This chapter identifies the problems created by the misfit between a limited human moral nature and globalized, highly advanced technology. It highlights the several ways of addressing the potential catastrophic consequences of this mismatch. The chapter discusses the development of a globally responsible liberalism, with the restriction of traditional liberal neutrality, inculcation of values and “moral education” to achieve restraint, promote cooperation, respect for equality, and other values now necessary for our survival as a global community. It also discusses some (...) consequences of the intuitive endorsement of the act‐omission doctrine. Environmental problems probably provide the most worrying example of the limitations of our cooperative dispositions in the contemporary world. In the world of today, when scientific progress has vastly increased our powers of action, societies need to inculcate norms that are conducive to the good of the world community of which these societies are an integral part. (shrink)

“Astrobiology as science” refers to how astrobiology is characterized and discussed in the philosophy of science.

There have through history been many attempts to define 'life' but there is no generally accepted definition of 'life' at this date. As a result, some have come to believe that defining 'life' is not a fruitful endeavour. This seems to be a minority view, however, since the quest to find or create a definition of 'life' is as active as ever.

I var tid ar ambitionen att sa mycket verksamhet som mojlig skall vila pa vetenskaplig grund. Darmed utokas vetenskapens domaner, samtidigt som begreppet som sadant forflackas. Filosofen Karl Poppers syn pa vetenskapen ar mera subtil. Enligt honom kan vi ingenting veta med sakerhet, ingenting bevisa, endast falsifiera, det vill saga visa att nagot ar oforenligt med faktiska forhallanden. Det som undandrar sig falsifieringen kan vi acceptera tillsvidare. Ulf Persson provar i denna bok Poppers teori pa ett antal vetenskapsomraden, daribland (...) ekonomi, pedagogik och evolutionsbiologi. (shrink)

Semmelweis’s work predates the discovery of the power of randomization in medicine by almost a century. Although Semmelweis would not have consciously used a randomized controlled trial (RCT), some features of his material—the allocation of patients to the first and second clinics—did involve what was in fact a randomization, though this was not realised at the time. This article begins by explaining why Semmelweis’s methodology, nevertheless, did not amount to the use of a RCT. It then shows why it is (...) descriptively and normatively interesting to compare what he did with the modern approach using RCTs. The argumentation centres on causal inferences and the contrast between Semmelweis’s causal concept and that deployed by many advocates of RCTs. It is argued that Semmelweis’s approach has implications for matters of explanation and medical practice. (shrink)

Fred Feldman has argued that consequentialists can answer the well-known by replacing the utilitarian axiology with one that makes the value of receiving pleasures and pains depend on how deserved it is. It is shown that this proposal is open to three interpretations: the Fit-idea, which operates with the degree of fit between what recipients get and what they deserve; the Merit-idea, which operates with the magnitude of the recipients' desert or merit; and the Fit-Merit idea which is a combination (...) of and. It is argued that none of these ideas will do, among other things because they fail to take into account the fact that justice involves inter-personal comparisons. (shrink)

There are no egalitarians in a pandemic. The scale of the challenge for health systems and public policy means that there is an ineluctable need to prioritize the needs of the many. It is impossible to treat all citizens equally, and a failure to carefully consider the consequences of actions could lead to massive preventable loss of life. In a pandemic there is a strong ethical need to consider how to do most good overall. Utilitarianism is an influential moral theory (...) that states that the right action is the action that is expected to produce the greatest good. It offers clear operationalizable principles. In this paper we provide a summary of how utilitarianism could inform two challenging questions that have been important in the early phase of the pandemic: (a) Triage: which patients should receive access to a ventilator if there is overwhelming demand outstripping supply? (b) Lockdown: how should countries decide when to implement stringent social restrictions, balancing preventing deaths from COVID‐19 with causing deaths and reductions in well‐being from other causes? Our aim is not to argue that utilitarianism is the only relevant ethical theory, or in favour of a purely utilitarian approach. However, clearly considering which options will do the most good overall will help societies identify and consider the necessary cost of other values. Societies may choose either to embrace or not to embrace the utilitarian course, but with a clear understanding of the values involved and the price they are willing to pay. (shrink)

