Karate-do Kyohan is on the book shelf. I'm not a stickler for Shotokan, especially the kata that was adapted for "competitive" use. But most people don't realize that up until the 1920's Japan had no idea of Karate-do and only practiced Judo, and that it was Funakoshi that brought it to the mainland from Okinawa.
There's another quote from a different time on theory; "doctrine is the haven of the unimaginative."
Like my dad used to say, "There's more than one way to kill a cat". Of course he also said, "The only good cat is a stir-fried cat". But I chalked that up to excessive time in the bush.
For the waywardness of the simple will kill them, and the complacency of fools will destroy them; -Proverbs 1:32