In virtue of what is something a reason for action? That is, what makes a consideration a reason to act? This is a metaphysical or meta-normative question about the grounding of reasons for action. The answer to the grounding question has been traditionally given in ‘pure’, univocal terms. This paper argues that there is good reason to understand the ground of practical normativity as a hybrid of traditional ‘pure’ views. The paper 1) surveys the three leading ‘pure’ answers to (...) the question of a normative ground, 2) examines one or two of the most difficult problems for each, proposing along the way a new objection to one, and 3) argues that a particular hybrid view about normative grounds –‘hybrid voluntarism’ – avoids each of the main problems faced by the three leading ‘pure’ views. (shrink)
Can hybridism about moral claims be made to work? I argue it can if we accept the conventional implicature approach developed in Barker (Analysis 2000). However, this kind of hybrid expressivism is only acceptable if we can make sense of conventional implicature, the kind of meaning carried by operators like ‘even’, ‘but’, etc. Conventional implictures are a form of pragmatic presupposition, which involves an unsaid mode of delivery of content. I argue that we can make sense of conventional implicatures, (...) but doing so requires we embrace a form of pure, non-hybrid expressivism. This is a cognitivist expressivism I have developed elsewhere. We need cognitivist expressivism to make sense of how we evaluate—judge as correct or incorrect—implicature-bearing sentences. Once we embraced the possibility of this pure expressivism, we might as well be pure expressivists about normative discourse too. I show how we can do that. The motivations for a specifically hybrid theory are dialectically undercut. (shrink)
This paper explores the possibility of developing a hybrid version of dispositional theories of aesthetic values. On such a theory, uses of aesthetic predicates express relational second-order dispositional properties. If the theory is not absolutist, it allows for the relativity of aesthetic values. But it may be objected to on the grounds that it fails to explain disagreement among subjects who are not disposed alike. This paper explores the possibility of adapting recent proposals of hybrid expressivist theories for (...) moral predicates to the case of aesthetic predicates. Hybrid expressivist theories make no explicit commitment about the kind of property expressed by the predicate, but make explicit commitments to implicated (or presupposed)expressive content. It is argued that dispositionalism about the properties expressed by aesthetic predicates, combined with expressive implicatures (or presuppositions), can account for aesthetic disagreements even in cases where subjects are not relevantly alike. (shrink)
In contemporary metaethics, various versions of hybrid expressivism have been proposed according to which moral sentences express both non-cognitive attitudes and beliefs. One important advantage with such positions, its proponents argue, is that they, in contrast to pure expressivism, have a straightforward way of avoiding the Frege-Geach problem. In this paper, I provide a systematic examination of different versions of hybrid expressivism with particular regard to how they are assumed to evade this problem. The major conclusion is that (...) none of these views succeeds to provide both a fully satisfying interpretation of moral sentences and a convincing response to the Frege-Geach problem. I end by briefly considering alternative hybrid views that employ the notion of conventional or conversational implicature. (shrink)
Many philosophers have claimed that we might do well to adopt a hybrid theory of well-being: a theory that incorporates both an objective-value constraint and a pro-attitude constraint. Hybrid theories are attractive for two main reasons. First, unlike desire theories of well-being, hybrid theories need not worry about the problem of defective desires. This is so because, unlike desire theories, hybrid theories place an objective-value constraint on well-being. Second, unlike objectivist theories of well-being, hybrid theories (...) need not worry about being overly alienating. This is so because, unlike objectivist theories, hybrid theories place a pro-attitude constraint on well-being. However, from the point of view of objectivists, hybrid theories are not objectivist enough, and this can be seen clearly in missing-desires cases. For instance, hybrid theories entail that, if someone lacks the desire for health, then health is not a component of her well-being. This, objectivists say, is implausible. It is obvious, objectivists say, that someone’s life goes better for herself inasmuch as she is healthy, and hence that health is a component of her welfare. This paper focuses on the missing-desires objection (as leveled by objectivists) to hybrid theories of well-being. My argument is that the missing-desires objection can be answered in a way that is generally convincing and, in particular, in a way that pays a good deal of respect to objectivist intuitions about well-being. My hope, then, is that this paper will help to persuade objectivists about well-being to become hybrid theorists. (shrink)
