Norton has recently argued that causation is merely a useful folk concept and that it fails to hold for some simple systems even in the supposed paradigm case of a causal physical theory – namely Newtonian mechanics. The purpose of this article is to argue against this devaluation of causality in physics. My main argument is that Norton’s alleged counterexample to causality within standard Newtonian physics fails to obey what I shall call the causal core of Newtonian mechanics. In particular, (...) I argue, Norton’s example is not in conformity with Newton’s first law. Moreover, Norton’s reformulation of this first law seems insufficient as a replacement for the original version since the notion of inertial frames in the resulting reformulated theory lacks a physical justification, and since an intelligible notion of time in Newtonian mechanics appears to be closely tied to Newton’s first law in its standard form. I will finally suggest how, given a plausible relationist account of time, the causal core of Newtonian mechanics may play a central role also in relativity and quantum theory. (shrink)

This thesis explores whether the three standard value relations, “better than”, “worse than” and “equally as good”, exhaust the possibilities in which things can relate with respect to their value. Or more precisely, whether there are examples in which one of these relations is not instantiated. There are cases in which it is not obvious that one of these relations does obtain; these are referred to as “hard cases of comparison”. These hard cases of comparison become interesting, since if it (...) not the case that the standard three value relations obtains in these cases then the three standard relations do not exhaust the possibility of instantiated value relations. It is argued that for some of the hard cases of comparison, the standard relations determinately obtain. For some it is indeterminate, due to vagueness, which of the three relations obtains, but it is determinate that one of them obtains. Thereafter it is argued that the influential Collapsing Argument fails in ruling out other accounts of the hard cases of comparison. Since one cannot depend on the Collapsing Argument in order to conclude that all items are related by the standard three relations, the investigation continues. It is argued that none of the hard cases of comparison are cases of incomparability. Furthermore, none of them are cases of a fourth basic positive value relation such as “parity”. Consequently, for all the hard cases of comparison one of the standard value relations holds, although sometimes we do not know which one and sometimes it is indeterminate which one holds. This means that there is no reason to assume that one of the standard three value relations does not hold between items we are comparing. This is followed by a brief discussion about the normative consequences of this result. The thesis ends with four different appendices in which related topics are discussed. (shrink)

Incommensurability is the impossibility to determine how two options relate to each other in terms of conventional comparative relations. This book features new research on incommensurability from philosophers who have shaped the field into what it is today, including John Broome, Ruth Chang and Wlodek Rabinowicz. The book covers four aspects relating to incommensurability. In the first part, the contributors synthesize research on the competing views of how to best explain incommensurability. Part II illustrates how incommensurability can help us deal (...) with seemingly insurmountable problems in ethical theory and population ethics. The contributors address the Repugnant Conclusion, the Mere Addition Paradox and so-called Spectrum Arguments. The chapters in Part III outline and summarize problems caused by incommensurability for decision theory. Finally, Part IV tackles topics related to risk, uncertainty and incommensurability. Value Incommensurability: Ethics, Risk, and Decision-Making will be of interest to researchers and advanced students working in ethical theory, decision theory, action theory, and philosophy of economics. (shrink)

Volume 22, Issue 3-4, November - December 2023.

The claim that there are bare particulars — individuals possessing no properties — is a highly controversial thesis in metaphysics. It has been heavily criticized and is often thought to be subject to a number of decisive counterarguments, some of which aim to show that there is something incoherent about the very idea of a bare particular. I believe that the theory of bare particulars can, given certain modifications, be defended from such accusations. But the fact that a theory is (...) not incoherent does not suffice for it to be a good theory, and I believe that the theory of bare particulars — although capable of coherence — is a deeply unsatisfactory theory in metaphysics, for reasons rarely appreciated in the discussion. In sections 2 and 3 of this paper, I introduce the notion of a bare particular by presenting two of the central theoretical tasks for which the postulation of such entities has been thought necessary. In section 4, I present three of the classical arguments intended to show that the theory of bare particulars is fundamentally flawed or even incoherent. In section 5, I argue that if we adopt what I call the minimal view of bare particulars, the theory can handle all of these objections. Finally, in section 6, I argue that despite not being undermined by the classical arguments, the minimal view of bare particulars makes it highly implausible to suppose that there are any entities of that kind. The theory of bare particulars can be made coherent only at the cost of being made highly theoretically unattractive. (shrink)

Walter applies the methodology of neurophilosophy to one of philosophy's centralchallenges, the notion of free will. Neurophilosophical conclusions are based on, and consistentwith, scientific knowledge about the brain and its functioning.

