Chemical Explanation

This treatise presents thoughts on the divide that exists in chemistry between those who seek their understanding within a universe wherein the laws of physics apply and those who prefer alternative universes wherein the laws are suspended or ‘bent’ to suit preconceived ideas. The former approach is embodied in the quantum theory of atoms in molecules (QTAIM), a theory based upon the properties of a system’s observable distribution of charge. Science is experimental observation followed by appeal to theory that, upon (...) occasion, leads to new experiments. This is the path that led to the development of the molecular structure hypothesis—that a molecule is a collection atoms with characteristic properties linked by a network of bonds that impart a structure—a concept forged in the crucible of nineteenth century experimental chemistry. One hundred and fifty years of experimental chemistry underlie the realization that the properties of some total system are the sum of its atomic contributions. The concept of a functional group, consisting of a single atom or a linked set of atoms, with characteristic additive properties forms the cornerstone of chemical thinking of both molecules and crystals and Dalton’s atomic hypothesis has emerged as the operational theory of chemistry. We recognize the presence of a functional group in a given system and predict its effect upon the static, reactive and spectroscopic properties of the system in terms of the characteristic properties assigned to that group. QTAM gives physical substance to the concept of a functional group. (shrink)

The 16th and 17th centuries marked a period of transition from the vitalistic ontology that had dominated Renaissance natural philosophy to the Early Modern mechanistic paradigm endorsed by, among others, the Cartesians and Newtonians. This paper focuses on how the tensions between vitalism and mechanism played themselves out in the context of 16th and 17th century chemistry and chemical philosophy. The paper argues that, within the fields of chemistry and chemical philosophy, the significant transition that culminated in the 18th century (...) Chemical Revolution was not a transition from vitalism to full-blown mechanism. Rather, chemical philosophy shifted from a vitalistic theory of matter and spirits to a naturalistic, physicalistic, and corpuscularian conception of chemical properties and reactions. Despite being naturalistic, physicalistic, and corpuscularian, however, this theory was not fully mechanistic. Special attention is paid to the contributions made by Paracelsus, Sebastien Basso, Jan Baptista van Helmont, and Robert Boyle to this ontological transition. (shrink)

Many theories require empirical patches or ad hoc assumptions to work properly in application to chemistry. Some examples include the Bohr quantum theory of atomic spectra, the Pauli exclusion principle, the Marcus theory of the rate-equilibrium correlation, Kekule’s hypothesis of bond oscillation in benzene, and the quantum calculation of reaction pathways. Often the proposed refinements do not grow out of the original theory but are devised and added ad hoc. This brings into question the goal of constructing theories derived from (...) first principles and the concept of ranking the merit of theories according to their freedom from empirical contamination. (shrink)

Because most chemical reactions, by definition, cannot avoid breaking of bonds, weakly bonded species exist fleetingly in almost every chemical change. Historically, chemical quantum mechanics was aimed at explaining the nature of strong bonds. The theory involved a number of approximations to the full solution of the Schrödinger equation. The study of non‐Kekulé molecules provides an opportunity to test whether modern quantum chemical computations are competent to deal with the nature of molecules with very weak bonds. †To contact the author, (...) please write to: Department of Chemistry, Yale University, New Haven, CT: 06520‐8107; e‐mail: jerome.berson@yale.edu. (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)

The "usual story" regarding molecular chemistry is that it is roughly an application of quantum mechanics. That is to say, quantum mechanics supplies everything necessary and sufficient, both ontologically and epistemologically, to reduce molecular chemistry to quantum mechanics. This is a reductive story, to be sure, but a key explanatory element of molecular chemistry, namely molecular structure, is absent from the quantum realm. On the other hand, typical characterizations of emergence, such as the unpredictability or inexplicability of molecular structure based (...) on quantum mechanics, do not characterize the relationship between molecular chemistry and quantum mechanics well either. A different scheme for characterizing reduction and emergence is proposed that accommodates the relationship between quantum mechanics and molecular chemistry and some initial objections to the scheme are considered. (shrink)

