Realism in Chemistry

The heated debates and severe conflicts between the atomists and the anti-atomists of the latter half of the nineteenth century are well known to the historian of science. The position of Dmitrii Ivanovich Mendeleev towards these nineteenth century debates on atomism will be studied in this paper. A first attempt will thus be offered to reconcile Mendeleev’s seemingly contradictory comments and ambiguous standpoints into one coherent view.

In this paper, we try to understand how Bunge’s scientific hylorealism can fit with several crystal chemistry’s objects and their properties. It is found that many of them, lying at the very core of this discipline, bring support to ontologi-cal emergentism. Building units, such as vacancies, their chemical potential, the crystal quantum number and many aspects of the spectroscopic properties of 4f electrons in ionic crystals, are presented as striking examples of emergent (or submergent) objects or properties encountered in the (...) single crystalline state. Among all the types of building. (shrink)

Dans cet article, nous essayons de comprendre comment l’hyloréalisme scientifique de Bunge peut s’accommoder avec plusieurs objets de la chimie des cristaux et leurs propriétés. Nous montrons que plusieurs d’entre eux, constituant le cœur de la discipline, soutiennent l’émergentisme ontologique. Les unités de construction, comme les lacunes, leur potentiel chimique, le nombre quantique cristallographique et plusieurs aspects des propriétés spectroscopiques des électrons 4f dans les cristaux ioniques, sont présentés comme des exemples remarquables d’objets ou de propriétés émergents (ou submergents) rencontrés (...) dans l’état cristallin. Parmi tous les types d’unités de construction, nous montrons que les lacunes s’avèrent ontologiquement réelles et matérielles. (shrink)

Invited review of the anthology of new papers _Philosophy of Chemistry: Growth of a New Discipline_.

Quine, taking the molecular constitution of matter as a paradigmatic example, offers an account of the relation between theory confirmation and ontology. Elsewhere, he deploys a similar ontological methodology to argue for the existence of mathematical objects. Penelope Maddy considers the atomic/molecular theory in more historical detail. She argues that the actual ontological practices of science display a positivistic demand for “direct observation,” and that fulfillment of this demand allows us to distinguish molecules and other physical objects from mathematical abstracta. (...) However, the confirmation of the atomic/molecular theory and the development of scientists’ ontological attitudes towards atoms was more complicated and subtle than even Maddy supposes. The present paper argues that the history of the theory in fact supports neither Quine’s and Maddy’s accounts of scientific ontology. There was no general demand from scientists to “see” atoms before they were reckoned to be real; but neither did the indispensable appearance of atoms in the best theory of chemical combination suffice to convince scientists of their reality. (shrink)

Recent work on Natural Kind Essentialism has taken a deflationary turn. The assumptions about the grounds of essentialist truths concerning natural kinds familiar from the Kripke-Putnam framework are now considered questionable. The source of the problem, however, has not been sufficiently explicated. The paper focuses on the Twin Earth scenario, and it will be demonstrated that the essentialist principle at its core (which I call IDENT)—that necessarily, a sample of a chemical substance, A, is of the same kind as another (...) sample, B, if and only if A and B have the same microstructure—must be re-evaluated. The Twin Earth scenario also assumes the falsity of another essentialist principle (which I call INST): necessarily, there is a 1:1 correlation between (all of ) the chemical properties of a chemical substance and the microstructure of that substance. This assumption will be questioned, and it will be argued that, in fact, the best strategy for defending IDENT is to establish INST. The prospects for Natural Kind Essentialism and microstructural essentialism regarding chemical substances will be assessed with reference to recent work in the philosophy of chemistry. Finally, a weakened form of INST will be presented. (shrink)

