To promise someone to do something is to commit oneself to that person to do that thing, but what does that commitment consist of? Some think a promissory commitment is an obligation to do what’s promised, and that while promising practices facilitate the creation of promissory obligations, they are not essential to them. I favor the broadly Humean view in which, when it comes to promises (and so promissory obligations), practices are of the essence. I propose the Practice Reason Account (...) of promises, according to which a promise is basically to give oneself a self-interested practice reason to do what’s promised. One achieves this feat by invoking self-enforcing independent practice rules thanks to which one’s doing what’s promised preserves one’s promissory trust(worthiness) and promising power. However, nothing in this account supports the Hume-Rawls claim that promise-keeping or promise-breaking is right just when and because it conforms to practice rules that are justified by their good- or right-making properties. (shrink)

This article offers a refutation of the corrective justice interpretation of tort law – the view that it is essentially a system of corrective justice. It introduces a distinction between primary and secondary tort duties and claims that tort law is best understood as the union of its primary and secondary duties. It then advances two independent criticisms of the corrective justice interpretation. The article first argues that primary tort duties have nothing fundamentally to do with corrective justice and that, (...) if one understands what is meant by ``primary tort duties,'' one is compelled to regard this fact as a decisive objection to the corrective justice interpretation. Second, it argues that, whatever relation there is between secondary tort duties and corrective justice, that relation also holds between corrective justice and secondary duties of other legal branches. In sum, the concept of corrective justice is neither capable of unifying tort law nor of demarcating it from other legal branches.The article also offers a general alternative interpretation of tort law. Rather than being essentially corrective, tort law is essentially protective. Under this picture, if tort law has a most important point, it is the protection of legal subjects and valuable social interests from harm. This is the overarching ambition that unifies primary and secondary tort duties. It does not, however, demarcate tort law from other legal branches. (shrink)

This volume, which comprises sixteen original contributions, is the first collection of philosophical papers on promises and agreements - topics enjoying a renaissance in social, moral, and legal philosophy.

Justice, you might think, is the first virtue of the law. After all, we call our judges justices, the administration of law the administration of justice, and the government's legal department the Justice Department. We should reject this Priority of Justice for the Law in favor of the more moderate Priority of Justice for the Courts, the view that justice is the first virtue of the law courts. Under its comparative conception, justice is distinguishable by its concern with the relative (...) positions of subjects. I claim that legal duties divide into primary and secondary, that primary legal duties are not essentially comparative, and that this impugns the Priority of Comparative Justice for the Law. Still, the bipolar structure of litigation appears to suggest that comparative justice is the first virtue of the courts. I explain why that is not so. I then introduce a desert-based conception of justice I dub requitative justice. I argue that the Priority of Justice for the Law cannot draw succor from this conception of justice because primary legal duties are no more requitative than they are comparative. However, the special affinity between law courts and secondary legal duties suggests that requitative justice is the first virtue of the courts. Finally, I concede that the Priority of Justice for the Courts gives us reason to accept the Priority of Justice for the Law after all, if we accept the common Priority of Courts for the Law, the view that the courts are the first institution of the law. We should not do so, however. (shrink)

Unrejectability is the property shared by things no one could reasonably reject. Following the lead of T. M. Scanlon, modern contractualists hold Principle Contractualism: An act is obligatory when conformity to unrejectable principles requires its performance. This article entertains Act Contractualism: An act is obligatory when its performance is unrejectable. The article hypothesizes that Principle Contractualism owes its initial plausibility to the assumption that following it somehow realizes unrejectability, if only indirectly. The article then argues that, whereas following Act Contractualism (...) realizes unrejectability, following Principle Contractualism realizes a convoluted, principle-mediated, non-causal conformity relation between acts and unrejectability. But then the notion that this relation is what matters ultimately in action does not seem to enjoy independent plausibility. After interrogating Scanlon's objection that the challenge to the principle-based nature of contractualism is , I conclude that Act Contractualism is the more fitting contractualist theory of obligation. (shrink)