In the preface to the second edition of his deservedly popular Practical Ethics, Peter Singer notes that one of the ‘two significant changes” of his ‘underlying ethical views” consists in dropping the tentative suggestion that ‘one might try to combine both the “total” and the “prior existence” versions of utilitarianism, applying the former to sentient beings who are not self-conscious and the latter to those who are”. On the total view our aim is ‘to increase the total amount of pleasure (...) ” regardless of ‘whether this is done by increasing the pleasure of existing beings, or increasing the number of beings who exist”, whereas on the prior existence view we ‘count only beings who already exist, prior to the decision we are taking, or at least will exist independently of that decision”. Instead he proposes ‘that preference utilitarianism draws a sufficiently sharp distinction between these two categories of being to enable us to apply one version of utilitarianism to all sentient beings”. (shrink)

We show that the common claim that internal validity should be understood as prior to external validity has, at least, three epistemologically problematic aspects: experimental artefacts, the implications of causal relations, and how the mechanism is measured. Each aspect demonstrates how important external validity is for the internal validity of the experimental result.

Several hundred thousand intellectually talented 12-to 13-year-olds have been tested nationwide over the past 16 years with the mathematics and verbal sections of the Scholastic Aptitude Test (SAT). Although no sex differences in verbal ability have been found, there have been consistent sex differences favoring males in mathematical reasoning ability, as measured by the mathematics section of the SAT (SAT-M). These differences are most pronounced at the highest levels of mathematical reasoning, they are stable over time, and they are observed (...) in other countries as well. The sex difference in mathematical reasoning ability can predict subsequent sex differences in achievement in mathematics and science and is therefore of practical importance. To date a primarily environmental explanation for the difference in ability has not received support from the numerous studies conducted over many years by the staff of Study of Mathematically Precocious Youth (SMPY) and others. We have studied some of the classical environmental hypotheses: attitudes toward mathematics, perceived usefulness of mathematics, confidence, expectations/ encouragement from parents and others, sex-typing, and differential course-taking. In addition, several physiological correlates of extremely high mathematical reasoning ability have been identified (left-handedness, allergies, myopia, and perhaps bilateral representation of cognitive functions and prenatal hormonal exposure). It is therefore proposed that the sex difference in SAT-M scores among intellectually talented students, which may be related to greater male variability, results from both environmental and biological factors. (shrink)

Today talk of rights is very much in vogue both in philosophical and popular ethics; so much so that it is common to find even philosophers unabashedly going straight to discussing what rights we have without touching on what their foundation might be. This is so in spite of there being a time-honoured tradition of scepticism about rights, conceived as ‘natural’ ones, going back at least to Jeremy Bentham. The present paper is intended as a contribution to this sceptical tradition (...) for I shall try to prove that there are no natural rights or that nobody is the holder of any such right. (shrink)

In Confrontations with the Reaper Fred Feldman puts forward puts forward an ethical theory called ‘justicized act utilitarianism’, JAU, according to which an act is morally right if and only if it maximizes universal justice level, i.e., brings it about that as many as possible get what they deserve. It is here argued that JAU is exposed to objections under the force of which it either loses its special emphasis on justice or its utilitarian character. It is also contended that, (...) contrary to what Feldman suggests, JAU does not deal more plausibly with procreation and abortion than do more familiar forms of utilitarianism. Rather, it deals less plausibly at least with abortion, due to difficulties in the concept of desert. (shrink)

In this article, we distinguish between three approaches to ethics in school, each giving an interpretation of the expression ‘ethics in school’: the descriptive facts about ethics approach, roughly consisting of teaching empirical facts about moral matters to students; the moral fostering approach, consisting of mediating a set of given values to students; and the philosophical ethics (PE) approach, consisting of critically discussing and evaluating moral issues with students. Thereafter, three influential arguments for why there ought to be ethics in (...) school are discussed, and each argument is interpreted given each approach to ethics in school, respectively. Thereby, we evaluate which interpretation of ‘ethics in school’ produces the strongest arguments, and thus, which approach is best supported by these arguments. The conclusion is that there ought to be PE in school. (shrink)