When scientists put forward hypotheses, they sometimes involve new kinds of entities, which we can call 'hypothetical entities.' Hypothetical entities are pervasive in the sciences, and some examples include caloric and, up until very recently, the Higgs boson. Some hypothetical entities are discovered, as was the case with the Higgs boson, while scientists conclude that others, like caloric, do not exist. Hypothetical entities pose a number of important challenges for the philosophy of science, and my goal is to develop and (...) defend what I will call the suppositionalist view of hypothetical entities. In chapter 1, I examine the extant views of hypothetical entities, which I draw from the scientific realism debate. I argue that these views are all committed to the claim that terms for hypothetical entities putatively refer to empirical entities. In chapter 2, I develop the suppositionalist view of hypothetical entities. On this view, terms for hypothetical entities refer to what are called 'objects of supposition.' Examples of such objects from other domains include fictional characters like Superman and mathematical objects like the natural numbers. I draw from analogies with fiction and mathematics in order to develop the suppositionalist view in the scientific domain. In chapter 3, I give a history of a hypothetical entity that I will later use as a test case for views of hypothetical entities. In the late-eighteenth century, Antoine Lavoisier hypothesized that muriatic acid is composed of oxygen and a hypothetical entity called the 'muriatic radical.' In the early-nineteenth century, Humphry Davy's work on muriatic acid showed that it is actually composed of hydrogen and chlorine, and so muriatic acid is hydrochloric acid. Finally, in chapter 4, I use the history of the muriatic radical in order to argue against the extant views, and for the suppositionalist view. I argue that the former are committed to giving a history of the muriatic radical that is either whiggish or incomplete. The latter, however, can give us a non-whiggish history that is more complete, and hence it is preferable to the extant views. (shrink)

Chemistry and physics are two sciences that are hard to connect. Yet there is significant overlap in their aims, methods, and theoretical approaches. In this book, the reduction of chemistry to physics is defended from the viewpoint of a naturalised Nagelian reduction, which is based on a close reading of Nagel's original text. This naturalised notion of reduction is capable of characterising the inter-theory relationships between theories of chemistry and theories of physics. The reconsideration of reduction also leads to a (...) new characterisation of chemical theories. This book is primarily aimed at philosophers of chemistry and chemists with an interest in philosophy, but is also of interest to the general philosopher of science. (shrink)

This paper discusses the proposal made by Lombardi and Labarca (Found Chem 7:125–148, 2005) that internal realism can secure the ontological autonomy of chemistry. I argue that internal realism is not, by itself, sufficient to accomplish this task. The fact that conceptual schemes may differ with respect to their theoretical virtues, and the possibility that the relations between them may be reductive undermine the premise that each conceptual scheme has an equal right to define its own ontology, which is a (...) key premise in Lombardi and Labarca’s proposal. (shrink)

In this paper I discuss the question whether orbitals can be observed or not. I argue that the answer depends on how the terms 'orbitals' and 'observed' are understood. The fact that different authors take radically different stances on the issue is caused by their employing different uses of either of the two terms. I furthermore discuss a recent argument by Labarca and Lombardi to the effect that the orbital concept in chemistry is discontinuous with that in quantum mechanics. I (...) argue that, quite to the contrary, there is continuity between the two. (shrink)

According to ontological reductionism, molecular chemistry refers, at last, to the quantum ontology; therefore, the ontological commitments of chemistry turn out to be finally grounded on quantum mechanics. The main problem of this position is that nobody really knows what quantum ontology is. The purpose of this work is to argue that the confidence in the existence of the physical entities described by quantum mechanics does not take into account the interpretative problems of the theory: in the discussions about the (...) relationship between chemistry and physics, difficulties are seen only on the side of chemistry, whereas matters highly controversial on the side of physics are taken for granted. For instance, it is usually supposed that the infinite mass limit in the Born-Oppenheimer approximation leads by itself to the concept of molecular framework used in molecular chemistry. We will argue that this assumption is implicitly based on an interpretative postulate for quantum mechanics, which, in turn, runs into difficulties when applied to the explanation of the simplest model of the hydrogen atom. (shrink)

