There is probably no more terrible instant of enlightenment than the one in which you discover your father is a man - with human flesh.

Most deadly errors arise from obsolete assumptions.

The function of science fiction is not always to predict the future but sometimes to prevent it.

Sympathy for the enemy -- a weakness of police and armies alike. Most perilous are the unconscious sympathies directing you to preserve your enemy intact because the enemy is your justification for existence.

And always, he fought the temptation to choose a clear, safe course, warning 'That path leads ever down into stagnation.

Highly organized research is guaranteed to produce nothing new.

Intelligence takes chances with limited data in an arena where mistakes are not only possible but also necessary.