[pjungwir]

I upvoted this comment as soon as I read it, but just to follow up: that link is amazing. I read lecture 9, then 10, 10.5, 11, . . . Eventually I bought the book and am reading it from the beginning. Godel and the Halting Problem has been a pet interest for ~17 years, and I've often wondered about implications similar to Penrose's argument. The recent death of a young promising friend has made me want to research these things more seriously, and Aaronson seems like a wonderful guide. Thank you so much!