The aim of the present paper is to analyze the problem of the relationship between chemistry and physics, by focusing on the widely discussed case of the atomic orbitals. We will begin by remembering the difference between the physical and the chemical interpretation of the concept of orbital. Then, we will refer to the claim made in 1999 that atomic orbitals have been directly imaged for the first time. On this basis, we will analyze the problem from a new approach, (...) by comparing the concept of orbital used in physics with the concept of orbital used in chemistry. Such an analysis will allow us to argue for an ontological pluralism that admits the coexistence of different ontologies without priorities or metaphysical privileges. From this philosophical framework, the concepts of chemical orbital and physical orbital correspond to two different ontologies. As a consequence, chemical orbitals are real entities belonging to the ontology of molecular chemistry, and can be observed like any other entity not belonging to the quantum mechanical ontology. DOI:10.5007/1808-1711.2010v14n3p309. (shrink)

In this paper we will address the problem of the existence of orbitals by analyzing the relationship between molecular chemistry and quantum mechanics. In particular, we will consider the concept of orbital in the light of the arguments that deny its referring character. On this basis, we will conclude that the claim that orbitals do not exist relies on a metaphysical reductionism which, if consistently sustained, would lead to consequences clashing with the effective practice of science in its different branches.

Mulliken proposed an Aufbauprinzip for the molecules on the basis of molecular spectroscopy while establishing, point by point, his concept of molecular orbit. It is the concept of electronic state which becomes the lever for his attribution of electronic configurations to a molecule. In 1932, the concept of orbit was transmuted into that of the molecular orbital to integrate the probabilistic approach of Born and to achieve quantitative accuracy. On the basis of the quantum works of Hund, Wigner, Lennard-Jones and (...) group theory, he suggested the fragment method to establish the characteristics of molecular orbital for polyatomic molecules. These developments make it possible to bring elements of thought on the relation between a molecular whole and its parts . An operational realism combined with the second law of thermodynamics can pave the way for interesting tracks in the mereological study of chemical systems. (shrink)

In September 1999 "Nature" magazine announced that atomic orbitals were di-rectly observed. Opposing it, Eric Scerri, editor-in-chief of "Foundations of Chemistry", claimed that what could be observed in the experiment was electron density, not orbitals. The main purpose of this paper is to consider philosophical and methodological aspects of the above controversy. Especially, the problems of direct observability and reality of theoretical entities are taken under detailed discussion. From the point of view of quantum mechanics there are not any reasons (...) to believe that orbitals exist. However, realistically treated orbitals are very effective tools in the laboratory practice of chemistry. (shrink)

Immanuel Kant has built up a dualistic epistemology that seems to fit to the peculiarities of chemistry quite well. Friedrich Paneth used Kant’s concept and characterised simple and basic substances which refer to the empirical and to the transcendental world, respectively. This paper takes account of the Kantian influences in Paneth’s philosophy of chemistry, and discusses pertinent topics, like observables, atomism and realism.

Microstructuralism in the philosophy of chemistry is the thesis that chemical kinds can be individuated in terms of their microstructural properties (Hendry in Philos Sci 73:864–875, 2006 ). Elements provide paradigmatic examples, since the atomic number should suffice to individuate the kind. In theory, Microstructuralism should also characterise higher-level chemical kinds such as molecules, compounds, and macromolecules based on their constituent atomic properties. In this paper, several microstructural theses are distinguished. An analysis of macromolecules such as moonlighting proteins suggests that (...) all the forms of microstructuralism cannot accommodate them. (shrink)

This paper suggests that the cases made for atoms and the aether in nineteenth-century physical science were analogous, with the implication that the case for the atom was less than compelling, since there is no aether. It is argued that atoms did not play a productive role in nineteenth-century chemistry any more than the aether did in physics. Atoms and molecules did eventually find an indispensable home in chemistry but by the time that they did so they were different kinds (...) of entities to those figuring in the speculations of those natural philosophers who were atomists. Advances in nineteenth-century chemistry were a precondition for rather than the result of the productive introduction of atoms into chemistry. (shrink)