The purpose of this paper is to discuss the responsibility of AI experts for guiding the development of AI in a desirable direction. More specifically, the aim is to answer the following research question: To what extent are AI experts responsible in a forward-looking way for effects of AI technology that go beyond the immediate concerns of the programmer or designer? AI experts, in this paper conceptualised as experts regarding the technological aspects of AI, have knowledge and control of AI (...) technology that non-experts do not have. Drawing on responsibility theory, theories of the policy process, and critical algorithm studies, we discuss to what extent this capacity, and the positions that these experts have to influence the AI development, make AI experts responsible in a forward-looking sense for consequences of the use of AI technology. We conclude that, as a professional collective, AI experts, to some extent, are responsible in a forward-looking sense for consequences of use of AI technology that they could foresee, but with the risk of increased influence of AI experts at the expense of other actors. It is crucial that a diversity of actors is included in democratic processes on the future development of AI, but for this to be meaningful, AI experts need to take responsibility for how the AI technology they develop affects public deliberation. (shrink)

Building on the strengths of the highly successful first edition, the extensively updated _Blackwell Guide to Ethical Theory_ presents a complete state-of-the-art survey, written by an international team of leading moral philosophers. __ A new edition of this successful and highly regarded _Guide_, now reorganized and updated with the addition of significant new material Includes 21 essays written by an international team of leading philosophers Extensive, substantive essays develop the main arguments of all the leading viewpoints in ethical theory Essays (...) new to this edition cover evolution and ethics, capability ethics, virtues and consequences, and the implausibility of virtue ethics. (shrink)

This article is the text of an interview with D. H. Mellor conducted in Cambridge on 30 May 2001 by Anna-Sofia Maurin and Johannes Persson for the philosophical journal Theoria.

Unfit for the Future argues that the future of our species depends on radical enhancement of the moral aspects of our nature. Population growth and technological advances are threatening to undermine the conditions of worthwhile life on earth forever. We need to modify the biological bases of human motivation to deal with this challenge.

To gain legitimacy for climate change adaptation decisions, the distribution of responsibility for these decisions and their implementation needs to be grounded in theories of just distribution and what those a ected by decisions see as just. The purpose of this project is to contribute to sustainable spatial planning and the ability of local and regional public authorities to make well-informed and sustainable adaptation decisions, based on knowledge about both climate change impacts and the perceptions of residents and civil servants (...) on what constitutes a sustainable distribution of responsibility. Our aims are: (1) a better understanding of the practical implications of theories about just distribution of responsibility for the choice of local and regional climate adaptation measures; (2) knowledge about what residents and civil servants consider a sustainable distribution of responsibility for climate adaptation measures; and (3) a better understanding of conflicts concerning the distribution of responsibilities and systematic knowledge about the possibilities to manage them. In this interdisciplinary project, we study six municipalities and their residents, and two county administrative boards, all in Sweden, using mixed methods: value theory, document studies, interviews, focus groups, and surveys. (shrink)

The ability to exchange samples and data is crucial for the rapidly growth of biobanking. However, sharing is based on the assumption that the donor has given consent to a given use of her or his sample. Biobanking stakeholders, therefore, must choose 1 of 3 options: obtain general consent enabling multiple future uses before taking a sample from the donor, try to obtain consent again before sharing a previously obtained sample, or look for a legally endorsed way to share a (...) sample without the donor's consent. In this study, we present the results of 36 semistructured qualitative interviews with Swiss biobanking stakeholders regarding these options and the role of ethics committees in the process of authorizing sharing. Our results show that despite a lack of legal or guideline-based barriers to general consent, some stakeholders and ethics committees have reservations about this method of consent. In most cases, however, a general consent form is already in use. Many interviewees describe processes involving the ethics committees as time-consuming and cumbersome and their requirements as too demanding for donors/patients. Greater awareness of donors' opinions and preferences and the content of guidelines and recommendations could therefore be helpful for a better justified perspective of biobanking stakeholders and ethical committee members, equally. Finally, it may be necessary to differentiate between procedures governing future samples, where general consent is clearly desirable, and the use of old yet still relevant samples, where the option of using them without consent can be highly beneficial for research. (shrink)

In this paper, we do three things. First, we put forth a novel hypothesis about judgments of moral responsibility according to which such judgments are a species of explanatory judgments. Second, we argue that this hypothesis explains both some general features of everyday thinking about responsibility and the appeal of skeptical arguments against moral responsibility. Finally, we argue that, if correct, the hypothesis provides a defense against these skeptical arguments.

