The coward wretch whose hand and heart Can bear to torture aught below, Is ever first to quail and start From the slightest pain or equal foe.

None but a coward dares to boast that he has never known fear.

A courageous foe is better than a cowardly friend

I do not pretend to start with precise questions. I do not think you can start with anything precise. You have to achieve such precision as you can, as you go along.

Work is of two kinds: first, altering the position of matter at or near the earth's surface relative to other matter; second, telling other people to do so.

It is possible that mankind is on the threshold of a golden age; but, if so, it will be necessary first to slay the dragon that guards the door, and this dragon is religion.