Hybrid languages have both modal and first-order characteristics: a Kripke semantics, and explicit variable binding apparatus. This paper motivates the development of hybrid languages, sketches their history, and examines the expressive power of three hybrid binders. We show that all three binders give rise to languages strictly weaker than the corresponding first-order language, that full first-order expressivity can be gained by adding the universal modality, and that all three binders can force the existence of infinite models and (...) have undecidable satisfiability problems. (shrink)
In this paper we argue that hybrid logic is the deductive setting most natural for Kripke semantics. We do so by investigating hybrid axiomatics for a variety of systems, ranging from the basic hybrid language to the strong Priorean language . We show that hybrid logic offers a genuinely first-order perspective on Kripke semantics: it is possible to define base logics which extend automatically to a wide variety of frame classes and to prove completeness using the (...) Henkin method. In the weaker languages, this requires the use of non-orthodox rules. We discuss these rules in detail and prove non-eliminability and eliminability results. We also show how another type of rule, which reflects the structure of the strong Priorean language, can be employed to give an even wider coverage of frame classes. We show that this deductive apparatus gets progressively simpler as we work our way up the expressivity hierarchy, and conclude the paper by showing that the approach transfers to first-order hybrid logic. (shrink)
Benedict XVI in Caritas in Veritate advances a positive view of businesses that are hybrids between several traditional categories. He expects that the “logic of gift” that animates civil society infuses the market and the State with relations typical for it—reciprocity, gratuitousness, and solidarity. His theological rationale offers an answer to two questions that have largely remained open in the literature—why hybridization of business occurs and why it is desirable. A rational reconstruction of hybrid enterprise that goes beyond a (...) simple taxonomy of types benefits from the Pope’s call for an intrinsic integration of institutions and processes traditionally attributed to disparate spheres. The relational model of the Trinity defines the unity in diversity that accounts for the benefits of truly hybrid businesses, and the “logic of gift” serves as the agent of integration. (shrink)
This is a draft of a chapter for the Routledge Handbook of Metaethics, edited by David Plunkett and Tristram McPherson. I offer an overview of hybrid views in metaethics, with main focus on hybrid cognitivist views such as those defended by Daniel Boisvert and David Copp, and on hybrid expressivist views such as those defended by Michael Ridge and myself.
This is a companion paper to Braüner where a natural deduction system for propositional hybrid logic is given. In the present paper we generalize the system to the first-order case. Our natural deduction system for first-order hybrid logic can be extended with additional inference rules corresponding to conditions on the accessibility relations and the quantifier domains expressed by so-called geometric theories. We prove soundness and completeness and we prove a normalisation theorem. Moreover, we give an axiom system first-order (...)hybrid logic. (shrink)
Ethical challenges that arise within healthcare delivery institutions are currently categorized as either clinical or organizational, based on the type of issue. Despite this common binary issue-based methodology, empirical study and increasing academic dialogue indicate that a clear line cannot easily be drawn between organizational and clinical ethics. Disagreement around end-of-life treatments, for example, often spawn value differences amongst parties at both organizational and clinical levels and requires a resolution to address both the case at hand and large-scale underlying system-level (...) confounders. I refer to issues that contain elements of both clinical and organizational issues as hybrids and propose a new taxonomy to characterize hybrid cases. I contend that salient contextual features of an ethical issue, such as where it is identified, who it impacts and where it is ideally resolved in relation to its scope of impact, should inform procedure. Implementation of a Hybrid taxonomy viewing ethical issues as existing on a continuum furthers that end. The primary goals are to 1) systematize thinking about ethical issues that arise within healthcare delivery institutions and 2) allow the content of the ethical challenge to drive the process, rather than continuing to rely on the traditional binary issue-based choice. Failure to capture the complexity of hybrid situations perpetuates incomplete information and ultimately an inchoate resolution that creates more questions than answers. (shrink)
This paper contributes to the principled construction of tableau-based decision procedures for hybrid logic with global, difference, and converse modalities. We also consider reflexive and transitive relations. For converse-free formulas we present a terminating control that does not rely on the usual chain-based blocking scheme. Our tableau systems are based on a new model existence theorem.
