In this innovative book, Hasok Chang constructs a philosophy of science for 'realistic people' interested in understanding and promoting the actual practices of inquiry in science and other knowledge-focused areas of life. Inspired by pragmatist philosophy, he reconceives the very notions of reality and truth on the basis of his concept of the 'operational coherence' of epistemic activities, and offers new pragmatist conceptions of truth and reality as operational ideals achievable in actual scientific practice. Rejecting the version of scientific (...) realism that is concerned with claiming that our theories correspond to an ultimate reality, he proposes instead an 'activist realism': a commitment to do all that we can actually do to improve our knowledge of realities. His book will appeal to scholars and students in philosophy, science and the history of science, and all who are concerned about the place of science and empirical truth in society. (shrink)

In this paper I seek to articulate and develop Roberto Torretti’s advocacy of pragmatic realism. At the core of Torrietti’s view is a rejection of the notion that the truth of scientific theories consists in their correspondence to the world. I propose to understand correspondence in that sense as a metaphorical notion. I articulate a notion of pragmatist coherence, on the basis of which I make new coherence theories of truth and reality. Then it becomes possible to say that (...) pragmatic realism consists in the pursuit of true knowledge of reality, in a way that is also consonant with Torretti’s pluralism. (shrink)

An interview with Hasok Chang, Professor of History and Philosophy of Science at the University of Cambridge, on the occasion of the 10th anniversary of the publication of his book Is Water H2O?, which won the Fernando Gil International Prize for the Philosophy of Science. So far, the last work of prof. Changa is a book of Realism for Realistic People. A New Pragmatist Philosophy of Science, published in late 2022 by Cambridge University Press.

This book exhibits deep philosophical quandaries and intricacies of the historical development of science lying behind a simple and fundamental item of common sense in modern science, namely the composition of water as H2O. Three main phases of development are critically re-examined, covering the historical period from the 1760s to the 1860s: the Chemical Revolution, early electrochemistry, and early atomic chemistry. In each case, the author concludes that the empirical evidence available at the time was not decisive in settling the (...) central debates and therefore the consensus that was reached was unjustified or at least premature. This leads to a significant re-examination of the realism question in the philosophy of science and a unique new advocacy for pluralism in science. Each chapter contains three layers, allowing readers to follow various parts of the book at their chosen level of depth and detail. The second major study in "complementary science", this book offers a rare combination of philosophy, history and science in a bid to improve scientific knowledge through history and philosophy of science. (shrink)

A popular and plausible response against Laudan's “pessimistic induction” has been what I call “preservative realism,” which argues that there have actually been enough elements of scientific knowledge preserved through major theory‐change processes, and that those elements can be accepted realistically. This paper argues against preservative realism, in particular through a critical review of Psillos's argument concerning the case of the caloric theory of heat. Contrary to his argument, the historical record of the caloric theory reveals that beliefs (...) about the properties of material caloric, rejected by subsequent theories, were indeed central to the successes of the caloric theory. Therefore caloric remains a favorable case for Laudan. Further, I argue that even confirmed cases of preservation do not warrant an inference to truth. (shrink)

I develop a concept of observability that pertains to qualities rather than objects: a quality is observable if it can be registered by human sensation (possibly with the aid of instruments) without involving optional interpretations. This concept supports a better description of observations in science and everyday life than the object-based observability concepts presupposing causal information-transfer from the object to the observer. It also allows a rehabilitation of the traditional empiricist distinction between observations and their interpretations, but without a presumption (...) that observations are infallible. Using this concept of observability, I also propose a re-formulation of constructive empiricism that is easier to defend against realist attacks, while open to reasonable realist intuitions. (shrink)

We argue against the common view that it is impossible to give a causal account of the distant correlations that are revealed in EPR-type experiments. We take a realistic attitude about quantum mechanics which implies a willingness to modify our familiar concepts according to its teachings. We object to the argument that the violation of factorizability in EPR rules out causal accounts, since such an argument is at best based on the desire to retain a classical description of nature that (...) consists of processes that are continuous in space and time. We also do not think special relativity prohibits the superluminal propagation of causes in EPR, for the phenomenon of quantum measurement may very well fall outside the domain of application of special relativity. It is possible to give causal accounts of EPR as long as we are willing to take quantum mechanics seriously, and we offer two such accounts. (shrink)

