Receptor‐mediated stimulation induces massive actin polymerization and cyto‐skeletal reorganization. The activity of a potent actin‐modulating protein, gelsolin, is regulated both by Ca2+ and polyphos‐phoinositides, and it may have a pivotal role in restructuring the actin cytoskeleton in response to agonist stimulation. Structure‐function analysis of gelsolin has (1) indicated that its NH2‐terminal half is primarily responsible for modulating actin filament length and polymerization; and (2) elucidated mechanisms by which Ca2+ and phospholipids may regulate such functions. Gelsolin is functionally and structurally similar (...) to villin, another Ca2+‐activated actin‐severing protein found in microvilli, suggesting that gelsolin may be a prototype of this family of actin‐modulating proteins. A molecular variant of gelsolin is secreted and may be involved in the clearance of actin filaments released during tissue damage. The two forms of gelsolin are encoded by a single gene, and distinct messages are derived by alternative message splicing. (shrink)

This is a collection of essays on themes of legal philosophy which have all been generated or affected by Hart's work. The topics covered include legal theory, responsibility, and enforcement of morals, with contributions from Ronald Dworkin, Rolf Sartorius, Neil MacCormach, David Lyons, Kent Greenawalt, Michael Moore, Joseph Raz, and C.L. Ten, among others.

This classic collection of essays, first published in 1968, represents H.L.A. Hart's landmark contribution to the philosophy of criminal responsibility and punishment. Unavailable for ten years, this new edition reproduces the original text, adding a new critical introduction by John Gardner, a leading contemporary criminal law theorist.

In this field questions arise which are certainly difficult; but as I listened last time to members of the group, I felt that the main difficulty perhaps lay in determining precisely what questions we are trying to answer. I have the conviction that if we could only say clearly what the questions are, the answers to them might not appear so elusive. So I have begun with a simple list of questions about discretion which in one form or another were, (...) as it seemed to me, expressed by the group last time. I may indeed have omitted something and inserted something useless: if so, no doubt I shall be informed of this later. The central questions then seem to me to be the following: 1. What is discretion, or what is the exercise of discretion? 2. Under what conditions and why do we in fact accept or tolerate discretion in a legal system? 3. Must we accept discretion or tolerate discretion, and if so, why? 4. What values does the use of discretion menace, and what values does it maintain or promote? 5. What can be done to maximize the beneficial operation of the use of discretion and to minimize any harm that it does? (shrink)

H. L. A. Hart; The Presidential Address: I—Prolegomenon to the Principles of Punishment, Proceedings of the Aristotelian Society, Volume 60, Issue 1, 1 June 196.

In his introduction to these closely linked essays Professor Hart offers both an exposition and a critical assessment of some central issues in jurisprudence and political theory. Some of the essays touch on themes to which little attention has been paid, such as Bentham's identification of the forms of mysitification protecting the law from criticism; his relation to Beccaria; and his conversion to democratic radicalism and a passionate admiration for the United States.

A representation is a remnant of previous experience that allows that experience to affect later behavior. This paper develops a metatheoretical view of representation and applies it to issues concerning representation in animals. To describe a representational system one must specify the following: thedomainor range of situations in the represented world to which the system applies; thecontentor set of features encoded and preserved by the system; thecodeor transformational rules relating features of the representation to the corresponding features of the represented (...) world; themedium, or the representation's physical instantiation; and thedynamics, or how the system changes with time. In part because of the behaviorist assumption that the hypothetical, covert changes occurring in an organism during learning correspond to the overt physical changes that are observed, issues of representation in animal behavior have been largely ignored as irrelevant or misleading. However, it can be inferred that representations, acting as models of environmental regularities, operate at many levels of behavioral functioning, both cognitive and noncognitive. Objections to the use of this concept in explanations of animal behavior, based on the claim that it is indeterminate and on behaviorist considerations of parsimony, can be answered. Animal representations may be specialized in terms of tasks and species. Data from tasks involving spatial memory, delayed matching-to-sample, and sequence learning suggest some foundations for a general theory of animal representations. (shrink)

H. L. A. Hart; The Presidential Address: I—Prolegomenon to the Principles of Punishment, Proceedings of the Aristotelian Society, Volume 60, Issue 1, 1 June 196.

This book examines the legal and moral theory behind the law of evidence and proof, arguing that only by exploring the nature of responsibility in fact-finding can the role and purpose of much of the law be fully understood. Ho argues that the court must not only find the truth to do justice, it must do justice in finding the truth.

This incisive book deals with the use of the criminal law to enforce morality, in particular sexual morality, a subject of particular interest and importance since the publication of the Wolfenden Report in 1957. Professor Hart first considers John Stuart Mill's famous declaration: "The only purpose for which power can be rightfully exercised over any member of a civilized community is to prevent harm to others." During the last hundred years this doctrine has twice been sharply challenged by two great (...) lawyers: Sir James Fitzjames Stephen, the great Victorian judge and historian of the common law, and Lord Devlin, who both argue that the use of the criminal law to enforce morality is justified. The author examines their arguments in some detail, and sets out to demonstrate that they fail to recognize distinction of vital importance for legal and political theory, and that they espouse a conception of the function of legal punishment that few would now share. (shrink)

Hans-Georg Gadamer's contribution to hermeneutics can be summarized in a nut shell in his thesis that there is a “wirkungsgeschichtliche” dimension in all understanding. In this article I make four remarks on the meaning of this concept. Firstly: the universal claim of Gadamer does not claim to describe the totality of understanding, but only an essential and forgotten dimension. Secondly: there are three ascending perspectives on art, tradition and speaking that constitute together the Wirkungsgeschichte. Every one of them demonstrates that (...) understanding is not primarily an action of objectification, but a happening of participation. Thirdly: there are similar thinking patterns by different philosophers that demonstrate that Gadamer's concept of the Wirkungsgeschichte is not so new and strange. Lastly: Gadamer's use of Aristotle's concept of phronesis or judgement (practical reasoning) is the concretization of the Wirkungsgeschichte and his great contribution to hermeneutics. S. Afr. J. Philos. Vol.21(4) 2002: 274-290. (shrink)

Open peer commentary on the article “Constructivist Model Building: Empirical Examples From Mathematics Education” by Catherine Ulrich, Erik S. Tillema, Amy J. Hackenberg & Anderson Norton. Upshot: I concur with Ulrich et al. that second-order models can be powerful tools for investigating students’ mathematical learning. I argue for a role that a dynamic, learner-centered perspective on context could play in constructivist model building.