I challenge Gareth Eaton’s recent claim that Theodore Richards should be counted among the discoverers of isotopes. In evaluating Eaton’s claim, I draw on two influential theories of scientific discovery, one developed by Thomas Kuhn, and one developed by Augustine Brannigan. I argue that though Richards’ experimental work contributed to the discovery, his work does not warrant attributing the discovery to him. Richards’ reluctance to acknowledge isotopes is well documented. Further, the fact that he made no claim to having made (...) the discovery also undermines Eaton’s argument. (shrink)

SummaryKekulé first suggested a hexagonal structure for benzene in 1865. For over a half-century after, chemists struggled to reconcile proposed structures for benzene and other aromatic compounds with their resistance to chemical transformation and tendency to maintain the type during reaction. The combined structural and reactivity features of these compounds were eventually covered by the term ‘aromaticity’. Kekulé, Bamberger and Thiele had each proposed a criterion for aromaticity; all were either empirically contradicted or incapable of evaluation. In the 1930s, two (...) rival quantum mechanical methods succeeded in establishing a physical basis for aromaticity. Using valence bond theory, Pauling attributed benzene's stability to its being a resonance hybrid of several Lewis structures. Calculating resonance energies was challenging but manipulating Lewis structures was not; that procedure provided qualitative insights into aromatic structure and reactivity. Resonance theory appealed especially to organic chemists and eclipsed Hückel's contemporaneous molecular orbital approach, which remained relatively inaccessible. In the 1950s, however, simple rules derived from Hückel's mathematics, combined with proton NMR data, provided seemingly universal criteria for aromaticity. In the event, post-1950 discoveries of non-organic, three-dimensional compounds such as ferrocene and the fullerenes that exhibit aromatic properties led chemists to doubt the utility and universality of ‘aromaticity’ as a concept. A recent consensus maintains that aromaticity is a multi-variable phenomenon that cannot be reduced to a strict definition, a property it shares with other core chemical concepts such as ‘acidity’ and ‘reactivity’. (shrink)

Are acids natural kinds? Or are they merely relevant kinds? Although acidity has been one of the oldest and most important concepts in chemistry, surprisingly little ink has been spilled on the natural kind question. I approach the question from the perspective of microstructural essentialism. After explaining why both Brønsted acids and Lewis acids are considered functional kinds, I address the challenges of multiple realization and multiple determination. Contra Manafu and Hendry, I argue that the stereotypical properties of acids are (...) not multiply realized. Instead, given the equivalence between the proton-donating and electron-accepting mechanisms of Brønsted and Lewis, respectively, I show that acidity as a property type can be identified with a unique microstructural property, namely the presence of a LUMO or other low energy empty orbital. In doing so, I defend the view that the Lewis theory encompasses Brønsted–Lowry, and that all Brønsted acids are also Lewis acids. Contra Hacking and Chang, I thus maintain that the different concepts of acidity do not crosscut, and that the hierarchy requirement is met. Finally, by characterizing natural kinds as powerful objects and by adopting a dispositional view of functions, I illustrate how the microessentialist can make sense of the latent and relational character of most acids. In sum, I contend that acids are genuine natural kinds, even for the microstructural essentialist. (shrink)

Recent publications by several leading philosophers of chemistry have focused on the definition, scope, utility, and nomenclature of issues dealing with acidity and basicity. In this paper, molecular orbital theory is used to explain all acid–base reactions, concluding that the interaction of the highest occupied molecular orbital (HOMO) of one substrate, “the base,” with the lowest unoccupied molecular orbital (LUMO) of a second substrate, “the acid,” determines the reactivity of such systems. This paradigm provides an understanding of all acid–base reactions (...) as well as other reactions which, on the surface, may not seem like acid–base reactions but which have fundamental underpinnings of that kind of chemistry. Rather than being unable to determine a unified understanding of acidity and basicity as suggested in the philosophy of chemistry literature, we propose that acidity and basicity fit securely in a classification of many other reactions that, using classical chemistry knowledge, pre-quantum chemistry, would not be possible. We strongly support the use of all scientific knowledge and experience in the development of the ideas in the philosophy science. We further suggest increased interactions between philosophers of science and scientists, so that all scholars benefit from the values, knowledge, and perspectives of other disciplines. (shrink)