I propose a reformulation of realism, as the pursuit of ontological plausibility in our systems of knowledge. This is dubbed plausibility realism, for convenience of reference. Plausibility realism is non-empiricist, in the sense that it uses ontological plausibility as an independent criterion from empirical adequacy in evaluating systems of knowledge. Ontological plausibility is conceived as a precondition for intelligibility, nor for Truth; therefore, the function of plausibilty realism is to facilitate the kind of understanding that is (...) not reducible to mere description or prediction. Difficulties in making objective judgements of ontological plausibility can be ameliorated if we adhere to the most basic ontological principles. The workings of plausibility realism are illustrated through a detailed discussion of how one ontological principle, which I call the principle of single value, can be employed with great effect. Throughout the paper the discussion draws on concrete examples from the history of science. (shrink)

I present philosophical reflections arising from a study of laboratory measurement methods in quantum physics. More specifically, I investigate three major methods of measuring kinetic energy, from the period during which quantum physics was developed and came to be widely accepted: magnetic deflection, electrostatic retardation, and material retardation. The historical material serves as a provocative focus at which many broader philosophical topics come together: the empirical testing of theories, the universal validity of physical laws, the interaction between theoretical and experimental (...) traditions, incommensurability, meaning and definition, realism and instrumentalism, the process of scientific change, and the unity of science. ;I begin the discussion by noting that the measurement methods in question were based on classical theory. Chapter 1 asks how the classical reasoning in measurements can be interpreted in quantum-mechanical terms, and concludes that only a "surface interpretation" is possible, since the classical methods involve many assumptions that conflict with quantum mechanics. Chapter 2 attempts to give a quantitative assessment of the inaccuracies that might result from using the "incorrect" classical theory in the design of measurement methods. Chapter 3 asks how we can know whether a measurement method is reliable, and investigates how different methods of measuring the same quantity can ground each other; this mutual grounding is also seen as a process of concept-formation. Chapter 4 argues that the customary quantum theories of measurement do not describe actual measurements well, and originate from an overly literal interpretation of the operator formalism of quantum mechanics. Chapter 5 examines how the classically reasoned measurement methods were incorporated into quantum physics; that history suggests a model of scientific development which can introduce fundamental changes while preserving much continuity with the old tradition. Chapter 6 develops a philosophical framework which allows a synthetic view of the concrete results presented in the earlier chapters: my work is an attempt to establish "conceptual coherence," creating and clarifying noncontradictory connections among the various conceptual activities that make up quantum physics. (shrink)

In today’s science-based civilization, people tend to accept without question the most basic things that science tells us. This is the case even for people who do not know much science or like it very much. For example, anyone with even the slightest acquaintance with modern science knows and accepts that water is H2O. Yet it was a very difficult thing for scientists to learn. That is the subject of my recently published book, Is Water H2O? Evidence, Realism and (...) Pluralism. If we take a closer look at the basic items of scientific knowledge that we take so much for granted, almost always we find that they were achieved only with great difficulty, and only after some very challenging questions were resolved, or set aside without being resolved. (shrink)

Hasok Chang is developing a new form of pragmatic scientific realism that aims to reorient the debate away from truth and towards practice. Central to his project is replacing truth as correspondence with his new notion of ‘operational coherence’, which is introduced as: 1) A success term with probative value to judge and guide epistemic activities. 2) A more useful alternative than truth as correspondence in guiding scientific practice. I argue that, given its current construal as neither necessary (...) nor sufficient for success, operational coherence is too weak and fails to satisfy both 1) and 2). I offer a stronger construal of operational coherence which aims to improve on Chang’s account by tying it to systematic success. This makes operational coherence necessary and sufficient for success. This new account, if successful, rescues 1) but not 2). I then take a step back and try to locate Chang’s pragmatic realism within the broader pragmatist tradition by comparing his views to the founding fathers Peirce, James and Dewey. I also assess to what extent we should consider Chang’s position ‘realist’, arguing that despite the many relativists threads running through it, Chang’s pragmatic realism is deserving of the realist label because its aims to maximize our learning from reality, even if it falls short of what many traditional realist are happy to accept as realism. I finish with comments on the epistemology of science pointing out that there is nothing intrinsic about a practice-based philosophy of science that precludes having both operational coherence and correspondence and highlighting that given a proper understanding these two notions could, in fact, be understood as complementary. I suggest one way this could be done. (shrink)

Hasok Chang’s latest book is pragmatist in its focus on practice, but also in linking evaluation of science and its practices to the aims of those practices. Al.

