of certain important principles of inference such as the substitution of identicals and existential generalization -- and intentional states --mental states such as beliefs, hopes, and desires that are directed towards the world. The theory offers a unified explanation of the various kinds of inferential failures associated with intensional logic but also unifies the study of intensional contexts (...) and intentional states by grounding the explanation of both phenomena in a single theory. When an axiomatized realm of abstract entities is added to the metaphysical structure of the world, we can use them to identify and individuate the contents of directed mental states. The special abstract entities can be viewed as the objectified contents of mental files, and they play a crucial role in the analysis of truth conditions of the sentences involved in inferential failures. (shrink)

The complement of intensional transitive verbs, like any nonreferential complement, can be replaced by a ‘special quantifier’ or ‘special pronoun’ such as 'something', 'the same thing', or 'what'. In this paper, I will defend the ‘Nominalization Theory’ of special quantifiers against a range of apparent counterexamples involving intensional transitive verbs.

This paper discusses the semantics of intensional transitive verbs such as 'need', 'want','recognize', 'find', and 'hire'. It proposes new linguistic criteria for intensionality and defends two semantic analyses for two different classes of intensional verbs. The paper also includes a systematic classification of intensional verbs according to the type of lexical meaning they involve.

INTENSIONAL LOGIC §1. Natural Language and Intensional Logic When we speak of a theory of meaning for a natural language such as English, we have in mind an ...

This paper defends the view that perceptual ascriptions such as “Jones sees a cat” are sometimes intensional. I offer a range of examples of intensional perceptual ascriptions, respond to objections to intensional readings of perceptual ascriptions, and show how widely accepted semantic accounts of intensionality can explain the key features of intensional perceptual ascriptions.

Routledge Encyclopedia entry on Intensionality and Hyperintensionality.

The traditional scope theory of intensionality (STI) (see Russell 1905; Montague 1973; Ladusaw 1977; Ogihara 1992, 1996; Stowell 1993) is simple, elegant, and, for the most part, empirically adequate. However, a few quite troubling counterexamples to this theory have lead researchers to propose alternatives, such as positing null situation pronouns (Percus 2000) or actuality operators (Kamp 1971; Cresswell 1990) in the syntax of natural language. These innovative theories do correct the undergeneration of the original scope theory, but at a (...) cost: the situation pronoun and operator theories overgenerate, as argued extensively by Percus (2000) and Keshet (2008). This paper presents new data that supports the STI over other analyses, such as structures where DPs lose their de re readings in positions where syntactic movement is blocked. These data point the way to a new theory of intensionality. This new theory, called split intensionality, is a modification of the STI which aims to solve the problems raised for the original scope theory without overgenerating. The proposal calls for an additional intensional abstraction operator that creates an expression denoting an intension from an expression denoting an extension. When a DP moves to a position above this operator, it is interpreted de re; otherwise it is de dicto. The crucial part of the new proposal is that a DP may move above this operator and yet remain, for instance, below an intentional verb or inside an if-clause. Therefore, a DP within an island for syntactic movement may be de re and yet not move out of the island when the intensional abstraction operator is also within the island. (shrink)

Propositionalism is the view that all intensional constructions (including nominal and clausal attitude reports) can be interpreted as relations to truth-evaluable propositional content. While propositionalism has long been silently assumed in semantics and the philosophy of language, it has only recently entered center stage in linguistic research. This article surveys the properties of intensional constructions, which require the introduction of fine-grained semantic values (intensions). It contrasts two ways of obtaining such values: through the introduction of either Russellian propositions or Frege-Church-style (...) senses. The article identifies propositionalism with a specific variant of the Russellian strategy, reviews key arguments for propositionalism, and compares familiar varieties of propositionalism on the basis of instructive examples. It closes by discussing various challenges for propositionalism and suggesting a generalization of propositionalism that meets some of these challenges. Because of the association of propositions with semantic information, the article also addresses the more general question of whether all information content (including mental and pictorial content) is propositional. (shrink)

CHAPTER 1. INTENSIONAL LOGIC §1. Natural Language and Intensional Logic When we speak of a theory of meaning for a natural language such as English, ...

A verb is transitive iff it usually occurs with a direct object, and in such occurrences it is said to occur transitively . Thus ‘ate’ occurs transitively in ‘I ate the meat and left the vegetables’, but not in ‘I ate then left’ (perhaps it is not the same verb ‘left’ in these two examples, but it seems to be the same ‘ate’). A verb is intensional if the verb phrase (VP) it forms with its complement is anomalous in at (...) least one of three ways: (i) interchanging expressions in the complement referring to the same entity can change the truth-value of the sentence embedding the VP; (ii) the VP admits of a special “unspecific” reading if it contains a quantifier, or a certain type of quantifier; and (iii) the normal existential commitments of names and existential quantifiers in the complement are suspended even when the embedding sentence is negation-free. (shrink)

NPs with intensional relative clauses such as 'the impact of the book John needs to write' pose a significant challenge for trope theory (the theory of particularized properties), since they seem to refer to tropes that lack an actual bearer. This paper proposes a novel semantic analysis of such NPs on the basis of the notion of a variable object. The analysis avoids a range of difficulties that an alternative analysis based on the notion of an individual concept would face.