This article reviews concepts of, as well as neurocognitive and genetic studies on, empathy. Whereas cognitive empathy can be equated with affective theory of mind, that is, with mentalizing the emotions of others, affective empathy is about sharing emotions with others. The neural circuits underlying different forms of empathy do overlap but also involve rather specific brain areas for cognitive (ventromedial prefrontal cortex) and affective (anterior insula, midcingulate cortex, and possibly inferior frontal gyrus) empathy. Furthermore, behavioral and imaging genetic studies (...) provide evidence for a genetic basis for empathy, indicating a possible role for oxytocin and dopamine as well as for a genetic risk variant for schizophrenia near the gene ZNF804A. (shrink)

A set of moral problems known as The Trolley Dilemmas was presented to 3000 randomly selected inhabitants of the USA, Russia and China. It is shown that Chinese are significantly less prone to support utility-maximizing alternatives, as compared to the US and Russian respondents. A number of possible explanations, as well as methodological issues pertaining to the field of surveying moral judgment and moral disagreement, are discussed.

Recent metaphysics has seen a surge of interest in grounding—a relation of non-causal determination underlying a distinctive kind of explanation common in philosophy. In this article, I investigate the connection between grounding and another phenomenon of great interest to metaphysics: ontological dependence. There are interesting parallels between the two phenomena: for example, both are commonly invoked through the use of “dependence” terminology, and there is a great deal of overlap in the motivations typically appealed to when introducing them. I approach (...) the question of the relationship between grounding and ontological dependence through an investigation of their modal connections. I argue, firstly, that on the common assumption that grounding is factive, it can be shown that no known variety of rigid ontological dependence is either necessary or sufficient for grounding. I also offer some suggestions in support of the claim that this generalizes to every possible form of rigid ontological dependence. I then broaden the discussion by considering a non-factive conception of grounding, as well as by looking at forms of generic ontological dependence. I argue that there is at least one form of rigid ontological dependence that is sufficient for non-factive grounding, and that a form of generic dependence may be necessary both for factive and non-factive grounding. However, justifying even these fairly weak modal connections between grounding and ontological dependence turns out to require some quite specific and substantive assumptions about the two phenomena that have only rarely been discussed. (shrink)

In this paper, we engage with the question of the normative content of the resilience concept. The issues are approached in two consecutive steps. First, we proceed from a narrow construal of the resilience concept – as the ability of a system to absorb a disturbance – and show that under an analysis of normative concepts as evaluative concepts resilience comes out as descriptive. In the second part of the paper, we argue that (1) for systems of interest (primarily social (...) systems or system with a social component) we seem to have options with respect to how they are described and (2) that this matters for what is to be taken as a sign of resilience as opposed to a sign of the lack of resilience for such systems. We discuss the implications of this for how the concept should be applied in practice and suggest that users of the resilience concept face a choice between versions of the concept that are either ontologically or normatively charged. (shrink)

It is well known that Niels Bohr insisted on the necessity of classical concepts in the account of quantum phenomena. But there is little consensus concerning his reasons, and what he exactly meant by this. In this paper, I re-examine Bohr’s interpretation of quantum mechanics, and argue that the necessity of the classical can be seen as part of his response to the measurement problem. More generally, I attempt to clarify Bohr’s view on the classical/quantum divide, arguing that the relation (...) between the two theories is that of mutual dependence. An important element in this clarification consists in distinguishing Bohr’s idea of the wave function as symbolic from both a purely epistemic and an ontological interpretation. Together with new evidence concerning Bohr’s conception of the wave function collapse, this sets his interpretation apart from both standard versions of the Copenhagen interpretation, and from some of the reconstructions of his view found in the literature. I conclude with a few remarks on how Bohr’s ideas make much sense also when modern developments in quantum gravity and early universe cosmology are taken into account. (shrink)

This is a review of contemporary philosophical discussions of population policies. The focus is on normative justification, and the main question is whether population policies can be ethically justified. Although few analytical philosophers have directly addressed this question – it has been discussed more in other academic fields – many arguments and considerations can be placed in the analytical philosophical discourse. This article offers a comprehensive review and analysis of ethically relevant aspects of population policies evaluated on the basis of (...) the main ethical theories. This analysis is preceded by a brief historical contextualisation of when and how population policies became ethically contentious and how this relates to philosophical debates in environmental ethics, population ethics and political philosophy. The article also includes a conceptual analysis of population policies in which the empirical intricacies around individual fertility decisions are sorted out and the different ways in which they can be affected are categorised in a taxonomy which highlight the most relevant ethical aspects of population policies. The ethical analysis shows that while population policies can be justified on the basis of most ethical theories, it all depends on what prior assumptions are made about what is at stake. (shrink)