structure of a laboratory report (generalized from Italian, Chinese and US sources), we distill a fifth flavor, the givens, whose flip side is the freedoms or tangibles of an experiment. (Stated in terms of computer science, we are trying to find inputs and outputs, but these turn out to be surprisingly vague in chemistry.) Then, in the service of a white-boxing ethos (which sounds less severe than ‘anti black-boxing’), we establish a movable boundary between givens and tangibles, with implications for (...) ‘ontological attitudes’ and for the future of chemistry. Next, in revisiting a 2002 exchange between Schummer and Laszlo, which might be paraphrased as the chemist-as-philosopher versus chemist-as-artisan, we apply a second kind of sliding scale which seems to harmonize the discussion. Finally, on a possibly quixotic note, we look briefly at a third kind of sliding scale, now aimed squarely at ontology itself. For illustrative purposes, we adopt an atomocentric viewpoint (as distinct from atomistic), and assign it the provisional name ‘Fuzzy CH4 Ontology’. (shrink)

A recent article by Vihalemm (Foundations of Chemistry, 2003) is critical of an earlier essay. We find that there is some justification for his criticism of vagueness in defining terms. Nevertheless the main conclusions of the earlier work, when carefully restated to deflect Vihalemm’s criticisms, are unaffected by his arguments. The various dicta that are used as the bases of chemical explanations are different in character, and are used in a different way from the laws and theories in classical physics.

This essay analyzes the historical and philosophical context that led to the basic concepts of stereochemistry proposed by Van’t Hoff and Le Bel. Although it is now well established that the key idea of tetrahedral carbon, and in general a geometric view of matter, was pioneered by other chemists, Van’t Hoff and Le Bel used this idea to solve the puzzle of optical activity, thereby establishing a direct linkage between structure and physical properties. It is also interesting to note that (...) their proposals came without experimental verification and they were largely based on experiments conducted by others. Philosophical arguments can, however, be invoked to satisfactorily validate this deductive reasoning. (shrink)

This is the second of a series of essays on the development and reception of Wilhelm Ostwald’s energetics. The first essay described the chemical origins of Ostwald’s interest in the energy concept and his motivations for seeking a comprehensive science of energy. The present essay and the next discuss his various attempts, beginning in 1891 and extending over almost 3 years, to develop a consistent and coherent energetic theory. A final essay will consider reactions to this work and Ostwald’s replies, (...) and will also seek to evaluate his program of research. Ostwald’s project – to reconstruct physics and chemistry “as a pure energetics” – is worth attending to for several reasons: first, because Ostwald did ground-breaking work in chemistry (he was awarded a Nobel Prize in 1909 for his studies in catalysis and rates of reaction); second, because an important school of physical chemistry formed around him at Leipzig, a school that promoted his ideas; and, finally, because he was a prominent and vigorous participant in debates at the end of the nineteenth century concerning the proper course of physical theory. (shrink)

This is the third of a series of essays on the development and reception of Wilhelm Ostwald’s energetics. The first essay described the chemical origins of Ostwald’s interest in the energy concept and his motivations for seeking a comprehensive science of energy. The second essay and the present one discuss his various attempts, beginning in 1891 and extending over almost 3 years, to develop a consistent and coherent energetic theory. A final essay will consider reactions to this work and Ostwald’s (...) replies, and will also seek to evaluate his program of research. Ostwald’s project—to reconstruct physics and chemistry “as a pure energetics”—is worth attending to for several reasons: first, because Ostwald did ground-breaking work in chemistry (he was awarded a Nobel Prize in 1909 for his studies in catalysis and rates of reaction); second, because an important school of physical chemistry formed around him at Leipzig, a school that promoted his ideas; and, finally, because he was a prominent and vigorous participant in debates at the end of the nineteenth century concerning the proper course of physical theory. (shrink)

