Abstract The debate between ontological reductionists and emergentists in chemistry has revolved around quantum mechanics. What Franklin and Seifert (BJPS 2020) add to the long-running dispute is an attention to the measurement problem. They contend that all three realist interpretations of the quantum formalism capable of resolving the measurement problem also obviate any need for chemical emergence. I push their argument further, arguing that the realist interpretations of quantum mechanics actually subvert the basis for reduction as well, by undercutting the idea that fundamental physical particles are actual parts of molecules. With both reduction and traditional synchronic emergence pictures ruled out, the only option for realists about quantum chemistry is strong Thomistic emergence.
Abstract The debate between ontological reductionists and emergentists in chemistry has revolved around quantum mechanics. What Franklin and Seifert (BJPS 2020) add to the long-running dispute is an attention to the measurement problem. They contend that all three realist interpretations of the quantum formalism capable of resolving the measurement problem also obviate any need for chemical emergence. I push their argument further, arguing that the realist interpretations of quantum mechanics actually subvert the basis for reduction as well, by undercutting the idea that fundamental physical particles are actual parts of molecules. With both reduction and traditional synchronic emergence pictures ruled out, the only option for realists about quantum chemistry is strong Thomistic emergence.
Abstract The question of whether chemical structure is reducible to Everettian Quantum Mechanics (EQM) should be of interest to philosophers of chemistry and philosophers of physics alike. Among the three realist interpretations of quantum mechanics, EQM resolves the measurement problem by claiming that measurements (now interpreted as instances of decoherence) have indeterminate outcomes absolutely speaking, but determinate outcomes relative to emergent worlds—Maudlin (Topoi, 14:7-15, 1995). Philosophers who wish to be sensitive to the practice of quantum chemistry e.g. Scerri (The changing views of a philosopher of chemistry on the question of reduction, 2016) should be interested in EQM because Franklin and Seifert (J. Philos. Sci, 2020) claim that resolving the measurement problem also resolves the reducibility of chemical structure, and EQM is the interpretation which involves no mathematical structure beyond that used by practicing scientists. Philosophers interested in the quantum interpretation debate should be interested in the reducibility of chemistry because chemical structure is precisely the kind of determinate three-dimensional fact which EQM should be able to ground if it is to be empirically coherent—see Allori (Quantum Rep, 5:80-101, 2023). The prospects for reduction of chemical structure are poor if it cannot succeed in EQM; the prospects for EQM as a guide to ontology are poor if it cannot reduce chemical structure. Unfortunately for proponents of chemical reduction and EQM, there are three serious barriers to the reduction of chemistry to EQM. The first concern is that quantum treatments of chemical structure rely on the Born-Oppenheimer approximation, which holds nuclear locations fixed while minimizing the energy of the electronic configuration—Hendry (Philosophical Perspectives in Quantum Chemistry, 147-172, 2022), but this approximation is not licensed by EQM. The Born-Oppenheimer approximation relies on nuclei and molecular orbitals being simultaneously present, but in the three-dimensional ontology following from the Everett interpretation these only emerge at different energy scales and are not simultaneously present—Miller (Found. Chem, 25:405-417, 2023). The second concern is that the emergent worlds of EQM are supposed to be decoherent at the macro-scale—Wilson (The Nature of Contingency: Quantum Physics as Modal Realism 2020), but the recent development of superchemistry suggests that chemical reactions can occur in coherent states—Zhang et al. (Nat. Phys, 1-5, 2023). The third concern is that emergent worlds are only pragmatic pseudo-processes—Wallace (The Emergent Multiverse: Quantum Theory According to the Everett Interpretation, 2012b), but this means EQM trades realist physics for mere instrumentalism about chemistry. Absent a commitment to chemical realism, reduction is an empty promise. The prospects for reduction of chemical structure to EQM are therefore poor.
Philosophers mainly refer to quantum chemistry in order to address questions about the reducibility or autonomy of chemistry relative to quantum physics, and to argue for or against ontological emergence. To make their point, they scrutinize quantum approximations and formalisms as if they were independent of the questions at stake. This paper proposes a return to history and to the laboratory so as to emphasize how quantum chemists never cease to negotiate the relationships between a molecule, its parts, and its environment. This investigation will enable us to draw methodological conclusions about the role of history within philosophical studies, and to examine how quantum chemistry can clarify important philosophical and mereological issues relatedto the emergence/reduction debate, or to the way instruments and contexts are involved in the material making and the formal description of wholes and parts.
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.
The philosophy of science in general, and the philosophy of physics in particular, have increasingly focused on cases of reduction and emergence in recent decades. While the paradigmatic examples arise in the context of thermodynamics and classical statistical mechanics, relevant cases have also emerged in the philosophy of quantum mechanics, such as that of quasiparticles. Traditionally, these entities have been regarded as mere mathematical tools that do not contribute to the construction of quantum ontology. However, this position has recently been challenged, and frameworks have been proposed in which some of these objects acquire a significant ontological status. In particular, phonons have been considered a case of emergence that may have either an epistemic or an ontological character. In this paper, we further enrich the discussion by emphasizing that quantum mechanics only refers to entities in the real world through the adoption of a specific interpretation. A century after the development of quantum theory, there is still no consensus on how to interpret it, and multiple competing interpretations are currently proposed. Consequently, the outcome may vary depending on the interpretation adopted. Based on this, we will show that the choice of interpretation not only influences the conceptual understanding of quantum mechanics but also determines the identification of its fundamental entities. Specifically, we will argue that, under the Modal-Hamiltonian Interpretation, phonons acquire a fundamental status, challenging the standard reading of their emergence and their relationship to quantum ontology.
Since its inception, the intricate mathematical formalism of quantum mechanics has empowered physicists to describe and predict specific physical events known as quantum processes. However, this success in probabilistic predictions has been accompanied by a profound challenge in the ontological interpretation of the theory. This interpretative complexity stems from two key aspects. Firstly, quantum mechanics is a fundamental theory that, so far, is not derivable from any more basic scientific theory. Secondly, it delves into a realm of invisible phenomena that often contradicts our intuitive and commonsensical notions of matter and causality. Despite its notorious difficulties of interpretation, the most widely accepted set of views of quantum phenomena has been known as the Copenhagen interpretation since the beginning of quantum mechanics. According to these views, the correct ontological interpretation of quantum mechanics is incompatible with ontological realism in general and with philosophical materialism in particular. Anti-realist and anti-materialist interpretations of quantum matter have survived until today. This paper discusses these perspectives, arguing that materialistic interpretations of quantum mechanics are compatible with its mathematical formalism, while anti-realist and anti-materialist views are based on wrong philosophical assumptions. However, although physicalism provides a better explanation for quantum phenomena than idealism, its downward reductionism prevents it from accounting for more complex forms of matter, such as biological or sociocultural systems. Thus, the paper argues that neither physicalism nor idealism can explain the universe. I propose then a non-reductionistic form of materialism called inclusive materialism. The conclusion is that the acknowledgment of the qualitative irreducibility of ontological emergent levels above the purely physical one does not deny philosophical materialism but enriches it.
Quantum measurement is the most sensitive part of quantum mechanics and physics. Researching it can incite much philosophical debate. One of hot topics currently is reduction. Many people argue that it is received wisdom that quantum measurement puts an end to reductionism. Psychology, emergence and holism are their arguments against reduction. Is reduction really dead? I will not only argue that reduction in quantum measurement is still animate, but also try to put forward some effective means which can eliminate conflict between quantum measurement and reduction.