Kent A. Peacock

RésuméCet article défend une approche à la philosophic et à l'éthique environnementale qui a originalement été avancée par Aldo Leopold. Selon cet auteur, l'éthique peut être comprise, d'un point de vue biologique, comme la forme spécifiquement humaine de la symbiose. La question cruciate de notre époque est de savoir si les humains peuvent coexister avec l'environnement global en un état de symbiose. La philosophie et les sciences humaines en général peuvent contribuer grandement à l'atteinte de ce but, à cause de la façon très spéciale dont le caractère même des actions et des æuvres humaines peut être amplifié par l'écosystème. Je critique un argument thermodynamique qui a été formulé contre la possibilité de la symbiose humaine; et je mets en garde contre les tendances à l'autoritarisme et è l'évasion par l'introspection qui sont typiques des cultures en état de crise écologique.

This paper is a report on the viability, both technical and ethical, of negative emissions technologies (NETs) in climate change mitigation. Given present levels of atmospheric carbon dioxide, NETs are almost certainly required in order to avoid the most serious consequences of anthropogenic carbonization. Critics argue that we should not rely on the promise of future NETs because that could be taken as an excuse to avoid decarbonization in the near term. The concern is genuine, but if the prima facie arguments for drawing down carbon as soon as possible are correct, ways must be found to counter the incentives to defer the immediate deployment of NETs and other forms of mitigation. A policy instrument is sketched which could help accomplish that task.

ABSTRACTJames Hansen and others have argued that climate scientists are often reluctant to speak out about extreme outcomes of anthropogenic carbonization. According to Hansen, such reticence lessens the chance of effective responses to these threats. With the collapse of the West Antarctic Ice Sheet as a case study, reasons for scientific reticence are reviewed. The challenges faced by scientists in finding the right balance between reticence and speaking out are both ethical and methodological. Scientists need a framework within which to find this balance. Such a framework can be found in the long-established practices of professional ethics.

James Hansen and others have argued that climate scientists are often reluctant to speak out about extreme outcomes of anthropogenic carbonization. According to Hansen, such reticence lessens the chance of effective responses to these threats. With the collapse of the West Antarctic Ice Sheet as a case study, reasons for scientific reticence are reviewed. The challenges faced by scientists in finding the right balance between reticence and speaking out are both ethical and methodological. Scientists need a framework within which to find this balance. Such a framework can be found in the long-established practices of professional ethics.

It continues to be alleged that superluminal in uences of any sort would be inconsistent with special relativity for the following three reasons: they would imply the existence of a ‘distinguished’ frame; they would allow the detection of absolute motion; and they would violate the relativity of simultaneity. This paper shows that the first two objections rest upon very elementary misunderstandings of Minkowski geometry and on lingering Newtonian intuitions about instantaneity. The third objection has a basis, but rather than invalidating the notion of faster-than-light influences it points the way to more general conceptions of simultaneity that could allow for quantum nonlocality in a natural way.

Suppose you woke up one morning having utterly forgotten what year it was, or, indeed, what century and what millennium it was, but with all your cognitive faculties otherwise intact. In particular, you remember that human population increases monotonically with time, implying that, in later years, there are far more positions you could be occupying in the whole set of all persons who have ever lived or will live. Then, John Leslie tells us, you will apply your knowledge of probability theory in a certain way and conclude that, whatever year you may be in, it is probable that it is uncomfortably close to the point at which the human species meets its quietus. You think, “My God, I’ve overslept and missed most of history.”

I present a thought experiment in quantum mechanics and tease out some of its implications for the doctrine of “peaceful coexistence”, which, following Shimony, I take to be the proposition that quantum mechanics does not force us to revise or abandon the relativistic picture of causality. I criticize the standard arguments in favour of peaceful coexistence on the grounds that they are question-begging, and suggest that the breakdown of Lorentz-invariant relativity as a principle theory would be a natural development, given the general trend of physics in this century.

It is generally believed that an invariant notion of a global present or "Now" cannot be defined in special relativity, because of the relativity of optical simultaneity. I argue that this may be a non sequitur since it is not necessarily the case that the psychological "Now" should be thought of as associated with constant time slices in spacetime. By considering a science fictional version of the Twin Paradox due to Robert A. Heinlein, I argue that it is psychologically plausible to associate the common specious present of several observers in relative motion with certain hypersurfaces of proper time of those observers corrected for acceleration history and relative motion in an obvious way. If this is correct then the relativity of optical simultaneity may be simply irrelevant to the question of the relativity of a globally distinguished "present".

This paper argues that fitness is most usefully understood as those properties of organisms that are explanatory of survival in the broadest sense, not merely descriptive of reproductive success. Borrowing from Rosenberg and Bouchard , fitness in this sense is ecological in that it is defined by the interactions between organisms and environments. There are three sorts of ecological fitness: the well-documented ability to compete, the ability to cooperate , and a third sense of fitness that has received insufficient attention in evolutionary theory, the ability to construct. Following Lotka, it can be understood thermodynamically as the ability to maintain or enlarge the energy-circulating capacity of an ecosystem. An organism that does this could end with its gene frequency unchanged but its probability of survival enhanced since it would sustain or increase the total carrying capacity of its ecosystem. Photosynthesizers and other autotrophs are obvious candidates for organisms that are fit in the constructive sense, but any organisms, including heterotrophs, can exhibit constructive fitness if they have some mechanism for channeling external flows of free energy into their ecosystems. I will briefly examine the prospects for the human species in the light of these considerations