Some interpretations of quantum mechanics use notions of possible states and possible trajectories. I investigate how this modal approach correlates with several metaphysical conceptions of a transition from potential to actual existence. The comparison is based on a discussion in contemporary analytical metaphysics of modality. I also consider an analogy between Leibniz's theory of the possibilities striving towards existence, wave mechanics of Schrodinger, and Feynman path integral.
We discuss some methodological aspects of the relation between physics and metaphysics by dealing specifically with the case of non-relativistic quantum mechanics. Our main claim is that current attempts to productively integrate quantum mechanics and metaphysics are best seen as approaches of what should be called `the metaphysics of science', which is developed by applying already existing metaphysical concepts to scientific theories. We argue that, in this perspective, metaphysics must be understood as an autonomous discipline. It results that this metaphysics cannot hope to derive any kind…
We discuss the hypothesis that the debate about the interpretation of the orthodox formalism of quantum mechanics (QM) might have been misguided right from the start by a biased metaphysical interpretation of the formalism and its inner mathematical relations. In particular, we focus on the orthodox interpretation of the congruence relation, '=', which relates equivalent classes of different mathematical representations of a vector in Hilbert space, in terms of metaphysical identity. We will argue that this seemingly "common sense" interpretation, at the semantic level, has severe difficulties…
Despite the importance of the variational principles of physics, there have been relatively few attempts to consider them for a realistic framework. In addition to the old teleological question, this paper continues the recent discussion regarding the modal involvement of the principle of least action and its relations with the Humean view of the laws of nature. The reality of possible paths in the principle of least action is examined from the perspectives of the contemporary metaphysics of modality and Leibniz's concept of essences or possibles striving for existence. I elaborate a modal int…
Nonreflexive quantum mechanics is a formulation of quantum theory based on a non-classical logic termed \ita{nonreflexive logic} (a.k.a. `non-reflexive'). In these logics, the standard notion of identity, as encapsulated in classical logic and set theories, does not hold in full. The basic aim of this kind of approach to quantum mechanics is to take seriously the claim made by some authors according to whom quantum particles are \ita{non-individuals} in some sense, and also to take into account the fact that they may be absolutely indistinguishable (or indiscernible). The nonreflexive formulat…
According to scientific realism, science gives us an approximately true description of what the world is like. But what does it mean? In this chapter, we focus on the ontological and metaphysical aspects of this discussion. That is, we are concerned with the following questions: what there is, according to our best scientific theories? And how are these things that theories say exist? We start from the assumption that a genuine scientific realism must deal with these issues. Taking non-relativistic quantum mechanics as a case study, we discuss some of the challenges currently faced by a genuin…
Quantum Mechanics (QM) has faced deep controversies and debates since its origin when Werner Heisenberg proposed the first mathematical formalism capable to operationally account for what had been recently discovered as the new field of quantum phenomena. Today, even though we have reached a standardized version of QM which is taught in Universities all around the world, there is still no consensus regarding the conceptual reference of the theory and, if or if not, it can refer to something beyond measurement outcomes. In this work we will argue that the reason behind the impossibility to reac…
In this paper we consider the notion of quantum entanglement from the perspective of the logos categorical approach [26, 27]. Firstly, we will argue that the widespread distinctions, on the one hand, between pure states and mixed states, and on the other, between separable states and entangled states, are completely superfluous when considering the orthodox mathematical formalism of QM. We will then argue that the introduction of these distinctions within the theory of quanta is due to another two completely unjustified metaphysical presuppositions, namely, the idea that there is a "collapse" …
The paper compares dispositionalism about laws of nature with primitivism. It argues that while the distinction between these two positions can be drawn in a clear-cut manner in classical mechanics, it is less clear in quantum mechanics, due to quantum non-locality. Nonetheless, the paper points out advantages for dispositionalism in comparison to primitivism also in the area of quantum mechanics, and of contemporary physics in general.