Essay review of Hasok Chang, Realism for Realistic People: A New Pragmatist Philosophy of Science.

For a period of several years the philosopher of science Hasok Chang has promoted various inter-related views including pluralism, pragmatism, and an associated view of natural kinds. He has also argued for what he calls the persistence of everyday terms in the scientific view. Chang claims that terms like phlogiston were never truly abandoned but became transformed into different concepts that remain useful. On the other hand, Chang argues that some scientific terms such as acidity have suffered a form (...) of “rupture”, especially in the case of the modern Lewis definition of acids. Chang also complains that the degree of acidity of a Lewis acid cannot be measured using a pH meter and seems to regard this as a serious problem. The present paper examines some of these views, especially what Chang claims to be a rupture in the definition of acidity. It is suggested that there has been no such rupture but a genuine generalization, on moving from the Brønsted-Lowry theory to the Lewis theory of acidity. It will be shown how the quantification and measurement of Lewis acidity can easily be realized through the use of equilibrium theory and the use of stability constants. (shrink)

This book presents the concept of “complementary science” which contributes to scientific knowledge through historical and philosophical investigations. It emphasizes the fact that many simple items of knowledge that we take for granted were actually spectacular achievements obtained only after a great deal of innovative thinking, painstaking experiments, bold conjectures, and serious controversies. Each chapter in the book consists of two parts: a narrative part that states the philosophical puzzle and gives a problem-centred narrative on the historical attempts to solve (...) the puzzle; and the analysis part which provides in-depth analyses of certain scientific, historical, and philosophical aspects of the story. (shrink)

Why do some epistemic objects persist despite undergoing serious changes, while others go extinct in similar situations? Scientists have often been careless in deciding which epistemic objects to retain and which ones to eliminate; historians and philosophers of science have been on the whole much too unreflective in accepting the scientists’ decisions in this regard. Through a re-examination of the history of oxygen and phlogiston, I will illustrate the benefits to be gained from challenging and disturbing the commonly accepted continuities (...) and discontinuities in the lives of epistemic objects. I will also outline two key consequences of such re-thinking. First, a fresh view on the (dis)continuities in key epistemic objects is apt to lead to informative revisions in recognized periods and trends in the history of science. Second, recognizing sources of continuity leads to a sympathetic view on extinct objects, which in turn problematizes the common monistic tendency in science and philosophy; this epistemological reorientation allows room for more pluralism in scientific practice itself. (shrink)

Building on my previous writings on presentism, pluralism, and “complementary science”, I develop an activist view of historiography. I begin by recognizing the inevitability of presentism. Our own purposes and perspectives do and should guide the production of our accounts of the past; like funerals, history-writing is for the living. There are different kinds of presentist history, depending on the historians’ purposes and perspectives. My particular inclination is pluralist. Science remembers its own history from a particular perspective, which views the (...) past as imperfect versions of the present; if professional historians of science shared this perspective, our work would be redundant. Instead, we can make it our task to illuminate the aspects of the past of science that scientists themselves tend to ignore and forget. History of science can also take a more productive role in the creation and improvement of scientific knowledge. Scientific progress as we know it tends to involve the shutting down of alternative paths of inquiry, resulting in a loss of potential and actual knowledge. A critical and sympathetic engagement with the past allows us to recover the lost paths, which can also suggest new paths. These points will be illustrated by a number of examples, especially from the history of chemistry and physics, including the recovery and extension of past experiments. (shrink)

