Do Dispositions and Propensities Have a Role in the Ontology of Quantum Mechanics? Some Critical Remarks

Abstract

In order to tackle the question posed by the title-notoriously answered in the positive, among others, by Heisenberg, Margenau, Popper and Redhead-I first discuss some attempts at distinguishing dispositional from non-dispositional properties, and then relate the distinction to the formalism of quantum mechanics. Since any answer to the question titling the paper must be interpretation-dependent, I review some of the main interpretations of quantum mechanics in order to argue that the ontology of theories regarding "wave collapse" as a genuine physical process could be interpreted as being irreducibly dispositional. In non-collapse interpretations, on the contrary, the appeal to dispositions is simply a way to reformulate the predictive content of the algorithm of the theory in a fancier metaphysical language.