  The possibility of consistency between the basic quantum principles of
quantum mechanics and wave function collapse is reexamined. A specific
interpretation of environment is proposed for this aim and applied to
decoherence. When the organization of a measuring apparatus is taken into
account, this approach leads also to an interpretation of wave function
collapse, which would result in principle from the same interactions with
environment as decoherence. This proposal is shown consistent with the
non-separable character of quantum mechanics.
