When a place gets crowded enough to require ID's, social collapse is not far away. It is time to go elsewhere. The best thing about space travel is that it made it possible to go elsewhere.

If a grasshopper tries to fight a lawnmower, one may admire his courage but not his judgement.

Love is that condition in which the happiness of another person is essential to your own.

You can sway a thousand men by appealing to their prejudices quicker than you can convince one man by logic.

Never underestimate the power of human stupidity.

Women and cats will do as they please, and men and dogs should relax and get used to the idea.

I never learned from a man who agreed with me.

A generation which ignores history has no past — and no future.

Don't ever become a pessimist... a pessimist is correct oftener than an optimist, but an optimist has more fun, and neither can stop the march of events.

May you live as long as you wish and love as long as you live.

It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so.

People say, that which doesn't kill you makes you stronger. But they are wrong. What doesn't kill you, doesn't kill you.

Life is a sacred bliss.

The loss of life will be irreplaceable.

ISIS is using the internet to recruit. ISIS is using the internet to intercept and do all sorts of things to our country. We have to be many steps ahead of them, and we will be.

Words are cold and formal things.

NATO is an alliance, so all parts of the alliance have to be capable.

We can love completely what we cannot completely understand.

One bacterium has 2,000 to 6,000 proteins.

Every cent we earn from Crocodile Hunter goes straight back into conservation. Every single cent.

The beginning and ending of the secret of handling Arabs is unremitting study of them.