Hedgehog proteins are of pivotal importance for development and maintenance of tissue patterns in adult organisms. Despite the role of Hedgehogs in differentiation and tumorigenesis, signal transduction of Hedgehog remains a relatively uncharted area of signalling biochemistry. For proper Hedgehog distribution into tissues, two highly unusual covalent modifications are necessary, palmitoylation of a secreted protein and the attachment of a cholesterol group, making Hedgehog the only established sterolated protein in nature. Hedgehog exerts its function via two membrane‐bound receptors, Patched and (...) Smoothened; presumably, Patched transports a cholesterol derivate out of cells which inhibits Smoothened. Binding of Hedgehog to Patched impedes this proposed pump function and thus Inhibition of Smoothened, which leads to expression of genetic Hedgehog targets via relief of transcriptional repression. These atypical features make Hedgehog physiology unique in biology and may explain why this field has attracted such significant attention. BioEssays 26:387–394, 2004. © 2004 Wiley Periodicals, Inc. (shrink)

This collection of new essays locates Boethius' Consolatio Philosophiae in the medieval context of Latin learning and vernacular translations. The first part is devoted to the Latin commentary tradition, while the other parts explore the vernacular traditions.

This article provides a historico-philosophical profile of late-medieval nominalism. It shows how nominalism placed limitations on the use of logic and natural reason in academic theology. In the first part, the historical meaning and use of the notions ‘moderni’ and ‘nominales’ are explored. In the second part, the methodology of the ‘moderni’ and ‘nominales’ is investigated, showing how nominalist understanding of logic and natural reason led to a separation of philosophy and theology. Three examples are discussed, taken from commentaries on (...) the Sentences. As these examples show, according to a number of ‘moderni’ and ‘nominales’ , logic and natural reason are not able to exclude all ambiguities and heresies from theological discourse. Thus logic loses its privileged function in theology as arbiter of true reasoning, clearing the way for the rules of traditional and ordinary speech, the ‘vulgus modus loquendi’. Only when logic and reason deal with the natural aspects of creation, do they remain authoritative. When applied to the divine, however, they may easily lead to heresy and error. (shrink)

This collection of essays delineates the history of the rather disparate intellectual tradition usually labeled as "Platonic" or "Neoplatonic". In chronological order, the book covers the most eminent philosophic schools of thought within that tradition. The most important terms of the Platonic tradition are studied together with a discussion of their semantic implications, the philosophical and theological claims associated with the terms, the sources that furnish the terms, and the intellectual traditions aligned with or opposed to them. The contributors thereby (...) provide a vivid intellectual map of the Middle Ages and the Early Modern period. Contributions are written in English or German. (shrink)

The commentary of the Italian physician and philosopher Pietro d'Abano on Bartholomew of Messina's Latin translation of Pseudo-Aristotle's 'Problemata Physica', published in 1310, constitutes an important historical source. In a section of the corpus Aristotelicum that was not part of the standard curriculum at the medieval university, the commentary of Pietro d'Abano investigates the complex relationship between text, translation, and commentary. The eight articles in this volume provide valuable insights into the manner in which Pietro d'Abano deals with the problems (...) of a translated text. They emphasize the idiosyncrasy of his approach in comparison to his contemporaries and successors, the particularities of his commentary in light of the habitual exegetical practices applied in the teaching of curricular texts, as well as the influence of philosophical traditions outside the strict framework of the medieval arts faculty. (shrink)

The present collection deals with philosophical thinking at the medieval university from the threefold perspective of Institution and Career, Organizational Forms and Literary Genres, and School Formation and School Conflict.

Colour has been shown to facilitate the recognition of scene images, but only when these images contain natural scenes, for which colour is ‘diagnostic’. Here we investigate whether colour can also facilitate memory for scene images, and whether this would hold for natural scenes in particular. In the first experiment participants first studied a set of colour and greyscale natural and man-made scene images. Next, the same images were presented, randomly mixed with a different set. Participants were asked to indicate (...) whether they had seen the images during the study phase. Surprisingly, performance was better for greyscale than for coloured images, and this difference is due to the higher false alarm rate for both natural and man-made coloured scenes. We hypothesized that this increase in false alarm rate was due to a shift from scrutinizing details of the image to recognition of the gist of the image. A second experiment, utilizing images without a nameable gist, confirmed this hypothesis as participants now performed equally on greyscale and coloured images. In the final experiment we specifically targeted the more detail-based perception and recognition for greyscale images versus the more gist-based perception and recognition for coloured images with a change detection paradigm. The results show that changes to images are detected faster when image-pairs were presented in greyscale than in colour. This counterintuitive result held for both natural and man-made scenes and thus corroborates the shift from more detailed processing of images in greyscale to more gist-based processing of coloured images. (shrink)