We show that basic hybridization (adding nominals and @ operators) makes it possible to give straightforward Henkin-style completeness proofs even when the modal logic being hybridized is higher-order. The key ideas are to add nominals as expressions of type t, and to extend to arbitrary types the way we interpret $@_i$ in propositional and first-order hybrid logic. This means: interpret $@_i\alpha _a$ , where $\alpha _a$ is an expression of any type $a$ , as an expression of type $a$ (...) that rigidly returns the value that $\alpha_a$ receives at the i-world. The axiomatization and completeness proofs are generalizations of those found in propositional and first-order hybrid logic, and (as is usual inhybrid logic) we automatically obtain a wide range of completeness results for stronger logics and languages. Our approach is deliberately low-tech. We don’t, for example, make use of Montague’s intensional type s, or Fitting-style intensional models; we build, as simply as we can, hybrid logicover Henkin’s logic. (shrink)
Does the English demonstrative pronoun 'that' (including complex demonstratives of the form 'that F') have sense and reference? Unlike many other philosophers of language, Frege answers with a resounding 'No'. He held that the bearer of sense and reference is a so-called 'hybrid proper name' (Künne) that contains the demonstrative pronoun and specific circumstances of utterance such as glances and acts of pointing. In this paper I provide arguments for the thesis that demonstratives are hybrid proper names. After (...) outlining why Frege held the hybrid proper name view, I will defend it against recent criticism, and argue that it is superior to views that take demonstrative pronouns to be the bearer of semantic properties. (shrink)
We explore the relationship between ethnomethodology (EM), ethnography and the needs of managers and designers in industry, considering both ethnomethodological and industrial criteria of adequacy and explicating their relationship through the concept of “audience.” We examine a range of studies in this light, with a view to their possible candidacy as hybrid studies and identify three types of application of EM studies of work: market research, design, and business improvement. Application in the first of these fields we dub “anthropological,” (...) in that it consists in studying and reporting back on the ways of exotic people (customers). This is the application most commonly found in studies of computer supported co-operative work (CSCW). A second CSCW application, “technomethodology,” involves the introduction of EM concepts into the design process. A further application, dubbed “holding-up-a-mirror,” involves reporting back to members of a setting upon their own activities. We argue that technomethodology and holding-up-a-mirror both offer the possibility of creating hybrid disciplines. We consider the objection that improvement and design involve the introduction of value judgements that threaten the practice of EM indifference, arguing that action research can serve as a guarantee of unique adequacy (UA) by testing the researcher’s understanding as analysis in action in the setting. Furthermore, the standard of reporting required by the UA criterion contributes to the effectiveness of proposed solutions. (shrink)
Sometimes logical support for a conclusion is provided exclusively by premises which are independently relevant to that conclusion. At other times, support is provided exclusively by independently irrelevant premises. On still other occasions, relevant and irrelevant premises may collectively offer a distinctive pattern of support. This paper provides a rigorous account of some of these differences in terms of a tripartite classification of convergent, linked and hybrid arguments. These various arguments are defined, diagrammed, and some of their logical properties (...) are explored. (shrink)
Hybrid logics are a principled generalization of both modal logics and description logics, a standard formalism for knowledge representation. In this paper we give the first constructive version of hybrid logic, thereby showing that it is possible to hybridize constructive modal logics. Alternative systems are discussed, but we fix on a reasonable and well-motivated version of intuitionistic hybrid logic and prove essential proof-theoretical results for a natural deduction formulation of it. Our natural deduction system is also extended (...) with additional inference rules corresponding to conditions on the accessibility relations expressed by so-called geometric theories. Thus, we give natural deduction systems in a uniform way for a wide class of constructive hybrid logics. This shows that constructive hybrid logics are a viable enterprise and opens up the way for future applications. (shrink)
The main aim of the present paper is to use a proof system for hybrid modal logic to formalize what are called false-belief tasks in cognitive psychology, thereby investigating the interplay between cognition and logical reasoning about belief. We consider two different versions of the Smarties task, involving respectively a shift of perspective to another person and to another time. Our formalizations disclose that despite this difference, the two versions of the Smarties task have exactly the same underlying logical (...) structure. We also consider the Sally-Anne task, having a more complicated logical structure, presupposing a “principle of inertia” saying that a belief is preserved over time, unless there is belief to the contrary. (shrink)