In this paper, domain-specificity is presented as an understudied problem in chemical education. This argument is unpacked by drawing from two bodies of literature: learning of science and epistemology of science, both themes that have cognitive as well as philosophical undertones. The wider context is students’ engagement in scientific inquiry, an important goal for science education and one that has not been well executed in everyday classrooms. The focus on science learning illustrates the role of domain specificity in scientific reasoning. (...) The discussion on epistemology of science presents ideas from the emerging field of philosophy of chemistry to highlight the much neglected area of epistemology in chemical education. Domain-specificity is exemplified in the context of chemical laws, in particular the Periodic Law. The applications of the discussion for chemical education are explored in relation to argumentation, itself an epistemologically grounded discourse pattern in science. The overall implications include the need for reconceptualization of the nature of teaching and learning in chemistry to include more particular epistemological aspects of chemistry. (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 the last years there has been a great improvement in the development of computational methods for combinatorial chemistry applied to drug discovery. This approach to drug discovery is sometimes called a “rational way” to manage a well known phenomenon in chemistry: serendipity discoveries. Traditionally, serendipity discoveries are understood as accidental findings made when the discoverer is in quest for something else. This ‘traditional’ pattern of serendipity appears to be a good characterization of discoveries where “luck” plays a key role. (...) In this sense, some initial failures in combinatorial chemistry are frequently attributed to a naïf appropriation of a “serendipity model” for discovery (a “serendipity mistake”). In this paper we try to evaluate this statement by criticizing its foundations. It will be suggested that the notion of serendipity has different aspects and that the criticism to the first attempts could be understood as a “serendipity mistake.” We will suggest that “serendipity” strategies, a kind of blind search, can be seen sometimes as a “genuine part” of scientific practice. A discussion will ensue about how this characterization can give us a better understanding of some aspects of serendipity discoveries. (shrink)

Magnani, Lorenzo (2001), Abduction, Reason, and Science: Processes of Discovery and Explanation. New York: Kluwer Academic/ Plenum Publishers. Magnani. Lorenzo, and Nancy Nersessian (eds.) (2002), Model-Based Reasoning: Technology, Science, Values. New York: Kluwer Academic/ Plenum Publishers. Joseph E. Earley, Sr. (ed.), Chemical Explanation: Characteristics, Development, Autonomy, Annals of the New York Academy of Sciences, vol. 988. New York Academy of Sciences (2003), 370 pp., $130.00 (cloth).

The most immediate reason why chemists are unenthusiastic about the philosophy of science is the historic hostility of important philosophers, to the concept of atoms. (Without atoms, discovery in chemistry would have proceeded with glacial slowness, if at all, in the last 200 years.) Other important reasons include the anti-realist influence of the philosophical dogmas of logical positivism, instrumentalism, of strict empiricism. Though (as has been said) these doctrines have recently gone out of fashion, they are still very influential.A diagram (...) of the methodology of experimental research is proposed, in the form of a flow sheet, with feedback. The model is developed as a multi-level expansion of a diagram of the hypothetico-deductive model. It recognizes that strong mutual support, or interlocking, of research endeavors is important, at the underlying level or levels where explanatory causation contributes to scientific understanding. (Mutual support at the laboratory level is generally weak or trivial.) The multiplicity of explanatory levels, and the interlocking, point to solutions to some well-known problems, such as the origin of the hypotheses, and even a resolution to the underdetermination problem. (shrink)

This article examines a scientific controversy that raged for twenty years in physical organic chemistry during the second half of the twentieth century. After explaining what was at stake in the non-classical ion debate, I attempt—by examining the methodological reflections of some of the participants—a partial explanation of what sustained this controversy, particularly during its early stages. Instead of suggesting a breakdown of scientific method or the unavoidable historical contingency of scientific development, the endurance of this controversy instead reveals the (...) heuristic and pragmatic character of many of the explanations and predictions generated by theoretical organic chemistry. The results in this case are used to suggest a new role for the study of scientific controversies in revealing the economics of scientific inquiry. 1 Introduction2 The Non-classical Ion Debate3 Models for the 2-Norbornyl System4 Soft Theories and Reasoning by Analogy5 Scientific Controversy and the Non-classical Ion Debate6 Conclusion. (shrink)