What can we conclude from a mere handful of case studies? The field of HPS has witnessed too many hasty philosophical generalizations based on a small number of conveniently chosen case studies. One might even speculate that dissatisfaction with such methodological shoddiness contributed decisively to a widespread disillusionment with the whole HPS enterprise. Without specifying clear mechanisms for history-philosophy interaction, we are condemned to either making unwarranted generalizations from history, or writing entirely "local" histories with no bearing on an overall (...) understanding of the scientific process. I propose a move away from the habit of viewing historical cases as an inductive evidence-base for general philosophical theses. The relation between historical and philosophical studies should not be seen as one between the particular and the general, but as a relation between the concrete and the abstract. An abstract framework is necessary for telling any concrete story at all. In this paper I explore how doing concrete history can help our abstract philosophizing. In the absence of ready-made philosophical concepts appropriate for understanding a given historical episode, the historian is compelled to craft new abstract philosophical concepts. Therefore, history-writing can be a very effective method of philosophical discovery. I will illustrate these claims through a discussion of two investigations in HPS from my own recent and current work: (1) temperature measurement and epistemic iteration; (2)constitution and laboratory practices in the Chemical Revolution. (This will also raise, and solve, a problem of reflexivity: how can we use case studies to show how to go beyond case studies?). (shrink)

Historians often feel that standard philosophical doctrines about the nature and development of science are not adequate for representing the real history of science. However, when philosophers of science fail to make sense of certain historical events, it is also possible that there is something wrong with the standard historical descriptions of those events, precluding any sensible explanation. If so, philosophical failure can be useful as a guide for improving historiography, and this constitutes a significant mode of productive interaction between (...) the history and the philosophy of science. I illustrate this methodological claim through the case of the Chemical Revolution. I argue that no standard philosophical theory of scientific method can explain why European chemists made a sudden and nearly unanimous switch of allegiance from the phlogiston theory to Lavoisier's theory. A careful re-examination of the history reveals that the shift was neither so quick nor so unanimous as imagined even by many historians. In closing I offer brief reflections on how best to explain the general drift toward Lavoisier's theory that did take place. (shrink)

Do sensory measurements deserve the label of “measurement”? We argue that they do. They fit with an epistemological view of measurement held in current philosophy of science, and they face the same kinds of epistemological challenges as physical measurements do: the problem of coordination and the problem of standardization. These problems are addressed through the process of “epistemic iteration,” for all measurements. We also argue for distinguishing the problem of standardization from the problem of coordination. To exemplify our claims, we (...) draw on olfactory performance tests, especially studies linking olfactory decline to neurodegenerative disorders. (shrink)

Introduction to Synthese SI: Systematicity: The Nature of Science?

Many of the experiments that produced the empirical basis of quantum mechanics relied on classical assumptions that contradicted quantum mechanics. Historically this did not cause practical problems, as classical mechanics was used mostly when it did not happen to diverge too much from quantum mechanics in the quantitative sense. That fortunate circumstances, however, did not alleviate the conceptual problems involved in understanding the classical experimental reasoning in quantum-mechanical terms. In general, this type of difficulty can be expected when a coherent (...) scientific tradition undergoes a theoretical upheaval. The problem may be circumvented through the use of phenomenological theory in experimentation during the period of theoretical instability. (shrink)

I seek to provide a systematic and comprehensive framework for the description and analysis of scientific practice—a philosophical grammar of scientific practice, ‘grammar’ as meant by the later Wittgenstein. I begin with the recognition that all scientific work, including pure theorizing, consists of actions, of the physical, mental, and ‘paper-and-pencil’ varieties. When we set out to see what it is that one actually does in scientific work, the following set of questions naturally emerge: who is doing what, why, and how? (...) More specifically, we must arrive at some coherent philosophical accounts of the following elements of scientific practice: the agent—free, embodied, and constantly in second-person interactions with other agents; the purposes and proximate aims of the agent; types of activities that the agent engages in; ontological principles necessarily presumed for the performance of particular activities; instruments and other resources that the agent pulls together for the performance of each activity. After sketching the general framework, I also give some illustrative contrasts between the more traditional descriptions of scientific practice and the kind of descriptions enabled by the proposed framework. (shrink)

Scientific progress remains one of the most significant issues in the philosophy of science today. This is not only because of the intrinsic importance of the topic, but also because of its immense difficulty. In what sense exactly does science makes progress, and how is it that scientists are apparently able to achieve it better than people in other realms of human intellectual endeavour? Neither philosophers nor scientists themselves have been able to answer these questions to general satisfaction.