We characterize the modal logics of elementary classes of Kripke frames as precisely those modal logics that are axiomatized by modal axioms synthesized in a certain effective way from "quasi-positive" sentences of hybrid logic. These are pure positive hybrid sentences with arbitrary existential and relativized universal quantification over nominals. The proof has three steps. The first step is to use the known result that the modal logic of any elementary class of Kripke frames is also the modal logic (...) of the closure of this class under disjoint unions, generated subframes, bounded morphic images, and ultraroots. This latter class can be defined by the first-order sentences of a special syntactic form (called pseudo-equations by Goldblatt) that are valid in the former class. The second step is to translate these pseudo-equations into equivalent quasi-positive hybrid sentences. In the third and main step, we show that any quasi-positive sentence S generates an infinite set of modal formulas called "approximants," which together axiomatize a canonical modal logic that is sound and complete for the class of frames validating S. The proof is analogous to standard proofs of Sahlqvist's theorem. It generalizes to sets of quasi-positive sentences. The main result now follows. (shrink)
The purpose of this paper is to argue that the hybrid formalism fits naturally in the context of David Lewis’s counterfactual logic and that its introduction into this framework is desirable. This hybridization enables us to regard the inference “The pig is Mary; Mary is pregnant; therefore the pig is pregnant” as a process of updating local information (which depends on the given situation) by using global information (independent of the situation). Our hybridization also has the following technical advantages: (...) (i) it preserves the completeness and decidability of Lewis’s logic; (ii) it allows us to characterize the Limit Assumption as a proof-rule with some side-conditions; and (iii) it enables us to establish a general Kripke completeness result by using the proof-rule corresponding to the Limit Assumption. (shrink)
Saba Bazargan proposes a novel “hybrid” justification for the killing of minimally responsible threats (MRTs). His account allegedly combines two elements, namely “the complex account of liability” and “the lesser-evil discounting view.” I argue that Bazargan’s conclusion that minimally responsible threats can sometimes be killed as well as certain other conclusions that Bazargan regards as a particular advantage of his hybrid account are single-handedly generated by one element of the “hybrid account,” namely by the lesser-evil discounting view. (...) The lesser-evil discounting view therefore does not need to be combined with “the complex account of liability,” nor, indeed, with any account of liability. Thus, Bazargan’s hybrid view is redundant. Moreover, I will argue that both the hybrid view and the lesser evil discounting view of killing MRTs have strongly counter-intuitive implications and should therefore be rejected. (shrink)
This book stands at the intersection of two topics: the decidability and computational complexity of hybrid logics, and the deductive systems designed for them. Hybrid logics are here divided into two groups: standard hybrid logics involving nominals as expressions of a separate sort, and non-standard hybrid logics, which do not involve nominals but whose expressive power matches the expressive power of binder-free standard hybrid logics.The original results of this book are split into two parts. This (...) division reflects the division of the book itself. The first type of results concern model-theoretic and complexity properties of hybrid logics. Since hybrid logics which we call standard are quite well investigated, the efforts focused on hybrid logics referred to as non-standard in this book. Non-standard hybrid logics are understood as modal logics with global counting operators ) whose expressive power matches the expressive power of binder-free standard hybrid logics. The relevant results comprise: 1. Establishing a sound and complete axiomatization for the modal logic K with global counting operators ), which can be easily extended onto other frame classes, 2. Establishing tight complexity bounds, namely NExpTime-completeness for the modal logic with global counting operators defined over the classes of arbitrary, reflexive, symmetric, serial and transitive frames ), MT), MD), MB), MK4) with numerical subscripts coded in binary. Establishing the exponential-size model property for this logic defined over the classes of Euclidean and equivalential frames ), MS5).Results of the second type consist of designing concrete deductive systems for standard and non-standard hybrid logics. More precisely, they include: 1. Devising a prefixed and an internalized tableau calculi which are sound, complete and terminating for a rich class of binder-free standard hybrid logics. An interesting feature of indicated calculi is the nonbranching character of the rule, 2. Devising a prefixed and an internalized tableau calculi which are sound, complete and terminating for non-standard hybrid logics. The internalization technique applied to a tableau calculus for the modal logic with global counting operators is novel in the literature, 3. Devising the first hybrid algorithm involving an inequality solver for modal logics with global counting operators. Transferring the arithmetical part of reasoning to an inequality solver turned out to be sufficient in ensuring termination.The book is directed to philosophers and logicians working with modal and hybrid logics, as well as to computer scientists interested in deductive systems and decision procedures for logics. Extensive fragments of the first part of the book can also serve as an introduction to hybrid logics for wider audience interested in logic.The content of the book is situated in the areas of formal logic and theoretical computer science with some elements of the theory of computational complexity. (shrink)