A short review of some recent developments in the philosophy of physics is presented. I focus on themes which illustrate relations and points of common interest between philosophy of physics and three of its `neighboring' elds: Physics, metaphysics and general philosophy of science. The main examples discussed in these three `border areas' are decoherence and the interpretation of quantum mechanics; time in physics and metaphysics; and methodological issues surrounding the multiverse idea in modern cosmology.

In 1997 John Broome presented the Collapsing Argument that was meant to establish that non-conventional comparative relations cannot exist. Broome's argument has faced a lot of scrutiny and a certain type of counterexample has been used to undermine it. Most of the counterexamples focus on the Collapsing Principle which plays a central role in Broome's argument. In this article we will take a closer look at the most common type of counterexample and propose how to adjust the Collapsing Principle in (...) order to avoid objections based on these counterexamples. We argue that a weaker version of the Collapsing Principle is not susceptible to the classical counterexamples. Furthermore, after an explorative discussion about the intuitions behind the original principle, we show that this weaker formulation is at least as intuitive as the principle suggested by Broome. (shrink)

30 years ago, R. Edward Freeman levied an influential challenge against the “separation thesis”, which maintains that ethical and business concerns are distinct and separable. However, achieving an integration of empirical and normative research continues to pose significant challenges. In this article, it is argued that the tradition of philosophical pragmatism offers a pathway to bridge this divide. While Freeman’s critique is rooted in pragmatism, it falls short of fully embracing the pragmatist turn as advocated by Charles S. Peirce and (...) John Dewey, who extended the methodologies of empirical inquiry to ethical issues. Typically, this pragmatist turn has been sidelined due to the formidable objection that norms and values cannot be empirically confirmed nor disconfirmed. This objection is critically examined, arguing that it is largely based on conceptions of science associated with positivism and logical empiricism, effectively challenged by pragmatism. Embracing a pragmatist perspective, it is argued, can substantially enhance both theoretical and empirical research within business ethics. This approach entails integrating observations that pertain to the values, norms and responsibilities of businesses. Conversely, with a comprehensive understanding of the theoretical underpinnings of such proposals, observations can help determine which ethical theories and perspectives best accommodate empirical findings. Additionally, pragmatism presents a novel approach to the role of business in society, enabling businesses to engage in democratic processes of inquiry into value. (shrink)

A number of single- and dual-process theories provide competing explanations as to how reasoners evaluate conditional arguments. Some of these theories are typically linked to different instructions—namely deductive and inductive instructions. To assess whether responses under both instructions can be explained by a single process, or if they reflect two modes of conditional reasoning, we re-analysed four experiments that used both deductive and inductive instructions for conditional inference tasks. Our re-analysis provided evidence consistent with a single process. In two new (...) experiments we established a double dissociation of deductive and inductive instructions when validity and plausibility of conditional problems were pitted against each other. This indicates that at least two processes contribute to conditional reasoning. We conclude that single-process theories of conditional reasoning cannot explain the observed results. Theories that postulate at least two processes are needed to account for our findings. (shrink)

The thesis investigates the implications for moral philosophy of research in psychology. In addition to an introduction and concluding remarks, the thesis consists of four chapters, each exploring various more specific challenges or inputs to moral philosophy from cognitive, social, personality, developmental, and evolutionary psychology. Chapter 1 explores and clarifies the issue of whether or not morality is innate. The chapter’s general conclusion is that evolution has equipped us with a basic suite of emotions that shape our moral judgments in (...) important ways. Chapter 2 presents and investigates the challenge presented to deontological ethics by Joshua Greene’s so-called dual process theory. The chapter partly agrees with his conclusion that the dual process view neutralizes some common criticisms against utilitarianism founded on deontological intuitions, but also points to avenues left to explore for deontologists. Chapter 3 focuses on Katarzyna de Lazari-Radek and Peter Singer’s suggestion that utilitarianism is less vulnerable to so-called evolutionary debunking than other moral theories. The chapter is by and large critical of their attempt. In the final chapter 4, attention is directed at the issue of whether or not social psychology has shown that people lack stable character traits, and hence that the virtue ethical view is premised on false or tenuous assumptions. Though this so-called situationist challenge at one time seemed like a serious threat to virtue ethics, the chapter argues for a moderate position, pointing to the fragility of much of the empirical research invoked to substantiate this challenge while also suggesting revisions to the virtue-ethical view as such. (shrink)

