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 quantumchemistry, 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 quantumchemistry. 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)
This paper first queries what type of concept of emergence, if any, could be connected with the different chemical activities subsumed under the label ‘quantumchemistry’. In line with Roald Hoffmann, we propose a ‘rotation to research laboratory’ in order to point out how practitioners hold a molecular whole, its parts, and the surroundings together within their various methods when exploring chemical transformation. We then identify some requisite contents that a concept of emergence must incorporate in order to (...) be coherent from the standpoint of the scientific practices involved. In this respect, we finally propose a relational form of emergence which pays attention to the constitutive role of the modes of intervention and to the co-definition of the levels of organization. No metaphysical distinction between the higher and basic levels of organization is supposed, but only a plurality of modes of access. Moreover, these modes of access are not construed as mere ways of revealing intrinsic patterns of organization but, on the contrary, are considered to be active elements on which the constitution of those patterns depends. What is at stake in this paper is therefore not an ontological form of emergence but an agnostic one which fits what chemists do in their daily work. (shrink)
Discussing the relationship of mathematics to chemistry is closely related to the emergence of physical chemistry and of quantumchemistry. We argue that, perhaps, the most significant issue that the 'mathematization of chemistry' has historically raised is not so much methodological, as it is philosophical: the discussion over the ontological status of theoretical entities which were introduced in the process. A systematic study of such an approach to the mathematization of chemistry may, perhaps, contribute (...) to the realist/antirealist debate. To this end, in this paper we briefly discuss Lewis' introduction of fugacity and activity to his chemical thermodynamics and more fully analyze the issues surrounding the appropriation of resonance by Linus Pauling into quantumchemistry, particularly as these issues arose in organic chemistry as discussed by George W. Wheland. (shrink)
After Heitler and London published their pioneering work on the application of quantum mechanics to chemistry in 1927, it became an almost unquestioned dogma that chemistry would soon disappear as a discipline of its own rights. Reductionism felt victorious in the hope of analytically describing the chemical bond and the structure of molecules. The old quantum theory has already produced a widely applied model for the structure of atoms and the explanation of the periodic system. This (...) paper will show two examples of the entry of quantum physics into more classical fields of chemistry: inorganic chemistry and physical chemistry. Due to their professional networking, George Hevesy and Michael Polanyi found their ways to Niels Bohr and Fritz London, respectively, to cooperate in solving together some problems of classical chemistry. Their works on rare earth elements and adsorption theory throws light to the application of quantum physics outside the reductionist areas. They support the heuristic and persuasive value of quantum thinking in the 1920–1930s. Looking at Polanyi’s later oeuvre, his experience with adsorption theory could be a starting point of his non-justificationist philosophy. (shrink)
This note is intended to address one particular issue in the relative status of QuantumChemistry in comparison to both Chemistry and Physics. It has been suggested, in the context of the question of the reduction relations between Chemistry and Physics that QuantumChemistry as a research programme is incapable of furnishing useful guidance to practising chemists. If true, this claim will let us qualify QuantumChemistry as a degenerating research programme, which, (...) due to its complexity has difficulty to be applied to Chemistry. This claim is shown to be false. The replacement claim I wish to make is that QuantumChemistry is perfectly capable of furnishing such guidance, but renders the ontological status of many models favored by chemists problematic. QuantumChemistry, however, validates these models in an instrumental fashion. I will argue that QuantumChemistry is a progressive research programme. (shrink)
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)
This paper analyses Richard Bader’s ‘operational’ view of quantum mechanics and the role it plays in the the explanation of chemistry. I argue that QTAIM can partially be reconstructed as an ‘austere’ form of quantum mechanics, which is in turn committed to an eliminative concept of reduction that stems from Kemeny and Oppenheim. As a reductive theory in this sense, the theory fails. I conclude that QTAIM has both a regulatory and constructive function in the theories of (...)chemistry. (shrink)
Differing views on reduction are briefly reviewed and a suggestion is made for a working definition of 'approximate reduction'. Ab initio studies in quantumchemistry are then considered, including the issues of convergence and error bounds. This includes an examination of the classic studies on CH2 and the recent work on the Si2C molecule. I conclude that chemistry has not even been approximately reduced.