By comparing three types of hybrid organizations—18th-century scientific academies, 19th-century institutions of higher vocational education, and 20th-century industrial research institutes—it is the purpose here to answer the question of why new hybrid organizations are continuously formed. Traditionally, and often implicitly, it is often assumed that emerging groups of potential knowledge users have their own organizational preferences and demands influencing the setup of new hybrid organizations. By applying the concepts epistemic and academic drift, it will be argued here, (...) however, that internal organizational dynamics are just as important as changing historical conjunctures in the uses of science when understanding why new hybrid organizations are formed. Only seldom have older hybrid organizations sought to make themselves relevant to new categories of knowledge users as the original ones have been marginalized. Instead, they have tended to accede to ideals supported by traditional academic organizations with higher status in terms of knowledge management, primarily universities. Through this process, demand has been generated for the founding of new hybrid organizations rather than the transformation of existing ones. Although this study focuses on Swedish cases, it is argued that since Sweden strove consistently to implement existing international policy trends during the periods in question, the observations may be generalized to apply to other national and transnational contexts. (shrink)
This is an extended version of the lectures given during the 12-thConference on Applications of Logic in Philosophy and in the Foundationsof Mathematics in Szklarska Poręba. It contains a surveyof modal hybrid logic, one of the branches of contemporary modal logic. Inthe ﬁrst part a variety of hybrid languages and logics is presented with adiscussion of expressivity matters. The second part is devoted to thoroughexposition of proof methods for hybrid logics. The main point is to showthat application (...) of hybrid logics may remarkably improve the situation inmodal proof theory. (shrink)
This paper examines and classifies the computational complexity of model checking and satisfiability for hybrid logics over frames with equivalence relations. The considered languages contain all possible combinations of the downarrow binder, the existential binder, the satisfaction operator, and the global modality, ranging from the minimal hybrid language to very expressive languages. For model checking, we separate polynomial-time solvable from PSPACE-complete cases, and for satisfiability, we exhibit cases complete for NP, PS pace , NE xp T ime , (...) and even N2E xp T ime . Our analysis includes the versions of all these languages without atomic propositions, and also complete frames. (shrink)
It has frequently been observed in the literature on hybrid wars that there is a grey zone between peace and war, and that hybrid wars are conflicts which are not clear cases of war. In this paper, I attempt to illuminate this grey zone and the concept and nature of war from the philosophical discussions of vagueness and institutional facts. Vague terms are characterized by the fact that there is no non-arbitrary boundary between entities which lie in their (...) extension, and entities which do not lie in their extension. I apply a theory of vagueness to notions such as “war” and “peace” and go on to suggest that the exact boundary for what counts as a war or not is arbitrary. However, the context in which the conflict occurs determines a range of possible locations for this boundary. The most important contextual parameter is in this respect how the parties to the conflict themselves conceptualize the conflict. I suggest that this can in various ways help us understand grey-zone conflicts. (shrink)
I examine two sets of experimental results about the semantics of general terms, by Genone and Lombrozo (2012) and by Nichols, Pinillos and Mallon (forthcoming) that allegedly reveal significant variations in semantic intuitions as regards the correct application of general terms. The two sets of authors propose two entirely different semantic treatments: Genone and Lombrozo espouse a hybrid semantics whereas Nichols, Pinillos and Mallon are inclined towards an appeal to ambiguity. I cast some doubts on the coherence of a (...)hybrid theory and argue in favor of the ambiguity approach. But I also argue that the sort of ambiguitiy Nichols, Pinillos and Mallon postulate is easy to incorporate to non-descriptivist approaches. (shrink)
We extend Moss and Parikh’s bi-modal system for knowledge and effort by means of hybrid logic. In this way, some additional concepts from topology related to knowledge can be captured. We prove the soundness and completeness as well as the decidability of the extended system. Special emphasis will be placed on algebras.
This paper introduces an axiomatisation for equational hybrid logic based on previous axiomatizations and natural deduction systems for propositional and first-order hybrid logic. Its soundness and completeness is discussed. This work is part of a broader research project on the development a general proof calculus for hybrid logics.
