sentences:  A mixed state is a mixture of probabilities of physical states, not a coherent superposition of physical states.The statement that the quantum mechanical wave function itself does not apply to a single system in one sense does not imply that the ensemble interpretation itself does not apply to single systems in the sense meant by the ensemble interpretation.The condition is that there is not a direct one-to-one correspondence of the wave function with an individual system that might imply, for example, that an object might physically exist in two states simultaneously.