Self-education is, I firmly believe, the only kind of education there is.

There is no belief, however foolish, that will not gather its faithful adherents who will defend it to the death.

But life is glorious when it is happy; days are carefree when they are happy; the interplay of thought and imagination is far and superior to that of muscle and sinew. Let me tell you, if you don't know it from your own experience, that reading a good book, losing yourself in the interest of words and thoughts, is for some people (me, for instance) an incredible intensity of happiness.

Never let your sense of morals get in the way of doing what's right.

Life is a journey, but don't worry, you'll find a parking spot at the end.

The fundamentalists deny that evolution has taken place; they deny that the earth and the universe as a whole are more than a few thousand years old, and so on. There is ample scientific evidence that the fundamentalists are wrong in these matters, and that their notions of cosmogony have about as much basis in fact as the Tooth Fairy has.

A robot must obey the orders given it by human beings except where such orders would conflict with the First Law. [The Second Law of Robotics]