Hybrid logics are extensions of standard modal logics, which significantly increase the expressive power of the latter. Since most of hybrid logics are known to be decidable, decision procedures for them is a widely investigated field of research. So far, several tableau calculi for hybrid logics have been presented in the literature. In this paper we introduce a sound, complete and terminating tableau calculus T H(@,E,D, ♦ −) for hybrid logics with the satisfaction operators, the universal (...) modality, the difference modality and the inverse modality as well as the corresponding sequent calculus S H(@,E,D, ♦ −) . They not only uniformly cover relatively wide range of various hybrid logics but they are also conceptually simple and enable effective search for a minimal model for a satisfiable formula. The main novelty is the exploitation of the unrestricted blocking mechanism introduced as an explicit, sound tableau rule. (shrink)
The case law of the Court of Justice of the European Union is shaped by the language in which it is drafted—i.e. French. However, because French is rarely the mother tongue of those drafting that case law, the texts produced are often stilted and awkward. In addition, those drafting such case law are constrained in their use of language and style of writing. These factors have led to the development of a ‘Court French’ which necessarily shapes the case law produced (...) and has implications for its development, particularly insofar as it inevitably leads to a type of precedent in that case law. That case law also undergoes many permutations of translation into and out of up to 23 different languages. The resultant texts that make up the case law are hybrid in nature—consisting of a blend of cultural and linguistic patterns, constrained by a rigid formulistic drafting style and put through many permutations of translation. The present paper investigates the production of the Court’s multilingual case law and considers whether the hybrid nature of that case law can actually aid the presentation of a ‘uniform’ EU case law. (shrink)
Representation of quantum states by statistical ensembles on the quantum phase space in the Hamiltonian form of quantum mechanics is analyzed. Various mathematical properties and some physical interpretations of the equivalence classes of ensembles representing a mixed quantum state in the Hamiltonian formulation are examined. In particular, non-uniqueness of the quantum phase space probability density associated with the quantum mixed state, Liouville dynamics of the probability densities and the possibility to represent the reduced states of bipartite systems by marginal distributions (...) are discussed in detail. These considerations are used to study ensembles of hybrid quantum-classical systems. In particular, nonlinear evolution of a single hybrid system in a pure state and unequal evolutions of initially equivalent ensembles are discussed in the context of coupled hybrid systems. (shrink)
The hybrid logic and the independence friendly modal logic IFML are compared for their expressive powers. We introduce a logic IFML c having a non-standard syntax and a compositional semantics; in terms of this logic a syntactic fragment of IFML is singled out, denoted IFML c . (In the Appendix it is shown that the game-theoretic semantics of IFML c coincides with the compositional semantics of IFML c .) The hybrid logic is proven to be strictly more expressive (...) than IFML c . By contrast, and the full IFML are shown to be incomparable for their expressive powers. Building on earlier research (Tulenheimo and Sevenster 2006), a PSPACE -decidable fragment of the undecidable logic is disclosed. This fragment is not translatable into the hybrid logic and has not been studied previously in connection with hybrid logics. In the Appendix IFML c is shown to lack the property of ‘quasi-positionality’ but proven to enjoy the weaker property of ‘ bounded quasi-positionality’. The latter fact provides from the IFML internal perspective an account of what makes the compositional semantics of IFML c possible. (shrink)
In this paper we give axiom systems for classical and intuitionistic hybrid logic. Our axiom systems can be extended with additional rules corresponding to conditions on the accessibility relation expressed by so-called geometric theories. In the classical case other axiomatisations than ours can be found in the literature but in the intuitionistic case no axiomatisations have been published. We consider plain intuitionistic hybrid logic as well as a hybridized version of the constructive and paraconsistent logic N4.
