QBism

“QBism, which combines quantum theory with probability theory, maintains that the wave function has no objective reality. Instead QBism portrays the wave function as a user’s manual, a mathematical tool that an observer uses to make wiser decisions about the surrounding world—the quantum world.”

“QBism explicitly takes the “subjective” or “judgmental” or “personalist” view of probability, which, though common among contemporary statisticians and economists, is still rare among physicists: probabilities are assigned to an event by an agent and are particular to that agent. The agent’s probability assignments express her own personal degrees of belief about the event.”