Embarrassingly belated reply on my part, but—thank you for these links! The "Two Solitudes" talk, especially, was really nice & also let me know about a few books that I had no idea about but look way interesting and are now on my Amazon wishlist :)

Also, re: credentialing: have you seen Michael O. Church's thoughts on why programmers need a profession? I don't really agree with all the ideas in his essay, but the ideas are presented in a really interesting/lively way, and he speculates on "how to handle credentialing without limiting/shutting out self-taught folks" and such.