Next SectionOne of the indisputable signs of the progress made in organic chemistry over the last two hundred years is the increased ability of chemists to manipulate, control, and design chemical reactions. The technological expertise manifest in contemporary synthetic organic chemistry is, at least in part, due to developments in the theory of organic chemistry. By appealing to a notable chemist's attempts to articulate and codify the heuristics of synthetic design, this paper investigates how understanding theoretical organic chemistry facilitates progress (...) in synthetic organic chemistry. The picture that emerges of how the applications of organic chemistry are grounded in its theory is contrasted with both standard and some more contemporary philosophical accounts of the applications of science. IntroductionTotal Synthesis as Applied ScienceUnderstanding Organic ChemistryThe Heuristics of Synthetic DesignAn Example: LongifoleneConclusion. (shrink)

The project of chemistry to classify substances and develop techniques for their transformation into other substances rests on assumptions about the means by which compounds are constituted and reconstituted. Robert Boyle not only proposed empirical tests for a metaphysics of material corpuscules, but also a principle for designing experimental procedures in line with that metaphysics. Later chemists added activity concepts to the repertoire. The logic of activity explanations in modern times involves hierarchies of activity concepts, transitions between levels through non-dispositional (...) groundings. Such hierarchies terminate in powerful particulars, such as elementary charged particles. Do these have a fundamental place in the most recent accounts of molecular architecture, stabilities and transformations? However, a close study of the contemporary chemistry of substances transforming reactions discloses a hybrid metaphysics, making use of both the Boylean corpuscles and Faradayan fields. This is illustrated by an analysis of the metaphysics inherent in John Polanyi’s use of “chemoluminescence” to follow the formation of products in chemical reactions. A brief sketch of a resolution of the tension between the two metaphysical schemes is drawn from Niels Bohr’s radical metaphysics extended from the quantum realm proper to chemistry (and perhaps beyond). (shrink)

Heisenberg’s explanation of how two coupled oscillators exchange energy represented a dramatic success for his new matrix mechanics. As matrix mechanics transmuted into wave mechanics, resulting in what Heisenberg himself described as …an extraordinary broadening and enrichment of the formalism of the quantum theory , the term resonance also experienced a corresponding evolution. Heitler and London’s seminal application of wave mechanics to explain the quantum origins of the covalent bond, combined with Pauling’s characterization of the effect, introduced resonance into the (...) chemical lexicon. As the Valence Bond approach gave way to a soon-to-be dominant Molecular Orbital method, our understanding of the term resonance, as it might apply to our understanding the chemical bond, has also changed. (shrink)

In this paper I investigate two views of theoretical explanation in quantum chemistry, advocated by John Clarke Slater and Charles Coulson. Slater argued for quantum‐mechanical rigor, and the primacy of fundamental principles in models of chemical bonding. Coulson emphasized systematic explanatory power within chemistry, and continuity with existing chemical explanations. I relate these views to the epistemic contexts of their disciplines.

In this article I sketch G. N. Lewis’s views on chemical bonding and Linus Pauling’s attempt to preserve Lewis’s insights within a quantum‐mechanical theory of the bond. I then set out two broad conceptions of the chemical bond, the structural and the energetic views, which differ on the extent in which they preserve anything like the classical chemical bond in the modern quantum‐mechanical understanding of molecular structure. †To contact the author, please write to: Department of Philosophy, Durham University, 50 Old (...) Elvet, Durham DH1 3HN, UK; e‐mail: r.f.hendry@durham.ac.uk. (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)

