Against the ‘no-go’ philosophy of quantum mechanics

Abstract

In the area of the foundations of quantum mechanics a true industry appears to have developed in the last decades, with the aim of proving as many results as possible concerning what there cannot be in the quantum realm. In principle, the significance of proving 'no-go' results should consist in clarifying the fundamental structure of the theory, by pointing out a class of basic constraints that the theory itself is supposed to satisfy. In the present paper I will discuss some more recent no-go claims and I will argue against the deep significance of these results, with a two-fold strategy. First, I will consider three results concerning respectively local realism, quantum covariance and predictive power in quantum mechanics, and I will try to show how controversial the main conditions of the negative theorem turn out to be -something that strongly undermines the general relevance of these theorems. Second, I will try to discuss what I take to be a common feature of these theoretical enterprises, namely that of aiming at establishing negative results for quantum mechanics in absence of a deeper understanding of the overall ontological content and structure of the theory. I will argue that the only way toward such an understanding may be to cast in advance the problems in a clear and well-defined interpretational framework -which in my view means primarily to specify the ontology that quantum theory is supposed to be about -and after to wonder whether problems that seemed worth pursuing still are so in the framework.2

Interpreting Quantum Theory

“…A short summary of some of the criticisms by Schlosshauer and Fine can be found at the end of Appendix C. 100. See (Laudisa [2014]) for a recent criticism of what he terms the 'no-go philosophy of quantum mechanics', arguing that the significance of the no-go objectivity, 158-61 in the assignment of quantum states, 57, 64-70 as explicitness, 79, 181n. 43 as invariance, 79, 181n.…”

No-Go Theorems and the Foundations of Quantum Physics

“…To this extent, recently Laudisa (2014) has questioned the validity of several no-go results within the foundations of QM. For the sake of clarity, it is important to notice that he does not claim that no-go theorems are less important for the conceptual and 1 It is interesting to note that physical theories supply salient information on the inherent limitations of knowledge we may have about the world: there are objective matters of fact about it that are not experimentally accessible to us according to specific theoretical frameworks, independently of the current technological resources available.…”

“…On the contrary, these theorems intend to clarify, imposing particular constraints, the structure of quantum theory; in fact, Laudisa points out correctly that [...] the significance of proving "no-go" results should consist in clarifying the fundamental structure of the theory, by pointing out a class of basic constraints that the theory itself is supposed to satisfy. (Laudisa (2014), p. 2) Nevertheless, he also underlines that often these theorems rely on dubious assumptions which could be questioned or rejected, since they are formulated within the standard or textbook framework of QM, a theory which is manifestly affected by conceptual difficulties, and that precludes a clear understanding of the physics at the microscopic level because of the lack of a clear ontology. 2 According to him, a sensible way toward such an understanding may be to cast in advance the problems in a clear and well-defined interpretational framework -which in my view means primarily to specify the ontology that quantum theory is supposed to be about -and after to wonder whether problems that seemed worth pursuing still are so in the framework.…”

Bohr meets Rovelli: a dispositionalist account of the quantum limits of knowledge

“…In both cases, we will see how the ways in which such theorems are typically used to argue in favor of the existence of impassable limits of our knowledge of the physical world depend to an important extent on implicit philosophical stances about the crucial question: what is quantum theory about? (Laudisa 2014) Rather than limiting in principle our knowledge of the external world, the structure of the Hilbert space poses some constraints on the ontology and metaphysics of quantum theory that certainly differ from those of classical physics and that are independently supported by the experimental practice and by a sound philosophical analysis. In a nutshell, my thesis is that both senses in which quantum mechanics can be legitimately regarded as a theory that sets important limits to our knowledge of the natural world (the formal and the experimental/philosophical one) that however don't justify Du-Boys Reymond's radically skeptical attitude to quantum mechanics 2.2 The mathematical no-go theorems As in the case of the impossibility theorems demonstrated by Gödel, the mathematical structure of the Hilbert space by itself can be used to rule out in a rigorous way certain natural, commonsensical as well as classical assumptions about the physical world, specifically the non-contextuality of possessed properties (Kochen and Specker 1967).…”