Sahlqvist formulas are a syntactically specified class of modal formulas proposed by Hendrik Sahlqvist in 1975. They are important because of their first-order definability and canonicity, and hence axiomatize complete modal logics. The first-order properties definable by Sahlqvist formulas were syntactically characterized by Marcus Kracht in 1993. The present paper extends Kracht's theorem to the class of ‘generalized Sahlqvist formulas' introduced by Goranko and Vakarelov and describes an appropriate generalization of Kracht formulas.

In the propositional modal treatment of two-variable first-order logic equality is modelled by a ‘diagonal’ constant, interpreted in square products of universal frames as the identity relation. Here we study the decision problem of products of two arbitrary modal logics equipped with such a diagonal. As the presence or absence of equality in two-variable first-order logic does not influence the complexity of its satisfiability problem, one might expect that adding a diagonal to product logics in general is similarly harmless. We (...) show that this is far from being the case, and there can be quite a big jump in complexity, even from decidable to the highly undecidable. Our undecidable logics can also be viewed as new fragments of first-order logic where adding equality changes a decidable fragment to undecidable. We prove our results by a novel application of counter machine problems. While our formalism apparently cannot force reliable counter machine computations directly, the presence of a unique diagonal in the models makes it possible to encode both lossy and insertion-error computations, for the same sequence of instructions. We show that, given such a pair of faulty computations, it is then possible to reconstruct a reliable run from them. (shrink)

Digital technologies can be an asset to serving communities and societies through data analytics and management to achieve greater good. However, care must be exercised in that societies without digital access do not get overlooked or, worse, face abuses of privacy disclosure or exploitation. Regulations exist to prevent this happening, but ethical considerations are important in deciding in what is allowable and what is not. The further risk of artificial intelligence where computers start to make autonomous decisions and the vulnerabilities (...) we are exposed to is considered. Steps are proposed to develop an ethics-based digital strategy and how to mitigate cyber risk. (shrink)

The globalization in business and tourism becomes crucial more and more for the economical sustainability of local communities. In the presence of an epidemic outbreak, there must be such a decision on the policy by the host community as whether to accept visitors or not, the number of acceptable visitors, or the condition for acceptable visitors. Making use of an SIRI type of mathematical model, we consider the influence of visitors on the spread of a reinfectious disease in a community, (...) especially assuming that a certain proportion of accepted visitors are immune. The reinfectivity of disease here means that the immunity gained by either vaccination or recovery is imperfect. With the mathematical results obtained by our analysis on the model for such an epidemic dynamics of resident and visitor populations, we find that the acceptance of visitors could have a significant influence on the disease’s endemicity in the community, either suppressive or supportive. (shrink)

Sociology has largely followed Durkheim’s lead in ignoring the question: why do people die by suicide? This negation prioritizes a positivist, structuralist approach and stymies sociology’s contribution by closing off a wide range of tools sociologists might employ. An interpretivist turn in suicide studies accompanied by the growing adoption of qualitative methodology has opened up an array of opportunities to produce insights lost in a Durkheimian approach, but has yet to confront their own weaknesses. This paper shows we need not (...) abandon either tradition, advocating for a third path that integrates the strengths of both approaches. (shrink)

The first major work in the history of philosophy to bear the title "Metaphysics" was the treatise by Aristotle that we have come to know by that name. But Aristotle himself did not use that title or even describe his field of study as 'metaphysics'; the name was evidently coined by the first century C.E. editor who assembled the treatise we know as Aristotle's Metaphysics out of various smaller selections of Aristotle's works. The title 'metaphysics' -- literally, 'after the Physics' (...) -- very likely indicated the place the topics discussed therein were intended to occupy in the philosophical curriculum. They were to be studied after the treatises dealing with nature (ta phusika). In this entry, we discuss the ideas that are developed in Aristotle's treatise. (shrink)

Our concern is the completeness problem for spi-logics, that is, sets of implications between strictly positive formulas built from propositional variables, conjunction and modal diamond operators. Originated in logic, algebra and computer science, spi-logics have two natural semantics: meet-semilattices with monotone operators providing Birkhoff-style calculi and first-order relational structures (aka Kripke frames) often used as the intended structures in applications. Here we lay foundations for a completeness theory that aims to answer the question whether the two semantics define the same (...) consequence relations for a given spi-logic. (shrink)