In this paper I expand Eric Scerri’s notion of Popper’s naturalised approach to reduction in chemistry and investigate what its consequences might be. I will argue that Popper’s naturalised approach to reduction has a number of interesting consequences when applied to the reduction of chemistry to physics. One of them is that it prompts us to look at a ‘bootstrap’ approach to quantum chemistry, which is based on specific quantum theoretical theorems and practical considerations that turn quantum ‘theory’ into quantum (...) ‘chemistry’ proper. This approach allows us to investigate some of the principles that drive theory formation in quantum chemistry. These ‘enabling theorems’ place certain limits on the explanatory latitude enjoyed by quantum chemists, and form a first step into establishing the relationship between chemistry and physics in more detail. (shrink)

Machine generated contents note: -- Preface -- Acknowledgments -- Introduction, by Michael Weisberg and Jeffrey Kovac. -- 1 Trying to Understand, Making Bonds, by Roald Hoffmann -- Part 1: Chemical Reasoning and Explanation -- 2. Why Buy That Theory?, by Roald Hoffmann. -- 3. What Might Philosophy of Science Look Like If Chemists Built It?, by Roald Hoffmann -- 4. Unstable, by Roald Hoffmann -- 5. Nearly Circular Reasoning, by Roald Hoffmann -- 6. Ockham's Razor and Chemistry, by Roald Hoffmann, (...) Vladimir I. Minkin, and Barry K. Carpenter -- 7. Qualitative Thinking in the Age of Modern Computational Chemistry, or What Lionel Salem Knows, by Roald Hoffmann -- 8. Narrative, by Roald Hoffmann -- 9. Learning from Molecules in Distress, by Roald Hoffmann and Henning Hopf -- 10. Why Think Up New Molecules? by Roald Hoffmann -- 11. Protean, by Roald Hoffmann and Pierre Laszlo -- 12. How Should Chemists Think? by Roald Hoffmann -- Part 2: Writing and Communicating in Chemistry -- 13. Under the Surface of the Chemical Article, by Roald Hoffmann -- 14. Representation in Chemistry, by Roald Hoffmann and Pierre Laszlo -- 15.. The Say of Things, by Roald Hoffmann and Pierre Laszlo -- 16. How Symbolic and Iconic Languages Bridge the Two Worlds of the Chemist: A Case Study from Contemporary Bioorganic Chemistry, by Emily R. Grosholz and Roald Hoffmann -- 17 How Nice to Be an Outsider, by Roald Hoffmann -- 18. The Metaphor, Unchained, by Roald Hoffmann, -- Part 3: Art and Science -- 19. Art in Science? by Roald Hoffmann -- 20. Science and Crafts by Roald Hoffmann -- 21. Molecular Beauty, by Roald Hoffmann -- Part 4 Chemical Education -- 22. Teach to Search by Roald Hoffmann -- 23. Some Heretical Thoughts on What Our Students Are Telling Us, by Roald Hoffmann and Brian P. Coppola -- 24 Very Specific Teaching Strategies, and Why They Work, by Roald Hoffmann and Saundra Y. McGuire -- Part 5 Ethics in Science -- 25. Mind the Shade, by Roald Hoffmann -- 26. Science and Ethics: A Marriage of Necessity and Choice for this Millennium," by Roald Hoffmann -- 27. Honesty to the Singular Object, by Roald Hoffmann -- 28. The Material and Spiritual Rationales Are Inseparable, by Roald Hoffmann -- Index. (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)

Building upon Nancy Cartwright's discussion of models in How the Laws of Physics Lie, this paper addresses solid state research in transition metal oxides. Historical analysis reveals that in this domain models function both as the culmination of phenomenology and the commencement of theoretical explanation. Those solid state chemists who concentrate on the description of phenomena pertinent to specific elements or compounds assess models according to different standards than those who seek explanation grounded in approximate applications of the Schroedinger equation. (...) Accurate accounts of scientific debate in this field must include both perspectives. (shrink)

