347,836 research outputs found
Value Pluralism and Consistency Maximisation in the Writings of Aldo Leopold: Moving Beyond Callicott's Interpretations of the Land Ethic
The 70th anniversary of Aldo Leopold’s A Sand County Almanac (1949) approaches.
For philosophers—environmental ethicists in particular—this text has been highly influential, especially the ‘Land Ethic’ essay contained therein. Given philosophers’ acumen for identifying and critiquing arguments, one might reasonably think a firm grasp of Leopold’s ideas to have emerged from such attention. I argue that this is not the case. Specifically, Leopold’s main interpreter and systematiser, philosopher J. Baird Callicott, has shoehorned Aldo Leopold’s ideas into differing monistic moral theories that ill-serve a proper understanding. Against Callicott, my paper argues that Aldo Leopold embraces a robust moral pluralism, one that goes beyond mere pragmatics, and he does so while seeking a consistency maximisation of values. A new, improved understanding of Leopold’s ideas thus emerges
Holographic Reconstruction and Renormalization in Asymptotically Ricci-flat Spacetimes
In this work we elaborate on an extension of the AdS/CFT framework to a
subclass of gravitational theories with vanishing cosmological constant. By
building on earlier ideas, we construct a correspondence between Ricci-flat
spacetimes admitting asymptotically hyperbolic hypersurfaces and a family of
conformal field theories on a codimension two manifold at null infinity. By
truncating the gravity theory to the pure gravitational sector, we find the
most general spacetime asymptotics, renormalize the gravitational action,
reproduce the holographic stress tensors and Ward identities of the family of
CFTs and show how the asymptotics is mapped to and reconstructed from conformal
field theory data. In even dimensions, the holographic Weyl anomalies identify
the bulk time coordinate with the spectrum of central charges with
characteristic length the bulk Planck length. Consistency with locality in the
bulk time direction requires a notion of locality in this spectrum.Comment: 44 pages, 4 figures. v2: minor changes in section
Conformal Field Theories, Graphs and Quantum Algebras
This article reviews some recent progress in our understanding of the
structure of Rational Conformal Field Theories, based on ideas that originate
for a large part in the work of A. Ocneanu. The consistency conditions that
generalize modular invariance for a given RCFT in the presence of various types
of boundary conditions --open, twisted-- are encoded in a system of integer
multiplicities that form matrix representations of fusion-like algebras. These
multiplicities are also the combinatorial data that enable one to construct an
abstract ``quantum'' algebra, whose - and -symbols contain essential
information on the Operator Product Algebra of the RCFT and are part of a cell
system, subject to pentagonal identities. It looks quite plausible that the
classification of a wide class of RCFT amounts to a classification of ``Weak
- Hopf algebras''.Comment: 23 pages, 12 figures, LateX. To appear in MATHPHYS ODYSSEY 2001
--Integrable Models and Beyond, ed. M. Kashiwara and T. Miwa, Progress in
Math., Birkhauser. References and comments adde
The development of the five mini-theories of self-determination theory: an historical overview, emerging trends, and future directions
Self-determination theory is a macro-theory of human motivation, emotion, and personality that has been under development for 40 years following the seminal work of Edward Deci and Richard Ryan. Self-determination theory (SDT; Deci & Ryan, 1985b, 2000; Niemiec, Ryan, & Deci, in press; Ryan & Deci, 2000; Vansteenkiste, Ryan, & Deci, 2008) has been advanced in a cumulative, research-driven manner, as new ideas have been naturally and steadily integrated into the theory following sufficient empirical support, which has helped SDT maintain its internal consistency. To use a metaphor, the development of SDT is similar to the construction of a puzzle. Over the years, new pieces have been added to the theory once their fit was determined. At present, dozens of scholars throughout the world continue to add their piece to the ‘‘SDT puzzle,’’ and hundreds of practitioners working with all age groups, and in various domains and cultures, have used SDT to inform their practice. Herein, we provide an historical overview of the development of the five mini-theories (viz., cognitive evaluation theory, organismic integration theory, causality orientations theory, basic needs theory, and goal content theory) that constitute SDT, discuss emerging trends within those mini-theories, elucidate similarities with and differences from other theoretical frameworks, and suggest directions for future researc
Symmetry of massive Rarita-Schwinger fields
We derive the general lagrangian and propagator for a vector-spinor field in
-dimensions and show that the physical observables are invariant under the
so-called point transformation symmetry. Until now the symmetry has not been
exploited in any non-trival way, presumably because it is not an invariance of
the classical action nor is it a gauge symmetry. Nevertheless, we develop a
technique for exploring the consequences of the symmetry leading to a conserved
vector current and charge. The current and charge are identically zero in the
free field case and only contribute in a background such as a electromagnetic
or gravitational field. The current can couple spin-3/2 fields to vector and
scalar fields and may have important consequences in intermediate energy hadron
physics as well as linearized supergravity. The consistency problem which
plagues higher spin field theories is then discussed and and some ideas
regarding the possiblity of solutions are presented.Comment: 26 pages, 1 figure; revised using referee comments, Journal ref.
adde
Between Philosophy and Art
Similarity and difference, patterns of variation, consistency and coherence: these are the reference points of the philosopher. Understanding experience, exploring ideas through particular instantiations, novel and innovative thinking: these are the reference points of the artist. However, at certain points in the proceedings of our Symposium titled, Next to Nothing: Art as Performance, this characterisation of philosopher and artist respectively might have been construed the other way around. The commentator/philosophers referenced their philosophical interests through the particular examples/instantiations created by the artist and in virtue of which they were then able to engage with novel and innovative thinking. From the artists’ presentations, on the other hand, emerged a series of contrasts within which philosophical and artistic ideas resonated. This interface of philosopher-artist bore witness to the fact that just as art approaches philosophy in providing its own analysis, philosophy approaches art in being a co-creator of art’s meaning. In what follows, we discuss the conception of philosophy-art that emerged from the Symposium, and the methodological minimalism which we employed in order to achieve it. We conclude by drawing out an implication of the Symposium’s achievement which is that a counterpoint to Institutional theories of art may well be the point from which future directions will take hold, if philosophy-art gains traction
Superstrings, Gauge Fields and Black Holes
There has been spectacular progress in the development of string and
superstring theories since its inception thirty years ago. Development in this
area has never been impeded by the lack of experimental confirmation. Indeed,
numerous bold and imaginative strides have been taken and the sheer elegance
and logical consistency of the arguments have served as a primary motivation
for string theorists to push their formulations ahead. In fact the development
in this area has been so rapid that new ideas quickly become obsolete. On the
other hand, this rapid development has proved to be the greatest hindrance for
novices interested in this area. These notes serve as a gentle introduction to
this topic. In these elementary notes, we briefly review the RNS formulation of
superstring theory, GSO projection, -branes, bosonic strings, dualities,
dynamics of -branes and the microscopic description of Bekenstein entropy of
a black hole.Comment: Lecture notes for talk delivered at NUS in 1997-1998. Some recent
updates added. The material may be somewhat outdated but it could still be
useful for physicists new to the fiel
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