A number of nonmonotonic reasoning formalisms have been introduced to model the set of beliefs of an agent. These include the extensions of a default logic, the stable models of a general logic program, and the extensions of a truth maintenance system among others. In [13] and [16], the authors introduced nonmonotomic rule systems as a nonlogical generalization of all essential features of such formulisms so that theorems applying to all could be proven once and for all. In this paper, (...) we extend Rieter's normal default theories, which have a number of the nice properties which make them a desirable context for belief revision, to the setting of nonmonotonic rule systems. Reiter defined a default theory to be normal if all the rules of the default theory satisfied a simple syntatic condition. However, this simple syntatic condition has no obvious analogue in the setting of nonmonotonic rule systems. Nevertheless, an analysis of the proofs of the main results on normal default theories reveals that the proofs do not rely on the particular syntactic form of the rules but rather on the fact that all rules have a certain consistency property. This led us to extend the notion of normal default theories with respect to a general consistency property. This extended notion of normal default theories, which we call Forward Chaining normal , is easily lifted to nonmonotomic rule systems and hence applies to general logic programs and truth maintenance. (shrink)

It is human nature to try to recognize patterns and to make sense of that which we observe. Unfortunately, our intuition is often wrong, and so there is a need to impose some objectivity on the methods by which observations are converted into knowledge. One definition of biostatistics could be precisely this, the rigorous and objective conversion of medical and/or biological observations into knowledge. Both consumers of biostatistical principles and biostatisticians themselves vary in the extent to which they recognize the (...) need to continue the improvement. Some may not recognize the need for (some or all of) the methods that have already been developed; others may accept these as they find them completely sufficient; still others recognize both the value and the shortcomings of these methods, and seek to develop even better methods to ensure that future medical conclusions are less subject to biases than current ones are. (shrink)

This book is a collection of Rush Rhees' recent articles on Wittgenstein along with a record of Wittgenstein's comments on continuity made in private conversations in 1938. The first part of the book is on the Tractatus. It begins with a review of Anscombe's Introduction of which Rhees generally approves and then goes on to discuss the "picture theory" and language's capacity to get hold of reality. Rhees argues against Maslow that elementary statements are more than psychological phenomena but must (...) be spoken of in a purely formal sense. Commenting on Black's Companion he argues that Wittgenstein did not have in mind any ontological implications of logic when he was working on the Tractatus. Rhees uses his critique of Pitcher's Philosophy of Wittgenstein and an article on that philosophy to form the transition to the discussion of the later Wittgenstein. He insists that Wittgenstein taught more a method of seeing the depth of certain problems than a set of solutions to those problems. He introduces the theme of "publicness" by arguing that language involves the ability to "say something" and must thus involve publicity. In his article on "Wittgenstein's Builders" he argues that this ability to say something rests on the interrelation of language games and the unity of a form of life. Using this as a basis, he speaks of the Wittgensteinean approach to ethics as one of studying the way of saying something ethically in a certain language game rather than one of studying ethics in general. The essay on continuity begins with a discussion of the dependence of mathematical language on everyday language for meaning. Here Wittgenstein argues that mathematical language derives its sense from experiential language and not from eternal and immutable objects. He discusses the mathematical notion of continuity with an eye to the limits of its sense and shows that its sense is limited by ordinary notions of space and continuity and tests relating to them. This book is worth reading for both the presentation of basic approaches to understanding Wittgenstein and for the record of Wittgenstein's remarks on continuity which are unavailable elsewhere.--J. V. W. (shrink)

This dissertation seeks to contribute to research in the philosophy of social science. The study focuses upon select epistemological and ontological aspects of Hannah Arendt’s work from which methodological implications are drawn pertaining to sociology. Arendt, although critical of the sociology of her time, has become increasingly cited and influential for emerging sociological research and this study seeks to contribute to this by focusing upon the problem of novelty. The aim is to explore the philosophical and methodological implications of novelty (...) for social science by working through three case studies that are theoretically pivotal for social science—action, the ‘social’, and the self—in terms of novelty as expressed in Arendt’s writing. Arendt is critical of methodology and epistemology, aiming to draw her readers to ontological concerns outlined from her preoccupation with the 'world' and social reality. In this aim, Arendt seeks to distance herself from social sciences that she claims ignore human novelty in favour of reading social regularities, tendencies and similarities. Despite her disdain for method, Arendt suggests a anti-methodological 'method' (outlined in an overlooked footnote) for keeping trained upon and for dealing with novel, anomalous events. In the seed of this method lies a unique opportunity for social science to reassess and extend its methods, addressing this oversight and in so doing bring to light the novel social object as a legitimate subject of social research. (shrink)

