Complementarity, quantum erasure and delayed choice with modified Mach-Zehnder interferometers

Often cited dictums in Quantum Mechanics include "observation disturbance causes loss of interference" and "ignorance is interference". In this paper we propose and describe a series of experiments with modified Mach-Zehnder interferometers showing that one has to be careful when applying such dictums. We are able to show that without interacting in any way with the light quantum (or quanta) expected to behave "wave-like", interference fringes can be lost by simply gaining (or having the potential to gain) the which-path knowledge. Erasing this information may revive the interference fringes. Delayed choice can be added, arriving to an experiment in line with Wheeler's original proposal. We also show that ignorance is not always synonym with having the interference fringes. The often-invoked "collapse of the wavefunction" is found to be a non-necessary ingredient to describe our experiments.Comment: 8 pages, 3 figures; to appear in EPJ

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

Unreflective epistemology

Virtue epistemological accounts of knowledge claim that knowledge is a species of a broader normative category, to wit of success from ability. Fake Barn cases pose a difficult problem for such accounts. In structurally analogous but non-epistemic cases, the agents attain the relevant success from ability. If knowledge is just another form of success from ability, the pressure is on to treat Fake Barn cases as cases of knowledge. The challenge virtue epistemology faces is to explain the intuitive lack of knowledge in Fake Barn cases, whilst holding on to the core claim that knowledge is success from ability. Ernest Sosa's version of virtue epistemology promises to rise to this challenge. Sosa distinguishes two types of knowledge, animal knowledge and reflective knowledge. He argues that while animal knowledge is present in Fake Barn cases, reflective knowledge is absent and ventures to explain the intuition of ignorance by the absence of reflective knowledge. This paper argues that Sosa's treatment of Fake Barn cases fails as it commits Sosa to a number of highly counterintuitive results elsewhere in epistemology

The Jurisprudence of Willfulness: An Evolving Theory of Excusable Ignorance

Ignorantia legis non excusat-ignorance of the law does not excuse-is a centuries-old criminal law maxim familiar to lawyer and layperson alike. Under the doctrine, an accused finds little protection in the claim But, I did not know the law, for all are presumed either to be familiar with the law\u27s commands or to proceed in ignorance at their own peril. The ignorant must be punished along with the knowing, the maxim teaches, to achieve a better educated and more law-abiding populace and to avoid the easy-to-assert and difficult-to-dispute claim of ignorance that would otherwise flow from the lips of any person facing criminal punishment. Despite this country\u27s long-standing allegiance to the hoary maxim, over the last century, and in particular over the last decade, the courts have seriously eroded the ignorantia legis principle by frequently construing the mens rea term willfully to require proof of an accused\u27s knowledge of the law. The erosive effect that these constructions have had on the ignorantia legis maxim is referred to in this Article as the jurisprudence of willfulness. Professor Davies demonstrates that, contrary to the maxim, the number of federal criminal statutes that have been construed to impose such a heightened mens rea requirement is already quite large. The Article reveals that, if the courts continue to employ their current interpretive approach to the term willfully, at least 160 additional federal statutes containing the term are at risk of similar treatment. The author argues that contemporary constructions of the troublesome scienter term to impose a knowledge of the law element have been grounded on doubtful, unchallenged logic and have bequeathed a legacy of grave interpretive confusion. Professor Davies maintains that much of the jurisprudence of willfulness is inimical to congressional judgments and, therefore, violative of rule of law and separation of powers principles. The Article urges a return to the ignorantia legis principle in all cases in which a clear legislative intent to abandon the maxim when employing the term willfully is missing

Forecasting the fast and frugal way: A study of performance and information-processing strategies of experts and non-experts when predicting the World Cup 2002 in soccer

This paper investigates forecasting performance and judgmental processes of experts and non-experts in soccer. Two circumstances motivated the paper: (i) little is known about how accurately experts predict sports events, and (ii) recent research on human judgment suggests that ignorance-based decision-strategies may be reliable. About 250 participants with different levels of knowledge of soccer took part in a survey and predicted the outcome of the first round of World Cup 2002. It was found that the participating experts (i.e., sport journalists, soccer fans, and soccer coaches) were not more accurate than the non-experts. Experts overestimated their performance and were overconfident. While the experts claimed to have relied on analytical approaches and much information, participants with limited knowledge stated that their forecasts were based upon recognition and few pieces of information. The paper concludes that a recognition-based strategy seems to be appropriate when forecasting worldwide soccer events.Expert predictions; Information use; Judgmental forecasting; Overconfidence; Recognition heuristic; Sports forecasting

