The changing Bell view of beables: a forgotten story

. John S. Bell is known, among other things, for the introduction of the notion of beable. The development of this notion inspired the so-called primitive ontology (PO) approach to the foundations of quantum mechanics, proposed for the first time by Detlef Dürr, Sheldon Goldstein and Nino Zanghì in 1992. It is not very well known, however, that the Bell theory of beables had an early formulation, in which Bell curiously adopts some Bohr-reminiscent insights to attack exactly the standard Copenhagen version of quantum mechanics. Here I reconstruct the two stages of the Bell theory of beables, showing that the first stage is in fact unable to adequately confront the foundational problem it was designed to address. Only the second stage of the Bell theory could represent a motivation for the PO approach: in this respect, it may be of some interest to compare the two-stage reconstruction of the Bell theory with recent analyses of the PO approach in terms of beables. I dedicate this paper to the dear memory of Detlef Dürr, a leading figure of the international community of the foundations of physics and a lovely man. He will be long remembered for his inspiring contributions: it was a privilege to enjoy his company and his doctrine.