Geoffrey Rose’s prevention paradox points to a tension between two prima facie plausible moral principles: that we should save the greater number and that weshould save the most at risk. This paper argues that a novel moral theory, ex-ante contractualism, captures our intuitions in many prevention paradox cases, regardless of our interpretation of probability claims. However, it goes on to show that it might be impossible to square ex-ante contractualism with all of our moral intuitions. It concludes that even if (...) ex-ante contractualism cannot furnish an entire ethics of risk, it does identify important considerations for any such theory. (shrink)

Geoffrey Rose’s prevention paradox points to a tension between two prima facie plausible moral principles: that we should save the greater number and that weshould save the most at risk. This paper argues that a novel moral theory, ex-ante contractualism, captures our intuitions in many prevention paradox cases, regardless of our interpretation of probability claims. However, it goes on to show that it might be impossible to square ex-ante contractualism with all of our moral intuitions. It concludes that even if (...) ex-ante contractualism cannot furnish an entire ethics of risk, it does identify important considerations for any such theory. (shrink)

Sebastian Gardner competently tackles one of Sartre's more complex and challenging works in this new addition to the Reader's Guides series.

In the Ukrainian-Russian relations, especially in pre-revolutionary times, the religious component played an important role. The attitude of the Russian authorities toward Southwest Russia was shaped by the influence of several conceptions made in the church circles, which also significantly influenced the formation of Russian national identity.

Our study presents an overview of the issues that were brought forward by participants of a moral case deliberation (MCD) project in two elderly care organizations. The overview was inductively derived from all case descriptions (N = 202) provided by participants of seven mixed MCD groups, consisting of care providers from various professional backgrounds, from nursing assistant to physician. The MCD groups were part of a larger MCD project within two care institutions (residential homes and nursing homes). Care providers are (...) confronted with a wide variety of largely everyday ethical issues. We distinguished three main categories: ‘resident’s behavior’, ‘divergent perspectives on good care’ and ‘organizational context’. The overview can be used for agendasetting when institutions wish to stimulate reflection and deliberation. It is important that an agenda is constructed from the bottom-up and open to a variety of issues. In addition, organizing reflection and deliberation requires effort to identify moral questions in practice whilst at the same time maintaining the connection with the organizational context and existing communication structures. Once care providers are used to dealing with divergent perspectives, inviting different perspectives (e.g. family members) to take part in the deliberation, might help to identify and address ethical ‘blind spots’. (shrink)

This is a comment to Graham Harman’s 2019 response to an article by Þóra Pétursdóttir and Bjørnar Olsen (2018) in which they propose that a materially grounded, archaeological perspective might complement Harman’s historical approach in Immaterialism (2016). Harman responds that his book is indeed already more archaeological than historical, stipulating that history is the study of media with a high density of information, whereas archaeology studies media with a low density of information. History, Harman holds, ends up in too much (...) detail, while archaeology has the advantage of lending itself to the imagination. Hence, his reading of history had the aim of tempering the historical information overload, in effect making the book a work of archaeology. In this comment, I want to do three things: (1) critique the idea that archaeological and historical media are inherently different with regard to their densities of information, (2) discuss how archaeology and history approach their media, and (3) reflect on conceptualisations of “archaeology” outside the discipline itself. (shrink)

Plato’s dialogue Cratylus focuses on being and human dependence on words, or the essential truths about the human condition. Arguing that comedy is an essential part of Plato's concept of language, S. Montgomery Ewegen asserts that understanding the comedic is key to an understanding of Plato's deeper philosophical intentions. Ewegen shows how Plato’s view of language is bound to comedy through words and how, for Plato, philosophy has much in common with playfulness and the ridiculous. By tying words, language, and (...) our often uneasy relationship with them to comedy, Ewegen frames a new reading of this notable Platonic dialogue. (shrink)

Nearly as famous as his denial of the existence of matter is Berkeley's insistence that his philosophy is somehow a defense of commonsense. This is most often taken to mean that Berkeley thinks of his philosophy as supporting commonsense beliefs. However, the inadequacies of such views have persuaded some to disregard entirely Berkeley's claims about commonsense. Both readings are undesirable. Extant interpretations misunderstand the relationship between Berkeley's philosophy and commonsense. In this paper, I present a new account of how to (...) understand Berkeley's so-called defense of commonsense; it is not a defense-cum­-apology for commonsense beliefs, but a defensive attack against a skeptical threat. I then examine two rival accounts of the defense of commonsense and show how each fails to satisfy the criteria for a successful account. Finally, I briefly address the implications this view has for future scholarship. (shrink)

V. 1. Journals AA-DD -- v. 2. Journals EE-KK -- v. 3. Notebooks 1-15 -- v. 4. Journals NB-NB5.