In recent years, several philosophers have recommended to moral realists that they adopt a hybrid cognitivist–expressivist moral semantics. Adopting a hybrid semantics enables the realist to account for the action-guiding character of moral discourse, and to account for the possibility of moral (dis)agreement between speakers whose moral sentences express different cognitive contents. I argue that realists should resist the temptation to embrace a hybrid moral semantics. In granting that moral judgments are partly constituted by conative attitudes, the (...) realist concedes too much to her anti-realist opponents: she concedes that, at its most fundamental level, moral disagreement is disagreement in attitude, and the resolution of deep moral disagreement is best guided by non-epistemic norms of inquiry. Furthermore, on a hybrid semantics, moral thought and truth ascriptions turn out to be more responsive to the conative contents of moral judgments than to the supposed propositional contents. Finally, a hybrid semantics makes it difficult to preserve the realist’s claim that moral truths are in a certain sense independent of appraisers’ attitudes. (shrink)
One important trend in the debate over expressivism and cognitivism is the emergence of ‘hybrid’ or ‘ecumenical’ theories. According to such theories, moral sentences express both beliefs, as cognitivism has it, and desire-like states, as expressivism has it. One may wonder, though, whether the hybrid move is as novel as its advocates seem to take it to be—or whether it simply leads us back to the conceptions of early expressivists, such as Charles Stevenson or Richard Hare. Michael Ridge (...) has recently argued that we ought not to see Hare as a hybrid expressivist because Hare’s approach allows for moral sentences that do not express any descriptive beliefs at all. Yet, Ridge’s reading has been challenged by John Eriksson, who even goes as far as to claim that modern hybrid expressivists should follow in Hare’s footsteps because it is Hare’s framework that actually provides a solution to the so-called ‘Frege-Geach problem’. In the present paper, I first want to show that we can defend Eriksson’s reading with regard to the official version of Hare’s theory. I will, secondly, argue that, in line with what we may take to be Ridge’s critical perspective on Hare, this official version faces serious difficulties, resulting from the possibility of unknown speaker standards. Thirdly, I will demonstrate that a modern reconstruction of Hare in terms of what I will refer to as ‘de dicto beliefs’, though in principle possible, will not allow us to solve the ‘Frege-Geach problem’. (shrink)
It is widely mooted that a plausible computational cognitive model should involve both symbolic and connectionist components. However, sound principles for combining these components within a hybrid system are currently lacking; the design of such systems is oftenad hoc. In an attempt to ameliorate this we provide a framework of types of hybrid systems and constraints therein, within which to explore the issues. In particular, we suggest the use of system independent constraints, whose source lies in general considerations (...) about cognitive systems, rather than in particular technological or task-based considerations. We illustrate this through a detailed examination of an interruptibility constraint: handling interruptions is a fundamental facet of cognition in a dynamic world. Aspects of interruptions are delineated, as are their precise expression in symbolic and connectionist systems. We illustrate the interaction of the various constraints from interruptibility in the different types of hybrid systems. The picture that emerges of the relationship between the connectionist and the symbolic within a hybrid system provides for sufficient flexibility and complexity to suggest interesting general implications for cognition, thus vindicating the utility of the framework. (shrink)
In this paper we argue that Prior and Reichenbach are best viewed as allies, not antagonists. We do so by combining the central insights of Prior and Reichenbach in the framework of hybrid tense logic. This overcomes a well-known defect of Reichenbach’s tense schema, namely that it gives multiple representations to sentences in the future perfect and the future-in-the-past. It also makes it easy to define an iterative schema for tense that allows for multiple points of reference, a possibility (...) noted by Prior and demanded by Comrie, and we sketch how this schema can be generalized to a shift-and-restrict pattern in which special propositional symbols act as restrictors on the range of tense operators. (shrink)
In this paper, we show the equivalence between the provability of a proof system of basic hybrid logic and that of translated formulas of the classical predicate logic with equality and explicit substitution by a purely proof–theoretic method. Then we show the equivalence of two groups of proof systems of hybrid logic: the group of labelled deduction systems and the group of modal logic-based systems.
We study hybrid logics in topological semantics. We prove that hybrid logics of separation axioms are complete with respect to certain classes of finite topological models. This characterisation allows us to obtain several further results. We prove that aforementioned logics are decidable and PSPACE-complete, the logics of T 1 and T 2 coincide, the logic of T 1 is complete with respect to two concrete structures: the Cantor space and the rational numbers.