According to a standard account of incomparability, two value bearers are incomparable if it is false that there holds a positive value relation between them. Due to the vagueness of the comparative predicates it may also be indeterminate as to which relation that holds - for each relation it is neither true nor false that it holds. John Broome has argued that indeterminacy cannot coexist with incomparability and since there seems to exist indeterminacy there cannot exist incomparability. At the core (...) of his argument lies the collapsing principle. There are several arguments against this principle; Erik Carlson has advanced most of these. In this paper two strategies in dealing with these arguments are discussed. One strategy is to deny the existence of a certain kind of properties; another strategy that has been advanced by Christian Constantinescu is to restrict the collapsing principle. In the paper it is argued that the first of these strategies is the most promising strategy. A novel argument in favour of this strategy is presented and several objections to the strategy are rebutted. Finally it is concluded that, even though this strategy deals with most objections, without a better argument in favour of the principle the debate seems to run into a stalemate. (shrink)

In this book, Henrik Lagerlund offers students, researchers, and advanced general readers the first complete history of what is perhaps the most famous of all philosophical problems: skepticism. As the first of its kind, the book traces the influence of philosophical skepticism from its roots in the Hellenistic schools of Phyrronism and the Middle Academy up to its impact inside and outside of philosophy today. Along the way, it covers skepticism during the Latin, Arabic, and Greek Middle Ages and (...) during the Renaissance before moving on to cover Descartes's methodological skepticism and Pierre Bayle's super-skepticism in the seventeenth century. In the eighteenth century, it deals with Humean skepticism and the anti-skepticism of Reid and Kant, taking care to also include reflections on the connections between idealism and skepticism. The book covers similar themes in a chapter on G.E. Moore and Ludwig Wittgenstein, and then ends its historical overview with a chapter on skepticism in contemporary philosophy. In the final chapter, Lagerlund captures some of skepticism's impact outside of philosophy, highlighting its relation to issues like the replication crisis in science and knowledge resistance. (shrink)

Pragmatism gained considerable attention in bioethical discussions in the early 21st century. However, some dimensions and contributions of pragmatism to bioethics remain underexplored in both research and practice. It is argued that pragmatism can make a distinctive contribution to bioethics through its concept, developed by Charles S. Peirce and John Dewey, that ethical issues can be resolved through experimental inquiry. Dewey’s proposal that policies can be confirmed or disconfirmed through experimentation is developed by comparing it to the confirmation of scientific (...) hypotheses, with a focus on the objection that the consequences of following a moral view or policy do not provide guidance on choosing among competing ethical perspectives. As confirmation of scientific hypotheses typically relies on evidence gathered from observation, the possibility of ethically relevant observation is then explored based on Peirce’s views on feelings as emotional interpretants. Finally, the connection between Dewey’s experimental ethics and democracy is outlined and compared to unfettered ethical progressivism. (shrink)

In this chapter, we argue that in order to understand the interdisciplinary and transdisciplinary dialectics in sustainability science, it is useful to see sustainability science as a kind of management science, and then to highlight the hard-soft distinction in systems thinking. First, we argue that the commonly made natural-social science dichotomy is relatively unimportant and unhelpful. We then outline the differences between soft and hard systems thinking as a more relevant and helpful distinction, mainly as a difference between perspectives in (...) systemic modeling toward models. We also illustrate that the distinction is methodologically useful to advance sustainability science by enabling us (i) to suggest novel ways of using existing theoretical, experimental, and computational resources of the sciences for renewable resource management, and (ii) to disentangle disciplinary disagreements in climate science. (shrink)

