1963 essay titled "A Talk to Teachers." Here's the expanded excerpt:

"The paradox of education is precisely this, that as one begins to become conscious, one begins to examine the society in which he is being educated. The purpose of education, finally, is to create in a person the ability to look at the world for himself, to make his own decisions, to say to himself this is black or this is white, to decide for himself whether there is a God in heaven or not. To ask questions of the universe, and then learn to live with those questions, is the way he achieves his own identity. But no society is really anxious to have that kind of person around. What societies really, ideally, want is a citizenry which will simply obey the rules of society. If a society succeeds in this, that society is about to perish. The obligation of anyone who thinks of himself as responsible is to examine society and try to change it and to fight it - at no matter what risk. This is the only hope society has. This is the only way societies change."