We prove that the problem of determining the minimum propositional proof length is NP- hard to approximate within a factor of 2 log 1 - o(1) n . These results are very robust in that they hold for almost all natural proof systems, including: Frege systems, extended Frege systems, resolution, Horn resolution, the polynomial calculus, the sequent calculus, the cut-free sequent calculus, as well as the polynomial calculus. Our hardness of approximation results usually apply to proof length measured either by (...) number of symbols or by number of inferences, for tree-like or dag-like proofs. We introduce the Monotone Minimum (Circuit) Satisfying Assignment problem and reduce it to the problems of approximation of the length of proofs. (shrink)

Ewald Hering's color-opponent-theory is still considered one of the foundations of the visual sciences. Prior to Hering, Hermann v. Helmholtz introduced a theory of color appearance, which was based primarily on the physical aspects of the stimulus. In contrast to Helmholtz, Hering's theory strongly emphasized the subject's perception of color. As a consequence, Hering considered Helmholtz' theory inadequate. Contrary to some historical accounts, he did not object to Helmholtz's three-receptor explanation for color-mixture. Instead of Helmholtz' fundamental colors red, green, and (...) blue, Hering suggested that the colors possess opponent character: blue-yellow; red-green; and, black-white. Helmholtz, on the other hand, refused to accept Hering's theory. Finally, a student with Helmholtz, Johannes v. Kries, developed the so-called zone-theory , which combines both, Young-Helmholtz's and Hering's theory at different stages of the visual information processing system. (shrink)

BackgroundTo prevent the planet from catastrophic global warming a reduction of greenhouse gas emissions to net zero is required. Thus, divestment from fossil fuels must be a strategic interest for health insurers. The aim of this study was to analyse the implementation of environmental, social and governance criteria in German private health insurers’ investments.MethodsIn 2019 a survey about ESG strategies was sent to German private health insurance companies. The survey evaluated investment strategies and thresholds for the exclusion of sectors and (...) business practices, as well as company strategies for sustainable business development.FindingsGiven their business reports, German private health insurers manage assets of more than €350 billion. 11 of 40 insurance companies provided quantitative data, 10 refused to answer. According to quantitative data, €66 billion of assets is managed according to any ESG criteria; this equals an average of 76% of each company’s bonds. None of these insurers excluded the production and sale of fossil fuels. All excluded coal mining but only at high thresholds. For €226 billion, no data were provided.InterpretationThe findings are in contrast to the expected intrinsic economic interest of the insurers to stop global warming and improve public health. The majority of assets are managed in a highly problematic manner, especially the absence of capital allocated in fields contrary to medical ethics cannot be presumed. Lack of transparency is a major problem that limits clients in choosing the insurer who has the most advanced ESG criteria. (shrink)

Several years ago, I was asked to participate in a forum on evolution. Flattered, I accepted, only discovering later that I was to participate in a “debate”, involving me and a scientist squaring off against two Creationists, Henry M. Morris and Duane T. Gish. The topic for discussion was which doctrine has the greatest scientific merit: organic evolution through natural processes set against the background of a very old earth, or special instantaneous appearance of all organisms, about 6000 years ago, (...) followed shortly thereafter by a world-wide flood? I very much doubt that many minds were changed on that particular evening—the bleachers were packed with ardent Baptists bussed in from all over Wisconsin and Illinois. The 10 or so in the audience who believed in evolution went on believing in evolution. The 5000 in the audience who took the early chapters of Genesis absolutely literally went on taking the early chapters of Genesis absolutely literally. But, people's time was far from wasted. Morris and Gish got the attention they crave. Their supporters were thrilled by the sight of heretics publicly proclaiming doctrines for which they would surely earn eternal damnation. And, I learnt what a hollow sham modern day Creationism really is: crude, dogmatic, Biblical literalism, masquerading as genuine science, in order to avoid the strictures of the first amendment to the U.S. Constitution, which bars the teaching of religion in schools. (shrink)