In his classic work The Mind and its Place in Nature published in 1925 at the height of the development of quantum mechanics but several years after the chemists Lewis and Langmuir had already laid the foundations of the modern theory of valence with the introduction of the covalent bond, the analytic philosopher C. D. Broad argued for the emancipation of chemistry from the crass physicalism that led physicists then and later—with support from a rabblement of philosophers who (...) knew as much about chemistry as etymologists—to believe that chemistry reduced to physics. Here Broad’s thesis is recast in terms more familiar to chemists. In the hard sell of particle physics, several prominent figures in chemistry—Hoffmann, Primas, and Pauling—have had their views interpreted to imply that they were sympathetic to greedy reductionism when in fact they were not. Indeed, being chemists without physicists as alter egos, they could not but side with Broad’s contention that chemistry, as a science that deals primarily in emergent phenomena which are beyond the purview of physicalism, owes no acquiescence to particle physics and its ethereal wares. Historically, among the most widely used expediencies in chemistry and materials science are additivity or mixture rules and their cohort transferability, all of which are devised and used under the mantle of naive reductionism. Here it is argued that while the transfer of functional groups between molecules works empirically to an extent, it is strictly outlawed by the no-cloning theorem of quantum mechanics. Several illustrative examples related to chemistry’s irreducibility to physics are presented and discussed. The failure of naive reductionism exhibited by the deep-inelastic scattering of leptons by A > 2 nuclei is traced to the same flawed reasoning that was the original basis of Moffitt’s ‘atoms in molecules’ hypothesis, the neglect of context, nuclei in the case of high-energy physics and molecules in the case of chemistry. A non-exhaustive list of other contexts from physics, chemistry, and molecular biology evidencing similar departures from the ideal of additivity or reductionism is provided for the perusal of philosophers. Had the call by the mathematician J. T. Schwartz for developments in mathematical linguistics possessed of a less single, less literal, and less simple-minded nature been met, perhaps it might have persuaded scientists to abandon their regressive fixation with unphysical reductionism and to adapt to new methodologies that engender a more nuanced handling of ubiquitous emergent phenomena as they arise in Nature than is the case today. (shrink)
This paper widens the scope of our previous paper (Harré and Llored in Found Chem 13:63–76, 2011) by scrutinizing how whole/parts relations are involved in the study of molecules. In doing so, we point out two mereological fallacies which endanger both philosophical and chemical inferences. We also further explore how the concept of affordance is related to our mereological investigation. We then refer to quantumchemistry in order to pave the way for a new mereological approach for (...) class='Hi'>chemistry. (shrink)
Intra-molecular connectivity (that is, chemical structure) does not emerge from computations based on fundamental quantum-mechanical principles. In order to compute molecular electronic energies (of C 3 H 4 hydrocarbons, for instance) quantum chemists must insert intra-molecular connectivity “by hand.” Some take this as an indication that chemistry cannot be reduced to physics: others consider it as evidence that quantumchemistry needs new logical foundations. Such discussions are generally synchronic rather than diachronic —that is, they neglect (...) ‘historical’ aspects. However, systems of interest to chemists generally are metastable . In many cases chemical systems of a given elemental composition may exist in any one of several different metastable states depending on the history of the system. Molecular structure generally depends on contingent historical circumstances of synthesis and separation, rather than solely or mainly on relative energies of alternative stable states, those energies in turn determined by relationships among components. Chemical structure is usually ‘kinetically-determined’ rather than ‘thermodynamically-determined.’ For instance, cyclical hydrocarbon ring-systems (as in cyclopropene) are produced only in special circumstances. Adequate theoretical treatments must take account of the persistent effects of such contingent historical events whenever they are relevant—as they generally are in chemistry. (shrink)
The concepts of atoms and bonds in molecules which appeared in chemistry during the nineteenth century are unavoidable to explain the structure and the reactivity of the matter at a chemical level of understanding. Although they can be criticized from a strict reductionist point of view, because neither atoms nor bonds are observable in the sense of quantum mechanics, the topological and statistical interpretative approaches of quantumchemistry (quantum theory of atoms in molecules, electron localization (...) function and maximum probability domain) provide consistent definitions which accommodate chemistry and quantum mechanics. (shrink)