C.F Gauss’s computational work in number theory attracted renewed interest in the twentieth century due to, on the one hand, the edition of Gauss’s Werke, and, on the other hand, the birth of the digital electronic computer. The involvement of the U.S. American mathematicians Derrick Henry Lehmer and Daniel Shanks with Gauss’s work is analysed, especially their continuation of work on topics as arccotangents, factors of n2 + a2, composition of binary quadratic forms. In general, this strand in Gauss’s reception (...) is part of a more general phenomenon, i.e. the influence of the computer on mathematics and one of its effects, the reappraisal of mathematical exploration. (shrink)

This collection of 17 articles offers an overview of the philosophical activities of a group of philosophers (who have been) working at the Groningen University. The meta-methodological assumption which unifies the research of this group, holds that there is a way to do philosophy which is a middle course between abstract normative philosophy of science and descriptive social studies of science. On the one hand it is argued with social studies of science that philosophy should take notice of what scientists (...) actually do. On the other hand, however, it is claimed that philosophy can and should aim to reveal cognitive patterns in the processes and products of scientific and common sense knowledge. Since it is thought that those patterns can function as guidelines in new research and/or in research in other disciplines, philosophy can nevertheless hold on to the normative aim which is characteristic of 'classical' philosophy of science. Compared to this common assumption, there is a diversity of subjects. Some papers deal with general problems of science, knowledge, cognition and argumentation, others with topics relating to foundational problems of particular sciences. Therefore this volume is of interest to philosophers of science, to philosophers of knowledge and argumentation in general, to philosophers of mind, as well as for scientists working in the physical and applied sciences, biology, psychology and economy who are interested in the foundations of their disciplines. After a foreword by Leszek Nowak and a general introduction by the editors, the book is divided into four parts, with special introductions. - I: Conceptual Analysis in Service of Various Research Programmes (Henk Zandvoort, Rein Vos, Rick Looijen, Gerben Stavenga, Renée Dalitz); - II: The Logic of the Evaluation of Arguments, Hypotheses, Default Rules, and Interesting Theorems (Erik Krabbe, Theo Kuipers, Alfons Keupink, Maarten Janssen/Yao-Hua Tan, Bert Hamminga); - III: Three Challenges to the Truth Approximation Programme (Sjoerd Zwart, Hinne Hettema/Theo Kuipers, Roberto Festa); - IV: Explicating Psychological Intuitions (Anne-Ruth Mackor, Jeanne Peijnenburg, Lex Guichard, Michel ter Hark). The Groningen research group was recently qualified, by an official international assessment committee, as one of the best philosophy research groups in the Netherlands. (shrink)

Philosophers and psychologists often assume that mirror reflections are optical illusions. According to many authors, what we see in a mirror appears to be behind it. I discuss two strategies to resist this piece of dogma. As I will show, the conviction that mirror reflections are illusions is rooted in a confused conception of the relations between location, direction, and visibility. This conception is unacceptable to those who take seriously the way in which mirrors contribute to our experience of the (...) world. My argument may be read as an advertisement of the neglected field of philosophical catoptrics, the philosophical study of the optical properties of mirrors. It enables us to recast familiar issues in the philosophy of perception. (shrink)

Relationalism maintains that perceptual experience involves, as part of its nature, a distinctive kind of conscious perceptual relation between a subject of experience and an object of experience. Together with the claim that perceptual experience is presentational, relationalism is widely believed to be a core aspect of the naive realist outlook on perception. This is a mistake. I argue that naive realism about perception can be upheld without a commitment to relationalism.

