What is the origin of the idiom "none the wiser" and when to use it?

The idiom "none the wiser" likely originated from the idea that when someone fails to understand or grasp a situation, they remain without increased knowledge or insight, hence "none the wiser." Its exact historical origin is unclear, but it has been in common usage since at least the 19th century. This expression is used to describe a situation in which someone does not gain any additional knowledge or understanding despite their efforts or experiences. It suggests that the person remains as ignorant or uninformed as they were before.