This paper combines naturalized metaphysics and a philosophical reflection on a recently evolving interdisciplinary branch of quantumchemistry, ab initio molecular dynamics. Bridging the gaps among chemistry, physics, and computer science, this cutting-edge research field explores the structure and dynamics of complex molecular many-body systems through computer simulations. These simulations are allegedly crafted solely by the laws of fundamental physics, and are explicitly designed to capture nature as closely as possible. The models and algorithms employed, however, involve (...) many approximations and significant degrees of idealization of their target systems. Therefore, for philosophers of science the pivotal question of whether relying only on the fundamental laws of physics supports a reductionist or realist stance arises. One conceivable answer to this question is that the irreducible approximations and idealizations support rather anti-realist positions. After reviewing an influential attitude in the philosophy of computer simulations and the debate concerning scientific realism, I offer a fair interpretation of such ab initio modelling in quantumchemistry within a naturalistic metaphysical framework that gives rise to a specific type of ontic structural realism. (shrink)
The many-faced relationship between chemistry and physics is one of the most discussed topics in the philosophy of chemistry. In his recent book Reducing Chemistry to Physics. Limits, Models, Consequences, Hinne Hettema (Reducing chemistry to physics. Limits, models, consequences, Rijksuniversiteit Groningen, Groningen, 2012) conceives this relationship as a reduction link, and devotes his work to defend this position on the basis of a “naturalized” concept of reduction. In the present paper I critically review three kinds of (...) issues stemming from Hettema’s argumentation: philosophical, scientific and methodological. (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)
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. (shrink)
Most contemporary chemists consider quantum mechanics to be the foundational theory of their discipline, although few of the calculations that a strict reduction would seem to require have ever been produced. In this essay I discuss contemporary algebraic and diagrammatic representations of molecular systems derived from quantum mechanical models, specifically configuration interaction wavefunctions for ab initio calculations and molecular orbital energy diagrams. My aim is to suggest that recent dissatisfaction with reductive accounts of chemical theory may stem from (...) both the inability of standard accounts of reduction to incorporate the diverse forms of representation found in chemical practice and our philosophical predilection to analyze all connections between theories in terms of logical reduction. (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. (shrink)
Some recent work in mathematical chemistry is discussed. It is claimed that quantum mechanics does not provide a conclusive means of classifying certain elements like hydrogen and helium into their appropriate groups. An alternative approach using atomic number triads is proposed and the validity of this approach is defended in the light of some predictions made via an information theoretic approach that suggests a connection between nuclear structure and electronic structure of atoms.
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)
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)
Using the notorious bridge law “water is H 2 O” and the relation between molecular structure and quantum mechanics as examples, I argue that it doesn’t make sense to aim for specific definition(s) of intertheoretical or interdiscourse relation(s) between chemistry and physics (reduction, supervenience, what have you). Proposed definitions of interdiscourse and part-whole relations are interesting only if they provide insight in the variegated interconnected patchwork of theories and beliefs. There is “automatically” some sort of interdiscourse relation if (...) different discourses claim to have something to say about the same situation (event, system), which is the basis of (contingent) local supervenience relations, which, proper empirically support being provided, can be upgraded to ceteris paribus bridge laws. Because of the ceteris paribus feature, and the discourse dependence of event identification, there is at best only global supervenience of the “special sciences” on the physical (and of parts of physics on other parts of physics). (shrink)
There is now a considerable body of published work on the epistemology of modern chemistry, especially with regard to the nature of quantumchemistry. 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)
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. (shrink)
This paper revisits the historical sequence in which some of the major developments of 20th-century physics occurred, and explores how theories could have turned out differently, if the sequence of developments had been different. It shows how a delay in founding special relativity theory until after (1) at least one puzzling problem in electromagnetic theory could be acknowledged, and (2) sat least some of the experimental observations pertinent to the development of quantum mechanics had become well known, could have (...) resulted in a larger theory that covers both domains in a manner quite different from that of any of the theories we use today. The revised theory dispenses with a separate postulate introducing Planck’s constant h, identifying instead a physical mechanism that implies the constant. Some important aspects of quantumchemistry then follow. (shrink)