Developments in contract law over the past century have led to the proliferation of interpretive theories according to which contract law is no longer a sui generisi legal branch. It is widely accepted that if there is a sui generis contractual obligation, it must somehow be based on the wills of the parties. But a new orthodoxy in contract theory claims that the role of the will of the parties in contract law has been progressively shrinking due to judicial doctrines (...) within the law of contract and also to general statutory provisions. It is no longer apparent that there is any interesting sense in which contractual liability is based on the will of the parties. Hence, so it is claimed, contract law has lost its sui generis nature. The article challenges this new orthodoxy. But rather than reverting to the old orthodoxy—the will theory of contracts (or its contemporary rendition, contract as promise)—it argues that we should resist being forced to choose between them. The article argues that the purpose of contractual liability is to support the practice of voluntary obligations. This view preserves an important connection between contractual liability and voluntary undertakings and meets the objections that beset the will theory. (shrink)

This article offers arefutation of the corrective justiceinterpretation of tort law – the view that itis essentially a system of corrective justice. It introduces a distinction between primary andsecondary tort duties and claims that tort lawis best understood as the union of its primaryand secondary duties. It then advances twoindependent criticisms of the correctivejustice interpretation. The article firstargues that primary tort duties have nothingfundamentally to do with corrective justice andthat, if one understands what is meant by``primary tort duties,'' one is (...) compelledto regard this fact as a decisive objection tothe corrective justice interpretation. Second,it argues that, whatever relation thereis between secondary tort duties and correctivejustice, that relation also holds betweencorrective justice and secondary duties ofother legal branches. In sum, the concept ofcorrective justice is neither capable ofunifying tort law nor of demarcating it fromother legal branches.The article also offers a general alternativeinterpretation of tort law. Rather thanbeing essentially corrective, tort law isessentially protective. Under this picture, iftort law has a most important point, it is theprotection of legal subjects and valuablesocial interests from harm. This is theoverarching ambition that unifies primary andsecondary tort duties. It does not, however,demarcate tort law from other legal branches. (shrink)

Many arguments have been made against gene editing. This paper addresses the commonly invoked argument that gene editing violates human dignity and is ultimately a subversion of human nature. There are several drawbacks to this argument. Above all, the concept of what human dignity means is unclear. It is not possible to condemn a practice that violates human dignity if we do not know exactly what is being violated. The argument’s entire reasoning is thus undermined. Analyses of the arguments involved (...) in this discussion have often led to the conclusion that gene editing contravenes the principle of genetic identity (genetic immutability) thereby subverting a requisite of human dignity and ultimately threatening human nature. This paper refutes these arguments and shows that any opposition to gene editing cannot rely on the human dignity argument. (shrink)

According to the doctrine of Super-Humeanism, the world’s mosaic consists only of permanent matter points and changing spatial relations, while all the other entities and features figuring in scientific theories are nomological parameters, whose role is merely to build the best law system. In this paper, I develop an argument against Super-Humeanism by pointing out that it is vulnerable to and does not have the resources to solve the well-known problem of immanent comparisons. Firstly, I show that it cannot endorse (...) a fundamentalist solution à la Lewis, since its two pillars—a minimalist ontology and a best system account of lawhood—would generate, together, a tedious problem of internal coherence. Secondly, I consider anti-fundamentalist strategies, proposed within Humeanism, and find them inapplicable to the Super-Humean doctrine. The concern is that, since it is impossible to choose the best law system within Super-Humeanism, this doctrine may be charged with incoherence. (shrink)

The utility of recognising emotion expressions for coordinating social interactions is well documented, but less is known about how continuously changing emotion displays are perceived. The nonlinear dynamic systems view of emotions suggests that mixed emotion expressions in the middle of displays of changing expressions may be decoded differently depending on the expression origin. Hysteresis is when an impression (e.g., disgust) persists well after changes in facial expressions that favour an alternative impression (e.g., anger). In expression changes based on photographs (...) (Study 1) and avatar images (Studies 2a–c, 3), we found hystereses particularly in changes between emotions that are perceptually similar (e.g., anger–disgust). We also consistently found uncertainty (neither emotion contributing to the mixed expression was perceived), which was more prevalent in expression sequences than in static images. Uncertainty occurred particularly in changes between emotions that are perceptually dissimilar, such as changes between happiness and negative emotions. This suggests that the perceptual similarity of emotion expressions may determine the extent to which hysteresis and uncertainty occur. Both hysteresis and uncertainty effects support our premise that emotion decoding is state dependent, a characteristic of dynamic systems. We propose avenues to test possible underlying mechanisms. (shrink)

