Although AGM theory contraction (Alchourrón et al., 1985; Alchourrón and Makinson, 1985) occupies a central position in the literature on belief change, there is one aspect about it that has created a fair amount of controversy. It involves the inclusion of the postulate known as Recovery. As a result, a number of alternatives to AGM theory contraction have been proposed that do not always satisfy the Recovery postulate (Levi, 1991, 1998; Hansson and Olsson, 1995; Fermé, 1998; Fermé and Rodriguez, 1998; (...) Rott and Pagnucco, 1999). In this paper we present a new addition, systematic withdrawal, to the family of withdrawal operations, as they have become known. We define systematic withdrawal semantically, in terms of a set of preorders, and show that it can be characterised by a set of postulates. In a comparison of withdrawal operations we show that AGM contraction, systematic withdrawal and the severe withdrawal of Rott and Pagnucco (1999) are intimately connected by virtue of their definition in terms of sets of preorders. In a future paper it will be shown that this connection can be extended to include the epistemic entrenchment orderings of Gärdenfors (1988) and Gärdenfors and Makinson (1988) and the refined entrenchment orderings of Meyer et al. (2000). (shrink)

Epistemic entrenchment, as presented by Gärdenfors and Makinson (1988) and Gärdenfors (1988), is a formalisation of the intuition that, when forced to choose between two beliefs, an agent will giveup the less entrenched one. While their formalisation satisfactorilycaptures the intuitive notion of the entrenchment of beliefs in a number ofaspects, the requirement that all wffs be comparable has drawn criticismfrom various quarters. We define a set of refined versions of theirentrenchment orderings that are not subject to the same criticism, andinvestigate (...) the relationship between the refined entrenched orderings,the entrenchment orderings of Gärdenfors and Makinson, and AGM theorycontraction (Alchourrón et al., 1985). To conclude, we compare refinedentrenchment with two related approaches to epistemic entrenchment. (shrink)

We explore the psychological foundations of Logic and Artificial Intelligence, touching on representation, categorisation, heuristics, consciousness, and emotion. Specifically, we challenge Dennett's view of the brain as a syntactic engine that is limited to processing symbols according to their structural properties. We show that cognitive psychology and neurobiology support a dual-process model in which one form of cognition is essentially semantical and differs in important ways from the operation of a syntactic engine. The dual-process model illuminates two important events in (...) Logic and Artificial Intelligence, namely the emergence of non-monotonicity and of embodiment, events that changed the traditional paradigms of ‘Logic = the study of deductive inference' and ‘Symbolic AI'. S. Afr. J. Philos. Vol.24(2) 2005: 137-151. (shrink)

We introduce and explore the notion of duality for entailment relations induced by preference orderings on states. We discuss the relationship between these preferential entailment relations from the perspectives of Boolean algebra, inference rules, and modal axiomatisation. Interpreting the preference relations as accessibility relations establishes modular Gödel-Löb logic as a suitable modal framework for rational preferential reasoning.

We model three examples of beliefs that agents may have about other agents' beliefs, and provide motivation for this conceptualization from the theory of mind literature. We assume a modal logical framework for modelling degrees of belief by partially ordered preference relations. In this setting, we describe that agents believe that other agents do not distinguish among their beliefs ('no preferences'), that agents believe that the beliefs of other agents are in part as their own ('my preferences'), and the special (...) case that agents believe that the beliefs of other agents are exactly as their own ('preference refinement'). This multi-agent belief interaction is frame characterizable. We provide examples for introspective agents. We investigate which of these forms of belief interaction are preserved under three common forms of belief revision. (shrink)

We model three examples of beliefs that agents may have about other agents’ beliefs, and provide motivation for this conceptualization from the theory of mind literature. We assume a modal logical framework for modelling degrees of belief by partially ordered preference relations. In this setting, we describe that agents believe that other agents do not distinguish among their beliefs (‘no preferences’), that agents believe that the beliefs of other agents are in part as their own (‘my preferences’), and the special (...) case that agents believe that the beliefs of other agents are exactly as their own (‘preference refinement’). This multi-agent belief interaction is frame characterizable. We provide examples for introspective agents. We investigate which of these forms of belief interaction are preserved under three common forms of belief revision. (shrink)

