ZusammenfassungBei der Programmierung der Rechenautomaten ist es Brauch, den Gedankengang mit Skizzen zu begleiten and dadurch an‐schaulich zu machen. Durch Graphschemata können auch zahlentheore‐tische Funktionen definiert werden. Kaluẑnin stellte die Aufgabe, die derart definierten zahlentheoretischen Funktionen je nach der Kompliziert‐heit der betreffenden Graphschemata in Klassen zu teilen. Es war zuvermuten, dass man auf diese Weise konstruktive Zwischenstufen zwischen den bekannten speziell‐rekursiven Funktionen und den allgemein‐rekursiven Funktionen erhaält. Die vorliegende Arbeit zeigt, dass dieser Weg nicht gangbar ist, da sich jede allgemein‐rekursive (...) Funktion durch Graphschemata von ähnlicher Struktur definieren lässt. (shrink)

In this paper, we examine the period that immediately followed the invention of the Leiden jar. Historians of science have developed narrations that emphasize the role of grounding during the process of charging the jar. In this respect, this episode shows significant aspects that can be used to characterize science, scientific knowledge production, and the nature of science. From our own experimentation, we learned that grounding was not necessary in order to produce the effect. These experiences inspired us to go (...) back to primary sources. In doing so, we came to a new understanding of the early period after Kleist’s and Musschenbroek’s initial creation of the effect. From our analysis, we conclude that it is not the grounding which was perceived as a major innovation during this early period of the discussion but the concept of an electrical circuit. This understanding was fundamental in characterizing the Leiden jar as a new device challenging the then current knowledge of experimental practices in the field of electricity. (shrink)

Georg Simon Ohm's work in the field of electricity led to what is now considered to be the most fundamental law of electrical circuits, Ohm's Law. Much less known is that only months earlier, Ohm had published another law—one that differed significantly from the now accepted one. The latter entailed a logarithmic relation between the length of the conductor and a parameter that Ohm called “loss of force.” This paper discusses how Ohm came up with an initial law that he (...) felt compelled to correct a few months later. We analyze Ohm's publication as well as his laboratory notes, relating them to our own laboratory experiences while using the replication method to study his work. We also discuss the conceptual background of Ohm's work. We conclude that he was significantly influenced by French studies in the field of electricity, most notably the ones by Charles Augustin Coulomb. (shrink)

Some experiments from the history of physics became so famous that they not only made it into the textbook canon but were transformed into lecture demonstration performances and student laboratory activities in the nineteenth and twentieth centuries. While, at first glance, some of these demonstrations as well as the related instruments do resemble their historical ancestors, a closer examination reveals significant differences both in the instruments themselves and in the practices and meanings associated with them. In this paper, I analyse (...) the relation between the research instruments and the respective teaching demonstrations. In doing so, I particularly distinguish between demonstrations that address the process of the actual experimental procedures, and those that focus on the outcome or results (the product) of the experiment. This distinction will be illustrated in some exemplary case studies from the late nineteenth century and the early twentieth in which both the historical experiment and the related educational devices are analysed. The tension between the historical experiment on the one hand, and the different variants of the teaching version on the other, result in the educational as well as epistemological problems that are discussed in this paper. (shrink)

Much of what we believe we know, we know through the testimony of others. While there has been long-standing evidence that people are sensitive to the characteristics of the sources of testimony, for example in the context of persuasion, researchers have only recently begun to explore the wider implications of source reliability considerations for the nature of our beliefs. Likewise, much remains to be established concerning what factors influence source reliability. In this paper, we examine, both theoretically and empirically, the (...) implications of using message content as a cue to source reliability. We present a set of experiments examining the relationship between source information and message content in people's responses to simple communications. The results show that people spontaneously revise their beliefs in the reliability of the source on the basis of the expectedness of a source's claim and, conversely, adjust message impact by perceived reliability; hence source reliability and message content have a bi-directional relationship. The implications are discussed for a variety of psychological, philosophical and political issues such as belief polarization and dual-route models of persuasion. (shrink)

The Hermotimus is Lucian’s longest piece of writing, surpassing even the two books of the True Tales, and at the same time his most successful effort to recreate the style and atmosphere of a Platonic dialogue, filled with a new—and for Lucian uncharacteristically serious—content, namely a sustained attack on “dogmatic” philosophical schools (the “haireseis” of its subtitle) and, inversely, a ringing endorsement of the tenets of Pyrrhonian Scepticism.... (review at BMCR).

First published in 1998, this volume why and how genetic engineering has emerged as the technology most likely to change our lives, for better or worse, in the opening century of the third millennium. Over twenty international experts, including moral philosophers and social scientists, describe the issues and controversies surrounding modern biotechnology and genetic engineering. They explore ways in which lay individuals and groups can join in an effective and constructive dialogue with scientists and industrialists over the assessment, exploitation and (...) safe management of these new and important technologies. Topics covered include a discussion of the issues surrounding 'Dolly', the cloned sheep, the politics and ethics of the international research programme to sequence the entire human genome, the ethical questions raised by the creation of transgenic farm animals, the morality of genetic experimentation on animals, the controversy surrounding the patenting of genetic material and of the transgenic animals themselves, the ethical implications of engineering animals for transplanting their organs into humans, and the environmental hazards of releasing genetically engineered organisms. (shrink)

Von Hippel & Trivers (VH&T) interpret belief in God and belief in strong government as the outcome of an active process of self-deception on a worldwide scale. We propose, instead, that these beliefs might simply be a passive spin-off of efficient cognitive processes.