The central idea of this work is the concept of prespace, a hypothetical structure that is postulated to underlie the fabric of space or space-time. I consider how such a structure could relate to space and space-time, and the implications of the existence of this structure for quantum theory. I compare space and space-time to other spaces used in physics, such as configuration space, phase space, and Hilbert space. I support the 'property view' of space, opposing both the traditional views of space and space-time, substantivalism and relationism. I argue that configuration space has a special…
`Shallow' and `deep' versions of scientific realism may be distinguished as follows: the shallow realist is satisfied with belief in the existence of the posits of our best scientific theories; by contrast, deep realists claim that realism can be legitimate only if such entities are described in metaphysical terms. We argue that this methodological discussion can be fruitfully applied in Everettian quantum mechanics, specifically on the debate concerning the existence of worlds and the recent dispute between Everettian actualism and quantum modal realism. After presenting what is involved in s…
The paper sets out a primitive ontology of the natural world in terms of primitive stuff, that is, stuff that has as such no physical properties at all, but that is not a bare substratum either, being individuated by metrical relations. We focus on quantum physics and employ identity-based Bohmian mechanics to illustrate this view, but point out that it applies all over physics. Properties then enter into the picture exclusively through the role that they play for the dynamics of the primitive stuff. We show that such properties can be local (classical mechanics), as well as holistic (quantum …
What defines an emergent quantum mechanics (EmQM)? Can new insight be advanced into the nature of quantum nonlocality by seeking new links between quantum and emergent phenomena as described by self-organization, complexity, or emergence theory? Could the development of a future EmQM lead to a unified, relational image of the cosmos? One key motivation for adopting the concept of emergence in relation to quantum theory concerns the persistent failure in standard physics to unify the two pillars in the foundations of physics: quantum theory and general relativity theory (GRT). The total contrad…
It is commonly claimed that quantum mechanics makes reference to a microscopic realm constituted by elementary particles. However, as first famously noticed by Erwin Schrödinger, it is not at all clear what these quantum particles really are. According to the specialized literature, it is not even clear if each of these microscopic entities possess their own identity. Recently, Jonas Arenhart proposed a distinction of quantum objects in terms of a dilemma which forces a choice between their characterization either as individuals or as non-individuals. In this work we attempt to address the (me…
Scientists often think of the world (or some part of it) as a dynamical system, a stochastic process, or a generalization of such a system. Prominent examples of systems are (i) the system of planets orbiting the sun or any other classical mechanical system, (ii) a hydrogen atom or any other quantum-mechanical system, and (iii) the earth's atmosphere or any other statistical mechanical system. We introduce a simple and general framework for describing such systems and show how it can be used to examine some familiar philosophical questions, including the following: how can we define nomologica…
The article suggests that quantum mechanics is a science of a new type, which refutes the classical metaphysical concept of reality. The notion of a quantum concept is introduced. The possibility of a Wittgensteinian 'dissolution' of the measurement problem with the help of the notion of a language game and the possibility of a metaphysical solution of this problem with the help of the Heideggerian notion of Dasein are considered.