The present study examined whether individuals with full-blown memories of highly implausible events are prone to commit source monitoring errors. Participants reporting previous-life memories and those without such memories completed a false fame task. This task provides an index of source monitoring errors . Participants with previous-life memories had a greater tendency to judge the names of previously presented non-famous people as famous than control participants. The two groups did not differ in terms of correct recognition of new non-famous names (...) and famous names. Although dissociation, cognitive failures, sleep-related experiences, depressive symptoms, and signs of psychological distress were all significantly higher in participants with previous-life memories than in controls, these variables did not predict the false fame illusion. (shrink)

This paper deals with the relation between politics and ethics in Spinoza’s philosophy. The first question that I address, is what Spinoza’s notion of political freedom entails. Is political freedom just a condition of peace and security for the collective, or does it also entail the moral freedom of the Ethics? The former interpretation seems plausible, since Spinoza’s politics is chiefly concerned with peace and security. Yet certain passages of the political works echo the moral ideal of the Ethics, namely (...) that of a free life through an adequate understanding of Nature and our place in it. I therefore argue that Spinoza’s political notions of reason and freedom are ultimately to be identified with their moral counterparts. They cannot be wholly reduced to peace. This interpretation immediately leads to a second problem - how can Spinoza combine his professed realism in politics with his moral perfectionism? It seems that collective moral freedom must be illusory to someone who claims to describe humans as they are, not as they ought to be. Through a detailed analysis of Spinoza’s view of the development of political freedom, I argue that this is in fact a coherent view. First, I show how living in a Spinozist state may stimulate a basic rational disposition in people. Then I turn to Spinoza’s view of rational development in the Ethics, and argue that he is in that work very aware of the limits that our finite existence puts on the moral ideal. This brings me to the suggestion that, if this ideal is to have any practical relevance, it must not be wholly separated from the sphere of the imagination. If we accept this, then the narratives that bring harmony to a collective - consisting of both imaginative and rational elements – may also be considered as sources of moral freedom. This prevents Spinoza’s politics from being utopian, since it roots his quest for collective freedom firmly in tradition. (shrink)

The present paper presents a philosophical analysis of earth science, a discipline that has received relatively little attention from philosophers of science. We focus on the question of whether earth science can be reduced to allegedly more fundamental sciences, such as chemistry or physics. In order to answer this question, we investigate the aims and methods of earth science, the laws and theories used by earth scientists, and the nature of earth-scientific explanation. Our analysis leads to the tentative conclusion that (...) there are emergent phenomena in earth science but that these may be reducible to physics. However, earth science does not have irreducible laws, and the theories of earth science are typically hypotheses about unobservable (past) events or generalised - but not universally valid - descriptions of contingent processes. Unlike more fundamental sciences, earth science is characterised by explanatory pluralism: earth scientists employ various forms of narrative explanations in combination with causal explanations. The main reason is that earth-scientific explanations are typically hampered by local underdetermination by the data to such an extent that complete causal explanations are impossible in practice, if not in principle. (shrink)

This article explores the republican critiques of commercial society of Jean‐Jacques Rousseau and Adam Ferguson, focusing on their kindred analyses of social alienation. The joint study of these thinkers reveals a Rousseauean strand of eighteenth‐century republicanism that effectively combined a traditional (yet idiosyncratic) Stoic view of human flourishing with an innovative, proto‐sociological analysis and critique of quintessentially modern social phenomena. Rousseau and Ferguson regard alienation as a loss of wholeness, both in humans individually and in their relations to their (social) (...) surroundings. The article addresses two specific aspects of alienation in commercial society as the two thinkers see it. The first aspect concerns the insincerity underpinning the new moral vocabulary of polite sociability; the second aspect concerns the division of labor. According to Rousseau and Ferguson, this division threatens true human flourishing as well as political liberty. Finally, the conservative dimension of their republican solutions for overcoming alienation and bolstering liberty is considered. (shrink)

Undergraduate geoscience students are rarely exposed to history and philosophy of science. I will describe the experiences with a short course unfavourably placed in the first year of a bachelor of earth science. Arguments how HPS could enrich their education in many ways are sketched. One useful didactic approach is to develop a broader interest by connecting HPS themes to practical cases throughout the curriculum, and develop learning activities that allow students to reflect on their skills, methods and their field (...) in relation to other disciplines and interactions with society with abilities gained through exposure to HPS. Given support of the teaching staff, the tenets of philosophy of science in practice, of conceptual history of knowledge, and of ethics of science for society can fruitfully and directly be connected to the existing curriculum. This is ideally followed by a capstone HPS course late in the bachelor programme. (shrink)

The concept of the future is re-emerging as an urgent topic on the academic agenda. In this article, we focus on the ‘politics of the future’: the social processes and practices that allow particular imagined futures to become socially performative. Acknowledging that the performativity of such imagined futures is well-understood, we argue that how particular visions come about and why they become performative is underexplained. Drawing on constructivist sociological theory, this article aims to fill this gap by exploring the question (...) ‘how do imagined futures become socially performative’? In doing so, the article has three aims to identify the leading social–theoretical work on the future; conceptualize the relationship of the imagination of the future with social practices and the performance of reality; provide a theoretical framework explaining how images of the future become performative, using the concepts ‘techniques of futuring’ and ‘dramaturgical regime’. (shrink)

John Hyman insists that Frege-style cases for depiction show that any sound theory of depiction must distinguish between the ‘sense’ and the ‘reference’ of a picture. I argue that this rests on a mistake. Making sense of the cases does not require the distinction.

