We can judge our progress by the courage of our questions and the depth of our answers, our willingness to embrace what is true rather than what feels good.
If you can force your heart and nerve and sinew to serve your turn long after they are gone, and so hold on when there is nothing in you except the will which says to them: 'Hold on!'
We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.
The point, which can hardly be repeated too often, is that differentiation is not separation. The head and the feet are different, but not separate, and though man is not connected to the universe by exactly the same physical relation as branch to tree or feet to head, he is nonetheless connected - and by physical relations of fascinating complexity.
The credit belongs to those who are actually in the arena, who strive valiantly; who know the great enthusiasums, the great devotions, and spend themselves in a worthy cause; who at best know the triumph of high achievement; and who, at worst, if they fail, fail while daring greatly, so that their place shall never be with those cold and timid souls who know neither victory nor defeat.