Geoengineering and Non-Ideal Theory

The strongest arguments for the permissibility of geoengineering (also known as climate engineering) rely implicitly on non-ideal theory—roughly, the theory of justice as applied to situations of partial compliance with principles of ideal justice. In an ideally just world, such arguments acknowledge, humanity should not deploy geoengineering; but in our imperfect world, society may need to complement mitigation and adaptation with geoengineering to reduce injustices associated with anthropogenic climate change. We interpret research proponents’ arguments as an application of a particular branch of non-ideal theory known as “clinical theory.” Clinical theory aims to identify politically feasible institutions or policies that would address existing (or impending) injustice without violating certain kinds of moral permissibility constraints. We argue for three implications of clinical theory: First, conditional on falling costs and feasibility, clinical theory provides strong support for some geoengineering techniques that aim to remove carbon dioxide from the atmosphere. Second, if some kinds of carbon dioxide removal technologies are supported by clinical theory, then clinical theory further supports using those technologies to enable “overshoot” scenarios in which developing countries exceed the cumulative emissions caps that would apply in ideal circumstances. Third, because of tensions between political feasibility and moral permissibility, clinical theory provides only weak support for geoengineering techniques that aim to manage incoming solar radiation

Morgan-Morgan-NUT disk space via the Ehlers transformation

Using the Ehlers transformation along with the gravitoelectromagnetic approach to stationary spacetimes we start from the Morgan-Morgan disk spacetime (without radial pressure) as the seed metric and find its corresponding stationary spacetime. As expected from the Ehlers transformation the stationary spacetime obtained suffers from a NUT-type singularity and the new parameter introduced in the stationary case could be interpreted as the gravitomagnetic monopole charge (or the NUT factor). As a consequence of this singularity there are closed timelike curves (CTCs) in the singular region of the spacetime. Some of the properties of this spacetime including its particle velocity distribution, gravitational redshift, stability and energy conditions are discussed.Comment: 18 pages, 5 figures, RevTex 4, replaced with the published versio

An infinite family of magnetized Morgan-Morgan relativistic thin disks

Applying the Horsk\'y-Mitskievitch conjecture to the empty space solutions of Morgan and Morgan due to the gravitational field of a finite disk, we have obtained the corresponding solutions of the Einstein-Maxwell equations. The resulting expressions are simply written in terms of oblate spheroidal coordinates and the solutions represent fields due to magnetized static thin disk of finite extension. Now, although the solutions are not asymptotically flat, the masses of the disks are finite and the energy-momentum tensor agrees with the energy conditions. Furthermore, the magnetic field and the circular velocity show an acceptable physical behavior.Comment: Submitted to IJTP. This paper is a revised and extended version of a paper that was presented at arXiv:1006.203

Stone-type representations and dualities for varieties of bisemilattices

In this article we will focus our attention on the variety of distributive bisemilattices and some linguistic expansions thereof: bounded, De Morgan, and involutive bisemilattices. After extending Balbes' representation theorem to bounded, De Morgan, and involutive bisemilattices, we make use of Hartonas-Dunn duality and introduce the categories of 2spaces and 2spaces$^{\star}$. The categories of 2spaces and 2spaces$^{\star}$ will play with respect to the categories of distributive bisemilattices and De Morgan bisemilattices, respectively, a role analogous to the category of Stone spaces with respect to the category of Boolean algebras. Actually, the aim of this work is to show that these categories are, in fact, dually equivalent

Building a Science of Animal Minds: Lloyd Morgan, Experimentation, and Morgan’s Canon

Conwy Lloyd Morgan (1852–1936) is widely regarded as the father of modern comparative psychology. Yet, Morgan initially had significant doubts about whether a genuine science of comparative psychology was even possible, only later becoming more optimistic about our ability to make reliable inferences about the mental capacities of non-human animals. There has been a fair amount of disagreement amongst scholars of Morgan’s work about the nature, timing, and causes of this shift in Morgan’s thinking. We argue that Morgan underwent two quite different shifts of attitude towards the proper practice of comparative psychology. The first was a qualified acceptance of the Romanesian approach to comparative psychology that he had initially criticized. The second was a shift away from Romanes’ reliance on systematizing anecdotal evidence of animal intelligence towards an experimental approach, focused on studying the development of behaviour. We emphasize the role of Morgan’s evolving epistemological views in bringing about the first shift – in particular, his philosophy of science. We emphasize the role of an intriguing but overlooked figure in the history of comparative psychology in explaining the second shift, T. Mann Jones, whose correspondence with Morgan provided an important catalyst for Morgan’s experimental turn, particularly the special focus on development. We also shed light on the intended function of Morgan’s Canon, the methodological principle for which Morgan is now mostly known. The Canon can only be properly understood by seeing it in the context of Morgan’s own unique experimental vision for comparative psychology

De Morgan classifying toposes

We present a general method for deciding whether a Grothendieck topos satisfies De Morgan's law (resp. the law of excluded middle) or not; applications to the theory of classifying toposes follow. Specifically, we obtain a syntactic characterization of the class of geometric theories whose classifying toposes satisfy De Morgan's law (resp. are Boolean), as well as model-theoretic criteria for theories whose classifying toposes arise as localizations of a given presheaf topos.Comment: 37 page

The teaching and learning research programme (TLRP) in Wales: research evidence for educational policy and practice in Wales

Alex Morgan and Jane Waters, Swansea University; Jane Williams