The catch is that you can know certain and impossible things without measurement by simply showing their amplitudes to be 1 and 0 respectively. In case of the c

The catch is that you can know certain and impossible things without measurement by simply showing their amplitudes to be 1 and 0 respectively. In case of the cat you have state after observation |dead>|see dead> + |alive>|see alive>, then project it to basis <see definite cat| <see indefinite cat| : <see definite cat|(|dead>|see dead> + |alive>|see alive>) = 1 <see indefinite cat|(|dead>|see dead> + |alive>|see alive>) = 0