Radical Enactivism holds that the best explanation of basic forms of cognition is provided without involving information of any sort. According to this view, the ability to perceive visual affordances should be accounted for in terms of extensional covariations between variables spanning the agent’s body and the environment. Contrary to Radical Enactivism, I argue that the intensional properties of cognition cannot be ignored, and that the way in which an agent represents the world has consequences on the explanation of basic (...) sensorimotor abilities. To support this claim, I show that the perception of visual affordances is not segregated from higher forms of cognition; rather, it is modulated by the agent’s ability to recognize the semantic identity of the visual target. Accordingly, since the semantic recognition of an object involves a way of representing it under a certain description, it can be inferred that the perception of visual affordances cannot be accounted for without considering the intensional properties of cognition. This poses an explanatory issue for Radical Enactivism. (shrink)

The Embracing Revenge account of semantic paradox avoids the expressive limitations of previous approaches based on the Kripkean fixed point construction by replacing a single language with an indefinitely extensible sequence of languages, each of which contains the resources to fully characterize the semantics of the previous languages. In this paper we extend the account developed in Cook, Cook, Schlenker, and Tourville and Cook via the addition of intensional operators such as ``is paradoxical''. In this extended framework we are able (...) to characterize the difference between sentences, such as the Liar and the Truth-teller, that receive the same semantic value in minimal fixed points yet seem to involve distinct semantic phenomena. (shrink)

In this paper we define intensional models for the classical theory of types, thus arriving at an intensional type logic ITL. Intensional models generalize Henkin's general models and have a natural definition. As a class they do not validate the axiom of Extensionality. We give a cut-free sequent calculus for type theory and show completeness of this calculus with respect to the class of intensional models via a model existence theorem. After this we turn our attention to applications. Firstly, it (...) is argued that, since ITL is truly intensional, it can be used to model ascriptions of propositional attitude without predicting logical omniscience. In order to illustrate this a small fragment of English is defined and provided with an ITL semantics. Secondly, it is shown that ITL models contain certain objects that can be identified with possible worlds. Essential elements of modal logic become available within classical type theory once the axiom of Extensionality is given up. (shrink)

There is an obvious difference between what a term designates and what it means. At least it is obvious that there is a difference. In some way, meaning determines designation, but is not synonymous with it. After all, “the morning star” and “the evening star” both designate the planet Venus, but don't have the same meaning. Intensional logic attempts to study both designation and meaning and investigate the relationships between them.

NPs with intensional relative clauses such as 'the book John needs to write' pose a significant challenge for semantic theory. Such NPs act like referential terms, yet they do not stand for a particular actual object. This paper will develop a semantic analysis of such NPs on the basis of the notion of a variable object. The analysis avoids a range of difficulties that a more standard analysis based on the notion of an individual concept would face. Most importantly, unlike (...) the latter, the proposed analysis can be carried over NPs such as 'the number of people that fit into the bus', which describe tropes (particularized properties). (shrink)

In the present paper we discuss a recent suggestion of Schroeder-Heister concerning the possibility of defining an intensional notion of harmony using isomorphism in second-order propositional logic. The latter is not an absolute notion, but its definition is relative to the choice of criteria for identity of proofs. In the paper, it is argued that in order to attain a satisfactory account of harmony, one has to consider a notion of identity stronger than the usual one (based on β- and (...) η-conversions) that the authors have investigated in recent work. (shrink)

We investigate the higher-order modal logic , which is a variant of the system presented in our previous work. A semantics for that system, founded on the theory of quasi sets, is outlined. We show how such a semantics, motivated by the very intuitive base of Schrödinger logics, provides an alternative way to formalize some intensional concepts and features which have been used in recent discussions on the logical foundations of quantum mechanics; for example, that some terms like 'electron' have (...) no precise reference and that 'identical' particles cannot be named unambiguously. In the last section, we sketch a classical semantics for quasi set theory. (shrink)

If a semantically open language has no constraints on self-reference, one can prove an absurdity. The argument exploits a self-referential function symbol where the expressed function ends up being intensional in virtue of self-reference. The prohibition on intensional functions thus entails that self-reference cannot be unconstrained, even in a language that is free of semantic terms. However, since intensional functions are already excluded in classical logic, there are no drastic revisionary implications here. Still, the argument reveals a new sort of (...) intensional context, one which does not depend on a propositional attitude verb, a modal operator, an idiom like 'so called', etc. Moreover, since classical logicians do not seem aware of the potential danger with self-reference, a word of warning is in order. (shrink)

This chapter gives a truthmaker-based account of the semantics of 'reifying' quantifiers like 'something' when they act as complements of intensional transitive verbs ('need', 'look for'). It argues that such quantifiers range over 'variable satisfiers' of the attitudinal object described by the verb (e.g. the need or the search).