In classical physics, probabilistic or statistical knowledge has been always related to ignorance or inaccurate subjective knowledge about an actual state of affairs. This idea has been extended to quantum mechanics through a completely incoherent interpretation of the Fermi-Dirac and Bose-Einstein statistics in terms of "strange" quantum particles. This interpretation, naturalized through a widespread "way of speaking" in the physics community, contradicts Born's physical account of Ψ as a "probability wave" which provides statistical information about outcomes that, in fact, cannot be interp…
Cramer's (1986) transactional interpretation of quantum mechanics posits retrocausal influences in quantum processes in an attempt to alleviate some of the interpretational difficulties of the Copenhagen interpretation. In response to Cramer's theory, Maudlin (2002) has levelled a significant objection against any retrocausal model of quantum mechanics. I present here an examination of the transactional interpretation of quantum mechanics and an analysis of Maudlin's critique. I claim that, although Maudlin correctly isolates the weaknesses of Cramer's theory, his justification for this weakne…
In this paper I present and defend Rovelli's relation quantum mechanics from some foreseeable objections, so as to clarify its philosophical implications vis a vis rival interpretations. In particular I ask whether RQM presupposes a hidden recourse to both a duality of evolutions and of ontology (the relationality of quantum world and the intrinsicness of the classical world, which in the limit must be recovered from the former). I then concentrate on the pluralistic, antimonistic metaphysical consequences of the theory, due to the impossibility of assigning a state to the quantum universe. Fi…
About twenty years ago, we proposed the mathematical formulation of Heisenberg's uncertainty principle, and further, we concluded that Heisenberg's uncertainty principle and EPR-paradox are not contradictory. This is true, however we now think that we should have argued about it under a certain firm interpretation of quantum mechanics. Recently we proposed the linguistic quantum interpretation (called quantum and classical measurement theory), which was characterized as a kind of metaphysical and linguistic turn of the Copenhagen interpretation. This turn from physics to language does not only…
In this paper we compare two different notions of 'power', both of which attempt to provide a realist understanding of quantum mechanics grounded on the potential mode of existence. For this propose we will begin by introducing two different notions of potentiality present already within Aristotelian metaphysics, namely, irrational potentiality and rational potentiality. After discussing the role played by potentiality within classical and quantum mechanics, we will address the notion of causal power which is directly related to irrational potentiality and has been adopted by many interpretati…
The main claim of the paper is that one can be 'realist' (in some sense) about quantum mechanics without requiring any form of realism about the wave function. We begin by discussing various forms of realism about the wave function, namely Albert's configuration-space realism, Duerr Zanghi and Goldstein's nomological realism about the wave function, Esfeld's dispositional reading of the wave function and Pusey Barrett and Rudolph's realism about the quantum state. By discussing the articulation of these four positions, and their interrelation, we conclude that instrumentalism about the wave fu…
Richard Feynman famously declared, "I think that I can safely say that nobody really understands quantum mechanics." Sean Carroll lamented the persistence of this sentiment in a recent opinion piece entitled, "Even Physicists Don't Understand Quantum Mechanics. Worse, they don't seem to want to understand it." Quantum mechanics is arguably the greatest achievement of modern science and by and large we absolutely understand quantum theory. Rather, the "understanding" to which these two statements evidently refer concerns the ontological status of theoretical constructs. For example, "Do quantum…
What is Physics For? Why Classical Physics is not the Limit of Quantum Mechanics
University of Rochester（罗切斯特大学）；Universidade Federal do Rio de Janeiro（里约热内卢联邦大学）；École Normale Supérieure / CNRS（巴黎高等师范学院/法国国家科学研究中心）；Linköping University（林雪平大学）；Dartmouth College（达特茅斯学院）；University of Sydney（悉尼大学）
The present essay provides a new metaphysical interpretation of Relational Quantum Mechanics (RQM) in terms of mereological bundle theory. The essential idea is to claim that a physical system in RQM can be defined as a mereological fusion of properties whose values may vary for different observers. Abandoning the Aristotelian tradition centered on the notion of substance, I claim that RQM embraces an ontology of properties that finds its roots in the heritage of David Hume. To this regard, defining what kind of concrete physical objects populate the world according to RQM, I argue that this t…
We develop the point of view where Quantum Mechanics results from the interplay between the quantized number of "modalities" accessible to a quantum system, and the continuum of "contexts" that are required to define these modalities. We point out the specific roles of "extracontextuality" and "extravalence" of modalities, and relate them to the Kochen-Specker and Gleason theorems.