One dimension of cognitive success concerns getting it right: having many true beliefs and no false ones. Another dimension of cognitive success concerns using the right concepts. For example, using a concept of a person that systematically excludes people of certain demographics from its extension is a sort of cognitive deficiency. This view, if correct, tasks inquirers with critically examining the concepts they are using and perhaps replacing those concepts with new and better ones. This task is often referred to (...) as “conceptual engineering”. However, so far it is unclear what exactly happens in cases of conceptual engineering. How does language change when we engineer a concept? This article offers an answer. I propose a view on which, when speakers assess the truth of propositions, they often rely on assumptions with regard to what is required for their truth. For example, when speakers assess whether unborn fetuses are people, they rely on assumptions with regard to what is required to be a person. Based on this idea, I develop a model of conceptual engineering according to which speakers “engineer concepts” when they change how they assess the truth of propositions. For example, speakers engineer the concept of a person when they change how they assess the truth of the proposition that unborn fetuses are people. (shrink)

We show that in the Maxwell–Lorentz theory of classical electrodynamics most initial values for fields and particles lead to an ill-defined dynamics, as they exhibit singularities or discontinuities along light-cones. This phenomenon suggests that the Maxwell equations and the Lorentz force law ought rather to be read as a system of delay differential equations, that is, differential equations that relate a function and its derivatives at different times. This mathematical reformulation, however, leads to physical and philosophical consequences for the ontological (...) status of the electromagnetic field. In particular, fields cannot be taken as independent degrees of freedom, which suggests that one should not add them to the ontology. (shrink)

Do numbers exist? Carnap (1956 [1950]) famously argues that this question can be understood in an “internal” and in an “external” sense, and calls “external” questions “non-cognitive”. Carnap also says that external questions are raised “only by philosophers” (p. 207), which means that, in his view, philosophers raise ”non-cognitive” questions. However, it is not clear how the internal/external distinction and Carnap’s related views about philosophy should be understood. This paper provides a new interpretation. I draw attention to Carnap’s distinction between (...) purely external statements, which are independent from all frameworks, and pragmatic external statements, which concern which framework one should adopt, and argue that the latter express noncognitive mental states. Specifically, I argue that “frameworks” are systems of rules for the assessment of statements, which are utterances of ordinary language sentences. Pragmatic external statements express noncognitive dispositions to follow only certain rules of assessment. For instance, “numbers exist” understood as a pragmatic external statement expresses a noncognitive disposition to use only rules of assessment according to which numbers do exist. Carnap can thereby be understood as proposing a distinctive form of noncognitivism about ontology that is in some respects analogous to norm-expressivism in metaethics. (shrink)

Although Chinese law imposes informed consent for medical treatments, the Chinese understanding of this requirement is very different from the European one, mostly due to the influence of Confucianism. Chinese doctors and relatives are primarily interested in protecting the patient, even from the truth; thus, patients are commonly uninformed of their medical conditions, often at the family’s request. The family plays an important role in health care decisions, even substituting their decisions for the patient’s. Accordingly, instead of personal informed consent, (...) what actually exists is ‘family informed consent’. From a Western perspective, these features of Chinese law and Chinese culture might seem strange, contradicting our understanding of doctor-patient relationship and even the very essence of self-determination and fundamental rights. However, we cannot forget the huge influence of cultural factors in these domains, and that ‘Western’ informed consent is grounded on the individualistic nature of Western culture. This article will underline the differences between the Western and the Chinese perspectives, clarifying how each of them must be understood in its own cultural environment. But, while still respecting Chinese particularities, this paper advocates that China adopt patient individual informed consent because this is the only solution compatible with human dignity and human rights. (shrink)

Ontological expressivism is the view that ontological existence claims express non-cognitive mental states. I develop a version of ontological expressivism that is modeled after Gibbard’s (2003) norm-expressivism. I argue that, when speakers assess whether, say, composite objects exist, they rely on assumptions with regard to what is required for composition to occur. These assumptions guide their assessment, similar to how norms may guide the assessment of normative propositions. Against this backdrop, I argue that “some objects have parts”, uttered in the (...) context of an ontological disagreement, expresses a noncognitive disposition to assess the truth of propositions by using only rules of assessment according to which the proposition that some objects have parts is to be evaluated as true. (shrink)

