Subjectivity in quantum physics refers to the role of conscious observers and the apparent influence they have on the behavior of quantum systems. This aspect of subjectivity arises primarily from the interpretation of quantum mechanics and the measurement problem.
The measurement problem in quantum mechanics refers to the challenge of understanding how a quantum system transitions from a superposition of multiple states to a definite state when it is measured or observed. According to the Copenhagen interpretation, which is one of the most widely accepted interpretations of quantum mechanics, the act of measurement causes the system to "collapse" into one of its possible states. This collapse is probabilistic, with the outcome determined by the system's wave function.
The measurement problem raises philosophical and conceptual questions about the nature of reality and the role of observers. It suggests that the act of measurement or observation plays a fundamental role in determining the outcome of a quantum system. This has led to debates and discussions about the nature of consciousness and its relationship to quantum physics.
Some interpretations of quantum mechanics, such as the many-worlds interpretation, propose that all possible outcomes of a measurement actually occur, but in separate branches of reality. In this view, subjectivity arises from the fact that observers are aware of only one outcome, leading to the illusion of a collapsed state.
Overall, the cause of subjectivity in quantum physics is still a topic of active research and debate among physicists and philosophers. It remains an intriguing and open question within the field of quantum mechanics.