The PBR Theorem and the Ontological Problem of Quantum States

Based on the analysis of the background and the presuppositions of the PBR theorem, this article investigates the influence of this theorem upon the landscape of interpretations of quantum mechanics. It points out that most of the interpretations except the stochastic interpretation are not affected by this theorem. According to this theorem, any viable stochastic theory of quantum mechanics should be a stochastic hidden variable theory, as is shown by Montina's results. Notwithstanding this, the ψepistemic approach is still possible if we follow Einstein's idea not to accept the ontological model of quantum mechanics.