Basic Considerations on the Interpretation of Quantum Mechanics A. Einstein (7)

Neither of these 2 data can be obtained from the Ψ function (1). From this (with the help of Born's interpretation) we can take only data which refers to a time universe of systems of the type under consideration. The fact that in the macro system under consideration in which not every function fulfilling the Schrödinger equation Ψ function corresponds to the real description in the sense of classical mechanics (approximated) is particularly clear when considering a Ψ function which results from the superposition of 2 solutions of type (1), whose frequencies (or energies) are considerably different from each other. This is because such a superposition does not correspond at all to any real case of classical mechanics (but it does correspond to a statistical universe of such real cases in the sense of Born's interpretation). In general, we can conclude that quantum mechanics describes time universes of systems, and not the individual system. The description using the Ψ function is, in this sense, an incomplete description of the single system, not a description of its real state. Note: One could argue the following against this conclusion. The case of the most extreme frequency exactness of the Ψ function we considered is a borderline case, for which the requirement of similarity with a problem of classical mechanics may well fail, as an exceptional case. If one permits a finite—even if it is a small range—temporal frequency, then it can be achieved by suitably selecting the amplitudes and phases of superimposed Ψ functions so that the resulting Ψ function becomes close to exact in terms of location and impulse.