Generalisations of theory change involving operations on arbitrary sets ofwffs instead of on belief sets (i.e., sets closed under a consequencerelation), have become known as base change. In one view, a base should bethought of as providing more structure to its generated belief set, whichmeans that it can be employed to determine the theory contraction operationassociated with a base contraction operation. In this paper we follow suchan approach as the first step in defining infobase change. We think of an infobase (...) as a finite set of wffs consisting of independently obtainedbits of information. Taking AGM theory change (Alchourrón et al. 1985) as the general framework, we present a method that uses the structure of aninfobase B to obtain an AGM theory contraction operation for contractingthe belief set Cn(B). Both the infobase and the obtained theory contraction operation then play a role in constructing a unique infobasecontraction operation. Infobase revision is defined in terms of an analogueof the Levi Identity, and it is shown that the associated theory revisionoperation satisfies the AGM postulates for revision. Because every infobaseis associated with a unique infobase contraction and revision operation, the method also allows for iterated base change. (shrink)

The concept of meaningful work is used to evaluate the quality of work. Typical cases of meaningless work that have been used to clarify this concept are assembly line work, and work involving other types of mindless tasks, but also David Graeber's ‘bullshit jobs’. I argue that there are at least two fundamental reasons to care about meaningful work: reasons from the wellbeing of the worker and reasons pertaining to meaningfulness of the worker's life. I first argue that a concept (...) of meaningful work needs to reflect these two values, but that these two values may come apart. Because of this, accounts that provide a single answer to the question to what extent a particular work context is meaningful work for a particular worker are unable to reflect these two values. I then survey three promising accounts of meaningful work: perfectionism, which captures the self-interested aspect of meaningful work well but fails to capture the meaningfulness aspect appropriately; consequentialism, which captures the meaningfulness aspect well but fails to capture the self-interested aspect; and Wolf's Fitting Fulfilment View of meaningful projects, which can be read as addressing both concerns but leads to implausible judgments about meaningful work. I then argue that we should conceive of the concerns that fall under the notion of meaningful work as two separate concepts and values. The best work incorporates both these dimensions but falling short on either dimension is problematic for different reasons. (shrink)

Preparing words in speech production is normally a fast and accurate process. We generate them two or three per second in fluent conversation; and overtly naming a clear picture of an object can easily be initiated within 600 msec after picture onset. The underlying process, however, is exceedingly complex. The theory reviewed in this target article analyzes this process as staged and feedforward. After a first stage of conceptual preparation, word generation proceeds through lexical selection, morphological and phonological encoding, phonetic (...) encoding, and articulation itself. In addition, the speaker exerts some degree of output control, by monitoring of self-produced internal and overt speech. The core of the theory, ranging from lexical selection to the initiation of phonetic encoding, is captured in a computational model, called WEAVER++. Both the theory and the computational model have been developed in interaction with reaction time experiments, particularly in picture naming or related word production paradigms, with the aim of accounting for the real-time processing in normal word production. A comprehensive review of theory, model, and experiments is presented. The model can handle some of the main observations in the domain of speech errors (the major empirical domain for most other theories of lexical access), and the theory opens new ways of approaching the cerebral organization of speech production by way of high-temporal-resolution imaging. (shrink)

Robert B. Brandom’s From Empiricism to Expressivism ranges widely over fundamental issues in metaphysics, with occasional forays into epistemology as well. The centerpiece is what Brandom calls ‘the Kant-Sellars thesis about modality’. This is ‘[t]he claim that in being able to use ordinary empirical descriptive vocabulary, one already knows how to do everything that one needs to know how to do, in principle, to use alethic modal vocabulary – in particular subjunctive conditionals’. Despite claiming descent from Sellars, Brandom defends here (...) a version of modal realism and tries hard to limit Sellarsian nominalism, all in the service of elaborating Brandom’s own version of pragmatism. The range of issues Brandom addresses defies adequate consideration in a critical notice, so I confine myself here to a single issue: What is.. (shrink)