Recently a lot has been written on the topic of value incomparability. While there is disagreement on how we are to understand incomparability, most seem to accept Ruth Chang's claim that all comparisons must proceed in some specific respect. Call this the Requirement for Specification. Interestingly, even though most seem to accept this requirement, next to nothing has been written on it. In this paper I focus on the requirement and discuss two different but related topics. First, an important observation (...) is made: as it turns out, the requirement plays an important explanatory role for the thesis that incomparability is to be understood in terms of vagueness. Second, I consider what is entailed by the Requirement for Specification. There is a general worry that the requirement entails that there is no such thing as goodness simpliciter. The line of thought is that if we always must specify in which way something is e.g., better than something else, then perhaps things cannot be better simpliciter. And if there is no such thing as betterness-simpliciter, then can there be such a thing as goodness simpliciter? Finally, I consider how an answer to this question affects the view that incomparability is vagueness. (shrink)

Clinical decisionmaking includes reasoning from prescientific or scientific theories, reasoning from uncontrolled or controlled experience, and reasoning based on empathic understanding and moral beliefe. The development of contemporary clinical thinking is discussed, and it is found that successive generations of medical practitioners have had different views of the rationality and relative importance of these modes of reasoning: that which is considered rational by one generation of doctors is sometimes denounced by the next. The author's book, Rational Diagnosis and Treatment , (...) which is an example of clinical thinking in the 1960s and early 70s, is used to illustrate one particular view of clinical decisionmaking. Keywords: rational, clinical decisionmaking, biological theory, controlled clinical studies, empathic understanding, ethical reasoning CiteULike Connotea Del.icio.us What's this? (shrink)

According to Ruth Chang the three standard positive value relations: “better than”, “worse than” and “equally good” do not fully exhaust the conceptual space for positive value relations. According to her, there is room for a fourth positive value relation, which she calls “parity”. Her argument for parity comes in three parts. First, she argues that there are items that are not related by the standard three value relations. Second, that these items are not incomparable, and third, that the phenomena (...) she has focused on are not due to the vagueness of the comparative predicates. This paper focuses on the second part of the argument and an objection is presented. By assuming the Small Unidimensional Difference Principle, which is a key premise for the second part of the argument, Chang’s argument could be accused of begging the question. More so, by assuming this principle, the space for incomparability gets severely limited. If these worries are justified, then Chang’s argument for parity as a fourth form of comparability is unsuccessful. (shrink)

By analyzing the meaning of time I argue, without endorsing operationalism, that time is necessarily related to physical systems which can serve as clocks. This leads to a version of relationism about time which entails that there is no time 'before' the universe. Three notions of metaphysical 'time' (associated, respectively, with time as a mathematical concept, substantivalism, and modal relationism) which might support the idea of time 'before' the universe are discussed. I argue that there are no good reasons to (...) believe that metaphysical 'time' can be identified with what we ordinarily call time. I also briefly review and criticize the idea of time 'before' the big bang, associated with some recent speculative models in modern cosmology, and I argue that if the big bang model is a (roughly) correct description of our universe, then the best current answer to the question in the title is that time did have a beginning. (shrink)

This volume distinguishes between two main traditions in the philosophy of science - the aristotelian, with its stress on explanation in terms of purpose and intentionality, and the galilean, which takes causal explanation as primary. It then traces the complex history of these competing traditions as they are manifested in such movements as positivism, idealism, Marxism and contemporary linguistic analysis. Hempels's theory of scientific explanation, the claims of cybernetics the rise of an analytic philosophy of action and the revival of (...) hermenuetics are all discussed. The volume also deals with causal explanation, intentionality and teleological explanation, and explanation in history and the social sciences. The author concludes that explanation of human actions cannot be reduced to simple causality, and discusses the implications of this conclusion for the disciplines of history and sociology. (shrink)

This article discusses the phenomenon of normative resilience, with a focus on evaluative resilience. An object can become more or less valuable. In addition to this change in an object's value, the object's value can become more or less resilient. If it is less resilient, it cannot withstand as much evaluative change without its degree of value changing, as compared to an object with more resilient value. The article consists of three parts. First, examples of resilience are presented to give (...) the reader an intuitive understanding of the phenomenon, Second, the Fitting Attitudes Analysis of value is invoked to provide a formal account of evaluative resilience. Third, the theoretical and practical advantages of acknowledging the existence of evaluative resilience are brought to light. (shrink)

Self-organized criticality (SOC) is based upon the idea that complex behavior can develop spontaneously in certain multi-body systems whose dynamics vary abruptly. This book is a clear and concise introduction to the field of self-organized criticality, and contains an overview of the main research results. The author begins with an examination of what is meant by SOC, and the systems in which it can occur. He then presents and analyzes computer models to describe a number of systems, and he explains (...) the different mathematical formalisms developed to understand SOC. The final chapter assesses the impact of this field of study, and highlights some key areas of new research. The author assumes no previous knowledge of the field, and the book contains several exercises. It will be ideal as a textbook for graduate students taking physics, engineering, or mathematical biology courses in nonlinear science or complexity. (shrink)