In this paper we give a full account of the work of William Thomson on absolute temperature, which to this day provides the theoretical underpinnings for the most rigorous measurements of temperature. When Thomson fashioned his concepts of ‘absolute’ temperature, his main concern was to make the definition of temperature independent of the properties of particular thermometric substances . He tried out a succession of definitions based on the thermodynamics of ideal heat engines; most notably, in 1854 he gave the (...) ratio of two temperatures as the ratio of quantities of heat taken in and given out at those temperatures in a Carnot cycle. But there were difficulties with using such definitions for experimental work, since it was not possible even to approximate an ideal Carnot engine in reality. More generally, it is not trivial to connect an abstract concept with concrete operations in order to make physical measurements possible. In the end, Thomson argued that an ideal gas thermometer would indicate his absolute temperature, and that the deviation of actual gas thermometers from the ideal could be estimated by means of the Joule‐Thomson effect. However, the measurement of the Joule‐Thomson effect itself required measurements of temperature, so there was a problem of circularity. (shrink)

Acidity provides an interesting example of an everyday concept that developed fully into a scientific one; it is one of the oldest concepts in chemistry and remains an important one. However, up to now there has been no unity to it. Currently two standard theoretical definitions coexist ; the standard laboratory measure of acidity, namely the pH, only corresponds directly to the Br⊘nsted-Lowry concept. The lasting identity of the acidity concept in modern chemistry is based on the persistence of the (...) quotidian concept. This is suggestive for considerations of other scientific concepts. (shrink)

The direct use of a physical law for the purpose of measurement creates a problem of circularity: the law needs to be empirically tested in order to ensure the reliability of measurement, but the testing requires that we already know the value of the quantity to be measured. This problem is discussed through some detailed examples of energy measurements in quantum physics; three major methods are analyzed in their interrelation, with a focus on the method of “material retardation.” It seems (...) that the only reasonable solution is to establish the law needed for the measurement by relying on an alternate method of measurement. This solution is also circular, since it amounts to letting different measurement methods justify each other. However, this circularity can be fruitful for the process of concept building; meaning can be created in a web of interconnected measurement methods. (shrink)

Customary discussions of quantum measurements are unrealistic, in the sense that they do not reflect what happens in most actual measurements even under ideal circumstances. Even theories of measurement which discard the projection postulate tend to retain two unrealistic assumptions of the von Neumann theory: that a measurement consists of a single physical interaction, and that the topic of every measurement is information wholly contained in the quantum state of the object of measurement. I suggest that these unrealistic assumptions originate (...) from an overly literal interpretation of the operator formalism of quantum mechanics. I also suggest, following Park, that some issues can be clarified by distinguishing the sense of the term ''''measurement'''' occurring in the quantum-mechanical operator formalism, and the sense of ''''measurement'''' that refers to actual processes of gaining information about the physical world. (shrink)

We continue our discussion of the competing arguments in favour of the unified theory and the pluralistic theory of radiation advanced by three nineteenth-century pioneers: Herschel, Melloni, and Draper. Our narrative is structured by a consideration of the epistemic criteria relevant to theory-choice; the epistemic focus highlights many little-known aspects of this relatively well-known episode. We argue that the acceptance of light-heat unity in this period cannot be credibly justified on the basis of common evaluative criteria such as simplicity and (...) standard notions of explanatory power. Whether the consensus was justified by some other criteria remains an open question.Keywords: Theory-choice; Epistemic values; Radiation; Simplicity; Explanatory power; Causal explanation. (shrink)

Hardly any ontological result of modern science is more firmly established than the fact that infrared radiation differs from light only in wavelength; this is part of the modern conception of the continuous spectrum of electromagnetic radiation reaching from radio waves to gamma radiation. Yet, like many such evident truths, the light-infrared unity was an extremely difficult thing to establish. We examine the competing arguments in favour of the unified and pluralistic theories of radiation, as put forward in the first (...) half of the nineteenth century by three of the most important early pioneers of the study of radiation: Herschel, Melloni and Draper. In this part of the paper, we conclude that there were no compelling reasons of observational adequacy to prefer the unified theory to the pluralistic theory. Keywords: Macedonio Melloni; John William Draper; William Herschel; Infrared; Observation; Theory-choice. (shrink)