Combating the identity problem is crucial and urgent as false identity has become a common denominator of many serious crimes, including mafia trafficking and terrorism. Without correct identification, it is very difficult for law enforcement authority to intervene, or even trace terrorists’ activities. Amongst several identity attributes, personal names are commonly, and effortlessly, falsified or aliased by most criminals. Typical approaches to detecting the use of false identity rely on the similarity measure of textual and other content-based characteristics, which are (...) usually not applicable in the case of highly deceptive, erroneous and unknown descriptions. This barrier can be overcome through analysis of link information displayed by the individual in communication behaviours, financial interactions and social networks. In particular, this paper presents a novel link-based approach that improves existing techniques by integrating multiple link properties in the process of similarity evaluation. It is utilised in a hybrid model that proficiently combines both text-based and link-based measures of examined names to refine the justification of their similarity. This approach is experimentally evaluated against other link-based and text-based techniques, over a terrorist-related dataset, with further generalization to a similar problem occurring in publication databases. The empirical study demonstrates the great potential of this work towards developing an effective identity verification system. (shrink)
This study investigates the complex relationship between the physical and digital spaces of the city of Douala, Cameroon by comparing its online representation with the social representations emerging orally by locals. Using the results of two existing studies reporting on the online image of the city, we investigate the social representations foreigners and locally relevant people have of Douala and uncover similarities and discrepancies of the two resulting representations. Outcomes from the analysis permit reflection on the implications of these and (...) show an unripe, intermediate stage of the “hybrid Douala,” where the virtual space seems still not to be affecting the way the physical space is experienced, as well as where the gaps in the digital divide are perpetuated. At the same time, strong local ownership of certain digital activities suggests how the online image of the city is in the process of being constructed and developed locally. As the spaces of the city start appearing online, the process of hybridization between physical and digital Douala is slowly taking place and offline and online narratives, now rather separated, will possibly communicate a different image of the city to global online narratives. (shrink)
Hybrid identities are sentences in a special second order language with identity. The model classes of sets of hybrid identities are called hybrid solid varieties. We give a Birkhoff-type-characterization of hybrid solid varieties and develop a hybrid equational logic.
First of all I would like to describe inductive and abductive reasoning in the light of the agent–based framework to the aim of clarifying their fallacious character and the role of the so-called ideal systems (logical and computational). Then I will analyze some inductive and abductive types of reasoning that in the perspective of classical and informal logic are defined fallacies. I will describe how in an agent-based reasoning this kind of fallacious reasoning can in some cases be redefined and (...) considered as a good way of reasoning. Finally, I will illustrate how what I call manipulative abduction can be interpreted as a form of practical reasoning a better understanding of which can furnish a description of human beings as hybrid reasoners in so far they are users of ideal and computational agents. (shrink)
According to Frege, neither demonstratives nor indexicals are singular terms; only a demonstrative together with ‘circumstances accompanying its utterance’ has sense and singular reference. While this view seems defensible for demonstratives, where demonstrations serve as non-verbal signs, indexicals, especially pure indexicals like ‘I’, ‘here’, and ‘now’, seem not to be in need of completion by circumstances of utterance. In this paper I argue on the basis of independent reasons that indexicals are in fact in need of completion; I identify the (...) completers as uses of circumstances of utterance by the speaker; and I show how these uses together with the utterance of indexical sentences express thoughts. The starting point of the paper is a criticism of Kripke’s and Künne’s alternative treatment of indexicals in Frege’s framework. (shrink)
In this paper two different natural deduction systems forhybrid logic are compared and contrasted.One of the systems was originally given by the author of the presentpaper whereasthe other system under consideration is a modifiedversion of a natural deductionsystem given by Jerry Seligman.We give translations in both directions between the systems,and moreover, we devise a set of reduction rules forthe latter system bytranslation of already known reduction rules for the former system.
In this paper a first-order version of hybrid logic is presented. The language is obtained by adding nominals, satisfaction operators and the down-arrow binder to classical first-order modal logic. The satisfaction operators are applied to both formulas and terms. Moreover adding the universal modality is discussed. This first-order hybrid language is interpreted over varying domains and a sound and complete, fully internalized tableau system for this logic is given.
Over the past decade artists have increasingly turned to science in order to investigate technology’s effect. The move from hardware-based technologies to live organisms as media, raises ethical issues that the broader art community is addressing. This paper tracks the history of instrumental disengagement to determine when and how the gradual codification of life contributed to the eventual use of live organisms in art practice.
We introduce a suitable notion of eight-shaped curve in the product S × ℝ of a Suslin line S for the real line ℝ, and we prove that if S is dense in itself, then every collection of pairwise disjoint eight-shaped curves in S × ℝ is countable. This parallels a folklore result which holds for the real plane.