One problem is the assumption that being right and novel on some things implies being consistently right/sane. An important feature that separates "insanity" and stupidity is that "insanity" doesn't preclude domain-specific brilliance. Certainly a person being unusually right on some things is evidence for them being consistently right on others, but not overwhelmingly strong evidence.
Good point. Many advances were made by people of dubious sanity.
Reply to: Shalmanese's Third Law
From an unpublished story confronting Vinge's Law, written in 2004, as abstracted a bit:
Spot the Bayesian problem, anyone? It's obvious to me today, but not to the me of 2004. Eliezer2004 would have seen the structure of the Bayesian problem the moment I pointed it out to him, but he might not have assigned it the same importance I would without a lot of other background.