According to Spinoza mental events and physical events are identical. What makes Spinoza's identity theory tempting is that it solves the problem of mind body interaction rather elegantly: mental events and physical events can be causally related to each other because mental events are physical events. However, Spinoza seems to deny that there is any causal interaction between mental and physical events. My aim is to show that Spinoza's apparent denial of mind body interaction can be reconciled with the identity (...) theory. I argue that Spinoza had both an extensional and an intensional concept of cause and when Spinoza seems to deny mind body interaction he is having in mind the intensional concept of cause. This intensional concept of cause corresponds to that of causal explanation. I will argue that Spinoza anticipated Donald Davidson's view that even though mental events cannot be explained by referring to physical events and vice versa, mental and physical events are causally related to each other. (shrink)

An integrated statement is made concerning the semantic status of nodes in a propositional semantic network, claiming that such nodes represent only intensions. Within the network, the only reference to extensionality is via a mechanism to assert that two intensions have the same extension in same world. This framework is employed in three application problems to illustrate the nature of its solutions.The formalism used here utilizes only assertional information and no structural, or definitional, information. This restriction corresponds to many of (...) the psychologically motivated network models. Some of the psychological implications of network processes called node merging and node splitting are discussed. Additionally, it is pointed out that both our networks and the psychologically based networks are prone to memory confusions about knowing unless augmented by domain‐specific inference processes, or by structural information. (shrink)

After the publication of Marshall’s theorem (2009), it has been widely accepted that the intrinsic/extrinsic distinction cannot be analyzed in broadly logical terms, but instead requires appealing to more robust metaphysical notions like grounding, naturalness or duplication. However, in this article I will defend that this is not so. Instead of showing the limitations of Marshall’s undoubtedly impressive result, I will present here a broadly logical definition of the intrinsic/extrinsic distinction, and show that it is extensional adequate regardless of our (...) preferred conception of property identity. (shrink)

Following on Westerståhl’s argument that many is not Conservative [9], I propose an intensional account of Conservativity as well as intensional versions of EXT and Isomorphism closure. I show that an intensional reading of many can easily possess all three of these, and provide a formal statement and proof that they are indeed proper intensionalizations. It is then discussed to what extent these intensionalized properties apply to various existing readings of many.

Classical first-order logic can be extended in two different ways to serve as a foundation for mathematics: introduce higher orders, type theory, or introduce sets. As it happens, both approaches have natural analogs for quantified modal logics, both approaches date from the 1960’s, one is not very well-known, and the other is well-known as something else. I will present the basic semantic ideas of both higher order intensional logic, and intensional set theory. Before doing so, I’ll quickly sketch some necessary (...) background material from quantified modal logic. Except for standard material concerning propositional modal logics, the paper is essentially self-contained. (shrink)

Paradigm intensional contexts result from the unmarked use of referential expressions as “self‐signs”, signs that refer to themselves as tokens, types, or members of Sellarsian “dot‐quoted” kinds. Self‐signing (but unquoted) linguistic expressions are more difficult to recognize than non‐linguistic self‐signs such as the color of a felt pen's casing that represents the color of ink inside. I will discuss non‐linguistic self‐signing, then examine self‐signing in quotation, in “said that …” contexts and in “believes that … ” contexts. The phenomenon of (...) intensionality may reduce to a kind of equivocation, a matter of notation rather than a necessary feature of language. (shrink)

According to a widespread view in medieval scholarship, theories of supposition are the medieval counterparts of theories of reference, and are thus essentially extensional theories. I propose an alternative interpretation: theories of supposition are theories of properties of terms, but whose aim is to allow for the interpretation of sentences. This holds especially of Ockham’s supposition theory, which is the main object of analysis in this paper. In particular, I argue for my intensional interpretation of his theory on the basis (...) of two key-phrases in his Summa Logicae: ‘denotatur’ and ‘propositio est distinguenda’. Finally, I offer a reconstruction of his theory as a set of instructions to be carried out in order to generate the possible readings of (certain) sentences. (shrink)

The syntactic structure of the deontic “ought” has been much debated in philosophy and linguistics. Schroeder argues that the deontic “ought” is syntactically ambiguous in the sense that it can be associated with either a control or raising construction. He distinguishes between deliberative and evaluative “ought”s and argues that the deliberative “ought” is control while the evaluative “ought” is raising. However, if there is a control sense of “ought,” it implies that there is a sense of “ought” in which the (...) word carries an external argument. Chrisman (2012) proposes two linguistic tests to verify this prediction. I add a new test, which I call the intensionality test, to the list. (shrink)

This paper aims to shed new light on certain philosophical theories of perceptual experience by examining the semantics of perceptual ascriptions such as “Jones sees an apple.” I start with the assumption, recently defended elsewhere, that perceptual ascriptions lend themselves to intensional readings. In the first part of the paper, I defend three theses regarding such readings: I) intensional readings of perceptual ascriptions ascribe phenomenal properties, II) perceptual verbs are not ambiguous between intensional and extensional readings, and III) intensional perceptual (...) ascriptions have a relational form. The second part of the paper describes the implications of I-III for theories of perceptual experience. I argue that I-III support and reconcile the three main views of perceptual experience, relationalism, disjunctivism, and representationalism. However, I-III leave open at least one important point of contention: particularism, the view that we experience external objects. I conclude by exploring the implications of accepting or denying particularism given I-III. (shrink)