This paper investigates the interface between philosophy and biochemistry. While it is problematic to justify the application of a particular philosophical model to biochemistry, it seems to be even more difficult to develop a special “Philosophy for Biochemistry”. Alternatively, philosophy can be used in biochemistry based on an alternative approach that involves an interdependent iteration process at a philosophical and (bio)chemical level (“Exeter Method”). This useful iteration method supplements more abstract approaches at the interface between philosophy and natural sciences, and (...) serves the biochemical community to systematically locate logical inconsistencies that arise from more theoretical aspects of the scientific process. Initial cycles of this iteration process identify the in vitro–in vivo problem as a central epistemological difficulty in biochemical research. While previous attempts have generated ad hoc rules to mend the gap between chemistry, biochemistry and biology in order to justify in vitro experimentation, this paper concludes that in vitro experimentation is heavily based on chemistry and cannot derive definite statements about biological processes. It can, however, generate results that will influence the direction of future biological research. The consequence is that the relationship between in vitro and in vivo experimentation is more of a psychological or social one than of a logical nature. Apart from highlighting these inconsistencies in biochemical thinking (“problem awareness”), the Exeter Method demands an improvement of biochemical terminology that contains separate and unequivocally defined terms for in vitro and in vivo systems. (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)

In 1870–75 Markovnikov enunciatedan empirical Rule which generalized theregiochemical outcome of addition reactions tounsymmetrical alkenes. This Rule remaineduseful for about 75 years, until suchreactions came to be better understood inmechanistic terms. Thereafter the Rule couldbe deduced from principles of relativecarbocation stabilization and ceased to servean independent purpose. Nevertheless, mostorganic textbooks continue to cite it (oftenin a historically inaccurate, anachronisticway), thereby distracting student attentionfrom the underlying principles. This paperadvocates doing away with the Rule in organicchemistry textbooks and classrooms.

The drastically increasing availability ofmodern computers coupled with the equally drasticallylower cost of a given amount of computer power inrecent years has resulted in the evolution of thetraditional experimental/theoretical dichotomy inchemistry into anexperimental/theoretical/computational trichotomy. This trichotomy can be schematically represented by atriangle with experimental,theoretical, and computational chemistry at the threevertices. The ET and EC edges of the ETC triangledepict the uses of theoretical and computationalchemistry, respectively, to predict and interpretexperimental results. The TC edge depicts therelationship between theoretical and computationalchemistry. Mathematics (...) plays an increasing role in allaspects of chemistry, particularly theoreticalchemistry, and has led to the evolution of thediscipline of mathematical chemistry. Research inmathematical chemistry can be considered to lie on achemistry-mathematics continuum depending on therelative depths of the underlying chemistry andmathematics. Examples of the author's own researchlying near each end of the chemistry-mathematicscontinuum include his work on applications of graphtheory and topology in inorganic coordination andcluster chemistry lying near the chemistry end and hiswork on chirality algebra lying near the mathematicsend. The general points in this essay are illustratedby an analysis of the roles of computational andtheoretical chemistry in developing an understandingof structure and bonding in deltahedral boranes andrelated carboranes. This work has allowed extensionof the concept of aromaticity from two dimensions asin benzene and other planar hydrocarbons to the thirddimension in deltahedral boranes. (shrink)

In contrast to the conventional homogeneous kinetics, there is no conception of a simple reaction in the solid-state reaction kinetics. The geometric-probabilistic phenomenology currently in use is not adequate for describing the interplay between the chemical mechanism and the observed kinetic behaviour. An attempt is made to formulate a conception of simple reaction in the solid state as a basis for constructing kinetic models of involved reactions.

