Unschooling is letting your kids learn from life, the same way adults learn new things. You provide opportunities for them to discover interests, and the kids pick up knowledge from pursuing those interests. For example, someone who loves sailing will naturally learn physics, meteorology, navigation, etc.
I don`t think I would like that way of teaching my kids. They have to learn to read and write and do math. I would push them in the direction of their individual interests. There so many things they need to be in school to learn unless you home school them. I don`t have the patience for that.