Several years ago, I was asked to participate in a forum on evolution. Flattered, I accepted, only discovering later that I was to participate in a “debate”, involving me and a scientist squaring off against two Creationists, Henry M. Morris and Duane T. Gish. The topic for discussion was which doctrine has the greatest scientific merit: organic evolution through natural processes set against the background of a very old earth, or special instantaneous appearance of all organisms, about 6000 years ago, (...) followed shortly thereafter by a world-wide flood? I very much doubt that many minds were changed on that particular evening—the bleachers were packed with ardent Baptists bussed in from all over Wisconsin and Illinois. The 10 or so in the audience who believed in evolution went on believing in evolution. The 5000 in the audience who took the early chapters of Genesis absolutely literally went on taking the early chapters of Genesis absolutely literally. But, people's time was far from wasted. Morris and Gish got the attention they crave. Their supporters were thrilled by the sight of heretics publicly proclaiming doctrines for which they would surely earn eternal damnation. And, I learnt what a hollow sham modern day Creationism really is: crude, dogmatic, Biblical literalism, masquerading as genuine science, in order to avoid the strictures of the first amendment to the U.S. Constitution, which bars the teaching of religion in schools. (shrink)

tephen Jay Gould's Wonderful Life: The Burgess Shale and the Nature of History , has become something of a watershed for those who study contingency and complexity, especially applied to organisms, societies, and history, and discussions of it can be found in many works. Walter Fontana and Leo Buss, for example, ask in the title of their chapter "What Would Be Conserved If 'The Tape Were Played Twice'?" This is a direct reference to Gould's suggestion in Wonderful Life that if (...) the tape of life were rewound to the time of the organisms found in the Canadian outcrop known as the Burgess Shale, dated to about 530 million years ago, and replayed with a few contingencies tweaked here and there, humans would most likely never have evolved. (shrink)

The authors of this volume discuss the relevance and influence of various Old and New Testament documents, and early Christian and Jewish texts in terms of their impact in shaping the moral character, identity, and behaviour of the specific communities in which they were produced as well as their ethical application throughout the centuries. Against a narrow understanding of ethics, the term "application" is not used to analyse the texts of the Bible as step-by-step manuals for moral conduct. Rather, the (...) contributors engage with biblical texts within the framework of a complex hermeneutical process of application of the relevance of these texts in contemporary ethical discourse. Contributors: Paul N. Anderson, Robert L. Brawley, Cilliers Breytenbach, Ulrich Busse, R. Alan Culpepper, Jan Willem van Henten, Rainer Hirsch-Luipold, Stephan Joubert, Craig R. Koester, Bart J. Koet, Michael Labahn, Tobias Nicklas, Bert Jan Lietaert Peerbolte, Udo Schnelle, Michael Theobald, D. Francois Tolmie, Joseph Verheyden, Ben Witherington, III, Ellen van Wolde, Michael Wolter, Mirjam Zimmermann, Ruben Zimmermann. (shrink)

Michael Ryan (d. 1840) remains one of the most mysterious figures in the history of medical ethics, despite the fact that he was the only British physician during the middle years of the 19th century to write about ethics in a systematic way. Michael Ryan’s Writings on Medical Ethics offers both an annotated reprint of his key ethical writings, and an extensive introductory essay that fills in many previously unknown details of Ryan’s life, analyzes the significance of his (...) ethical works, and places him within the historical trajectory of the field of medical ethics. (shrink)

Michael Psellos has long been known as a key figure in the history of Byzantine literary and intellectual culture, but his theoretical and critical reflections on literature and art are little known outside of a small circle of specialists. Most famous for his Chronographia, a history of eleventh-century Byzantine emperors and their reigns, Psellos also excelled in describing as well as prescribing practices and rules for literary discourse and visual culture. The ambition of Michael Psellos on Literature and (...) Art is to illustrate an important chapter in the history of Greek literary and art criticism and introduce precisely this aspect of Psellian writing to a wider public. The editors of this volume present thirty Psellian texts, all of which have been translated - some in part, most in their entirety - into English. In the majority of cases, the works are translated for the first time in any modern language, and several are discussed at length here for the first time. They are grouped into two separate sections, which roughly translate to two areas of theoretical reflection associated with the modern terms 'literature' and 'art.'0. (shrink)

Miranda Fricker appeals to the idea of moral-epistemic disappointment in order to show how our practices of moral appraisal can be sensitive to cultural and historical contingency. In particular, she thinks that moral-epistemic disappointment allows us to avoid the extremes of crude moralism and a relativism of distance. In my response I want to investigate what disappointment is, and whether it can constitute a form of focused moral appraisal in the way that Fricker imagines. I will argue that Fricker is (...) unable to appeal to disappointment as standardly understood, but that there is a more plausible way of understanding the notion that she can employ. There are, nevertheless, significant worries about the capacity of disappointment in this sense to function as a form of moral appraisal. I will argue, finally, that even if Fricker can address these worries, her position might end up closer to moralism than she would like. (shrink)