Standard views of good death in human and veterinary medicine considerably differ from one another. Whereas the good death ideal in palliative medicine emphasizes the positive aspects of non-induced dying, veterinarians typically promote a quick and painless killing with the aim to end suffering. Recent developments suggest a convergence of both professions and professional attitudes, however. Palliative physicians are confronted with patients wishing to be ‘put to sleep’, while veterinarians have begun to integrate principles and practices from hospice care. We (...) will argue that the discourses on good human and animal deaths are not distinct, but that they interact and influence each other. On the one hand, veterinary medicine adapts techniques like chemotherapy or sedation from palliative end-of-life care. On the other hand, philosophers, veterinarians, pet owners, patients and the general public alike make certain assumptions about the analogy of human and animal dying or killing. Unfortunately, these interactions have only scarcely been reflected normatively, especially on the part of human medicine. Conflicts and misattributions with potential serious negative consequences for the patients’ wellbeing are provoked. For these reasons, palliative physicians and veterinarians are invited to engage in the debate around human and animal end-of-life care. (shrink)

Much disease and disability is the result of lifestyle behaviours. For example, the contribution of imprudence in the form of smoking, poor diet, sedentary lifestyle, and drug and alcohol abuse to ill-health is now well established. More importantly, some of the greatest challenges facing humanity as a whole – climate change, terrorism, global poverty, depletion of resources, abuse of children, overpopulation – are the result of human behaviour. In this chapter, we will explore the possibility of using advances in the (...) cognitive sciences to develop strategies to intentionally manipulate human motivation and behaviour. While our arguments apply also to improving prudential motivation and behaviour in relation to health, we will focus on the more controversial instance: the deliberate targeted use of biomedicine to improve moral motivation and behaviour. We do this because the challenge of improving human morality is arguably the most important issue facing humankind (Persson and Savulescu, forthcoming). We will ask whether using the knowledge from the biological and cognitive sciences to influence motivation and behaviour erodes autonomy and, if so, whether this makes it wrong. (shrink)

We examine the philosophical and ethical issues associated with conjoined twins and their surgical separation. In cases in which there is an extensive sharing of organs, but nevertheless two distinguishable functioning brains, there are a number of philosophical and ethical challenges. This is because such conjoined twins: 1. give rise to puzzles concerning our identity, about whether we are identical to something psychological or biological;2. force us to decide whether what matters from an ethical point of view is the biological (...) life of our organisms or the existence of our consciousness or mind; 3. raise questions concerning when, if ever, it is morally acceptable to sacrifice one of us to save another;4. force us to reflect on the conditions for ownership of organs and the justification of removal of organs for transplantation which causes the death of the donor; 5. raise questions about who should take decisions about life-risking treatments when this cannot be decided by patients themselves.We examine and suggest answers to these questions. (shrink)

THERE WAS A TIME when many philosophers agreed that metaphysics was dead. Anyone aquatinted with the works of D.H. Mellor knows that the subject is alive and well. Two young philosophers who are familiar with his work, Anna-Sofia Maurin and Johannes Persson, met him in Cambrige for an interview.

Traditionally, interdisciplinarity has been taken to require conceptual or theoretical integration. However, in the emerging field of sustainability science this kind of integration is often lacking. Indeed sometimes it is regarded as an obstacle to interdisciplinarity. Drawing on examples from sustainability science, we show that problem-feeding, i.e. the transfer of problems, is a common and fruitful-looking way of connecting disparate disciplines and establishing interdisciplinarity. We identify two species of problem-feeding: unilateral and bilateral. Which of these is at issue depends on (...) whether solutions to the problem are fed back to the discipline in which the problem originated. We suggest that there is an interesting difference between the problem-feeding approach to interdisciplinarity and the traditional integrative perspective suggested by among others Erich Jantsch and his colleagues. The interdisciplinarity resulting from problem-feeding between researchers can be local and temporary and does not require collaboration between proximate disciplines. By contrast, to make good sense of traditional integrative interdisciplinarity we must arguably associate it with a longer-term, global form of close, interdisciplinary collaboration. (shrink)