For a long time, philosophers of science have expressed little interest in the so-called demarcation project that occupied the pioneers of their field, and most now concur that terms like “pseudoscience” cannot be defined in any meaningful way. However, recent years have witnessed a revival of philosophical interest in demarcation. In this paper, I argue that, though the demarcation problem of old leads to a dead-end, the concept of pseudoscience is not going away anytime soon, and deserves a fresh look. (...) My approach proposes to naturalize and down-size the concept, anchoring it in real-life doctrines and fields of inquiry. First, I argue against the definite article “the” in “the demarcation problem”, distinguishing between territorial and normative demarcation, and between different failures and shortcomings in science apart from pseudoscience. Next, I argue that pseudosciences can be fruitfully regarded as simulacra of science, doctrines that are not epistemically warranted but whose proponents try to create the impression that they are. In this element of imitation or mimicry, I argue, lies the clue to their common identity. Despite the huge variety of doctrines and beliefs gathered under the rubric of “pseudoscience”, and the wide range of defects from which they suffer, pseudosciences all engage in similar strategies to create an impression of epistemic warrant. The indirect, symptomatic approach defended here leads to a general characterization of pseudosciences in all domains of inquiry, and to a useful diagnostic tool. (shrink)

For an arbitrary similarity type of Boolean Algebras with Operators we define a class of Sahlqvist identities. Sahlqvist identities have two important properties. First, a Sahlqvist identity is valid in a complex algebra if and only if the underlying relational atom structure satisfies a first-order condition which can be effectively read off from the syntactic form of the identity. Second, and as a consequence of the first property, Sahlqvist identities are canonical, that is, their validity is preserved under taking canonical (...) embedding algebras. Taken together, these properties imply that results about a Sahlqvist variety V van be obtained by reasoning in the elementary class of canonical structures of algebras in V. We give an example of this strategy in the variety of Cylindric Algebras: we show that an important identity called Henkin's equation is equivalent to a simpler identity that uses only one variable. We give a conceptually simple proof by showing that the firstorder correspondents of these two equations are equivalent over the class of cylindric atom structures. (shrink)

This article undertakes a comparative study of the conjectural histories of Jean-Jacques Rousseau and Adam Ferguson, focusing on the convergences in the moral and political ideals expressed and grounded in these histories. In comparison with Scots like Adam Smith and John Millar, the conjectural histories of Ferguson and Rousseau follow a similar historical trajectory as regards the development and progress of commercial, political and cultural arts. However, their assessment of the moral progress of humanity does not, or in a much (...) more limited way than in Smith and Millar, correlate with this trajectory. Rousseau and Ferguson see a candour and vigour in savage and barbarian societies that is much less easily supported by the complex socio-economic framework of modern, commercial societies. It is argued that the convergences in their conjectural histories arise from a similar fusion of these histories with Stoic and republican perspectives. While Rousseau and Ferguson do not see history as cyclical, they think that the forces that push towards moral decline are strong and can, on the political level, only be countered by firm republican policies. Furthermore, their shared Stoic ideal of the life lived according to nature informs their solutions for modern societies. (shrink)

This article undertakes a comparative study of the conjectural histories of Jean-Jacques Rousseau and Adam Ferguson, focusing on the convergences in the moral and political ideals expressed and grounded in these histories. In comparison with Scots like Adam Smith and John Millar, the conjectural histories of Ferguson and Rousseau follow a similar historical trajectory as regards the development and progress of commercial, political and cultural arts. However, their assessment of the moral progress of humanity does not, or in a much (...) more limited way than in Smith and Millar, correlate with this trajectory. Rousseau and Ferguson see a candour and vigour in savage and barbarian societies that is much less easily supported by the complex socio-economic framework of modern, commercial societies. It is argued that the convergences in their conjectural histories arise from a similar fusion of these histories with Stoic and republican perspectives. While Rousseau and Ferguson do not see history as cyclical, they think that the forces that push towards moral decline are strong and can, on the political level, only be countered by firm republican policies. Furthermore, their shared Stoic ideal of the life lived according to nature informs their solutions for modern societies. (shrink)

