Eric Scerri

This article considers two important traditions concerning the chemical elements. The first is the meaning of the term “element” including the distinctions between element as basic substance, as simple substance and as combined simple substance. In addition to briefly tracing the historical development of these distinctions, I make comments on the recent attempts to clarify the fundamental notion of element as basic substance for which I believe the term “element” is best reserved. This discussion has focused on the writings of Fritz Paneth which are here analyzed from a new perspective. The other tradition concerns the reduction of chemistry to quantum mechanics and an understanding of chemical elements through their microscopic components such as protons, neutrons and electrons. I claim that the use of electronic configurations has still not yet settled the question of the placement of several elements and discuss an alternative criterion based on maximizing triads of elements. I also point out another possible limitation to the reductive approach, namely the failure, up to now, to obtain a derivation of the Madelung rule. Mention is made of some recent similarity studies which could be used to clarify the nature of ‘elements’. Although it has been suggested that the notion of element as basic substance should be considered in terms of fundamental particles like protons and electrons, I resist this move and conclude that the quantum mechanical tradition has not had much impact on the question of what is an element which remains an essentially philosophical issue

The philosopher of chemistry Andrea Woody has recently published a wide-ranging article concerning the turn to practice in the philosophy of science. Her primary example consists of the use of different forms of representations by Lothar Meyer and Mendeleev when they presented their views on chemical periodicity. Woody believes that this distinction can cast light on various issues including why Mendeleev was able to make predictions while Meyer was not. Secondly, she claims that it can clarify the much-debated question concerning the relative values of prediction and accommodation of data in the way that the periodic system was accepted. Thirdly, Woody believes that such differences in the representation of periodicity can be used to argue for the explanatory nature of the periodic table in contrast with the more traditional view that the periodic table is not explanatory.

The term philosophy of chemistry is here construed broadly to include some publications from the history of chemistry and chemical education. Of course this initial selection of material has inevitably been biased by the interests of the author. This bibliography supersedes that of van Brakel and Vermeeren (1981), although no attempt has been made to include every single one of their entries, especially in languages other than English. Also, readers interested particularly in articles in German may wish to consult the bibliography by Dittus and Mayer which also contains some material not included here (Dittus and Mayer, 1992). The aim is to maintain an up-to-date version of this bibliography and to publish a revised version in due course. Suggestions for further inclusions should be sent to the author.

Two articles on the reduction of chemistry are examined. The first, by McLaughlin (1992), claims that chemistry is reduced to physics and that there is no evidence for emergence or for downward causation between the chemical and the physical level. In a more recent article, Le Poidevin (2005) maintains that his combinatorial approach provides grounding for the ontological reduction of chemistry, which also circumvents some limitations in the physicalist program. †To contact the author, please write to: Department of Chemistry and Biochemistry, UCLA, 607 Charles E. Young Drive East, Box 951569, Los Angeles, CA 90095-1569; e-mail: [email protected].

The philosophy of chemistry has been sadly neglected by most contempory literature in the philosophy of science. This paper argues that this neglect has been unfortunate and that there is much to be learned from paying greater philosophical attention to the set of issues defined by the philosophy of chemistry. The potential contribution of this field to such current topics as reduction, laws, explanation, and supervenience is explored, as are possible applications of insights gained by such study to the philosophy of mind and the philosophy of social 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.

The debate about the relative epistemic weights carried in favour of a theory by predictions of new phenomena as opposed to accommodations of already known phenomena has a long history. We readdress the issue through a detailed re-examination of a particular historical case that has often been discussed in connection with it—that of Mendeleev and the prediction by his periodic law of the three ‘new’ elements, gallium, scandium and germanium. We find little support for the standard story that these predictive successes were outstandingly important in the success of Mendeleev's scheme. Accommodations played an equal role—notably that of argon, the first of the ‘noble gases’ to be discovered; and the methodological situation in this chemical example turns out to be in interesting ways different from that in other cases—invariably from physics—that have been discussed in this connection. The historical episode when accurately analysed provides support for a different account of the relative weight of prediction and accommodation—one that is further articulated here