Im Beitrag werden Veränderungen der Kommunikation durch digitale Medien, ihre psychischen Bedeutungen und Folgen, u. a. anhand von empirischen Befunden zu Social-Media-Praktiken von Jugendlichen und von Eltern thematisiert. Bezugsrahmen der Analyse sind dabei kulturelle Wandlungen sowie soziale und psychische Bedeutungen von Aufmerksamkeit: geteilte Aufmerksamkeit als ein Kern der Kommunikation, aber auch die für psychische Entwicklung notwendige geschenkte, für den anderen oder für anderes offene Aufmerksamkeit als ein wesentliches Moment der Zuwendung, Empathie und Bezogenheit – im Gegensatz zu selbstbezogener Aufmerksamkeit und (...) instrumenteller Aufmerksamkeitslenkung. Überdies werden Folgen fragmentierter Aufmerksamkeit, wie sie aus der Überlagerung von Online- und Offline-Kommunikation resultiert, für psychische Entwicklungen betrachtet. (shrink)

The aim of this paper is to define a notion of supervenience which can adequately describe the systematic dependence of extrinsic as well as of intrinsic higher-level properties on base-level features. We argue that none of the standard notions of supervenience—the concepts of weak, strong and global supervenience—fulfil this function. The concept of regional supervenience, which is purported to improve on the standard conceptions, turns out to be problematic as well. As a new approach, we develop the notion of property-dependent (...) supervenience. This notion is founded on a criterion of relevance adapting the supervenience base to the considered higher-level properties in a specific way, such that only features which are relevant to the instantiation of the higher-level properties under consideration are taken into account. (shrink)

Easy Ontologists, most notably Thomasson (2015), argue that ontological questions are shallow. They think that these questions can either be answered by using our ordinary conceptual competence—of course tables exist!—or are meaningless, or else should be answered through conceptual re-engineering. Ontology thus is “easy”, requiring no distinctively metaphysical investigation. This paper raises a two-stage objection to Easy Ontology. We first argue that questions concerning which entities exist are inextricably bound up with “ontological category questions”, which are questions concerning the identity (...) of and differences between kinds of entities. We then argue that ontological category questions do not have trivial answers, are meaningful, and cannot be answered through conceptual re-engineering. Easy Ontology hence does not constitute a comprehensive ontological methodology. While some of ontology might be easy, category questions form a central part of ontology and are not answered easily. (shrink)

In introducing the present issue, I clarify in which sense knowledge and philosophy can discriminate and marginalize some individuals. In the first part, I focus on the traditional exclusion of women from philosophy and explore some feminist projects of re-reading the philosophical canon. In my analysis, I pay particular attention to the gender gap in philosophy and the so-called “demographic problem” in academia. In the second part, I examine the best practices for remedying these forms of injustice and promoting diversity (...) in philosophy. (shrink)

ABSTRACTPrevious research suggests that labelling emotions, or describing affective states using emotion words, facilitates emotion regulation. But how much labelling promotes emotion regulation? And which emotion regulation strategies does emotion labelling promote? Drawing on cognitive theories of emotion, we predicted that labelling emotions using fewer words would be less confusing and would facilitate forms of emotion regulation requiring more cognitively demanding processing of context. Participants mentally immersed themselves in an emotional vignette, were randomly assigned to an exhaustive or minimal emotion (...) labelling manipulation, and then completed an emotion regulation strategy planning task. Minimal emotion labelling promoted higher subjective emotional clarity. Furthermore, in terms of specific emotion regulation strategies, minimal emotion labelling prompted more plans for problem solving and marginally more plans for reappraisal, but did not affect plans for behav... (shrink)