Roboethics is a recently developed field of applied ethics which deals with the ethical aspects of technologies such as robots, ambient intelligence, direct neural interfaces and invasive nano-devices and intelligent soft bots. In this article we look specifically at the issue of (moral) responsibility in artificial intelligent systems. We argue for a pragmatic approach, where responsibility is seen as a social regulatory mechanism. We claim that having a system which takes care of certain tasks intelligently, learning from experience and making (...) autonomous decisions gives us reasons to talk about a system (an artifact) as being “responsible” for a task. No doubt, technology is morally significant for humans, so the “responsibility for a task” with moral consequences could be seen as moral responsibility. Intelligent systems can be seen as parts of socio-technological systems with distributed responsibilities, where responsible (moral) agency is a matter of degree. Knowing that all possible abnormal conditions of a system operation can never be predicted, and no system can ever be tested for all possible situations of its use, the responsibility of a producer is to assure proper functioning of a system under reasonably foreseeable circumstances. Additional safety measures must however be in place in order to mitigate the consequences of an accident. The socio-technological system aimed at assuring a beneficial deployment of intelligent systems has several functional responsibility feedback loops which must function properly: the awareness and procedures for handling of risks and responsibilities on the side of designers, producers, implementers and maintenance personnel as well as the understanding of society at large of the values and dangers of intelligent technology. The basic precondition for developing of this socio-technological control system is education of engineers in ethics and keeping alive the democratic debate on the preferences about future society. (shrink)

Skeptical worries about moral responsibility seem to be widely appreciated and deeply felt. To address these worries—if nothing else to show that they are mistaken—theories of moral responsibility need to relate to whatever concept of responsibility underlies the worries. Unfortunately, the nature of that concept has proved hard to pin down. Not only do philosophers have conflicting intuitions; numerous recent empirical studies have suggested that both prosaic responsibility judgments and incompatibilist intuitions among the folk are influenced by a number of (...) surprising factors, sometimes prompting apparently contradictory judgments. In this paper, we show how an independently motivated hypothesis about responsibility judgments provides a unified explanation of the more important results from these studies. According to this ‘Explanation Hypothesis’, to take an agent to be morally responsible for an event is to take a relevant motivational structure of the agent to be part of a significant explanation of the event. We argue that because of how explanatory interests and perspectives affect what we take as significant explanations, this analysis accounts for the puzzling variety of empirical results. If this is correct, the Explanation Hypothesis also provides a new way of understanding debates about moral responsibility. (shrink)

For many years, some urban architecture has aimed to exclude unwanted groups of people from some locations. This type of architecture is called “defensive” or “hostile” architecture and includes benches that cannot be slept on, spikes in the ground that cannot be stood on, and pieces of metal that hinder one’s ability to skateboard. These defensive measures have sparked public outrage, with many thinking such measures lead to suffering, are disrespectful, and violate people’s rights. In this paper, it is argued (...) that these views are difficult to defend and that much more empirical research on the topic is needed. (shrink)

PROBEX (PROBabilities from EXemplars), a model of probabilistic inference and probability judgment based on generic knowledge is presented. Its properties are that: (a) it provides an exemplar model satisfying bounded rationality; (b) it is a “lazy” algorithm that presumes no pre‐computed abstractions; (c) it implements a hybrid‐representation, similarity‐graded probability. We investigate the ecological rationality of PROBEX and find that it compares favorably with Take‐The‐Best and multiple regression (Gigerenzer, Todd, & the ABC Research Group, 1999). PROBEX is fitted to the point (...) estimates, decisions, and probability assessments by human participants. The best fit is obtained for a version that weights frequency heavily and retrieves only two exemplars. It is proposed that PROBEX implements speed and frugality in a psychologically plausible way. (shrink)

Research groups around the world are currently busy trying to invent new life in the laboratory, looking for extraterrestrial life, or making machines increasingly more life-like. In the case of astrobiology, any newly discovered life would likely be very old, but when discovered it would be new to us. In the case of synthetic organic life or life-like machines, humans will have invented life that did not exist before. Together, these endeavors amount to what we call the emerging plurality of (...) lives because we see a future where we are surrounded by, and interact with, life of many different origins, as well as entities that we have not traditionally seen as being alive. In the future these entities will likely possess properties that we so far have only associated with living beings, thereby transcending and perhaps blurring the borders between life and non-life. (shrink)

International scientific collaboration has increased both in volume and importance. In this article, the authors study the interpretation of macro-level data on international co authorship collaboration. They address such questions as how one might explain country- to-country differences in the rates of international coauthorship, networks of interna tional scientific collaboration among countries, and patterns of international collaboration in scientific fields. Attention is drawn to cognitive, social, historical, geopolitical, and economic factors as potential determinants of the observed patterns. They present a (...) methodology that gives one a measure, independent of size, of countries'propensities to collaborate internationally. (shrink)

