Earlier quoted context omitted.
I mean, much of Graham's "investment philosophy" has been thoroughly invalidated by the Modigliani-Miller theorem published in the 1960s. But like Deepak Chopra, he's still around!
I'm not sure how a theorem is even supposed to invalidate a philosophy. Invalidation is normally done by experimental evidence not making up a theorem.
http://www8.gsb.columbia.edu/rtfiles/cbs/hermes/Buffett1984....