This paper examines how scientists conceptualize their research methodologies. Do scientists raise concerns about vague criteria and genuine uncertainties in experimental practice? If so, what sorts of issues do they identify as problematic? Do scientists acknowledge the presence of value judgments in scientific research, and do they reflect on the relation between epistemic and non-epistemic criteria for decisionmaking? We present findings from an analysis of qualitative interviews with 63 scientific researchers who talk about their views on good research practice. We (...) argue that analysts of science should care about scientists’ conceptualizations of the criteria and of the practical judgments that scientific inquiry involves. While scientists’ accounts of their own research methodologies alone do not give us a full picture of how science really works, they can point us to areas of concern. They can inspire and direct philosophical reflections about how science works. Throughout the interviews, the participating researchers provided specific examples from their own research contexts as illustrations of their methodological points. These examples reveal that scientists often struggle to evaluate the quality of their data, to figure out whether the available evidence confirms their hypothesis, whether a replication was successful, or to what extent they can rely on peer-reviewed papers. General ideas about good research methods do not directly translate into specific evaluation criteria or strategies that can guide research and help validate empirical data. (shrink)

This paper examines how scientists conceptualize their research methodologies. Do scientists raise concerns about vague criteria and genuine uncertainties in experimental practice? If so, what sorts of issues do they identify as problematic? Do scientists acknowledge the presence of value judgments in scientific research, and do they reflect on the relation between epistemic and non-epistemic criteria for decisionmaking? We present findings from an analysis of qualitative interviews with 63 scientific researchers who talk about their views on good research practice. We (...) argue that analysts of science should care about scientists’ conceptualizations of the criteria and of the practical judgments that scientific inquiry involves. While scientists’ accounts of their own research methodologies alone do not give us a full picture of how science really works, they can point us to areas of concern. They can inspire and direct philosophical reflections about how science works. Throughout the interviews, the participating researchers provided specific examples from their own research contexts as illustrations of their methodological points. These examples reveal that scientists often struggle to evaluate the quality of their data, to figure out whether the available evidence confirms their hypothesis, whether a replication was successful, or to what extent they can rely on peer-reviewed papers. General ideas about good research methods do not directly translate into specific evaluation criteria or strategies that can guide research and help validate empirical data. (shrink)

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)

Electronegativity is a quantified, typical chemical concept, which correlates the ability of chemical species to attract electrons during their contact with other species with measurable quantities such as dissociation energies, dipole moments, ionic radii, ionization potentials, electron affinities and spectroscopic data. It is applied to the description and explanation of chemical polarity, reaction mechanisms, other concepts such as acidity and oxidation, the estimation of types of chemical compounds and periodicity. Although this concept is very successful and widely used, and in (...) spite of the fact that it is still subject to scientific investigations, neither a more than intuitive definition nor a generally accepted, logically clear and standardized quantification model has been developed. In the present work, electronegativity is presented and discussed with respect to its main conceptual and operational continuities and discontinuities. We try to analyze the epistemological status of electronegativity, conceived as a typical notion of chemical sciences. Under ‘epistemological status’ we subsume the issues of its reference, its historical persistence, and the relationship between its measurement and quantification. (shrink)

In this short essay I address the central topic of the Centenary Workshop on Acidity, that is the relations of the classical protonist acid–base theory by Brønsted and the electronist approach by Lewis. Emphasis is laid on the empirical background of both approaches and the over-theoretization of chemical phenomena (essentialism) is criticized.

Recent years have seen enticing empirical approaches to solving the epistemological problem of the theory-ladenness of observation. I group these approaches in two categories according to their method of choice: testing and refereeing. I argue that none deliver what friends of theory-neutrality want them to. Testing does not work because both evidence from cognitive neuroscience and perceptual pluralism independently invalidate the existence of a common observation core. Refereeing does not work because it treats theory-ladenness as a kind of superficial, removable (...) bias. Even if such treatment is plausible, there is likely no method to ascertain that effects of this bias are not present. More importantly, evidence from cognitive neuroscience suggests that a deeper, likely irremovable kind of theory-ladenness lies within the perceptual modules. (shrink)