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

In this article I examine several related views expressed by Robin Hendry concerning molecular structure, emergence and chemical bonding. There is a long-standing problem in the philosophy of chemistry arising from the fact that molecular structure cannot be strictly derived from quantum mechanics. Two or more compounds which share a molecular formula, but which differ with respect to their structures, have identical Hamiltonian operators within the quantum mechanical formalism. As a consequence, the properties of all such isomers yield precisely the same calculated quantities such as their energies, dipole moments etc. The only means through which the difference between the isomers can be recovered is to build their structures into the quantum mechanical calculations, something that is carried out by the application of the Born-Oppenheimer approximation. Consequently, it has been argued by many authors that molecular structure is written in ‘by hand’ rather than derived. Robin Hendry is one such author, but he goes a great deal further by proposing that this situation implies the existence of emergence and downward causation. In the current article I argue that there are alternative explanations which render emergence and downward causation redundant. Such an alternative lies in the notion of quantum decoherence and the appeal to work in the foundations of physics, which posits that the various isomers exist as a superposition until their wavefunctions are collapsed either by observation or by interacting with their environment. Hendry also alludes to a debate among chemists as to whether chemical bonds are real or not, in the sense of directional connections between two or more nuclei in any given molecule. I reject this view and propose that the structural and energetic views of chemical bonding, that have been discussed by some philosophers of chemistry including Hendry, do not refer to any essential ontological differences. I agree that chemists view bonding in a more realistic fashion and may consider bonds to be in some senses real, while physicists may consider bonding in more abstract energetic terms. However, I do not believe that such differences in scientific practice and attitudes should be considered to offer a window as to the ontological status of bonding or whether bonding is real. Finally, I discuss the kinetic energy school of chemical bonding which would seem to challenge any notion of bonds as directional entities, since bonding is no longer regarded as being primarily due to the build-up of electron density between nuclei.

One of the consequences of the renewed interest in philosophical aspects of chemistry has been the corresponding renewed interest in the periodic system of the elements which embodies so much chemical knowledge in an implicit form.We have therefore decided to further promote scholarship on the periodic system by compiling a bibliography of previously published material. As the title of this article implies, we restrict ourselves to secondary sources. Readers interested in primary material can consult a number of useful references for this purpose. These include the classical treatment on the History of the periodic system by van Spronsen as well as Mazurs’s compilation of over 700 forms of the periodic system. Mazurs also includes a detailed bibliography of articles and books in several different languages. Additional sources of primary articles which come to mind include David Knight’s Classics in the History of Chemistry, Carmen Giunta’s web pages for the history of chemistry and entries under individual scientists in the Dictionary of Scientific Biography. Turning to the present compilation we do not claim this to be a comprehensive list, since it partly reflects the interests of the senior author (E.R.S.), namely the relationship between the periodic system and quantum mechanics. For example, in addition to articles specifically on the periodic system we include a number of articles which deal with the related themes of electronic configurations of the elements. This bias also explains the disproportionate number of references to the work of the senior author.We have tried to include as many as possible of the articles on the periodic system which have appeared in the philosophy of science literature. These include Bensaude, Christie, Hettema and Kuipers, Kultgen, Lipton, Maher, Scerri, Shapere and Sundaram, among others.

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

This comprehensive volume marks a new standard in scholarship in the still emerging field of the philosophy of chemistry. With selections drawn from a wide range of scholarly disciplines, philosophers, chemists, and historians of science here converge to ask some of the most fundamental questions about the relationship between philosophy and chemistry. What can chemistry teach us about longstanding disputes in the philosophy of science over such issues as reductionism, autonomy, and supervenience? And what new issues may chemistry bring to the forefront now that it has joined physics and biology as a serious topic for philosophical reflection? This newest addition to the prestigious Boston Studies in the Philosophy of Science series marks the true arrival of philosophy of chemistry within the corpus of the philosophy of science.

Sir Karl Popper is one of the few authors to have discussed the reduction of chemistry. His approach consists of what I term naturalistic reduction, which I suggest bears close similarities to the way in which scientists regard reduction. The present article aims to build on Popper's insights into the nature of reduction in science and more specifically to suggest an approach to characterizing a specific sense of the notion of approximate reduction in the context of chemistry. In the course of the discussion, one of Popper's better known passages on the reduction of chemistry is analysed in some detail.

I claim that the question of whether chemistry is reduced to quantum mechanics is more ambiguous and multi-faceted than generally supposed. For example, chemistry appears to be both reduced and not reduced at the same time depending on the perspective that one adopts. Similarly, I argue that some conceptual issues in quantum mechanics are ambiguous and can only be laid to rest by embracing paradox and ambiguity rather than regarding them as obstacles to be overcome. Recent work in the reduction of chemistry is also reviewed, including discussions of the ontological reduction of chemistry and the question of the emergence of chemistry from physics