Shortly before his death, Richard Bader commented in this Journal on the dichotomy that exists within chemistry and between chemists. We believe that the dichotomy results from different goals and objectives inherent in the chemical disciplines. At one extreme are designers who synthesize new molecules with interesting properties. For these chemists, the rationale underpinning molecular synthesis is far less important than the end product—the molecules themselves. At the other extreme are the chemists who seek a fundamental understanding of molecular (...) properties. We suggest that the Quantum Theory of Atoms in Molecules, by virtue of the rich hierarchical structure inherent in the theory, offers a bridge through which to unite these two groups. However, if there is to be reconciliation, it falls to the theorists to develop “quantum mechanically” correct tools and concepts useful to the synthetic and applied chemist. (shrink)
Henry Eyring's absolute rate theory explains the size of chemical reaction rate constants in terms of thermodynamics, statistical mechanics, and quantumchemistry. In addition it uses a number of unique concepts such as the 'transition state'. A key feature of the theory is that the explanation it provides relies on the comparison of reaction rate constant expressions derived from these individual theories. In this paper, the example is used to develop a naturalized notion of reduction and the unity (...) of science. This characterization provides the necessary clues to the sort of inter-theoretic linkages that are present in the theory of reaction rates. The overall theory is then further characterized as a theory network, establishing connections between non-reductive notions of inter-theory connections. This characterization also sheds new light on the unity of science. (shrink)
El propósito del presente trabajo consiste en abordar la pregunta por la ontología de la química cuántica. Para ello nos concentraremos en el concepto de enlace químico desde la perspectiva de los dos enfoques a través de los cuales la ecuación de Schrödinger se aplica a los sistemas químicos moleculares: la teoría del enlace de valencia (EV) y la teoría del orbital molecular (OM). Sobre la base de la presentación de ambos enfoques y su comparación, señalaremos que, a pesar de (...) su denominación tradicional, no pueden considerarse estrictamente como teorías científicas, sino que se ajustan mejor a la noción de modelo; en particular, son modelos que incorporan conceptos y leyes tanto del ámbito de la mecánica cuántica como del de la química estructural. Estas consideraciones nos permitirán argumentar que la química cuántica no posee un referente ontológico autónomo, sino que se trata de un ámbito científico cuya vigencia descansa sobre su éxito práctico en el cálculo y la predicción. Finalmente, indicaremos de qué modo los enfoques EV y OM del enlace químico abren una nueva perspectiva respecto de la noción misma de modelo en ciencias empíricas. (shrink)
Periodic tables (PTs) are the ‘ultimate paper tools’ of general and inorganic chemistry. There are three fields of open questions concerning the relation between PTs and physics: (i) the relation between the chemical facts and the concept of a periodic system (PS) of chemical elements (CEs) as represented by PTs; (ii) the internal structure of the PS; (iii)␣The relation between the PS and atomistic quantumchemistry. The main open questions refer to (i). The fuzziness of the concepts (...) of chemical properties and of chemical similarities of the CE and their compounds guarantees the autonomy of chemistry. We distinguish between CEs, Elemental Stuffs and Elemental Atoms. We comment on the basic properties of the basic elements. Concerning (ii), two sharp physical numbers (nuclear charge and number of valence electrons) and two coarse fuzzy ranges (ranges of energies and of spatial extensions of the atomic orbitals, AOs) characterize the atoms of the CEs and determine the two-dimensional structure of the PS. Concerning (iii), some relevant ‘facts’ about and from quantumchemistry are reviewed and compared with common ‘textbook facts’. What counts in chemistry is the whole set of nondiffuse orbitals in low-energy average configurations of chemically bonded atoms. Decisive for the periodicity are the energy gaps between the core and valence shells. Diffuse Rydberg orbitals and minute spin–orbit splittings are important in spectroscopy and for philosophers, but less so in chemical science and for the PS. (shrink)
A personal account is presented for the present status of mathematical chemistry, with emphasis on non-numerical applications. These use mainly graph-theoretical concepts. Most computational chemical applications involve quantumchemistry and are therefore largely reducible to physics, while discrete mathematical applications often do not. A survey is provided for opinions and definitions of mathematical chemistry, and then for journals, books and book series, as well as symposia of mathematical chemistry.
