> Many worlds does postulate its many worlds rather than predict them as it provides no way their existence can ever be tested for. Many Worlds just postulates

> Many worlds does postulate its many worlds rather than predict them as it provides no way their existence can ever be tested for. Many Worlds just postulates that if you put a cat in a superposition of two quantum states (alive + dead), there is no sensation associated with that superposition. The cat is in a superposition of having the sensation of being alive, and having the sensation of being dead, but there is no observable quality of "being in a superposition of alive and dead". Both of the superimposed pure states of the cat feel decidedly one way or the other. Hence, when a human is in a superposition, we would not know it. Both of our superimposed states are experiencing the feeling of being in a pure state of looking at an instrument measuring a photon with polarization ↑, or looking at an instrument measuring a photon with polarization ↓. Being in an (↑ + ↓) superposition doesn't feel like looking at an instrument display and seeing a blurry reading. We feel like we saw the instrument reading ↑, and we (as an element of the quantum system) cannot interact with the branch of the wavefunction that we are superimposed with in which we saw the instrument reading ↓. This isn't a separate postulate, it's just straightforward quantum theory applied to quantum systems large enough to have opinions about their own state.