This article offers arefutation of the corrective justiceinterpretation of tort law – the view that itis essentially a system of corrective justice. It introduces a distinction between primary andsecondary tort duties and claims that tort lawis best understood as the union of its primaryand secondary duties. It then advances twoindependent criticisms of the correctivejustice interpretation. The article firstargues that primary tort duties have nothingfundamentally to do with corrective justice andthat, if one understands what is meant by``primary tort duties,'' one is (...) compelledto regard this fact as a decisive objection tothe corrective justice interpretation. Second,it argues that, whatever relation thereis between secondary tort duties and correctivejustice, that relation also holds betweencorrective justice and secondary duties ofother legal branches. In sum, the concept ofcorrective justice is neither capable ofunifying tort law nor of demarcating it fromother legal branches.The article also offers a general alternativeinterpretation of tort law. Rather thanbeing essentially corrective, tort law isessentially protective. Under this picture, iftort law has a most important point, it is theprotection of legal subjects and valuablesocial interests from harm. This is theoverarching ambition that unifies primary andsecondary tort duties. It does not, however,demarcate tort law from other legal branches. (shrink)

MARK LOŠONC, PREDRAG KRSTIĆ, HOLOKAUST I FILOZOFIJA, INSTITUT ZA FILOZOFIJU I DRUŠTVENU TEORIJU, BEOGRAD, 2018.Vera Mevorah.

We study regularity properties related to Cohen, random, Laver, Miller and Sacks forcing, for sets of real numbers on the Δ31\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\varvec{\Delta}^1_3}$$\end{document} level of the projective hieararchy. For Δ21\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\varvec{\Delta}^1_2}$$\end{document} and Σ21\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\varvec{\Sigma}^1_2}$$\end{document} sets, the relationships between these properties follows the pattern of the well-known Cichoń diagram for cardinal characteristics of the continuum. It is known that (...) assuming suitable large cardinals, the same relationships lift to higher projective levels, but the questions become more challenging without such assumptions. Consequently, all our results are proved on the basis of ZFC alone or ZFC with an inaccessible cardinal. We also prove partial results concerning Σ31\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\varvec{\Sigma}^1_3}$$\end{document} and Δ41\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\varvec{\Delta}^1_4}$$\end{document} sets. (shrink)

In this paper, I discuss whether the results of loop quantum gravity (LQG) constitute a fatal blow to Humeanism. There is at least a prima facie reason for believing so: while Humeanism regards spatiotemporal relations as fundamental, LQG describes the fundamental layer of our reality in terms of spin networks, which are not in spacetime. However, the question should be tackled more carefully. After explaining the importance of the debate on the tenability of Humeanism in light of LQG, and having (...) presented the Humean doctrine, I review two cases which present serious threats to Humeanism, one concerning the fundamentality of vectorial quantities and the other concerning quantum entanglement. In particular, I recall the strategies that are usually employed in these two cases in order to save Humeanism: in the first case, the strategy consists in amending the characterization of the Humean mosaic; in the second case, it consists in adopting a realist or nomological interpretation of the wave function. These solutions will turn out to be helpful in my discussion of LQG where, after describing LQG, I show that Humeans might save their doctrine either by endorsing a realist interpretation of spin networks, or by giving them a nomological status and, at the same time, by revisiting the characterization of the Humean mosaic. However, I conclude that both solutions are wanting. (shrink)

In a time marked by the development of innovative treatments in healthcare and the need for health professionals to deal with resulting ethical dilemmas in clinical practice, this study was developed to determine the influence of the bioethics teaching on the moral competence of medical and nursing students. The authors conduct a longitudinal study using the Moral Competence Test extended version before and after attending the ethics curricular unit, in three nursing schools and three medical schools of Portugal. In this (...) questionnaire the participant is confronted with three ethical dilemmas and asked to evaluate arguments for and against the attitude of the main character. For both nursing and medical students, C-score was lower after the attendance of the ethics curricular units, with a statistically significant decrease in the total score for nursing students and a decrease not statistically significant for medical students. A multivariate analysis did not find any association between this decrease and gender, course, or age. The phenomenon of moral segmentation was observed, with better performance in the worker and judge dilemma, than in the doctor dilemma. These results highlight the need to reflect on the curricular strategies that can be implemented for health professionals to better develop moral competence and decision-making, allowing for the provision of humanized health care. (shrink)