Traditional philosophy of science regards theoretical reasoning, based on the example of Euclidian geometry, as the hallmark of a mature science. There is, however, a parallel tradition of practical reasoning based on specific cases that goes back to Aristotle. In this paper I argue that practical reasoning is an essential part of the practice of chemistry and should be understood and appreciated on its own merits rather than regarded as a symbol of the immaturity and inferiority of chemistry as a (...) science. (shrink)

Attempts to explain the periodic system as a manifestation of regularities in the structure of the atoms of the elements are as old as the system itself. The paper analyses some of the most important of these attempts, in particular such works that are historically connected with the recognition of the electron as a fundamental building block of all matter. The history of the periodic system, the discovery of the electron, and ideas of early atomic structure are closely interwoven and (...) transcend the physics–chemistry boundary. It is pointed out that J. J. Thomson's discovery of the electron in 1897 included a first version of his electron atomic model and that it was used to suggest how the periodic system could be understood microphysically. Thomson's theory did not hold what it promised, but elements of it were included in Niels Bohr's first atomic model. In both cases, Thomson's and Bohr's, the periodic system played an important role, heuristically as well as justificatory. (shrink)

A major obstacle to chemistry being a deductive science is that its core concepts very often are defined in a circular manner: it is impossible to explain what an acid is without reference to the complementary concept of a base. There are many such dual pairs among the core concepts of chemistry. Such circulation of concepts, rather than an infirmity chemistry is beset with, is seen as a source of vitality and dynamism.

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)

Chemistry deals with substances and their transformations. School chemistry provides a picture of this in terms of small balls called atoms and ball-and-stick structures called molecules which, despite its crudity, has been taken to justifiably reflect a reductionist conception of macroscopic concepts like the chemical substances and chemical reactions. But with the recent interest in chemistry within the philosophy of science, an extensive and determined criticism has developed of the idea that the macroscopic world has been, or is likely to (...) be, reduced to microscopic theory. From this perspective, it is of interest to see macroscopic ontology treated autonomously. I try to take a first few steps towards spelling this out. It involves recognising entities falling into two broad categories: continuants-things which can have different properties at different times — and processes — things whose temporal parts may have different features, but which themselves stand in contrast to continuants in this respect. The character of each and their interrelations depends on their mereological structure of parts, the exploration of which is one of the prime purposes of the paper. (shrink)

This paper surveys some ways in which the chemical realm can be described and outlined in terms of the concept of supervenience. The particular contours of general chemical theory provide a ready basis for interpretation of determination, covariance, and nonreduction—the characteristic metaphysical facets of the supervenience relation—in mutual terms. Building on this, the extent to which chemically characterized properties and entities can be described in terms of a supervenience-scaffolded structure represents a particularly vivid application that philosophers in general interested in (...) supervenience would do well to attend to. In addition, the model of chemical supervenience given here can be used as a rubric on which to decide on issues already raised by philosophers of chemistry. (shrink)

The current status of explanation worked out by Physics for the Periodic Law is considered from philosophical and methodological points of view. The principle gnosiological role of approximations and models in providing interpretation for complicated systems is emphasized. The achievements, deficiencies and perspectives of the existing quantum mechanical interpretation of the Periodic Table are discussed. The mainstream ab initio theory is based on analysis of selfconsistent one-electron effective potential. Alternative approaches employing symmetry considerations and applying group theory usually require some (...) empirical information. The approximate dynamic symmetry of one-electron potential casts light on the secondary periodicity phenomenon. The periodicity patterns found in various multiparticle systems (atoms in special situations, atomic nuclei, clusters, particles in the traps, etc) comprise a field for comparative study of the Periodic Laws found in nature. (shrink)

Although chemical phenomena are primarily associated with electrons in atoms, ions, and molecules, the masses, charges, spins, and other properties of the nuclei in these species contribute significantly as well. Isotopes, for instance, have proven invaluable in chemistry, in particular the elucidation of reaction mechanisms. Elements with unstable nuclei, for example carbon-14 undergoing beta decay, have enriched chemistry and many other scientific disciplines. The nuclei of all elements have a much more subtle and largely unknown effect on chemical phenomena. All (...) nuclei are innately chiral and, because electrons can penetrate nuclei, all atoms and molecules are likewise chiral. This article describes in considerable detail the discovery of chiral nuclei, how this unusual chirality may influence the chemical behavior of atoms and molecules, and how atomic chirality may have been responsible for the synthesis of optically active molecules in the pre-biotic world. (shrink)