From If Many-Worlds had Come First:
the thought experiment goes: 'Hey, suppose we have a radioactive particle that enters a superposition of decaying and not decaying. Then the particle interacts with a sensor, and the sensor goes into a superposition of going off and not going off. The sensor interacts with an explosive, that goes into a superposition of exploding and not exploding; which interacts with the cat, so the cat goes into a superposition of being alive and dead. Then a human looks at the cat,' and at this point Schrödinger stops, and goes, 'gee, I just can't imagine what could happen next.' So Schrödinger shows this to everyone else, and they're also like 'Wow, I got no idea what could happen at this point, what an amazing paradox'. Until finally you hear about it, and you're like, 'hey, maybe at that point half of the superposition just vanishes, at random, faster than light', and everyone else is like, 'Wow, what a great idea!'"
Obviously this is a parody and Eliezer is making an argument for many worlds. However, this isn't that far from how the thought experiment is presented in introductory books and even popularizations. Why, then, don't more people realize that many worlds is correct? Why aren't tons of bright middle-school children who read science fiction and popular science spontaneously rediscovering many worlds?
Why, then, don't more people realize that many worlds is correct?
I am going to try and provide short answer, as I see it. (Fighting urge to write about different levels of "physical reality".)
Many Words is an Interpretation. An interpretation should translate from mathematical formalism towards practical algorithms, but MWI does not go all the way. Namely, it does not specify the quantum state an Agent should use for computation. One possible state agrees with "Schroedinger's experiment was definitely set up and started", another sta...
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.