Sorry if this has been asked (every similar question has a title that basically tags Schrödinger's cat)

If after the superposition of the cat being dead and alive at one time was created, and the person outside the box heard a meow- would the superposition be lost and the cat be 100% alive?

  • $\begingroup$ A cat could not meow in the first place if it was in a superposition. Good luck performing the biochemical processes necessary for life without quantum decoherence. $\endgroup$
    – forest
    Jan 12, 2019 at 14:19
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    $\begingroup$ If I were sitting in a box for a few years, you wouldn't know if I were dead or alive. But I can make a sound to let everyone know that I am. $\endgroup$
    – WarreG
    Jan 12, 2019 at 14:32
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    $\begingroup$ What's the point of the box if the inside is observable from the outside? You might as well give it transparent sides. You might as well run a wire from the Geiger counter (that really does the observation/irreversible-collapse) to the outside. $\endgroup$ Jan 12, 2019 at 14:56
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    $\begingroup$ It is a postulate of the gendanken experiment that prevents observation of the internal system. That postulate is not restricted to visual observation. $\endgroup$ Jan 12, 2019 at 23:59

1 Answer 1


Yes, the superposition state of 'dead and alive' would then be projected onto the 'alive' state because in a way the person measures 'alive'. I assume the cat won't meow if it were dead. The quantum system (the cat) will be in contact with the outside world and as a result decoherence will erase all quantum behavior.


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