The Problem of Molecular Structure Just Is The Measurement Problem
co-written with Alexander Franklin
(Accepted/in Press) The British Journal for the Philosophy of Science
Abstract. Whether or not quantum physics can account for molecular structure is a matter of considerable controversy. Three of the problems raised in this regard are the problems of molecular structure. We argue that these problems are just special cases of the measurement problem of quantum mechanics: insofar as the measurement problem is solved, the problems of molecular structure are resolved as well. In addition, we explore one consequence of our argument: that claims about the reduction or emergence of molecular structure cannot be settled independently of the choice of a particular resolution to the measurement problem. Specifically, we consider how three standard putative solutions to the measurement problem inform our understanding of a molecule in isolation, as well as of chemistry’s relation to quantum physics.
Do molecules have structure in isolation? How models can provide the answer
(Under proof) In Book: Philosophical Perspectives on Quantum Chemistry
ed. by Olimpia Lombardi, Sebastian Fortin, and Juan Camilo Martínez González (Synthese Library, Springer)
Abstract. I argue that molecules may not have structure in isolation. I support this by investigating how quantum models identify structure for isolated molecules. Specifically, I distinguish between two sets of models: those that identify structure in isolation and those that do not. The former identify structure because they presuppose structural information about the target system via the Born Oppenheimer approximation. However, it is an idealisation to assume structure in isolation because there is no empirical evidence of this. In fact, whenever structure is empirically examined it is always partially determined by factors that are absent in isolation. Together with the growing empirical evidence that isolated molecules behave in non-classical ways, this shows that the quantum models that do not identify structure are more faithful representations of isolated molecules.
The Strong Emergence of Molecular Structure
European Journal for Philosophy of Science
Abstract. One of the most plausible and widely discussed examples of strong emergence is molecular structure. The only detailed account of it, which has been very influential, is due to Robin Hendry and is formulated in terms of downward causation. This paper explains Hendry’s account of the strong emergence of molecular structure and argues that it is coherent only if one assumes a diachronic reflexive notion of downward causation. However, in the context of this notion of downward causation, the strong emergence of molecular structure faces three challenges that have not been met and which have so far remained unnoticed. First, the putative empirical evidence presented for the strong emergence of molecular structure equally undermines supervenience, which is one of the main tenets of strong emergence. Secondly, it is ambiguous how the assumption of determinate nuclear positions is invoked for the support of strong emergence, as the role of this assumption in Hendry’s argument can be interpreted in more than one way. Lastly, there are understandings of causation which render the postulation of a downward causal relation between a molecule’s structure and its quantum mechanical entities, untenable.
Referring to chemical elements and compounds: Colourless airs in late eighteenth century chemical practice
co-written with Geoffrey Blumenthal & James Ladyman
In book: What Is A Chemical Element? A Collection of Essays by Chemists, Philosophers, Historians, and Educators
ed. by Eric Scerri and Elena Ghibaudi (Oxford University Press)
The Role of Idealisations in Describing an isolated molecule
Foundations of Chemistry
Abstract. The investigation of the relation between chemistry and quantum mechanics includes examining how the two theories each describe an isolated molecule. This paper focuses on one particular characteristic of chemistry’s and quantum mechanics’ descriptions of an isolated molecule; namely on the assumptions made by each description that an isolated molecule is stable and has structure. The paper argues that these assumptions are an idealisation. First, this is because stability and structure are partially determined by factors that concern the context in which a molecule is considered (i.e. thermodynamic conditions, time-range of experiment, environment, etc.). Secondly, the stability and structure of a molecule can only be empirically identified with reference to those factors. This paper examines these assumptions in the context of the philosophical literature on idealisations. This examination is a novel contribution that raises interesting questions about the relation between the two theories, the nature of stability and structure, and the function of these assumptions in the two theories.
Internet Encyclopedia of Philosophy
This encyclopedia article presents how chemistry’s relation to physics has been understood in philosophy. Chemistry’s relation to physics, and in particular to quantum mechanics, is one of the most discussed issues in the philosophy of chemistry literature. This article situates this discussion around the dilemma between reduction and emergence. While there is a broad consensus that chemistry is not epistemically reducible to quantum mechanics, some have argued that there are epistemic and metaphysical connections between the two sciences which can be spelled out by an alternative form of reduction or unity. On the other side of the spectrum, there are philosophers who argue for the autonomy of chemistry from quantum mechanics in terms of different accounts of pluralism and emergence. The aim of this article is to present the central views on this debate.
Foundations of Chemistry
Abstract. Harold Kincaid in Individualism and the Unity of Science postulates a model of unity-without-reduction in order to accurately describe the relation between individualism and macroeconomics. I present this model and apply it to the description of the relation between chemistry and quantum mechanics. I argue that, when it comes to the description of molecular structure, chemistry and quantum mechanics are unified in Kincaid’s sense. Specifically, the two disciplines contribute to the formation of a unified body of knowledge with respect to molecular structure.
Essays in the Philosophy of Chemistry
Review of the book Essays in the Philosophy of Chemistry, edited by Eric Scerri and Grant Fisher, New York, Oxford University Press, 2016, x + 410 pp., ISBN 9780190494599, US$59.95, £38.99 (hardback)
A Philosophical Analysis of the Relation between Chemistry and Quantum Mechanics: The case of a single inert molecule
University of Bristol
Abstract. This thesis investigates the epistemological and metaphysical relations between chemistry and quantum mechanics. These relations are examined with respect to how chemistry and quantum mechanics each describe a single inert molecule. A review of how these relations are understood in the literature shows that there is a proliferation of positions which focus on how chemistry is separate from quantum mechanics. This proliferation is accompanied by a tendency within the philosophy of chemistry community to connect the legitimacy of the field with the autonomy of chemistry. First, it is argued that this connection should not be made. Secondly, it is argued that chemistry and quantum mechanics are unified in accordance with Harold Kincaid’s model of non-reductive unity because the two theories exhibit particular epistemic and metaphysical interconnections. Thirdly, a metaphysical account is examined which is incompatible with Kincaid’s model of unity; namely strong emergence as understood by Robin Hendry. According to Hendry, the structure of a single inert molecule strongly emerges from its quantum mechanical entities in the sense that there is downward causation. However, Hendry’s defense of this account faces certain problems. Moreover, the putative empirical evidence for his understanding of strong emergence can be explained without invoking strong emergence. This is shown by considering how quantum mechanics assumes an idealized understanding of a molecule’s stability and structure. In the light of the philosophical literature on idealizations, this idealization can be interpreted in two different ways, both of which explain why quantum mechanics describes the structure of a single molecule the way it does, without assuming strong emergence in Hendry’s sense. Each interpretation has philosophical implications regarding the nature of chemical properties, and the relation of chemistry and quantum mechanics. These implications are consistent with Kincaid’s model of unity and thus further support chemistry’s unity with quantum mechanics (as per Kincaid).