The significant problems we have cannot be solved at the same level of thinking with which we created them.
I have lived to prove Thoreau's contention that a man is rich in proportion to the number of things which he can afford to let alone.
Only a life lived for others is a life worthwhile.
Time is what the clock says.
If I were not a Jew I would be a Quaker.
Only six men in the world know about relativity. I am not one of them. When I ask them to explain, they confused me.