Throughout the twentieth century, German writers, philosophers, theologians, and historians turned to Gnosticism to make sense of the modern condition. While some saw this ancient Christian heresy as a way to rethink modernity, most German intellectuals questioned Gnosticism's return in a contemporary setting. In No Spiritual Investment in the World, Willem Styfhals explores the Gnostic worldview's enigmatic place in these discourses on modernity, presenting a comprehensive intellectual history of Gnosticism's role in postwar German thought. Establishing the German-Jewish philosopher Jacob (...) Taubes at the nexus of the debate, Styfhals traces how such figures as Hans Blumenberg, Hans Jonas, Eric Voegelin, Odo Marquard, and Gershom Scholem contended with Gnosticism and its tenets on evil and divine absence as metaphorical detours to address issues of cultural crisis, nihilism, and the legitimacy of the modern world. These concerns, he argues, centered on the difficulty of spiritual engagement in a world from which the divine has withdrawn. Reading Gnosticism against the backdrop of postwar German debates about secularization, political theology, and post-secularism, No Spiritual Investment in the World sheds new light on the historical contours of postwar German philosophy. (shrink)

Throughout more than two millennia philosophers adhered massively to ideal standards of scientific rationality going back ultimately to Aristotle’s Analytica posteriora. These standards got progressively shaped by and adapted to new scientific needs and tendencies. Nevertheless, a core of conditions capturing the fundamentals of what a proper science should look like remained remarkably constant all along. Call this cluster of conditions the Classical Model of Science. In this paper we will do two things. First of all, we will propose a (...) general and systematized account of the Classical Model of Science. Secondly, we will offer an analysis of the philosophical significance of this model at different historical junctures by giving an overview of the connections it has had with a number of important topics. The latter include the analytic-synthetic distinction, the axiomatic method, the hierarchical order of sciences and the status of logic as a science. Our claim is that particularly fruitful insights are gained by seeing themes such as these against the background of the Classical Model of Science. In an appendix we deal with the historiographical background of this model by considering the systematizations of Aristotle’s theory of science offered by Heinrich Scholz, and in his footsteps by Evert W. Beth. (shrink)

A concise yet rigorous introduction to logic and discrete mathematics. This book features a unique combination of comprehensive coverage of logic with a solid exposition of the most important fields of discrete mathematics, presenting material that has been tested and refined by the authors in university courses taught over more than a decade. The chapters on logic - propositional and first-order - provide a robust toolkit for logical reasoning, emphasizing the conceptual understanding of the language and the semantics of classical (...) logic as well as practical applications through the easy to understand and use deductive systems of Semantic Tableaux and Resolution. The chapters on set theory, number theory, combinatorics and graph theory combine the necessary minimum of theory with numerous examples and selected applications. Written in a clear and reader-friendly style, each section ends with an extensive set of exercises, most of them provided with complete solutions which are available in the accompanying solutions manual. Key Features: Suitable for a variety of courses for students in both Mathematics and Computer Science. Extensive, in-depth coverage of classical logic, combined with a solid exposition of a selection of the most important fields of discrete mathematics Concise, clear and uncluttered presentation with numerous examples. Covers some applications including cryptographic systems, discrete probability and network algorithms. Logic and Discrete Mathematics: A Concise Introduction is aimed mainly at undergraduate courses for students in mathematics and computer science, but the book will also be a valuable resource for graduate modules and for self-study. (shrink)

Evolutionary psychologists tend to view the mind as a large collection of evolved, functionally specialized mechanisms, or modules. Cosmides and Tooby (1994) have presented four arguments in favor of this model of the mind: the engineering argument, the error argument, the poverty of the stimulus argument, and combinatorial explosion. Fodor (2000) has discussed each of these four arguments and rejected them all. In the present paper, we present and discuss the arguments for and against the massive modularity hypothesis. We conclude (...) that Cosmides and Tooby's arguments have considerable force and are too easily dismissed by Fodor. (shrink)