Michael J. Zimmerman offers a conceptual analysis of the moral ‘ought’ that focuses on moral decision-making under uncertainty. His central case, originally presented by Frank Jackson, concerns a doctor who must choose among three treatments for a minor ailment. Her evidence suggests that drug B will partially cure her patient, that one of either drug A or C would cure him completely, but that the other drug would kill him. Accepting the intuition that the doctor ought to choose drug (...) B, Zimmerman argues that moral obligation consists in performing the action that is ‘prospectively best,’ that is ‘that which, from the moral point of view, it is most reasonable for the agent to choose’ given the evidence available to her at the time.Zimmerman defends his Prospective View of moral obligation against two main competitors in the long, first chapter of the book. According to the Objective View, a person ought to choose what is, in fact, the best option. The doctor ought to give her patient whichever drug will actually cure him. The fact that the doctor cannot know whether this is drug …. (shrink)

In Truth as One and Many, Michael Lynch offers a new theory of truth. There are two kinds of theory of truth in the literature. On the one hand, we have logical theories, which seek to construct formal systems that are consistent, while also containing a predicate which have as many as possible of the properties which we ordinarily take the English predicate ‘is true’ to have; salient examples include Tarski’s and Kripke’s theories of truth. On the other hand, (...) we have metaphysical theories, which seek to give a non-formal account of the nature of truth – of what truth consists in, of what it means to say that something is true; salient examples include correspondence, coherence and deflationary theories of truth. Lynch’s theory – functionalism about truth – is of the second sort.The theory takes its start from a number of principles which Lynch classifies as truisms about truth:Objectivity: The belief that p is true if, and only if, with respect to the belief that p, things are as they are believed to be.Norm of Belief: It is prima facie correct to believe that p if and only if the proposition that p is true.End of Inquiry: Other things being equal, true beliefs are a worthy goal of inquiry.Lynch argues that other familiar principles can be derived from these: for example, Objectivity together with some auxiliary principles and definitions yields versions of the T-schema, and of the principle that beliefs can be true without being warranted and vice versa. These principles are supposed to give the nominal essence of truth – to constitute our folk theory of truth. Lynch …. (shrink)

This is an obituary for Michael H. Robins.

Buss, S.R., The undecidability of k-provability, Annals of Pure and Applied Logic 53 75-102. The k-provability problem is, given a first-order formula ø and an integer k, to determine if ø has a proof consisting of k or fewer lines . This paper shows that the k-provability problem for the sequent calculus is undecidable. Indeed, for every r.e. set X there is a formula ø and an integer k such that for all n,ø has a proof of k sequents if (...) and only if n ε X. (shrink)

Because of the difficulty posed by the contrast between the search for truth and truth itself, Michael Polanyi believes that we must alter the foundation of epistemology to include as essential to the very nature of mind, the kind of groping that constitutes the recognition of a problem. This collection of essays, assembled by Marjorie Grene, exemplifies the development of Polanyi's theory of knowledge which was first presented in Science, Faith, and Society and later systematized in Personal Knowledge. Polanyi (...) believes that the dilemma of the modern mind arises from the peculiar relation between the positivist claim for total objectivity in scientific knowledge and the unprecedented moral dynamism characterizing the social and political aspirations of the last century. The first part of Knowing and Being deals with this theme. Part two develops Polanyi's idea that centralization is incompatible with the life of science as well as his views on the role of tradition and authority in science. The essays on tacit knowing in Part Three proceed directly from his preoccupation with the nature of scientific discovery and reveal a pervasive substructure of all intelligent behavior. Polanyi believes that all knowing involves movement from internal clues to external evidence. Therefore, to explain the process of knowing, we must develop a theory of the nature of living things in general, including an account of that aspect of living things we call "mind." Part Four elaborates upon this theme. (shrink)

Le présent volume réunit les contributions d'un colloque sur la pensée sémiotique et linguistique des Idéologues qui s'est tenu à Berlin du 3 au 5 octobre 1983. Ce recueil d'articles fait suite à un fascicule de la revue Histoire Epistémologie Langage qui était consacré au même sujet et dont il complète et amplifie les perspectives en ce qui concerne la portée européenne de la discussion. Le volume manifeste l'intérêt que beaucoup d'entre nous portent, surtout dans les sciences du langage, à (...) ces philosophes longtemps négligés par l'histoire de la pensée. (shrink)