Nucleation and motion of kink pairs on partial dislocations are examined by elasticity theory for materials with a high Peierls stress. Two approaches are used: one considers the change in average stacking-fault energy due to alloying elements and the other considers the change in local SFE due to a nearby solute atom. Both approaches highlight the role of SFE on kink nucleation, propagation and annihilation and both furnish strain rate as a function of stress, temperature and SFE. Model predictions are (...) compared with yield stress data for two systems: firstly, an intermetallic, MoSi 2 , which softens for alloying elements that decrease the SFE and hardens for Re additions that increase the SFE; secondly, a ceramic oxide, MgO-Al 2 O 3 spinel, which softens with increasing addition of excess alumina and at the same time exhibits a decrease in SFE. The average SFE approach agrees qualitatively with the data while quantitative agreement is obtained with the local SFE approach. The possibility is considered that the model applies to other materials, such as TiAl, HfV 2 and Fe 3 Al, which show softening with certain alloying additions. One requirement is that the dislocations are dissociated more than a few atomic distances; otherwise kink nucleation occurs on the perfect dislocation . Hence the model does not apply to materials such as bcc metals which only have a core dissociation. Normal hardening effects of solutes from size and modulus misfits are additive with any softening effects from a decrease in SFE and so may mask the latter, as occurs for W additions to MoSi 2. (shrink)

This treatise on aesthetics criticizes various psychological theories of art, offers new theories and interpretations, and draws important inferences concerning ...

What is science? How is scientific knowledge affected by the society that produces it? Does scientific knowledge directly correspond to reality? Can we draw a line between science and pseudo-science? Will it ever be possible for computers to undertake scientific investigation independently? Is there such a thing as feminist science? In this book the author addresses questions such as these using a technique of 'cognitive play', which creates and explores new links between the ideas and results of contemporary history, philosophy, (...) and sociology of science. New ideas and approaches are applied to a wide range of case studies, many of them from controversial and contested science. This book will be of interest to historians and sociologists of science, to anyone interested in science studies, and to educated general readers with an interest in the history, philosophy, and social context of science. (shrink)

This early work by Robin G. Collingwood was originally published in 1939 and we are now republishing it with a brand new introductory biography. 'An Autobiography' is the story of Collingwood's personal and academic life. Robin George Collingwood was born on 22nd February 1889, in Cartmel, England. He was the son of author, artist, and academic, W. G. Collingwood. He was greatly influenced by the Italian Idealists Croce, Gentile, and Guido de Ruggiero. Another important influence was his father, a professor (...) of fine art and a student of Ruskin. He published many works of philosophy, such as Speculum Mentis (1924), An Essay on Philosophic Method (1933), and An Essay on Metaphysics (1940). (shrink)

Of these lines Markland wrote in 1728 ‘patet ignari cuiusdam et barbari interpolatoris esse’; Dr. Trapp in 1735 found them ‘in themselves flat, and improper, and altogether unworthy of Virgil’; ‘in his ipsis miror qui factum sit ut Viri Doctissimi non agnouerint orationis uim et elegantiam’ ; ‘finding in them … all Virgil's usual ease and suavity … [we] hail those verses with joy, and reinstate them in their rightful … position as the commencing verses of the great Roman epic’ (...) ; ‘uersus praeclarissimos iniuria poeta abiudicauerunt editores plerique’. (shrink)

The distinction between propositional and doxastic justification has been of undisputed theoretical importance in a wide range of contemporary epistemological debates. Yet there are a host of intimately related issues that have rarely been discussed in connection with this distinction. For instance, the distinction not only applies to an individual’s beliefs, but also to group beliefs and to various other attitudes that both groups and individuals can take: credence, commitment, suspension, faith, and hope. Moreover, discussions of propositional and doxastic justification (...) have rarely focused on broader meta-epistemological issues, and yet meta-epistemological positions can have important implications for first-order views about this distinction. This volume addresses these and other issues by bringing together 16 essays that advance the state-of-the-art thinking on propositional and doxastic justification and explore how such thinking shapes and is shaped by a range of issues previously neglected in contemporary epistemology. (shrink)

Information can be public among a group. Whether or not information is public matters, for example, for accounts of interdependent rational choice, of communication, and of joint intention. A standard analysis of public information identifies it with (some variant of) common belief. The latter notion is stipulatively defined as an infinite conjunction: for p to be commonly believed is for it to believed by all members of a group, for all members to believe that all members believe it, and so (...) forth. This analysis is often presupposed without much argument in philosophy. Theoretical entrenchment or intuitions about cases might give some traction on the question, but give little insight about why the identification holds, if it does. The strategy of this paper is to characterize a practical-normative role for information being public, and show that the only things that play that role are (variants of) common belief as stipulatively characterized. In more detail: a functional role for “taking a proposition for granted” in non-isolated decision making is characterized. I then present some minimal conditions under which such an attitude is correctly held. The key assumption links this attitude to beliefs about what is public. From minimal a priori principles, we can argue that a proposition being public among a group entails common commitment to believe among that group. Later sections explore partial converses to this result, the factivity of publicity and publicity from the perspective of outsiders to the group, and objections to the aprioricity of the result deriving from a posteriori existential presuppositions. (shrink)

This paper presents evidence and arguments against an interpretation of david Hume's idea of history which insists that he held to a static conception of human nature. This interpretation presumes that hume lacks a genuine historical perspective, and that consequently his notion of historiography contains a fallacy (viz., Of the universal man). It is shown here that this interpretation overlooks an important distinction between methodological and substantive uniformity in hume's discussion of human nature and action. When this distinction is appreciated, (...) the above criticisms appear misrepresentative of hume's ideas of history, human nature, and their connection. A different interpretation of these concepts is then developed. (shrink)

What I call the Doxastic Puzzle, is the impression that while each of these claims seems true, at least one of them must be false: (a) Claims of the form ‘S ought to have doxastic attitude D towards p at t’ are sometimes true at t, (b) If Φ-ing at t is not within S’s effective control at t, then it is false, at t, that ‘S ought to Φ at t’, (c) For all S, p, and t, having doxastic (...) attitude D towards p at t is not within S’s effective control at t. All three natural replies to the puzzle have been pursued. Some have claimed that doxastic attitudes like believing that p are, in fact, within our effective control, or sufficiently so. Others have claimed that doxastic ought-claims, strictly speaking, are always false. And some have denied that effective control is required for the adequacy of doxastic ought-claims in general. I here pursue and examine a different strategy. In the first part of this paper, I argue that these claims are not only each true but actually not in tension with each other in the first place. Instead of attempting to dispel the puzzle, this solution proposes to evade it instead: to solve it by properly understanding, and by thereby accepting without contradiction, all of its constitutive claims. In the second part of the paper, I argue that the evasive strategy forces us to re-think our understanding of the place of normative reasons in epistemology. More exactly, it seems to come at the cost of one central way of thinking about our reasons for having doxastic attitudes, one where such reasons are good-standing exemplars of normative reasons in general. The evasive strategy, that is, threatens to lead us very quickly to a deflationary picture of epistemic normativity: it rescues normative talk, but sacrifices normative substance. I conclude by explaining why I think this is more consequential than some have made it out to be, and by suggesting that these consequences are welcome nonetheless. (shrink)