Zuidema et al. illustrate how empirical AGL studies can benefit from computational models and techniques. Computational models can help clarifying theories, and thus in delineating research questions, but also in facilitating experimental design, stimulus generation, and data analysis. The authors show, with a series of examples, how computational modeling can be integrated with empirical AGL approaches, and how model selection techniques can indicate the most likely model to explain experimental outcomes.

People maintain systems of beliefs that provide them with a sense of belongingness, control, identity, and meaning, more generally. Recent research shows that when these beliefs are threatened a syndrome of negatively valenced arousal is evoked that motivates people to seek comfort in their ideologies or other personally valued beliefs. In this paper we will provide an overview of this process and discuss areas for future research. Beginning with the neural foundations of meaning violations, we review findings that show the (...) anterior cingulate cortex (ACC) is responsible for detecting inconsistencies, and importantly, that this is experienced as aversive. Next, we evaluate the evidential support for a psychophysiological arousal response as measured by cardiography and skin conductance. We discuss how current theorizing proposes that subsequent behavioral approach ameliorates the negative arousal and serves as an effective, well-adapted coping response, but we also aim to further integrate this process in the existing threat-compensation literature. Finally, we speculate on whether approach motivation is likely to result when one feels capable of handling the threat, thereby incorporating the biopsychosocial model that distinguishes between challenge and threat into the motivational threat-response literature. We believe the current literature on threat and meaning has much to offer and we aim to provide new incentives for further development. (shrink)

This chapter defends the hypothesis that Quechua was brought to Cajamarca during the final expansion of the Huari state. It offers an alternative for the traditional view that Cajamarca Quechua originated on the central coast of Peru, immediately south-east of Lima. Archaic features of Cajamarca Quechua suggest that it became separated from the main body of the Quechua II branch of the family before it attained its present state of internal differentiation. Possibly the least innovative Quechua II dialect spoken today (...) is that of Ayacucho region, where the Huari capital lay. Together this suggests that population movements underlying the existence of present-day Cajamarca Quechua may have originated in the Huari heartland. This association of Quechua II with Huari prompts a reconsideration of the prevalent view that Ayacucho, including Huari, would have been an exclusive stronghold of the Aymaran languages. (shrink)

This paper concentrates on some aspects of the history of the analyticsynthetic distinction from Kant to Bolzano and Frege. This history evinces considerable continuity but also some important discontinuities. The analytic-synthetic distinction has to be seen in the first place in relation to a science, i.e. an ordered system of cognition. Looking especially to the place and role of logic it will be argued that Kant, Bolzano and Frege each developed the analytic-synthetic distinction within the same conception of scientific rationality, (...) that is, within the Classical Model of Science: scientific knowledge as cognitio exprincipiis. But as we will see, the way the distinction between analytic and synthetic judgments or propositions functions within this model turns out to differ considerably between them. (shrink)

The previously introduced algorithm \sqema\ computes first-order frame equivalents for modal formulae and also proves their canonicity. Here we extend \sqema\ with an additional rule based on a recursive version of Ackermann's lemma, which enables the algorithm to compute local frame equivalents of modal formulae in the extension of first-order logic with monadic least fixed-points \mffo. This computation operates by transforming input formulae into locally frame equivalent ones in the pure fragment of the hybrid mu-calculus. In particular, we prove that (...) the recursive extension of \sqema\ succeeds on the class of `recursive formulae'. We also show that a certain version of this algorithm guarantees the canonicity of the formulae on which it succeeds. (shrink)

We provide syntactic necessary and sufficient conditions on the formulae reducible by the second-order quantifier elimination algorithm DLS. It is shown that DLS is compete for all modal Sahlqvist and Inductive formulae, and that all modal formulae in a single propositional variable on which DLS succeeds are canonical.

