Personally, I think it's a good way to let a child start right in with the laws of Nature before he's old enough to be surprised at them.

Knowledge cannot be changed, but the use to which it may be put can very easily be changed.

When we refuse to accept our limitations, Nature, who is a stern realist, pays us out.

It is a very dangerous thing to have an idea that you will not practice.

Our responsibility to ourselves comes first -- because in a sense what one is oneself is the responsibility that one has for others!

To see a shadow and think it is a tree that is a pity; but to see a tree and to think it a shadow can be fatal.

What are so mysterious as the eyes of a child?