The purpose of the article is to analyze the meaning of examples in C. Hempel’s works. Hempel uses many examples referring to readings of magnetic hand, burning of white phosphorus, predictions of properties of some elements of the table of Mendeleev, to astrophysical hypotheses, terms of total solar eclipse, throwing of dice, as well as on unmarried men, on white and black swans, green mermaids, black crows and white shoes, blue roses, predictions of Jones’ recovery, the eruption of Vesuvius, the (...) assassination of Julius Caesar, and other “special cases” and “concrete facts”. The question is raised as to whether the case studies are mere illustrative material, a form of argumentation; a way of verifying Hempel’s ideas, their “demonstrable confirmation”, and in this sense a definite empirical basis for the study. The necessity of analyzing concrete examples in the context of Hempel’s theoretical research is shown, for which the examples turn out to be an occasion for investigating the logic of confirmation and the logic of explanation, for analyzing the structures of explanans and explanandum, for understanding the differences in inductive and deductive logical constructions, and for analyzing “quasi-induction”. The paper discusses Hempel’s famous example, the crow paradox, which is named in his honor and is a kind of logical provocation. (shrink)

In this paper we introduced various classes of weakly associative relation algebras with polyadic composition operations. Among them is the class RWA of representable weakly associative relation algebras with polyadic composition operations. Algebras of this class are relativized representable relation algebras augmented with an infinite set of operations of increasing arity which are generalizations of the binary relative composition. We show that RWA is a canonical variety whose equational theory is decidable.

Popper’s ‘Situational Analysis’ (SA) constitutes his methodological proposal for the social sciences. We claim that the two hallmarks of SA are: (i) that scientists assume they possess a ‘wider’ view of the problem-situation than actors do, and (ii) use the model as an ideal ‘benchmark’ scenario to identify thedeviationof actors’ actual behaviour from the former. We argue that SA is not a generalization of the neoclassical theory of individual behaviour but captures instead the methodology adopted by modern behavioural economists. Last, (...) we argue that SA highlights a way of acquiring knowledge that has gone unnoticed in the literature. (shrink)

Assuming that every set is constructible, we find a${\text{\Pi }}_1^1 $maximal cofinitary group of permutations of$\mathbb{N}$which is indestructible by Cohen forcing. Thus we show that the existence of such groups is consistent with arbitrarily large continuum. Our method also gives a new proof, inspired by the forcing method, of Kastermans’ result that there exists a${\text{\Pi }}_1^1 $maximal cofinitary group inL.

Most courts around the world have been refusing wrongful life actions. The main argument invoked is that the supposed compensable injury cannot be classified as such, since life is always a blessing no matter how hard and painful it is.In opposition to mainstream scholars and the dominant case law, this article sustains that life must be distinguished from living conditions, the former being the real injury at stake, since some living conditions are so intolerable that in themselves they justify a (...) compensation within wrongful life actions. (shrink)

‘Situational Analysis’ constitutes Popper's methodological proposal for the social sciences. There is an apparent inconsistency in the fact that, on the one hand, Popper maintains that we lear...

The events surrounding COVID-19, combined with the mandatory quarantines widely imposed in Asia and Europe since the virus outbreak, have reignited discussion of the balance between individual rights and liberties and public health during epidemics and pandemics. This article analyses this issue from the perspectives of precaution and necessity. There is a difficult relationship between these two seemingly opposite principles, both of which are frequently invoked in this domain. Although the precautionary principle encourages the use of quarantines, including mandatory quarantines, (...) and associated restrictive measures, the principle of necessity puts a break on such measures. The COVID-19 pandemic reveals once again the different interrelations between these two principles. However, the alleged conflict between the PN and the PP is based on a superficial analysis. The relation between these two principles is far more complex, as this article will demonstrate. (shrink)

With each projective geometry we can associate a Lyndon algebra. Such an algebra always satisfies Tarski's axioms for relation algebras and Lyndon algebras thus form an interesting connection between the fields of projective geometry and algebraic logic. In this paper we prove that if G is a class of projective geometries which contains an infinite projective geometry of dimension at least three, then the class L(G) of Lyndon algebras associated with projective geometries in G has an undecidable equational theory. In (...) our proof we develop and use a connection between projective geometries and diagonal-free cylindric algebras. (shrink)