I'm finally starting to understand Quantum Physics a little bit, thanks to Kumar's fascinating overview of its historical and theoretical developments. Parts were hard to follow, but I think a lot of that is because it's a hard topic, not because Kumar wasn't able to break it down. The last quarter was where it really started to (kind of) make sense for me. I empathise with Einstein - it seems like madness to accept there's no reality apart from observation. But I'm starting to get Bohr's point - that there can never be an objective observer or an unaffected observation, so it makes no sense to talk about an objective reality. It's a trick we use in thinking about the world, but it's still just a trick. The interesting implication of the Copenhagen interpretation of Quantum Mechanics is that there seems to be no way to posit a supernatural realm either. It can only be thought about as a trick, but ultimately unknowable, and irrational to seriously consider. I have more thoughts about QM, but they're still congealing. I think QM, rationality, and Relativity are all related.....