“So it is said that if you know your enemies and know yourself,...

“So it is said that if you know your enemies and know yourself, you will not be put at risk even in a hundred battles.
If you only know yourself, but not your opponent, you may win or may lose.
If you know neither yourself nor your enemy, you will always endanger yourself.”

Art of War.

I have tested all three of these premises - right here on the ASX , centuries  after Sun Tzu wrote (or started) the book.
I  intuit Mr Buffet uses the first one quite a bit when determining what stocks to buy...