ABSTRACT I propose a division of the literature on natural kinds into metaphysical worries, semantic worries, and methodological worries. I argue that the latter set of worries, which concern how classification influences scientific practices, should occupy centre stage in philosophy of science discussions about natural kinds. I apply this methodological framework to the problems of classifying chemical species and nanomaterials. I show that classification in nanoscience differs from classification in chemistry because the latter relies heavily on compositional identity, whereas the (...) former must consider additional properties, namely, size, shape, and surface chemistry. I use this difference to argue for a scale-dependent theory of scientific classification. _1_ Introduction _2_ The Methodological Problem of Kinds _3_ Chemical Kindhood: Reactivity, Microstructure, and the Structure–Property Paradigm _4_ Scale-Dependence and Nanoscale Kinds _5_ Conclusion. (shrink)

This article examines the distinction between active matter and active materials, and it offers foundational remarks toward a system of classification for active materials. Active matter is typically identified as matter that exhibits two characteristic features: self-propelling parts, and coherent dynamical activity among the parts. These features are exhibited across a wide range of organic and inorganic materials, and they are jointly sufficient for classifying matter as active. Recently, the term “active materials” has entered scientific use as a complement, supplement, (...) and extension of “active matter.” At the same time, new work in the philosophy of science has considered the problem of how to classify the products of synthetic and laboratory processes, and the extent to which the aims of classifying natural kinds compare and contrasts with the aims of classifying these synthetic kinds. In this article, I apply those considerations to the problems of classifying and characterizing active materials. In doing so, I also argue for a conception of active materials’ coherent dynamical activity as multiscale, rather than emergent, and I discuss how the special non-equilibrium status of active materials factors in to classificatory concerns. (shrink)

This paper draws on the notion of “objects of research” in psychology as clusters of phenomena (Feest in Philos Sci 84:1165–1176, 2017) to analyze the productive role of folk psychological concepts—and the operational definitions that arise from them—in the development of concepts in scientific psychology. Using the case study of similarity, I discuss the role of the folk psychological concept in the regimentation of different measures of similarity judgments. I propose that by giving rise to operational definitions that lead to (...) experimental dissociation on the one hand, and by providing the concept with unity on the other hand, the folk psychological concept generates a productive tension that facilitates empirical and theoretical development of the scientific concept. (shrink)

Are acids natural kinds? Or are they merely relevant kinds? Although acidity has been one of the oldest and most important concepts in chemistry, surprisingly little ink has been spilled on the natural kind question. I approach the question from the perspective of microstructural essentialism. After explaining why both Brønsted acids and Lewis acids are considered functional kinds, I address the challenges of multiple realization and multiple determination. Contra Manafu and Hendry, I argue that the stereotypical properties of acids are (...) not multiply realized. Instead, given the equivalence between the proton-donating and electron-accepting mechanisms of Brønsted and Lewis, respectively, I show that acidity as a property type can be identified with a unique microstructural property, namely the presence of a LUMO or other low energy empty orbital. In doing so, I defend the view that the Lewis theory encompasses Brønsted--Lowry, and that all Brønsted acids are also Lewis acids. Contra Hacking and Chang, I thus maintain that the different concepts of acidity do not crosscut, and that the hierarchy requirement is met. Finally, by characterizing natural kinds as powerful objects and by adopting a dispositional view of functions, I illustrate how the microessentialist can make sense of the latent and relational character of most acids. In sum, I contend that acids are genuine natural kinds, even for the microstructural essentialist. (shrink)

According to retail realism, we ought to abandon wholesale arguments, which purport to demonstrate realism or anti-realism about theoretical entities in general, and embrace retail arguments, which purport to demonstrate realism or anti-realism about specific kinds of theoretical entities. My aim is to argue that there is a further wholesale element that retail realism must avoid in order to qualify as a viable position. In order to do so, I distinguish between what I call wholesale and retail treatments of theoretical (...) entities. Wholesale treatments individuate theoretical entities in such a way that the same entity can appear in distinct theories. In that case, realism about a given entity implies realism about that entity as it appears in a number of distinct theories. Retail treatments, on the other hand, individuate theoretical entities more finely, so that distinct theories actually involve distinct entities. In that case, realism about one entity needn't imply realism about a similar, but distinct, entity. I argue that retail realists ought to reject wholesale treatments in favor of retail treatments, and I do so by examining a case from the history of chemistry involving the hypothetical constituent of hydrochloric acid known as the muriatic radical. I argue that there are distinct muriatic radicals in distinct theories, and that we ought to be realists about some, but not others. Hence, in this case, a retail treatment is preferable to a wholesale one, and I conclude by discussing why the combination of retail realism and retail treatments constitutes an attractive position within the scientific realism debate more generally. (shrink)