It is generally accepted that quantum mechanics entails a revision of the classical propositional calculus as a consequence of its physical content. However, the universal claim according to which a new quantum logic is indispensable in order to model the propositions of every quantum theory is challenged. In the present essay we critically discuss this claim by showing that classical logic can be rehabilitated in a quantum context by taking into account Bohmian mechanics. It will be argued, indeed, that such a theoretical framework provides the necessary conceptual tools to reintroduce a clas…
I begin by examining the question of the quantum limits of knowledge by briefly presenting the constraints of the theory that derive from its mathematical structure (in particular the no-go theorems formulated by von Neumann and Kochen and Specker). I then argue that these theorems reflect on a formal level those practical and experimental settings that are needed to come to know the properties of physical systems. In particular, I discuss some aspects of this relationist and contextualist conception of reality by comparing, in their apparent diversity, Bohr holistic and Rovelli relationist in…
I analyze the meaning of mass in Newtonian mechanics. First, I explain the notion of primitive ontology, which was originally introduced in the philosophy of quantum mechanics. Then I examine the two common interpretations of mass: mass as a measure of the quantity of matter and mass as a dynamical property. I claim that the former is ill-defined, and the latter is only plausible with respect to a metaphysical interpretation of laws of nature. I explore the following options for the status of laws: Humeanism, primitivism about laws, dispositionalism, and ontic structural realism.
Classical physics is generally regarded as deterministic, as opposed to quantum mechanics that is considered the first theory to have introduced genuine indeterminism into physics. We challenge this view by arguing that the alleged determinism of classical physics relies on the tacit, metaphysical assumption that there exists an actual value of every physical quantity, with its infinite predetermined digits (which we name \emph{principle of infinite precision}). Building on recent information-theoretic arguments showing that the principle of infinite precision (which translates into the attrib…
I show how Hamilton's philosophical commitments led him to a causal interpretation of classical mechanics. I argue that Hamilton's metaphysics of causation was injected into his dynamics by way of a causal interpretation of force. I then detail how forces remain indispensable to both Hamilton's formulation of classical mechanics and what we now call Hamiltonian mechanics (i.e., the modern formulation). On this point, my efforts primarily consist of showing that the orthodox interpretation of potential energy is the interpretation found in Hamilton's work. Hamilton called the potential energy f…
In this paper we investigate the history of relationalism and its present use in some interpretations of quantum mechanics. In the first part of this article we will provide a conceptual analysis of the relation between substantivalism, relationalism and relativism in the history of both physics and philosophy. In the second part, we will address some relational interpretations of quantum mechanics, namely, Bohr's relational approach, the modal interpretation by Kochen, the perspectival modal version by Bene and Dieks and the relational interpretation by Rovelli. We will argue that all these i…
Harrigan and Spekkens (2010) provided a categorization of quantum ontological models classifying them as $ψ$-ontic or $ψ$-epistemic if the quantum state describes respectively either a physical reality or mere observers' knowledge. Moreover, they claimed that Einstein - who was a supporter of the statistical interpretation of quantum mechanics - endorsed an epistemic view of $ψ$. In this essay we critically assess such a classification and some of its consequences by proposing a two-fold argumentation. Firstly, we show that Harrigan and Spekkens' categorization implicitly assumes that a comple…
The concept of individuality in quantum mechanics shows radical differences from the one used in classical physics. In particular, it is not possible to consider the fundamental particles described by quantum theory as individual distinguishable objects. In this paper we present arguments in favor of quantum non-individuality, which -in addition to those based on quantum statistics- relate to the Kochen-Specker theorem and the principle of superposition. Then, we analyze the possibility of referring to 'possible individuals' instead of 'actual individuals', and show that the Modal-Kochen-Speck…
In the present study we attempt to incorporate the philosophical dialogue about physical reality into the instructional process of quantum mechanics. Taking into account that both scientific realism and constructivism represent, on the basis of a rather broad spectrum, prevalent philosophical currents in the domain of science education, the compatibility of their essential commitments is examined against the conceptual structure of quantum theory. It is argued in this respect that the objects of science do not simply constitute 'personal constructions' of the human mind for interpreting nature…
To date, quantum mechanics has proven to be our most successful theoretical model. However, it is still surrounded by a "mysterious halo" that can be summarized in a simple but challenging question: Why quantum phenomena are not understood under the same logic as classical ones? Although this is an open question (probably without an answer), from a pragmatist's point of view there is still room enough to further explore the quantum world, marveling ourselves with new physical insights. We just need to look back in the historical evolution of the quantum theory and thoroughly reconsider three k…
