F. A. Muller

The quest for finding the right interpretation of Quantum Mechanics is as old as QM and still has not ended, and may never end. The question what an interpretation of QM is has hardly ever been raised explicitly, let alone answered. We raise it and answer it. Then the quest for the right interpretation can continue self-consciously, for we then know exactly what we are after. We present a list of minimal requirements that something has to meet in order to qualify as an interpretation of QM. We also raise, as a side issue, the question how the discourse on the interpretation of QM relates to hermeneutics in Continental Philosophy.

The notorious ‘measurement problem’ has been roving around quantum mechanics for nearly a century since its inception, and has given rise to a variety of ‘interpretations’ of quantum mechanics, which are meant to evade it. We argue that no less than six problems need to be distinguished, and that several of them classify as different types of problems. One of them is what traditionally is called ‘the measurement problem’. Another of them has nothing to do with measurements but is a profound metaphysical problem. We also analyse critically Maudlin’s (Topoi 14:7–15, 1995) well-known statement of ‘three measurements problems’, and the clash of the views of Brown (Found Phys 16:857–870, 1986) and Stein (Maximal of an impossibility theorem concerning quantum measurement. In: R. S. Cohen et al. (Eds.), Potentiality, entanglement and passion-at-a-distance, 1997) on one of the six measurement problems. Finally, we summarise a solution to one measurement problem which has been largely ignored but tacitly if not explicitly acknowledged.

We discuss the case against Factorism, which is the standard assumption in quantum mechanics that the labels of the $$\otimes$$ ⊗ -factor Hilbert-spaces in direct-product Hilbert-spaces of composite physical systems of similar particles refer to particles, either directly or descriptively. We distinguish different versions of Factorism and argue for their truth or falsehood. In particular, by introducing the concepts of snapshot Hilbert-space and Schrödinger-movie, we demonstrate that there are Hilbert-spaces and $$\otimes$$ ⊗ -factorisations where the labels do refer, even descriptively, to similar particles, which renders them probabilistically absolutely discernible.

We inquire into the question whether the Aristotelean or classical \emph{ideal} of science has been realised by the Model Revolution, initiated at Stanford University during the 1950ies and spread all around the world of philosophy of science --- \emph{salute} P.\ Suppes. The guiding principle of the Model Revolution is: \emph{a scientific theory is a set of structures in the domain of discourse of axiomatic set-theory}, characterised by a set-theoretical predicate. We expound some critical reflections on the Model Revolution; the conclusions will be that the philosophical problem of what a \emph{scientific theory} is has \emph{not} been solved yet --- \emph{pace} P.\ Suppes. While reflecting critically on the Model Revolution, we also explore a proposal of how to complete the Revolution and briefly address the intertwined subject of \emph{scientific representation}, which has come to occupy center stage in philosophy of science over the past decade.

In his influential After Finitude. An Essay on the Necessity of Contingency (2008), Quentin Meillassoux argues that *Correlationism* (an umbrella-term encompassing most varieties of Idealism) gives rise to an irresolvable paradox, called "the Paradox of the Arche-fossil", which is essentially a clash between philosophical principles and scientific findings. This irresolvable paradox of Correlationism then paves the way for the "Speculative Turn" and the ensuing rise of burgeoning "speculative realism" in Continental Philosophy: noumenal reality, as-it-is-in-and-of-itself, "the Great Outdoors", is back on the Continental stage, open for speculative thought and even metaphysical knowledge. We attempt to provide a thorough and charitable analysis of the Paradox of the Arche-fossil. Our analyses lead us to conclude that Meillassoux's argument fails, due to an ambiguity with regard to the concept of being that cannot be repaired. We end by directing attention to another ominous threat to Correlationism, ignored by Meillassoux and all "speculative realists" alike, which is still breathing.

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