Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering.

I don't believe in astrology; I'm a Sagittarius and we're skeptical.

The limits of the possible can only be defined by going beyond them into the impossible.

The only way to discover the limits of the possible is to go beyond them into the impossible.

I don't pretend we have all the answers. But the questions are certainly worth thinking about.

The best measure of a man's honesty isn't his income tax return. It's the zero adjust on his bathroom scale.

The Irish are a fair people - they never speak well of one another.

He who has a why to live can bear almost any how.

Sex: the thing that takes up the least amount of time and causes the most amount of trouble.

The people are to be taken in very small doses.

A learning experience is one of those things that says, 'You know that thing you just did? Don't do that.

We can never obtain peace in the outer world until we make peace with ourselves.

In the confrontation between the stream and the rock, the stream always wins - not through strength, but through persistence.

If you put off everything till you're sure of it, you'll never get anything done.

Know thyself? A maxim as pernicious as it is ugly. Whoever observes himself arrests his own development. A caterpillar who wanted to know itself well would never become a butterfly.