Measurement Problem from the Perspective of Wittgenstein’s Philosophy

We analyze the measurement problem in quantum mechanics from two aspects of Wittgenstein’s philosophy. First, Wittgenstein emphasizes how the first false step can be voided so that a philosophical problem is dissolved, rather than solved. In the unsuccessful theories of the measurement problem, the postulate of classicality of apparatus (PCA) turned out to be the first false step implicitly adopted. By discarding the PCA and by adopting the microscopic quantum jump interpretation simultaneously, the measurement problem itself disappeared completely. Second, from Wittgenstein’s view of languages, the microscopic world is described by quantum mechanics, whose language is the Schrödinger equation, while the macroscopic world is described by classical physics, whose language is either calculus for Newtonian mechanics or vector analysis for electromagnetism. Both worlds are described by mathematical languages, but they are distinct. The measurement problem deals with the transition from microscopic to macroscopic. There is no single physical theory to explain this transition, and there is no corresponding mathematical language to describe it. This shows why the measurement problem must be described by an ordinary language in use. As concrete examples of the unsuccessful theories, we discuss the works of Niels Bohr and John von Neumann. This is a unique situation in which philosophy is used to assess the validity of physical theories. Finally, we show the classicality of a one-particle state with an extreme number of bosons. Therefore, there is no change in language in a macroscopic quantum jump.