Calpains are a family of calcium‐dependent thiol‐proteases which are proposed to be involved in many physiological processes as well as pathological conditions. Calpains are likely to be involved in processing of numerous enzymes and cytoskeletal components, thereby linking their activity to a variety of intracellular events. Although widely studied, the precise mechanism(s) involved in calpain activation and activity in vivo remain poorly understood. Initial studies suggested that calpain exists primarily as an inactive proenzyme that required autolytic cleavage for activation. It (...) was also hypothesized that calpain associated with membrane phospholipids, serving to increase calcium sensitivity, facilitating autolytic conversion and thus activating the enzyme. These hypotheses, however, have not been universally accepted and there is increasing evidence that intact, non‐autolyzed calpain is the physiologically active calpain form. (shrink)

Things and Their Place in Theories Our talk of external things, our very notion of things, is just a conceptual apparatus that helps us to foresee and ...

Over the last decades, it has become evident that highly complex networks of regulators govern post‐transcriptional regulation of gene expression. A novel class of Argonaute (Ago)‐associated RNA molecules, the agotrons, was recently shown to function in a Drosha‐ and Dicer‐independent manner, hence bypassing the maturation steps required for canonical microRNA (miRNA) biogenesis. Agotrons are found in most mammals and associate with Ago as ∼100 nucleotide (nt) long RNA species. Here, we speculate on the functional and biological relevance of agotrons: (i) (...) agotrons could serve as non‐promiscuous miRNA‐like regulators with reduced off‐targeting or (ii) agotrons could encompass other putative functions, such as protecting Ago proteins from taking up aberrant short RNAs or by rescuing and stabilizing otherwise unloaded Ago‐proteins from degradation. Collectively, agotrons have emerged as a novel class of interesting non‐coding RNA molecules, but their full functional potential and biological impact still remain to be disclosed. (shrink)

W. V. Quine is one of the most eminent philosophers alive today. Now in his mid-eighties he has produced a sharp, sprightly book that encapsulates the whole of his philosophical enterprise, including his thinking on all the key components of his epistemological stance--especially the value of logic and mathematics. New readers of Quine may have to go slowly, fathoming for themselves the richness that past readers already know lies between these elegant lines. For the faithful there is much to ponder. (...) In this short book, based on lectures delivered in Spain in 1990, Quine begins by locating his work historically. He provides a lightning tour of the history of philosophy (particularly the history of epistemology), beginning with Plato and culminating in an appreciative sketch of Carnap's philosophical ambitions and achievements. This leads, in the second chapter, to an introduction to Quine's attempt to naturalize epistemology, which emphasizes his continuities with Carnap rather than the differences between them. The next chapters develop the naturalistic story of the development of science to take account of how our conceptual apparatus is enhanced so that we can view the world as containing re-identifiable objects. Having explained the role of observation sentences in providing a checkpoint for assessing scientific theories, and having despaired of constructing an empirical criterion to determine which sentences are meaningful, Quine in the remaining chapters takes up a variety of important issues about knowledge. He concludes with an extended treatment of his views about reference and meaning and his attitudes toward psychological and modal notions. The presentation is distinctive, and the many small refinements of detail and formulation will fascinate all who know Quine's philosophy. (shrink)

A compact, coherent introduction to the study of rational belief, this text provides points of entry to such areas of philosophy as theory of knowledge, methodology of science, and philosophy of language. The book is accessible to all undergraduates and presupposes no philosophical training.

Our only channel of information about the world is the impact of external forces on our sensory surfaces. So says science itself. There is no clairvoyance. How, then, can we have parlayed this meager sensory input into a full-blown scientific theory of the world? This is itself a scientific question. The pursuit of it, with free use of scientific theory, is what I call naturalized epistemology. The Roots of Reference falls within that domain. Its more specific concern, within that domain, (...) is reference to concrete and abstract objects: what such reference consists in, and how we achieve it. (shrink)