Summary Opinion is divided as to whether chemistry is reducible to physics. The problem can be given a satisfactory solution provided three conditions are met: that a science not be identified with its theories; that several notions of theory dependence be distinguished; and that quantumchemistry, rather than classical chemistry, be compared with physics. This paper proposes to perform all three tasks. It does so by analyzing the methodological concepts concerned as well as by examining the (...) way a chemical rate constant is derivable with the help of the quantum atomic theory. The conclusion is that chemistry, and in particular quantumchemistry, is not a part of physics although it is certainly based on the latter. (shrink)
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 quantum theory of atoms in molecules (QTAIM) uses physics to define an atom and its contribution to observable properties in a given system. It does so using the electron density and its flow in a magnetic field, the current density. These are the two fields that Schrödinger said should be used to explain and understand the properties of matter. It is the purpose of this paper to show how QTAIM bridges the conceptual gulf that separates the observations of (...)chemistry from the realm of physics and do so in a manner that is both rigorous and conceptually simple. Since QTAIM employs real measurable fields, it enables one to present the findings of complex quantum mechanical calculations in a pictorial manner that isolates the essential physics. The time has arrived for a sea change in our attempts to predict and classify the observations of chemistry, time to replace the use of simplified and arbitrary models with the full predictive power of physics, as applied to an atom in a molecule. (shrink)
The recent exchange on the quantum justification of the Periodic System of the Elements in this Journal between Scerri [Foundations of Chemistry 6: 93–116, 2004] and Friedrich [Foundations of Chemistry 6: 117–132, 2004] is supplemented by some methodological comments.
This paper traces the origins of Eugene Wigner's pioneering application of group theory to quantum physics to his early work in chemistry and crystallography. In the early 1920s, crystallography was the only discipline in which symmetry groups were routinely used. Wigner's early training in chemistry, and his work in crystallography with Herman Mark and Karl Weissenberg at the Kaiser Wilhelm institute for fiber research in Berlin exposed him to conceptual tools which were absent from the pedagogy available (...) to physicists for many years to come. This both enabled and pushed him to apply the group theoretic approach to quantum physics. It took many years for the approach first introduced by Wigner in the 1920s – and whose reception by the physicists was initially problematical – to assume the pivotal place it now holds in physical theory and education. This is but one example that attests to the historic contribution made by the periphery in initiating new types of thought-perspectives and scientific careers. (shrink)
It is argued that the conventional descriptions of chemical bonds as covalent, ionic, metallic, and Van der Waals are compromising the usefulness of quantum mechanics in the synthesis and design of new molecules and materials. Parallels are drawn between the state of chemistry now and when the idea that phlogiston was an element impeded the development of chemistry. Overcoming the current obstacles will require new methods to describe molecular structure and bonding, just as new concepts were needed (...) before the phlogiston theory could be set aside. (shrink)
Atomic states are rigorously characterized by the total orbital angular momentum and the total spin angular momentum, but chemists persist in the use of electron configurations based on one-electron quantum numbers and simplified rules for predicting ground state configurations. This practice is defended against two lines of criticism, and its use in teaching chemistry is encouraged with the claim that the inductive approach of Mendeleev and the deductive approach initiated by Schrödinger compose the consummate example of that interaction (...) of empirical and rational epistemologies that defines how chemists think. (shrink)
Work on the central problems of the philosophy of science has led the author to attempt to create an intelligible version of quantum theory. The basic idea is that probabilistic transitions occur when new stationary or particle states arise as a result of inelastic collisions.
This article will explore whether there are arguments for Aristotle's concept mixis which can aid our current discussions within the philosophy of chemistry. We remain troubled by the way and extent to which chemical substance in bulk can be identified with or reduced to the stability and structure of molecules, and whether these in turn can be identified with or reduced to elemental atoms and the quantum theoretical characterization of their electrons. Aristotle was as determined as we are (...) to think through the implications of substances comprised of constituents and to question their status in chemical compounds. (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)