the wise man does not really needs to make mistake before they learn, this life we have two type of people.
the first set of people are those that receive or accept theoritical correction, and the second set of people are those that accept only practical correction.
I would like to explain a little, there are some people when you correct them about something or you tell them about a knowledge of something, the except they think about it a little you digest it and accept the truth.
but the second set of people, no matter what you tell them they will never answer and they will agree with you they only learn from practical, so they have to experience something that will teach them in that situation before they accept that philosophy.
and sometimes when situation teaches them, the scar they have from that experience will be much that they won't be able to recover from it for their lifetime
so will let us learn how to except knowledge accept truth without experiencing mistakes or loss I think that is a proof of wisdom