accumulated knowledge, both individually and in the totale of society. We are a microcosm of the entire learning experience of humanity. We, had we the time, could learn everything learned, but we haven't the time, so we have schools.
Schools are not buildings, but a place to share knowledge and challenge you to apply it.
Every one cheats. You determine if cheating is your modus operandi or will you eschew it knowing you will integrate that learning experience into your library.
But you never leave school. You could figure out how to put tackstrip into terrazzo flooring through trial and error, or you could go to the carpet supplier and find out a hammer drill is your solution.
We all need answers, and often rely on experts over experience. Experts often use experience to become experts and then write books or make videos.
Does learning from a book or video make one an expert? I'd say you can't play a piano without tickling the ivories.

And if you want to feed you brain, learn what every tool in the shed was designed to do.