Background: We define compassion as an enduring disposition that centers upon empathetic concern for another person's suffering and the motivation to act to alleviate it. The contribution of specific candidate genes to the development of dispositional compassion for others is currently unknown. We examine candidate genes in the oxytocin and dopamine signaling pathways.Methods: In a 32-year follow-up of the Young Finns Study, we examined with multiple indicators latent growth curve modeling the molecular genetic underpinnings of dispositional compassion for others across (...) the life span. We selected five single nucleotide polymorphisms whose functions are known in humans: rs2268498, rs3796863, rs1800497, rs4680, and rs1611115. Compassion was measured with Cloninger's Temperament and Character Inventory on three repeated observations spanning 15 years. Differences between gender were tested.Results: We did not find an effect of the five SNPs in oxytocin and dopamine pathway genes on the initial levels of dispositional compassion for others. Individuals who carry one or two copies of the T-allele of DBH rs1611115, however, tend to increase faster in compassion over time than those homozygotes for the C-allele, b = 0.063. This effect was largely driven by male participants, 0.206, and was not significant in female participants when analyzed separately.Conclusions: Men who are known to have, on average, lower compassion than women seem to reduce this difference over time if they carry the T-allele of DBH rs1611115. The direction of the association indicates that dopamine signaling activity rather than overall dopamine levels might drive the development of compassion. (shrink)

This volume distinguishes between two main traditions in the philosophy of science - the aristotelian, with its stress on explanation in terms of purpose and intentionality, and the galilean, which takes causal explanation as primary. It then traces the complex history of these competing traditions as they are manifested in such movements as positivism, idealism, Marxism and contemporary linguistic analysis. Hempels's theory of scientific explanation, the claims of cybernetics the rise of an analytic philosophy of action and the revival of (...) hermenuetics are all discussed. The volume also deals with causal explanation, intentionality and teleological explanation, and explanation in history and the social sciences. The author concludes that explanation of human actions cannot be reduced to simple causality, and discusses the implications of this conclusion for the disciplines of history and sociology. (shrink)

This article explores the concept of metaphysically opaque grounding, a largely neglected form of metaphysical grounding that challenges the commonly held assumptions that grounding is an especially intimate and powerful connection between facts and that it is necessarily connected with the essences of things. I provide a definition of opaque grounding, identify some interesting philosophical views that are committed to it, and explore some consequences for the general theory of grounding. Finally, I briefly address some natural initial doubts about opaque (...) grounding and find them unwarranted. The upshot is that the notion deserves more attention than it has previously received. (shrink)

Many scientists regard mass and energy as the primary currency of nature. In recent years, however, the concept of information has gained importance. In this book, eminent scientists, philosophers, and theologians chart various aspects of information, from quantum information to biological and digital information, in order to understand how nature works. Beginning with a historical treatment of the topic, the book also examines physical and biological approaches to information, and the philosophical, theological, and ethical implications.

Why is democracy good, or preferable to other systems of governance and political decision-making? Democracy has been argued to incorporate or promote central values, such as equality or freedom. On the other hand, many contemporary defenses of democracy have relied on arguments that attempt to show that democracy promotes or enables some second-order good, such as the validity, justification or legitimacy of political decision-making. Recent decades have seen the rise of epistemic arguments for democracy that belong to this latter type. (...) For example, David Estlund has proposed that democracy is epistemically preferable among the societal arrangements that could be acceptable to all citizens. In turn... (shrink)

Using Butz and Moerdijk's topological groupoid representation of a topos with enough points, a ‘syntax-semantics’ duality for geometric theories is constructed. The emphasis is on a logical presentation, starting with a description of the semantic topological groupoid of models and isomorphisms of a theory. It is then shown how to extract a theory from equivariant sheaves on a topological groupoid in such a way that the result is a contravariant adjunction between theories and groupoids, the restriction of which is a (...) duality between theories with enough models and semantic groupoids. Technically a variant of the syntax-semantics duality constructed in 1 for first-order logic, the construction here works for arbitrary geometric theories and uses a slice construction on the side of groupoids—reflecting the use of ‘indexed’ models in the representation theorem—which in several respects simplifies the construction and the characterization of semantic groupoids. (shrink)