an LLM tells me there is no evidence that Bernard Shaw ever said any such thing :)

It's Sturgill Simpson all the way down: https://en.wikipedia.org/wiki/Turtles_All_the_Way_Down_(song...

In my defense, I was suffering from white line fever.

Well sure, it was George Bernard Shaw, not the old CNN anchor. Also, turtles are tight lipped by nature.