why do we have universal education

Why do we have universal education? When the teacher asked us this question, the first thing I thought about is to have a better environment. Children having school is mandatory in Taiwan. We are required to have 12 years of education before we go into the society.  The reason why we go to school is to learn. We learn how to differentiate the rights and the wrongs, how to cooperate with people, and basic things of live. A hundred years back then, there is not public school. Education was for the rich people. Most of the children at our ages had to go to work, boys need to help the family to farm, while girls were taking care of the youngs. Since they didn't go to school, they are very easy to believe in people, because they don't have the ability to know what is the right and wrong. My grandfather didn't go to school when he was little. Every time he heard something, he believes it. When he got sick, he didn't want to go to hospital. He trusted the people in the small clinic. Of course the people there would just tell him to take the medicine and he will be fine. He didn't even know that he had cancer until the last moment, because he believes that his illness would recover by eating those medicine that he randomly bought from the store. We should have education to help us learn things that we should know.