The traditional ontology within which chemistry has developed involved various versions of a general substance/attribute scheme. Recently this has been challenged by two versions of Dynamism. One version is derived from the writings of A. N. Whitehead and the other from several sources, including G. Leibniz and I. Kant. Both involve the idea of flux of actual occasions. Unlike the former scheme, the latter involves a foundation of causal powers and the energetics of field theory. The situation has been made (...) more interesting because of the revival of trope theory, based on an ontology of particularized attributes. This notion is claimed to resolve philosophical problems about the nature of universals and of substances through the introduction of spatial and temporal sequences of tropes. While trope theory seems, at first sight, to work as an attractive alternative to substance/attribute close inspection shows that it is beset with difficulties that are more problematic that the dynamist ontology based on casual powers, dispositions and affordances. (shrink)

Despite the currently perceived urgent need among contemporary philosophers of chemistry for adjudicating between two rival metaphysical conceptual frameworks—is chemistry primarily a science of substances or processes?—this essay argues that neither provides us with what we need in our attempts to explain and comprehend chemical operations and phenomena. First, I show the concept of a chemical property can survive the abandoning of the metaphysical framework of substance. While this abandonment means that we will need to give up essential properties, contingent (...) properties can give us all the stability we need to account for chemical continuity as well as change. I then go on to show that this attention to clusters of contingent properties does not force us into the arms of an alternative process metaphysical framework either. Finally, I sketch a view I call particularism with respect to chemical properties on analogy with moral particularism. I conclude by sketching some of the implications for the field of philosophy of chemistry of my proposal that we abandon our interest in the metaphysical question of what chemistry is primarily about in favor of a broadly scientific particularism with respect to kinds and properties. (shrink)

Had more philosophers of science come from chemistry, their thinking would have been different. I begin by looking at a typical chemical paper, in which making something is the leitmotif, and conjecture/refutation is pretty much irrelevant. What in fact might have been, might be, different? The realism of chemists is reinforced by their remarkable ability to transform matter; they buy into reductionism where it serves them, but make no real use of it. Incommensurability is taken without a blink, and actually (...) serves. The preeminence of synthesis in chemistry could have led philosophers of science to take more seriously questions of aesthetics within science, and to find a place in aesthetics for utility. The necessary motion twixt macroscopic and microscopic views of matter in modern chemistry leads to the coexistence of symbolic and iconic representations. And in another way to the deliberate, creative violation of categories. (shrink)

Ellis argues that certain essential properties of objects in the world not only determine the nature of these objects but also how they will behave in any situation. In this paper I will critique Ellis's essentialism from the perspective of the philosophy of chemistry, arguing that our current knowledge of chemistry in fact does not lend itself to essentialist interpretations and that this seriously undercuts Ellis's project. In particular I will criticize two key distinctions Ellis draws between internal vs. external (...) properties and essential vs. accidental properties, showing that at the chemical level such distinctions are insupportable. If essential properties only exist at the level of sub-atomic physics, then Ellis's hopes that essentialism will provide a theoretical basis for a philosophy of chemistry are at best hopes for a very distant future, since the argument that chemical structure and dynamics can be explained at the quantum level derived is purely from analogy to much simpler systems than those chemists actually study. This suggests that we have very little scientific evidence that scientific essentialism is a viable ontology. †To contact the author, please write to: Department of Philosophy, University of Notre Dame, Notre Dame, IN 46556; e-mail: [email protected]. (shrink)

