Non-Reductive Safety

Safety principles in epistemology are often hailed as providing us with an explanation of why we fail to have knowledge in Gettier cases and lottery examples, while at the same time allowing for the fact that we know the negations of sceptical hypotheses. In a recent paper, Sinhababu and Williams have produced an example—the Backward Clock—that is meant to spell trouble for safety accounts of knowledge. I argue that the Backward Clock case is, in fact, unproblematic for the more sophisticated formulations of safety in the literature. However, I then proceed to construct two novel examples that turn out problematic for those formulations—one that provides us with a lottery-style case of safe ignorance and one that is a straightforward case of unsafe knowledge. If these examples succeed, then safety as it is usually conceived in the current debate cannot account for ignorance in all Gettier and lottery-style cases, and neither is it a necessary condition for knowledge. I conclude from these troublesome examples that modal epistemologists ought to embrace a much more simple and non-reductive version of safety, according to which the notion of similarity between possible worlds that determines in which worlds the subject must believe truly is an epistemic notion that cannot be defined or reduced to notions independent of knowledge. The resulting view is shown to also lead to desirable results with respect to lottery cases, certain quantum phenomena, and a puzzling case involving a cautious brain-in-a-vat

Conversational Implicatures (and How to Spot Them)

In everyday conversations we often convey information that goes above and beyond what we strictly speaking say: exaggeration and irony are obvious examples. H.P. Grice introduced the technical notion of a conversational implicature in systematizing the phenomenon of meaning one thing by saying something else. In introducing the notion, Grice drew a line between what is said, which he understood as being closely related to the conventional meaning of the words uttered, and what is conversationally implicated, which can be inferred from the fact that an utterance has been made in context. Since Grice’s seminal work, conversational implicatures have become one of the major research areas in pragmatics. This article introduces the notion of a conversational implicature, discusses some of the key issues that lie at the heart of the recent debate, and explicates tests that allow us to reliably distinguish between semantic entailments and conventional implicatures on the one hand and conversational implicatures on the other

Contextualism, Subject‐Sensitive Invariantism, and the Interaction of ‘Knowledge’‐Ascriptions with Modal and Temporal Operators

Jason Stanley has argued recently that Epistemic Contextualism and Subject‐Sensitive Invariantism are explanatorily on a par with regard to certain data arising from modal and temporal embeddings of ‘knowledge’‐ascriptions. This paper argues against Stanley that EC has a clear advantage over SSI in the discussed field and introduces a new type of linguistic datum strongly suggesting the falsity of SSI

Foundationalism and Coherentism From a Contextualist Point of View

Here is the picture classical foundationalism draws of empirical justification: Our system of beliefs is structured like a pyramid, it consists of a broad foundation of perceptual beliefs, i.e. beliefs reporting the contents of our perceptual states, and a superstructure of worldly beliefs, i.e. beliefs reporting what is going on in the world around us. The beliefs building the foundation, the perceptual beliefs, are to be justified noninferentially, by direct appeal to our perceptual experiences, while the beliefs in the superstructure, beliefs about what is going on in the world around us, are to be justified inferentially, i.e. by appeal to other beliefs. Ultimately, our worldly beliefs thus rest on our perceptual beliefs, which in turn draw upon our perceptual experiences

Statistical Evidence, Normalcy, and the Gatecrasher Paradox

Martin Smith has recently proposed, in this journal, a novel and intriguing approach to puzzles and paradoxes in evidence law arising from the evidential standard of the Preponderance of the Evidence. According to Smith, the relation of normic support provides us with an elegant solution to those puzzles. In this paper I develop a counterexample to Smith’s approach and argue that normic support can neither account for our reluctance to base affirmative verdicts on bare statistical evidence nor resolve the pertinent paradoxes. Normic support is, as a consequence, not a successful epistemic anti-luck condition

Gradability and Knowledge

Epistemic contextualism (‘EC’), the view that the truth-values of knowledge attributions may vary with the context of ascription, has a variety of different linguistic implementations. On one of the implementations most popular in the early days of EC, the predicate ‘knows p’ functions semantically similarly to gradable adjectives such as ‘flat’, ‘tall’, or ‘empty’. In recent work Jason Stanley and John Hawthorne have presented powerful arguments against such implementations of EC. In this article I briefly systematize the contextualist analogy to gradable adjectives, present Stanley’s argument against the analogy, and offer a contextualist response that abandons the analogy in favor of modeling the semantics of ‘knows p’ along the lines of quantifier expressions. I then present Hawthorne’s objection to the views presented, and finally conclude by outlining an argument to the effect that ‘knows p’ is an automatic indexical and as such to be expected to function differently from many other indexicals that the term has been compared to in the literature. I finally point out that no analogy should be expected to be perfect, and that no harm is done by postulating some unique behavior of ‘knows p’

The Pioneer Anomaly and a Rotating G\"odel Universe

Based upon a simple cosmological model with no expansion, we find that the rotational terms appearing in the G/"odel universe are too small to explain the Pioneer anomaly. Although it contributes, universal rotation is not the cause of the Pioneer effect.Comment: 13 pages, 2 figure

High purity silica reflective heat shield development

A hyperpure vitreous silica material is being developed for use as a reflective and ablative heat shield for planetary entry. Various purity grades and forms of raw materials were evaluated along with various processing methods. Slip casting of high purity grain was selected as the best processing method, resulting in a highly reflective material in the wavelength bands of interest (the visible and ultraviolet regions). The selected material was characterized with respect to optical, mechanical and physical properties using a limited number of specimens. The process has been scaled up to produce a one-half scale heat shield (18 in. dia.) (45.72 cm) for a Jupiter entry vehicle. This work is now being extended to improve the structural safety factor of the heat shield by making hyperpure silica material tougher through the addition of silica fibers

Ridesharing as an Alternative to Ambulance Transport for Voluntary Psychiatric Patients in the Emergency Department

Introduction: Emergency department (ED) crowding is a growing problem. Psychiatric patients have long ED lengths of stay awaiting placement and transportation to a psychiatric facility after disposition.Methods: Retrospective analysis of length of ED stay after disposition for voluntary psychiatric patients before and after the use of Lyft ridesharing services for inter-facility transport.Results: Using Lyft transport to an outside crisis center shortens time to discharge both statistically and clinically from 113 minutes to 91 minutes (p = 0.028) for voluntary psychiatric patients. Discharge time also decreased for involuntary patients from 146 minutes to 127 minutes (p = 0.0053).Conclusion: Ridesharing services may be a useful alternative to medical transportation for voluntary psychiatric patients