Lucky Ignorance, Modality and Lack of Knowledge

I argue against the Standard View of ignorance, according to which ignorance is defined as equivalent to lack of knowledge, that cases of environmental epistemic luck, though entailing lack of knowledge, do not necessarily entail ignorance. In support of my argument, I contend that in cases of environmental luck an agent retains what I call epistemic access to the relevant fact by successfully exercising her epistemic agency and that ignorance and non-ignorance, contrary to what the Standard View predicts, are not modal in the sense that knowledge is. After responding to objections, I conclude by sketching an alternative account of ignorance centered on the notions of epistemic access and epistemic agency

Google Search and the creation of ignorance: The case of the climate crisis

The article examines the relationship between commercial search engines, using Google Search as an example, and various forms of ignorance related to climate change. It draws on concepts from the field of agnotology to explore how environmental ignorances, and specifically related to the climate crisis, are shaped at the intersection of the logics of Google Search, everyday life and civil society/politics. Ignorance refers to a multi-facetted understanding of the culturally contingent ways in which something may not be known. Two research questions are addressed: How are environmental ignorances, and in particular related to the climate crisis, shaped at the intersection of the logics of Google Search, everyday life and civil society/politics? In what ways can we conceptualise Google's role as configured into the creation of ignorances? The argument is made through four vignettes, each of which explores and illustrates how Google Search is configured into a different kind of socially produced ignorance: (1) Ignorance through information avoidance: climate anxiety; (2) Ignorance through selective choice: gaming search terms; (3) Ignorance by design: algorithmically embodied emissions; (4) Ignorance through query suggestions: directing people to data voids. The article shows that while Google Search and its underlying algorithmic and commercial logic pre-figure these ignorances, they are also co-created and co-maintained by content producers, users and other human and non-human actors, as Google Search has become integral of social practices and ideas about them. The conclusion draws attention to a new logic of ignorance that is emerging in conjunction with a new knowledge logic

Soul Substance (jīva dravya) – As Expounded In Dravyasamgraha

Soul substance (jīva dravya) is ubiquitous but unseen. Driving force within each one of us, it has been, since time immemorial, a subject matter of research by philosophers, religious leaders and laity. Still, ambiguity and misconceptions prevail as regard its real nature. Some negate the existence of soul and attribute consciousness to the union of four basic substances – earth (prthvī), water (jala), fire (agni), and air (vāyu); death leads to its annihilation. Some believe it to be momentary, devoid of self-existence. Still others consider it a product of illusion (māyā) or ignorance (avidyā) as all objects are manifestations of Brahma; only the one eternally undivided Brahma exists. All such conceptions are based on absolutism like: existence (bhāvaikānta) and non-existence (abhāvaikānta), non-dualism (advaita-ekānta) and separateness (prthaktva-ekānta), and permanence (nityatva-ekānta) and momentariness (ksanika-ekānta). Jaina epistemology goes beyond the superficial and examines objects of knowledge from all possible points of view. It asserts that the entity (dharmī) and its attributes (dharma) are neither absolutely dependent (āpeksika) nor absolutely independent (anāpeksika). Only an entity which has general (sāmānya – concerning the substance, dravya) and particular (viśesa – concerning the mode, paryāya) attributes can be the subject of knowledge. Substance without its modification and modification without its substance cannot be the subject of valid knowledge; only their combination can be the subject of knowledge

When Knowledge is not Enough: HIV/AIDS Information and Risky Behavior in Botswana

The spread of the HIV/AIDS epidemic is still fueled by ignorance in many parts of the world. Filling in knowledge gaps, particularly between men and women, is considered key to preventing future infections and to reducing female vulnerabilities to the disease. However, such knowledge is arguably only a necessary condition for targeting these objectives. In this paper, we describe the extent to which HIV/AIDS knowledge is correlated with less risky sexual behavior. We ask: even when there are no substantial knowledge gaps between men and women, do we still observe sex-specific differentials in sexual behavior that would increase vulnerability to infection? We use data from two recent household surveys in Botswana to address this question. We show that even when men and women have very similar types of knowledge, they have different probabilities of reporting safe sex. Our findings are consistent with the existence of non-informational barriers to behavioral change, some of which appear to be sex-specific. The descriptive exercise in this paper suggests that it may be overly optimistic to hope for reductions in risky behavior through the channel of HIV-information provision alone.