To the youngsters of today, I say "Believe in the future, the world is getting better; there still is plenty of opportunity. " Why, would you believe it, when I was a kid I thought it was already too late for me to make good at anything.
To teach means scarcely anything more than to show how things differ from one another in their different purposes, forms, and origins. . . . Therefore, he who differentiates well teaches well.