This article undertakes a comparative study of the conjectural histories of Jean-Jacques Rousseau and Adam Ferguson, focusing on the convergences in the moral and political ideals expressed and grounded in these histories. In comparison with Scots like Adam Smith and John Millar, the conjectural histories of Ferguson and Rousseau follow a similar historical trajectory as regards the development and progress of commercial, political and cultural arts. However, their assessment of the moral progress of humanity does not, or in a much (...) more limited way than in Smith and Millar, correlate with this trajectory. Rousseau and Ferguson see a candour and vigour in savage and barbarian societies that is much less easily supported by the complex socio-economic framework of modern, commercial societies. It is argued that the convergences in their conjectural histories arise from a similar fusion of these histories with Stoic and republican perspectives. While Rousseau and Ferguson do not see history as cyclical, they think that the forces that push towards moral decline are strong and can, on the political level, only be countered by firm republican policies. Furthermore, their shared Stoic ideal of the life lived according to nature informs their solutions for modern societies. (shrink)

Eighteenth century river hydraulics used both theory and measurement to address problems of flood safety, navigation and defense related to the rivers. In the late eighteenth century the Dutch overseer of the rivers, Christiaan Brunings, integrated hydraulic theory and meteorological practices, which enabled him to design a unique instrument for measuring river flow. The question is whether the unprecedented detail of measurements fits the putative empirical stance in the eighteenth century. The interactions between theory, instrument, measurement, and other knowledge practices (...) are here assessed using experiences in similar measurement practices. I argue that Brunings had theoretical and embodied understanding of hydrodynamics, as he knew how to design an instrument for flow measurement of sufficient accuracy for his purpose in the sociopolitical context of river management. (shrink)

Part of the distinction between artefacts, objects made by humans for particular purposes, and natural objects is that artefacts are subject to normative judgements. A drill, say, can be a good drill or a poor drill, it can function well or correctly or it can malfunction. In this paper I investigate how such judgements fit into the domain of the normative in general and what the grounds for their normativity are. Taking as a starting point a general characterization of normativity (...) proposed by Dancy, I argue how statements such as ‘this is a good drill’ or ‘this drill is malfunctioning’ can be seen to express normative facts, or the content of normative statements. What they say is that a user who has a desire to achieve a particular relevant outcome has a reason to use, or not to use, the artefact in question. Next this analysis is extended to show that not just statements that say that an artefact performs its function well or poorly, but all statements that ascribe a function to an artefact can be seen as expressing a normative fact. On this approach the normativity of artefacts is analyzed in terms of reasons on grounds of practical, and to a lesser extent theoretical, rationality. I close by investigating briefly to what extent reasons on moral grounds are, in the analysis adopted here, involved in the normativity of artefacts.Keywords: Artefact; Normativity; Instrumental reason; Practical rationality; Function; Use. (shrink)

One way to address such questions about artifact kinds is to look for clues in the available literature on parallel questions that have been posed with respect to kinds in the natural domain. Philosophers have long been concerned with the ...

This chapter contains sections titled: Introduction Object and Aims of Earth Science The Autonomy of Earth Science Explanation in Earth Science Conclusion Acknowledgment References.

What makes beliefs thrive? In this paper, we model the dissemination of bona fide science versus pseudoscience, making use of Dan Sperber's epidemiological model of representations. Drawing on cognitive research on the roots of irrational beliefs and the institutional arrangement of science, we explain the dissemination of beliefs in terms of their salience to human cognition and their ability to adapt to specific cultural ecologies. By contrasting the cultural development of science and pseudoscience along a number of dimensions, we gain (...) a better understanding of their underlying epistemic differences. Pseudoscience can achieve widespread acceptance by tapping into evolved cognitive mechanisms, thus sacrificing intellectual integrity for intuitive appeal. Science, by contrast, defies those deeply held intuitions precisely because it is institutionally arranged to track objective patterns in the world, and the world does not care much about our intuitions. In light of these differences, we discuss the degree of openness or resilience to conceptual change (evidence and reason), and the divergent ways in which science and pseudoscience can achieve cultural “success”. (shrink)