Abstract

In QBism the wave function does not represent an element of physical reality external to the agent, but represent an agent’s personal probability assignments, reflecting his subjective degrees of belief about the future content of his experience. In this paper, I argue that this view of the wave function is not consistent with protective measurements. The argument does not rely on the realist assumption of the ψ-ontology theorems, namely the existence of the underlying ontic state of a quantum system.