The End of Time?

I discuss J. Barbour's Machian theories of dynamics, and his proposal that a Machian perspective enables one to solve the problem of time in quantum geometrodynamics (by saying that there is no time). I concentrate on his recent book 'The End of Time' (1999).Comment: 48 pages Latex. A shortened version will appear in 'The British Journal for Philosophy of Science

Experience applicable to the Viking lander from a study of related space flight projects

Related space mission data for baseline evaluation of Viking Lander design and operatio

Macroevolution and macroecology through deep time

The fossil record documents two mutually exclusive macroevolutionary modes separated by the transitional Ediacaran Period. Despite the early appearance of crown eukaryotes and an at least partially oxygenated atmosphere, the pre-Ediacaran biosphere was populated almost exclusively by microscopic organisms exhibiting low diversity, no biogeographical partitioning and profound morphological/evolutionary stasis. By contrast, the post-Ediacaran biosphere is characterized by large diverse organisms, bioprovinciality and conspicuously dynamic macroevolution. The difference can be understood in terms of the unique escalatory coevolution accompanying the early Ediacaran introduction of eumetazoans, followed by their early Cambrian (Tommotian) expansion into the pelagic realm. Eumetazoans reinvented the rules of macroecology through their invention of multitrophic food webs, large body size, life-history trade-offs, ecological succession, biogeography, major increases in standing biomass, eukaryote-dominated phytoplankton and the potential for mass extinction. Both the pre-Ediacaran and the post-Ediacaran biospheres were inherently stable, but the former derived from the simplicity of superabundant microbes exposed to essentially static, physical environments, whereas the latter is based on eumetazoan-induced diversity and dynamic, biological environments. The c. 100-myr Ediacaran transition (extending to the base of the Tommotian) can be defined on evolutionary criteria, and might usefully be incorporated into the Phanerozoic

Drug checking to improve monitoring of new psychoactive substances in Australia

As has been reported previously in the Journal, 1 novel psychoactive stimulant drugs are now increasingly prevalent in patients presenting to hospital emergency departments. A further cluster of 11 patients showing confusing hallmarks of sympathomimetic poisoning but no identifiable substance presented to St Vincent ’ s Hospital in Sydney over a public holiday weekend in April 2015. Also, the start to the 2015 e 2016 summer festival season has included multiple deaths and hospitalisations following drug use at festivals, leading to calls for novel actions to protect public health. 2 Here, we take the opportunity to describe a method of harm minimisation that has been deployed in Europe and could potentially be deployed locally to tackle this problem. As has been reported previously in the Journal, 1 novel psychoactive stimulant drugs are now increasingly prevalent in patients presenting to hospital emergency departments. A further cluster of 11 patients showing confusing hallmarks of sympathomimetic poisoning but no identifiable substance presented to St Vincent ’ s Hospital in Sydney over a public holiday weekend in April 2015. Also, the start to the 2015 e 2016 summer festival season has included multiple deaths and hospitalisations following drug use at festivals, leading to calls for novel actions to protect public health. 2 Here, we take the opportunity to describe a method of harm minimisation that has been deployed in Europe and could potentially be deployed locally to tackle this problem

The Oxford Questions on the foundations of quantum physics

The twentieth century saw two fundamental revolutions in physics -- relativity and quantum. Daily use of these theories can numb the sense of wonder at their immense empirical success. Does their instrumental effectiveness stand on the rock of secure concepts or the sand of unresolved fundamentals? Does measuring a quantum system probe, or even create, reality, or merely change belief? Must relativity and quantum theory just co-exist or might we find a new theory which unifies the two? To bring such questions into sharper focus, we convened a conference on Quantum Physics and the Nature of Reality. Some issues remain as controversial as ever, but some are being nudged by theory's secret weapon of experiment.Comment: 8 page

Causation, Measurement Relevance and No-conspiracy in EPR

In this paper I assess the adequacy of no-conspiracy conditions employed in the usual derivations of the Bell inequality in the context of EPR correlations. First, I look at the EPR correlations from a purely phenomenological point of view and claim that common cause explanations of these cannot be ruled out. I argue that an appropriate common cause explanation requires that no-conspiracy conditions are re-interpreted as mere common cause-measurement independence conditions. In the right circumstances then, violations of measurement independence need not entail any kind of conspiracy (nor backwards in time causation). To the contrary, if measurement operations in the EPR context are taken to be causally relevant in a specific way to the experiment outcomes, their explicit causal role provides the grounds for a common cause explanation of the corresponding correlations.Comment: 20 pages, 1 figur