I The Mystery of Eigenstate Preference in Quantum Mechanics

[intervoxel]

If any superposition of quantum states is stable, why the preference for one of the eigenstates of the observable at the measurement? What is the attraction of such state?

 

[Nugatory]

If any superposition of quantum states is stable, why the preference for one of the eigenstates of the observable at the measurement? What is the attraction of such state?

It's a postulate of quantum mechanics. As with any postulate (test this with Euclid's postulates), you aren't going to get very far asking why it works; the only answer is that that's how the universe we live in works.