Constructivism rejects the metaphysical position that “truth”, and thus knowledge in science, can represent an “objective” reality, independent of the knower. It modifies the role of knowledge from “true” representation to functional viability. In this interview, Ernst von Glasersfeld, the leading proponent of Radical Constructivism underlines the inaccessibility of reality, and proposes his view that the function of cognition is adaptive, in the biological sense: the adaptation is the result of the elimination of all that is not adapted. There is (...) no rational way of knowing anything outside the domain of our experience and we construct our world of experiences. In addition to these philosophical claims, the interviewee provides some personal insights; he also gives some suggestions about better teaching and problem solving. These are the aspects of constructivism that have had a major impact on instruction and have modified the manner many of us teach. The process of teaching as linguistic communication, he says, needs to change in a way to involve actively the students in the construction of their knowledge. Because knowledge is not a transferable commodity, learning is mainly identified with the activity of the construction of personal meaning. This interview also provides glimpses on von Glasersfeld’s life. (shrink)

Research into learners' ideas about science suggests that students often have alternative conceptions about important science concepts. Because of this dissatisfaction, constructivism has been adopted as a theoretical framework by many teachers and researchers, and it has had a curricular influence in many countries. Constructivism is much more than an educational doctrine and we are aware that a ‘science war’ about the possibility of objectivity is in progress. ‘Constructivism’ cannot necessary be a package deal: it must be possible to accept (...) educational suggestions deemed useful without buying all the epistemology or the metaphysical implications. The claim that cognitive agents understand the world by constructing mental representations of it can be a shared suggestion for changing science instruction. Many teachers are much more concerned in finding productive teaching methods than about philosophical questions as if knowledge must be considered an objective representation of the real world or not. We have to ponder if some ideas from the constructivist theory of instruction can help instructors to become better teachers. The pragmatic suggestions that come from the constructivist theory of instruction developed by von Glasersfeld, the leading proponent of radical constructivism, could be a good start in this␣search. (shrink)

A review of the chemical education research literature suggests that the term constructivism is used in two ways: experience-based constructivism and discipline-based constructivism. These two perspectives are examined as an epistemology in relation to the teaching and learning of the concept of idealization in chemistry. It is claimed that experience-based constructivism is powerless to inform the origin of such concepts in chemistry and while discipline-based constructivism can admit such theoretical concepts as idealization it does not offer any unique perspectives that (...) cannot be obtained from other models. Chemical education researchers do not consistently appeal to constructivism as an epistemology or as a teaching/learning perspective and it is shown that, while it draws attention to worthwhile teaching/learning strategies, it cannot be considered as foundational to chemical education research and tends to be used more as an educational label than as an undergirding theory. (shrink)

During the 1930s and 1940s, American physical organic chemists employed electronic theories of reaction mechanisms to construct models offering explanations of organic reactions. But two molecular rearrangements presented enormous challenges to model construction. The Claisen and Cope rearrangements were predominantly inaccessible to experimental investigation and they confounded explanation in theoretical terms. Drawing on the idea that models can be autonomous agents in the production of scientific knowledge, I argue that one group of models in particular were functionally autonomous from the (...) Hughes–Ingold theory. Cope and Hardy’s models of the Claisen and Cope rearrangements were resources for the exploration of the Hughes–Ingold theory that otherwise lacked explanatory power. By generating ‘how-possibly’ explanations, these models explained how these rearrangements could happen rather than why they did happen. Furthermore, although these models were apparently closely connected to theory in terms of their construction, I argue that partial autonomy issued in extra-logical factors concerning the attitudes of American chemists to the Hughes–Ingold theory. And in the absence of a complete theoretical hegemony, a degree of consensus was reached concerning modelling the Claisen rearrangement mechanism.Keywords: Models; Explanation; Physical organic chemistry; Rearrangements. (shrink)

In this paper, aspects of observable and non-observable based models are discussed. A survey of recent literature was done to show how using non-observable-based language carelessly may cause disagreement, even in professional research programs and incorrect assertions, even in prestigious journals. The relation between physical measurements and observables is discussed and it is shown that, in contrast to general belief, this relation may be complicated and not always straightforward. The decomposition of the system into basic subsystems (physical or conceptual) is (...) traced as the origin of non-observable-based languages. The possibility of defining new quantum mechanical observables for open quantum subsystems and of replacing them with non-observable-based concepts has been mentioned and the AIM theory is explained as an example. An account of some current non-observable-based models for molecular geometry is discussed and it is shown that not all non-observable-based languages possess the same effectiveness. In the end, the need to develop a clear chemical language is stressed. (shrink)

