Relativistic Constraints for a Naturalistic Metaphysics of Time

The traditional metaphysical debate between static and dynamic views in the philosophy of time is examined in light of considerations concerning the nature of time in physical theory. Adapting the formalism of Rovelli (1995, 2004), I set out a precise framework in which to characterise the formal structure of time that we find in physical theory. This framework is used to provide a new perspective on the relationship between the metaphysics of time and the special theory of relativity by emphasising the dual representations of time that we find in special relativity. I extend this analysis to the general theory of relativity with a view to prescribing the constraints that must be heeded for a metaphysical theory of time to remain within the bounds of a naturalistic metaphysics

Quantum causal models, faithfulness and retrocausality

Wood and Spekkens (2015) argue that any causal model explaining the EPRB correlations and satisfying no-signalling must also violate the assumption that the model faithfully reproduces the statistical dependences and independences---a so-called "fine-tuning" of the causal parameters; this includes, in particular, retrocausal explanations of the EPRB correlations. I consider this analysis with a view to enumerating the possible responses an advocate of retrocausal explanations might propose. I focus on the response of N\"{a}ger (2015), who argues that the central ideas of causal explanations can be saved if one accepts the possibility of a stable fine-tuning of the causal parameters. I argue that, in light of this view, a violation of faithfulness does not necessarily rule out retrocausal explanations of the EPRB correlations, although it certainly constrains such explanations. I conclude by considering some possible consequences of this type of response for retrocausal explanations

Mercury in Florida Bay fish: spatial distribution of elevated concentrations and possible linkages to Everglades restoration

Health advisories are now posted in northern Florida Bay, adjacent to the Everglades, warning of high mercury concentrations in some species of gamefish. Highest concentrations of mercury in both forage fish and gamefish have been measured in the northeastern corner of Florida Bay, adjacent to the dominant freshwater inflows from the Everglades. Thirty percent of spotted seatrout (Cynoscion nebulosus Cuvier, 1830) analyzed exceeded Florida’s no consumption level of 1.5 μg g−1 mercury in this area. We hypothesized that freshwater draining the Everglades served as the major source of methylmercury entering the food web supporting gamefish. A lack of correlation between mercury concentrations and salinity did not support this hypothesis, although enhanced bioavailability of methylmercury is possible as freshwater is diluted with estuarine water. Stable isotopes of carbon, nitrogen, and sulfur were measured in fish to elucidate the shared pathways of methylmercury and nutrient elements through the food web. These data support a benthic source of both methylmercury and nutrient elements to gamefish within the eastern bay, as opposed to a dominant watershed source. Ecological characteristics of the eastern bay, including active redox cycling in near-surface sediments without excessive sulfide production are hypothesized to promote methylmercury formation and bioaccumulation in the benthos. Methylmercury may then accumulate in gamefish through a food web supported by benthic microalgae, detritus, pink shrimp (Farfantepenaeus duorarum Burkenroad, 1939), and other epibenthic feeders. Uncertainty remains as to the relative importance of watershed imports of methylmercury from the Everglades and in situ production in the bay, an uncertainty that needs resolution if the effects of Everglades restoration on mercury levels in fish are to be modeled and managed

Vision and Reading Difficulties Part 5: Clinical protocol and the role of the eye-care practitioner

This series of articles has described various aspects of visual characteristics of reading difficulties and the background behind techniques such as the use of coloured filters in helping to reduce the difficulties that are experienced. The present article, which is the last in series, aims to describe a clinical protocol that can be used by the busy eye care practitioner for the investigation and management of such patients. It also describes the testing techniques that can be used for the various assessments. Warning: DO NOT LOOK AT FIGURE 7 IF YOU HAVE MIGRAINE OR EPILEPSY

Vision and Reading Difficulties Part 4: Coloured filters - how do they work?

This article is the fourth in a series of five about vision and reading difficulties. The first article provided a general overview and the second covered conventional optometric correlates of reading difficulties (e.g. binocular vision problems). The present article continues on from the third article by describing the use of coloured filters in treating a condition now known as visual stress. Visual stress is often associated with reading difficulties, but also a variety of other neurological conditions. This article concentrates on the possible mechanisms for the benefit from coloured filters, beginning with obvious peripheral factors. The terminology for this condition has changed over the years (e.g. Scotopic Sensitivity Syndrome, and Meares-Irlen Syndrome) and the issue of terminology is discussed at the end of this article. Warning: DO NOT LOOK AT FIGURE 6 ON PAGE 33 IF YOU HAVE A MIGRAINE OR EPILEPSY

Vision and Reading Difficulties Part 1: Specific learning difficulties and vision

This article is the first in a series of five about vision and reading difficulties, and provides an introduction and an overview of learning disabilities and specific learning difficulties. It outlines the role of the optometrist in helping people with such problems; it describes the symptoms that optometrists should look for and it provides an introduction of the evidence-based approach. The second article in this series will cover the optometric and orthoptic correlates of reading difficulties. Articles three and four will describe the use of coloured filters, including background, techniques, evidence, and mechanism. The final article will draw together the themes in the series of articles and discuss the clinical protocol and the role of the eye care practitioner in managing visual factors associated with reading difficulties

Vision and Reading Difficulties Part 3: Coloured filters - do they work?

This is the third article in a series of five on Vision and Reading Difficulties. The first article provided a general overview of learning disabilities and specific learning difficulties (SpLD). It outlined the role of the optometrist in helping people with SpLD. The second article covered conventional optometric correlates of reading difficulties (e.g. binocular vision problems) This article and the next will describe the use of coloured filters to treat a condition now know as "visual stress", which is often associated with reading difficulties; the symptoms of visual stress were described in Part 1. The terminology for this condition has changed over the years (e.g. Scotopic Sensitivity syndrome, Meares-Irlen syndrome). Terminology is discussed more in Part 4

Perspectival Objectivity or: How I Learned to Stop Worrying and Love Observer-Dependent Reality

Building on self-professed perspectival approaches to both scientific knowledge and causation, I explore the potentially radical suggestion that perspectivalism can be extended to account for a type of objectivity in science. Motivated by recent claims from quantum foundations that quantum mechanics must admit the possibility of observer-dependent facts, I develop the notion of 'perspectival objectivity', and suggest that an easier pill to swallow, philosophically speaking, than observer-dependency is perspective-dependency, allowing for a notion of observer-independence indexed to an agent perspective. Working through the case studies of colour perception and causal perspectivalism, I identify two places within which I claim perspectival objectivity is already employed, and make the connection to quantum mechanics through Bohr's philosophy of quantum theory. I contend that perspectival objectivity can ensure, despite the possibility of perspective-dependent scientific facts, the objectivity of scientific inquiry