Since what Scott Aaronson is saying in point 2 sounds very interesting to me, would someone be so nice and elaborate on the following sentence (so that I don't have to wait until I am able to reduce the inferential distance :-):

If I didn't know that in real life, people pretty much never encounter pure states, but only more general objects that (to paraphrase Jaynes) scramble together "subjective" probabilities and "objective" amplitudes into a single omelette, the view that quantum states are "states of knowledge" that "live in the mind, not in the world" would probably also strike me as meaningless nonsense.