In a previous work we introduced the algorithm \SQEMA\ for computing first-order equivalents and proving canonicity of modal formulae, and thus established a very general correspondence and canonical completeness result. \SQEMA\ is based on transformation rules, the most important of which employs a modal version of a result by Ackermann that enables elimination of an existentially quantified predicate variable in a formula, provided a certain negative polarity condition on that variable is satisfied. In this paper we develop several extensions of (...) \SQEMA\ where that syntactic condition is replaced by a semantic one, viz. downward monotonicity. For the first, and most general, extension \SSQEMA\ we prove correctness for a large class of modal formulae containing an extension of the Sahlqvist formulae, defined by replacing polarity with monotonicity. By employing a special modal version of Lyndon's monotonicity theorem and imposing additional requirements on the Ackermann rule we obtain restricted versions of \SSQEMA\ which guarantee canonicity, too. (shrink)

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According to Vallicella's‘Relations, Monism, and the Vindication of Bradley's Regress’ , if relations are to relate their relata, some special operator must do the relating. No other options will do. In this paper we reject Vallicella's conclusion by considering an important option that becomes visible only if we hold onto a precise distinction between the following three feature‐pairs of relations: internality/externality, universality/particularity, relata‐specificity/relata‐unspecificity. The conclusion we reach is that if external relations are to relate their relata, they must be relata‐specific (...) . As it eschews unmereological complexes, this outcome is of relevance to defenders of the extensionality of composition. (shrink)

In three experiments, picture quality between test items was manipulated to examine whether subjects’ expectations about the fluency normally associated with these different stimuli might influence the effects of fluency on preference or familiarity-based recognition responses. The results showed that fluency due to pre-exposure influenced responses less when objects were presented with high picture quality, suggesting that attributions of fluency to preference and familiarity are adjusted according to expectations about the different test pictures. However, this expectations influence depended on subjects’ (...) awareness of these different quality levels. Indeed, imperceptible differences seemed not to induce expectations about the test item fluency. In this context, fluency due to both picture quality and pre-exposure influenced direct responses. Conversely, obvious, and noticed, differences in test picture quality did no affect responses, suggesting that expectations moderated attributions of fluency only when fluency normally associated with these different stimuli was perceptible but difficult to assess. (shrink)

Dr. Willem Meijer [van W. G. van der Tak]--Lijst der in druk verschenen geschriften van dr. W. Meijer. [Door E. E. Eckstein]--Benedicti de Spinoza philosophiæ brevis commentatio.--Extracten uit de jaarverslagen van den secretaris der vereeniging Het Spinozahuis over het tijdvak 1897-1922.--Lijst der in de verslagen van de vereeniging Het Spinozahuis besproken boeken en tijdschriftartikels.

Robotics can be seen as a cognitive technology, assisting us in understanding various aspects of autonomy. In this paper I will investigate a difference between the interpretations of autonomy that exist within robotics and philosophy. Based on a brief review of some historical developments I suggest that within robotics a technical interpretation of autonomy arose, related to the independent performance of tasks. This interpretation is far removed from philosophical analyses of autonomy focusing on the capacity to choose goals for oneself. (...) This difference in interpretation precludes a straightforward debate between philosophers and roboticists about the autonomy of artificial and organic creatures. In order to narrow the gap I will identify a third problem of autonomy, related to the issue of what makes one’s goals genuinely one’s own. I will suggest that it is the body, and the ongoing attempt to maintain its stability, that makes goals belong to the system. This issue could function as a suitable focal point for a debate in which work in robotics can be related to issues in philosophy. Such a debate could contribute to a growing awareness of the way in which our bodies matter to our autonomy. (shrink)

In the history of Jewish, Christian and Muslim culture, religious identity was not only formed by historical claims, but also by the usage of certain images: “images of God”, “images of the others”, “images of the self.”This book includes a discussion of the role of these images in society and politics, in theology and liturgy, yesterday and today.