  Recently I proposed the linguistic interpretation of quantum mechanics, which
is characterized as the linguistic turn of the Copenhagen interpretation of
quantum mechanics. This turn from physics to language does not only extend
quantum theory to classical theory but also yield the quantum mechanical world
view. Although the wave function collapse is prohibited in the linguistic
interpretation, in this paper I show that the phenomenon like wave function
collapse can be realized in the linguistic interpretation. And furthermore, I
propose the justification of the von Neumann-L\"uders projection postulate.
After all, I conclude that the wave function collapse should not be adopted in
the Copenhagen interpretation.
