Hilbert Space Quantum Mechanics is Contextual (Reply to R. B. Griffiths) (1502.05396v2)

Abstract: In a paper Griffiths [38] has argued, based on the consistent histories interpretation, that Hilbert space quantum mechanics (QM) is noncontextual. According to Griffiths the problem of contextuality disappears if the apparatus is "designed and operated by a competent experimentalist" and we accept the Single Framework Rule (SFR). We will argue from a representational realist stance that the conclusion is incorrect due to the misleading understanding provided by Griffiths to the meaning of quantum contextuality and its relation to physical reality and measurements. We will discuss how the quite general incomprehension of contextuality has its origin in the "objective-subjective omelette" created by Heisenberg and Bohr. We will argue that in order to unscramble the omelette we need to disentangle, firstly, representational realism from naive realism, secondly, ontology from epistemology, and thirdly, the different interpretational problems of QM. In this respect, we will analyze what should be considered as Meaningful Physical Statements (MPS) within a theory and will argue that Counterfactual Reasoning (CR) -considered by Griffiths as "tricky"- must be accepted as a necessary condition for any representational realist interpretation of QM. Finally we discuss what should be considered as a problem (and what not) in QM from a representational realist perspective.