This article examines the effects of globalization on changing notions of the ‘savage’. We compare discussions taking place in different contexts in the late 18th century concerning two Swedish scholars and travellers to Africa: Anders Sparrman (1748–1820), a naturalist and Linnaean disciple, and Carl Bernhard Wadström (1746–99), an engineer and economist. Both moved in Swedish Swedenborgian circles, and both became involved in the British abolitionist movement. Nevertheless, their images of African ‘Others’ diverged in crucial respects, reflecting differences in their ideological (...) outlooks, institutional affiliations, and understandings of how the world was changing. More specifically, we argue that the perception of global change brought about by a new economic framework of production and consumption provides a key for reading and comparing Wadström’s and Sparrman’s texts. Comparing their divergent uses of ‘savagery’, the article also highlights the versatility of the savage as a tool for presenting distant parts of the world to a domestic audience. (shrink)

abstract As history shows, some human beings are capable of acting very immorally. 1 Technological advance and consequent exponential growth in cognitive power means that even rare evil individuals can act with catastrophic effect. The advance of science makes biological, nuclear and other weapons of mass destruction easier and easier to fabricate and, thus, increases the probability that they will come into the hands of small terrorist groups and deranged individuals. Cognitive enhancement by means of drugs, implants and biological (including (...) genetic) interventions could thus accelerate the advance of science, or its application, and so increase the risk of the development or misuse of weapons of mass destruction. We argue that this is a reason which speaks against the desirability of cognitive enhancement, and the consequent speedier growth of knowledge, if it is not accompanied by an extensive moral enhancement of humankind. We review the possibilities for moral enhancement by biomedical and genetic means and conclude that, though it should be possible in principle, it is in practice probably distant. There is thus a reason not to support cognitive enhancement in the foreseeable future. However, we grant that there are also reasons in its favour, but we do not attempt to settle the balance between these reasons for and against. Rather, we conclude that if research into cognitive enhancement continues, as it is likely to, it must be accompanied by research into moral enhancement. (shrink)

The authors respond to a wide range of objections defending our argument that some forms of behaviour modification utilising advances in the cognitive sciences are desirable and need not necessarily undermine autonomy or freedom.

In this paper, we are mainly concerned with coherentism as an approach to ethical dialog in school. We have two different but connected aims with the paper. The first aim is to say something about general philosophical questions relating to coherentism as a theory in metaethics, and especially in relation to value education; the second aim is to explore some possible implications of coherentism as a method in studying the enterprise of discussing ethical issues and questions with children as well (...) as the study of the actual ethical discussion in school. Furthermore, we evaluate the connection between a coherentistic approach to justification and the methodological parts of a Philosophy with Children, or Community of Inquiry, approach to ethics in school. Related to this, we scrutinize what implications this has for evaluating ethical learning within Philosophy with Children, or Community of Inquiry, as well as implications for evaluation of the Philosophy with Children, or Community of Inquiry, approaches as methods for dealing with ethical matters in school. (shrink)

Human beings have wondered about the stars since the dawn of the species. Does life exist out there – intelligent life, even – or are we alone? The quest for life in the universe touches on fundamental hopes and fears. It touches on the essence of what it means to formulate a theory, grasp a concept, and have an imagination. This book traces the history of the science of this area and the development of new schools in philosophy. Its essays (...) seek to establish the history and philosophy of astrobiology as research fields in their own right by addressing cognitive, linguistic, epistemological, ethical, cultural, societal, and historical perspectives on astrobiology. (shrink)

We find that the nature and origin of the proposed “dialogical cognitive representations” in the target article is not sufficiently clear. Our proposal is that (triadic) bodily mimesis and in particular mimetic schemas – prelinguistic representational, intersubjective structures, emerging through imitation but subsequently interiorized – can provide the necessary link between private sensory-motor experience and public language. In particular, we argue that shared intentionality requires triadic mimesis.

The paper discusses the concept of explanation in metaphysics. Different types of explanation are identified and explored. Scientific explanation is compared with metaphysical explanation. The comparison illustrates the difficulties with applying the concept of explanation in metaphysics.