If there is any institution that can legitimately claim to be worldwide, it is probably the school. However different the cultures may be, the schools resemble one another remarkably. The system of education they provide is founded on the presupposition that children go to school to learn. They learn basic skills, like reading, writing, and arithmetic proficiencies. And they learn content, like geography, history, and literature.

A cynical commentator once observed that human beings invented speech in order to conceal their thoughts. The same observer might have added that they send their children to school to learn in order to keep them from thinking. If so, it is a tactic that has had only limited success. Children are not easily prevented from thinking. Indeed, it is often the case that our most cherished recollections of our school years are of those moments when we thought for ourselves – not, of course, because of the educational system, but in spite of it.

Yet there has always been a strand of educational thought that held that the strengthening of the child's thinking should be the chief business of the schools and not just an incidental outcome – if it happened at all. Some have argued in this way because they thought that the schooling of future citizens in democracy entailed getting them to be reasonable and that this could be done by fostering children's reasoning and judgment.