Ask HN: What are the most inspirational blog posts you've ever read?

A transcript of the brilliant speech by Heinz von Foerster titled "Ethics and Second Order Cybernetics". When I read this I found it truly amazing, because it effortlessly connected the existential questions I was facing with the formalism of mathematics and the insight of the humanities, all tied into a beautiful circle.

http://www.stanford.edu/group/SHR/4-2/text/foerster.html