What does “Experience keeps a dear school, but fools will learn in no other” mean?

thanks :]

Found this on Wikipedia, it sums it up quite nicely.
“Only the foolish learn from experience — the wise learn from the experience of others.” – Romanian Proverb.
(Fools go out, make their own mistakes and learn from them. Smart people learn from others’ mistakes.)

“Experience keeps a dear school, but fools will learn in no other.” – Benjamin Franklin
(Fools don’t learn in school from textbooks or teachers. Fools learn from their own mistakes. They can’t learn this in a school classroom.) A fool will only learn from his personal experiences

As it’s used here, “dear” is an archaic term for “expensive”. So: learning things by experience will be costly (literally or figuratively), but there isn’t any other way for a fool to learn their lesson. The implication is that, if one is wise, he/she would attend to what others try to teach them and thereby avoid making similar mistakes.

Dear School