It was childish to feel disappointed, but childishness comes almost as naturally to a man as to a child.
Democracy cannot survive overpopulation.
There is nothing so eternally adhesive as the memory of power.
To make discoveries, you have to be curious about why the universe is the way it is.
All of a sudden, space isn't friendly. All of a sudden, it's a place where people can die. . . . Many more people are going to die. But we can't explore space if the requirement is that there be no casualties; we can't do anything if the requirement is that there be no casualties.
Life is glorious when it is happy; days are carefree when they are happy; the interplay of thought and imagination is far superior to that of muscle and sinew.