It's what you learn after you know it all that counts. To think is to differ. The critical factor is not class size but rather the nature of the teaching as it affects learning. Anyone who stops learning is old, whether at twenty or eighty. Anyone who keeps learning stays young.
Education can be dangerous.
It is very difficult to make it not dangerous. In fact, it is almost impossible. When inspiration does not come to me, I go half way to meet it. In the practical use of our intellect, forgetting is as important as remembering. All people by nature desire to know.