Constructivism has been a key referent for research into the learning of science for several decades. There is little doubt that the research into learners’ ideas in science stimulated by the constructivist movement has been voluminous, and a great deal is now known about the way various science topics may commonly be understood by learners of various ages. Despite this significant research effort, there have been serious criticisms of this area of work: in terms of its philosophical underpinning, the validity (...) of its most popular constructs, the limited scope of its focus, and its practical value to science teaching. This paper frames this area of work as a Lakatosian Research Programme (RP), and explores the major criticisms of constructivism from that perspective. It is argued that much of the criticism may be considered as part of the legitimate academic debate expected within any active RP, i.e. arguments about the auxiliary theory making up the ‘protective belt’ of the programme. It is suggested that a shifting focus from constructivism to ‘contingency in learning’ will allow the RP to draw upon a more diverse range of perspectives, each consistent with the existing hard core of the programme, which will provide potentially fruitful directions for future work and ensure the continuity of a progressive RP into learning science. (shrink)

The rich and ongoing debate about constructivism in chemistry education includes questions about the relationship, for better or worse, between applications of the theory in pedagogy and in epistemology. This paper presents an examination of the potential to use connections of epistemological and pedagogical constructivism to one another. It examines connections linked to the content, processes, and premises of science with a goal of prompting further research in these areas.

There is now a considerable body of published work on the epistemology of modern chemistry, especially with regard to the nature of quantum chemistry. In addition, the question of the metaphysical underpinnings of chemistry has received a good deal of attention. The present article concentrates on metaphysical considerations including the question of whether elements and groups of elements are natural kinds. It is also argued that an appeal to the metaphysical nature of elements can help clarify the re-emerging controversies among (...) chemists regarding the placement of the elements hydrogen and helium in the periodic system and the question of whether there exists a best form of the periodic table. (shrink)

In the problem of the relationship between chemistry and physics, many authors take for granted the ontological reduction of the chemical world to the world of physics. The autonomy of chemistry is usually defended on the basis of the failure of epistemological reduction: not all chemical concepts and laws can be derived from the theoretical framework of physics. The main aim of this paper is to argue that this line of argumentation is not strong enough for eliminate the idea of (...) a hierarchical dependence of chemistry with respect to physics. The rejection of the secondary position of chemistry and the defense of the legitimacy of the philosophy of chemistry require a radically different philosophical perspective that denies not only epistemological reduction but also ontological reduction. Only on the basis of a philosophically grounded ontological pluralism it is possible to accept the ontological autonomy of the chemical world and, with this, to reverse the traditional idea of the ‘superiority’ of physics in the context of natural sciences. (shrink)

الكيمياء علمٌ تجريبي بطبيعته، يشتغل معمليًا بالجواهر تحليلاً وتركيبًا، ويُقيم بناءاته النسقية استرشادًا بقواعد محددة تحكم إجراءات البحث التجريبي ونتائجه. وكشأن أي نشاط علمي آخر، تستلزم الممارسة الكيميائية لغة جزئية خاصة تصف بناءاتها التجريبية وتُنمّط أشكالها. وما دام التحليل والتركيب – كإجراءين تجريبيين – هما عمادا البحث الكيميائي وجوهره، فمن الضروري أن تحوي لغة الكيمياء تمثيلات صورية توصف بدورها بأنها صيغٌ أو عبارات تحليلية وتركيبية. يمكننا إذن الزعم بأن ثمة علاقة اعتماد متبادلة بين لغة الكيمياء وممارساتها المعملية؛ فاللغة تؤثر مباشرة (...) – وبأكثر من طريقة – على مجرى البحث الكيميائي وتطوره, ومن خلالها يمكن تحديد مدى قوته أو ضعفه ... تقدمه أو تخلفه ... شرعية تنبؤاته أو افتقادها لسمة الشرعية المنطقية؛ كما أن سُبل البحث المعملي للكيمياء تنعكس بالضرورة على قواعد الصياغة الصورية لهذه اللغة ومدى إمكانية تطويرها وتنقيتها من شوائب اللغة العادية التي اشتُقت منها. ويعني ذلك – بعبارة أخرى – أن اللغة والتجريب شقان مُكملان لبعضهما البعض؛ وجهان لعملة واحدة تحمل اسم الممارسة العلمية. فهل تختلف اللغة الكيميائية عن غيرها من لغات العلم الخاصة؟ وكيف يستخدم الكيميائيون لغتهم؟ ما هي القواعد الحاكمة لهذه اللغة؟, وما هي نتائج استخدامها بالنسبة للكيمياء ككل؟. (shrink)

