Quantum

EY had many reasons to write about quantum physics, including (emphases mine):

1. “the many-worlds issue is just about the only case I know of where you can bring the principles of Science and Bayesianism into direct conflict.” It’s important to have different mental buckets for “science” and “rationality”, as they are different concepts. Bringing the two principles into direct conflict is helpful for illustrating what science is and is not, and what rationality is and is not. Otherwise you end up trusting in what you call “science”, which won’t be strict enough. […]
2. “part of what goes into becoming a rationalist, is learning to live into a counterintuitive world — learning to find things underneath the surface that are unlike the world of surface forms.” Quantum mechanics makes a good introduction to that, when done correctly without the horrible confusion and despair. It breaks you of your belief in an intuitive universe, counters naive realism, destroys your trust in the way that your cognitive algorithms look from inside—and then you’re ready to start seeing your mind as a mind, not as a window onto reality. […]
3. "But there were physicists talking complete nonsense about Occam’s Razor without knowing the probability theory of it, so my hand was forced" […]
4. “knowing about many worlds, helps you visualize probabilities as frequencies, which is helpful to many points I want to make.” […]
5. “reducing time to non-time is a powerful example of the principle, in reductionism, that you should reduce something to something other than itself.” […]
6. “transhumanist mailing lists have been arguing about issues of personal identity for years, and a tremendous amount of time has been wasted on it.” Probably most who argue, will not bother to read what I have set forth; but if it stops any intelligent folk from wasting further time, that too is a benefit. […]

In summary,

1. Case study of where science as a social toolkit breaks down, and you need to seriously understand Occam's Razor
2. Learning to live in a counterintuitive world
3. Using many-worlds to help you visualize probabilities as frequencies (although I suppose you don't need to accept MWI to use it as a metaphor)
4. Issues of personal identity / continuity of consciousness

seems to me there is also something it could say with anthropic reasoning involved, about your location in the multiverse?

• Physics
• Evidence behind many-worlds

• Portal: Rationality