Recent experimental work suggests that the concept of contextual fields should be generalized to allow the modulation of local information extraction by both external and internal context. The external context relates to the coherent information of the stimulus; the internal context refers to the parts of this information which are relevant for behavior. This dual interaction, present at every level of the hierarchy, requires a fundamental unit of processing more complex than a single neuron appears today. We argue that the (...) cortical column supplies the required mechanisms for a separate top-down and bottom-up processing and allows for interaction without destructive cross-talk. This flexibility might explain why the same basic architecture of a cortical column is used in the whole isocortex. (shrink)

This paper discusses essential elements of the philosophical works of Ludwik Fleck and their potential interpretation for the teaching and learning of science. In the early twentieth century, Fleck made substantial contributions to understanding the sociological character of the nature of science and explaining the embedding of science in society. His works have several parallels to the later and very popular work, The Structure of Scientific Revolutions, by Thomas S. Kuhn, although Kuhn only indirectly referred to the influence of Fleck (...) on his own theories. Starting from a short review of the life of Ludwik Fleck, his philosophical work and its connections to Kuhn, this paper elaborates upon and illustrates how his theories can be considered for science education in order to provide learners with a better understanding of the nature of scientific endeavor and the bi-directional science-to-society links. (shrink)

In this essay, we consider helicases, defined as enzymes that use the free energies of binding and hydrolysis of ATP to drive the unwinding of double‐stranded nucleic acids, and ask how they function within, and are “coupled” to, the macromolecular machines of gene expression. To illustrate the principles of the integration of helicases into such machines, we consider the macromolecular complexes that direct and control DNA replication and DNA‐dependent RNA transcription, and use these systems to illustrate how machines centered around (...) coupled polymerase–helicase systems can be regulated by small changes in the interactions of their functional components. BioEssays 25:1168–1177, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

Since the spectrum of possibilities in linguistic theory construction is much broader and more variegated than students of linguistics have perhaps been led to believe, the Current Issues in Linguistic Theory series has been established in order to provide a forum for the presentation and discussion of linguistic opinions of scholars who do not necessarily accept the prevailing mode of thought in linguistic science. CILT is a theory-oriented series which welcomes contributions from scholars who have significant proposals to make towards (...) the advancement of our understanding of language, its structure, functioning, and development. Current Issues in Linguistic Theory is especially designed, by offering an alternative outlet for meaningful contributions to the current linguistic debate, to furnish the community of linguists the diversity of opinion which a healthy discipline must have. (shrink)

This article addresses the ability of Parallel Distributed Processing (PDP) networks to generate stagewise cognitive development in accordance with Piaget's theory of cognitive epigenesis. We carried out a replication study of the simulation experiments by McClelland (1989) and McClelland and Jenkins (1991) in which a PDP network learns to solve balance scale problems. In objective tests motivated from catastrophe theory, a mathematical theory of transitions in epigenetical systems, no evidence for stage transitions in network performance was found. It is concluded (...) that PDP networks lack the ability to recover the positive outcomes of analogous catastrophe analyses of real cognitive developmental data. In an attempt to further characterize the learning behaviour of PDP networks, we carried out a second simulation study using the discrimination‐shift paradigm. The results thus obtained indicate that PDP learning is compatible with the learning of stimulus‐response relationships, not with the acquisition of mediating rules such as conceived in (neo‐)Piagetian theory. In closing, we speculate about the feasibility of simulating stagewise development with alternative network architectures. (shrink)

Voegelin's magisterial account of medieval political thought opens with a survey of the structure of the period and continues with an analysis of the Germanic invasions, the fall of Rome, and the rise of empire and monastic Christianity. The political implications of Christianity and philosophy in the period are elaborated in chapters devoted to John of Salisbury, Joachim of Flora, Frederick II, Siger de Brabant, Francis of Assisi, Roman law, and climaxing in a remarkable study of Saint Thomas Aquinas's mighty (...) thirteenth-century synthesis. Although _History of Political Ideas_ was begun as a textbook for Macmillan, Voegelin never intended it to be a conventional chronological account. He sought instead an original comprehensive interpretation, founded on primary materials and taking into account the most advanced specialist scholarship—or science as he called it—available to him. Because of this, the book grew well beyond the confines of an easily marketable college survey and until now remained unpublished. In the process of writing it, Voegelin himself outgrew the conceptual frame of a "History of Political Ideas," turning to compose _Order and History_ and the other works of his maturity. _History of Political Ideas_ became the ordered collection of materials from which much of Voegelin's later theoretical elaboration grew, structured in a manner that reveals the conceptual intimations of his later thought. As such, it provides an unparalleled opportunity to observe the working methods and the intellectual evolution of one of our century's leading political thinkers. In its embracing scope, _History of Political Ideas_ contains both analyses of themes Voegelin developed in his later works and discussions of authors and ideas to which he did not return or which he later approached from a different angle and with a different emphasis. _The Middle Ages to Aquinas_ has withstood the test of time. What makes it still highly valuable is its thoroughly revisionist approach, cutting through all the convenient clichés and generalizations and seeking to establish the experiential underpinnings that typified the medieval period. (shrink)