4 ms·

That defeats the point of the exercise. The whole point was about the state of some isolated system. Otherwise we could say that the detector observes the state

• megaloblasto 2y ago
  It doesn't defeat the point of the exercise, it just shows that the exercise is nonsense. The cat is an observer therefore collapses the quantum wave function and is either alive or dead.
  • baq 2y ago
    In what sense the cat is an observer? Having eyes and a brain doesn't really mean anything in QM.
    • lupusreal 2y ago
      If the particle interacts, that collapses the superposition. Cats aren't any more or less blessed as observers than physicists. If either of them can observe the outcome, then both can.
      • murftown 2y ago
        Hmm. Maybe what "counts as an observer" is relative to your reference frame, and so is the concept of "superposition". And thus, though the cat is making observations within its environment, since the environment is sealed off, the cat is not "an observer" from our reference frame because there is no interaction between us and the cat. From the cat's reference frame it is probably not in a superposition - If it is observing anything, it is alive, and if it is dead, it is not observing anything. But if we observe the cat, the wave function is collapsed from our reference frame and the cat is in one or the other state. My understanding of quantum mechanics is pretty shallow so take this with an ocean of salt.
        • theGnuMe 2y ago
          That would mean we are all alive and dead.
          • dTal 2y ago
            Well yes. That is many-worlds.
      • danbruc 2y ago
        If the particle interacts, that collapses the superposition. Not at all, the superposition spreads to the interacting particles. What destroys superpositions are measurements and we do not know what measurements really are.
        • lupusreal 2y ago
          You can't measure something without interacting with it. So either it's the interaction that collapses it, or it's some sort of soul mumbo jumbo. If it's somehow the latter, there's no justification beyond shear anthropocentrism to suppose that physicists can do it but cats can't. Therefore, the cat observes itself.
          • dTal 2y ago
            The result is the same if you replace the cat with a physicist. The relevant distinction is whether the animal in question is inside or outside the sealed box - not species.
        • dTal 2y ago
          We do know what measurements are. "Superposition" and "collapse" are only really valid concepts in a particular reference frame. A "measurement" is an interaction in your preferred reference frame. The cat cannot "collapse" anything from your perpective - only its own. Indeed the cat itself does not experience superposition.