Abstract

It has been widely thought that the ontology of quantum mechanics is real, physical fields. In this paper, I will present a new argument against the field ontology of quantum mechanics by analyzing one-body systems such as an electron. First, I argue that if the physical entity described by the wave function of an electron is a field, then this field is massive and charged. Next, I argue that if a field is massive and charged, then any two parts of the field in space will have gravitational and electromagnetic interactions, while the existence of such self-interactions for an electron contradicts quantum mechanics and experimental observations. This poses a serious difficulty for the field ontology of quantum mechanics. Third, I argue that a particle ontological interpretation of the wave function may avoid the difficulty by providing a plausible explanation of the non-existence of self-interactions. According to this explanation, the wave function of an electron is a description of the state of the random motion of the electron as a particle, and in particular, the modulus squared of the wave function gives the probability density that the electron appears in every possible position in space. Finally, I answer a major objection to the explanation of the non-existence of self-interactions in terms of particle ontology.