According to ‘standard histories’ of nanotechnology, the colorful pictures of atoms produced by scanning probe microscopists since the 1980s essentially inspired visions of molecular nanotechnology. In this paper, I provide an entirely different account that, nonetheless, refers to aesthetic inspiration, First, I argue that the basic idea of molecular nanotechnology, i.e., producing molecular devices, has been the goal of supramolecular chemistry that emerged earlier, without being called nanotechnology. Secondly, I argue that in supramolecular chemistry the production of molecular devices was (...) inspired by an aesthetic phenomenon of gestalt switch, by certain images that referred to both molecules and ordinary objects, and thus symbolically bridged the two worlds. This opened up a new way of perceiving and drawing molecular images and new approaches to chemical synthesis. Employing Umberto Eco’s semiotic theory of aesthetics, I analyze the gestalt switch and the inspiration to build molecular devices and to develop a new sign language for supramolecular chemistry. More generally, I argue that aesthetic phenomena can play an important role in directing scientific research and that aesthetic theories can help understand such dynamics, such that they need to be considered in philosophy of science. (shrink)

A puzzle for identity statements using massnouns, central to the expression of chemicaltypes, arises if one accepts that both `Wateris H2O' and `Ice is H2O' are identitystatements, since they jointly entail that`Water is ice'. The puzzle is resolved if itcan be shown that the `is' of such statementsis not the `is' of identity.

Traditional nomological accounts of scientific explanation have assumed that a good scientific explanation consists in the derivation of the explanandum’s description from theory (plus antecedent conditions). But in more recent philosophy of science the adequacy of this approach has been challenged, because the relation between theory and phenomena in actual scientific practice turns out to be more intricate. This critique is here examined for an explanatory paradigm that was groundbreaking for 20th century physics and chemistry (and their interrelation): Bohr’s first (...) model of the atom and its explanatory relevance for the spectrum of hydrogen. First, the model itself is analysed with respect to the principles and assumptions that enter into its premises. Thereafter, the origin of the model’s explanandum is investigated. It can be shown that the explained “phenomenon” is itself the product of a host of modelling accomplishments that stem from an experimental tradition related to 19th century chemistry, viz. spectroscopy. The relation between theory and phenomenon is thus mediated in a twofold way: by (Bohr’s) theoretical model and a phenomenological model from spectroscopy. In the final section of the paper an account is outlined that nevertheless permits us to acknowledge this important physico-chemical achievement as a case of (nomological) explanation. (shrink)

Eric Scerri and other authors have acknowledged that the reality of chemical orbitals is not compatible with quantum mechanics. Recently, however, Scerri and Sharon Crasnow have argued that if chemists cannot consider orbitals as real entities, then chemistry is in danger of being reduced to physics. I argue that the question of the existence of orbitals is best viewed as an issue of explanation, not metaphysics: In many chemically important cases orbitals do not make sufficiently accurate predictions, and must be (...) replaced. Chemists and physicists can acknowledge this fact while maintaining the utility of orbitals and the autonomy of chemistry. (shrink)

Research into learners' ideas aboutscience suggests that school and collegestudents often hold alternative conceptionsabout `the atom'. This paper discusses whylearners acquire ideas about atoms which areincompatible with the modern scientificunderstanding. It is suggested that learners'alternative ideas derive – at least in part –from the way ideas about atoms are presented inthe school and college curriculum. Inparticular, it is argued that the atomicconcept met in science education is anincoherent hybrid of historical models, andthat this explains why learners commonlyattribute to atoms properties (...) (such as beingthe constituent particles of all substances, orof being indivisible and conserved inreactions) that more correctly belong to otherentities (such as molecules or sub-atomicparticles). Bachelard suggested that archaicscientific ideas act as `epistemologicalobstacles', and here it is argued thatanachronistic notions of the atom survive inthe chemistry curriculum. These conceptualfossils encourage learners to develop an`atomic ontology' (granting atoms `ontologicalpriority' in the molecular model of matter); tomake the `assumption of initial atomicity' whenconsidering chemical reactions; and to developan explanatory framework to rationalisechemical reactions which is based on thedesirability of full electron shells. Theseideas then act as impediments to thedevelopment of a modern chemical perspective onthe structure of matter, and an appreciation ofthe nature of chemical changes at the molecularlevel. (shrink)

If chemistry is to be taught successfully, teachers must have a good subject matter knowledge (SK) of the ideas with which they are dealing, the nature of this falling within the orbit of philosophy of chemistry. They must also have a good pedagogic content knowledge (PCK), the ability to communicate SK to students, the nature of this falling within the philosophy and psychology of chemical education. Taking the case of models and modelling, important themes in the philosophy of chemistry, an (...) interview-based study was conducted into the SK and PCK of a sample of teachers in Brazil. This paper focuses on the results of the university chemistry teacher sub-sample in that enquiry, analyses their SK and PCK, and speculates on the implications of this for the education of school teachers. Finally, it suggests approaches to the professional development of university chemistry teachers that place an emphasis on the philosophy of chemistry. (shrink)

The main thrust of the paper involves a theoretical and philosophical analysis of the claim made in September 1999 that atomic orbitals have been directly imaged for the first time. After a brief account of the recent claims the paper reviews the development of the orbit and later orbital concepts and analyzes the theoretical status of atomic orbitals. The conclusion is that contrary to these claims, atomic orbitals have not in fact been observed. The non-referring nature of modern atomic orbitals (...) is discussed in the context of Laudan's writings on realism, the success of theories, and whether or not scientific terms refer. I conclude that the failure to observe orbitals is a good prima facie case for divorcing the success of theories from the question of whether their central terms refer. The added relevance of this case is that it concerns a current and highly successful theory. Finally, the relevance of this 'floating model' to contemporary discussions on scientific models is briefly considered. (shrink)

The main thrust of the paper involves a theoretical and philosophical analysis of the claim made in September 1999 that atomic orbitals have been directly imaged for the first time. After a brief account of the recent claims the paper reviews the development of the orbit and later orbital concepts and analyzes the theoretical status of atomic orbitals. The conclusion is that contrary to these claims, atomic orbitals have not in fact been observed. The non-referring nature of modern atomic orbitals (...) is discussed in the context of Laudan's writings on realism, the success of theories, and whether or not scientific terms refer. I conclude that the failure to observe orbitals is a good prima facie case for divorcing the success of theories from the question of whether their central terms refer. The added relevance of this case is that it concerns a current and highly successful theory. Finally, the relevance of this ‘floating model’ to contemporary discussions on scientific models is briefly considered. (shrink)

The article disputes the recent claim featured in "Nature" magazine and many other science magazines to the effect that atomic orbitals have been observed for the first time. The claim is incorrect in view of the unconvincing nature of the evidence adduced and since atomic orbitals are deemed unobservable in principle by quantum mechanics. In addition, the possible educational drawbacks of this incorrect claim are discussed.