Everything is theoretically impossible, until it is done.

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.

I don't see how an article of clothing can be indecent. A person, yes.

An armed society is a polite society. Manners are good when one may have to back up his acts with his life.

Writing is not necessarily something to be ashamed of, but do it in private and wash your hands afterwards.

Everything is theoretically impossible, until it is done.

Being right too soon is socially unacceptable.

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.

It's an indulgence to sit in a room and discuss your beliefs as if they were a juicy piece of gossip.

One man's "magic" is another man's engineering. "Supernatural" is a null word.

One of the sanest, surest, and most generous joys of life comes from being happy over the good fortune of others.

Sex without love is merely healthy exercise.

By cultivating the beautiful we scatter the seeds of heavenly flowers, as by doing good we cultivate those that belong to humanity.

Be wary of strong drink. It can make you shoot at tax collectors... and miss.

A society that gets rid of all its troublemakers goes downhill.

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

Don't handicap your children by making their lives easy.

Anyone who considers protocol unimportant has never dealt with a cat.

There is no way that writers can be tamed and rendered civilized or even cured. The only solution known to science is to provide the patient with an isolation room, where he can endure the acute stages in private and where food can be poked in to him with a stick.

You can have peace. Or you can have freedom. Don't ever count on having both at once.

One man's theology is another man's belly laugh.

When any government, or any church for that matter, undertakes to say to its subjects, This you may not read, this you must not see, this you are forbidden to know, the end result is tyranny and oppression no matter how holy the motives.

For me, politeness is a sine qua non of civilization.

To be matter-of-fact about the world is to blunder into fantasy - and dull fantasy at that, as the real world is strange and wonderful.

Theology is never any help; it is searching in a dark cellar at midnight for a black cat that isn't there. Theologians can persuade themselves of anything.

The supreme irony of life is that hardly anyone gets out of it alive.

Yield to temptation. It may not pass your way again.

I am free because I know that I alone am morally responsible for everything I do. I am free, no matter what rules surround me. If I find them tolerable, I tolerate them; if I find them too obnoxious, I break them. I am free because I know that I alone am morally responsible for everything I do.

The difference between science and the fuzzy subjects is that science requires reasoning while those other subjects merely require scholarship.

A competent and self-confident person is incapable of jealousy in anything. Jealousy is invariably a symptom of neurotic insecurity.

Never insult anyone by accident.

Never worry about theory as long as the machinery does what it's supposed to do.

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.

One could write a history of science in reverse by assembling the solemn pronouncements of highest authority about what could not be done and could never happen.

No statement should be believed because it is made by an authority.

Never underestimate the power of human stupidity.

They didn't want it good, they wanted it Wednesday.

Political tags - such as royalist, communist, democrat, populist, fascist, liberal, conservative, and so forth - are never basic criteria. The human race divides politically into those who want people to be controlled and those who have no such desire.

I never learned from a man who agreed with me.

The universe never did make sense; I suspect it was built on government contract.

Love is that condition in which the happiness of another person is essential to your own... Jealousy is a disease, love is a healthy condition. The immature mind often mistakes one for the other, or assumes that the greater the love, the greater the jealousy.

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

Abstract knowledge is always useful, sooner or later.

Being a mother is an attitude, not a biological relation.

One man's "magic" is another man's engineering.

Beware of altruism. It is based on self-deception, the root of all evil.

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

One should not attend even the end of the world without a good breakfast.

Citizenship is an attitude a state of mind an emotional conviction that the whole is greater than the part. and that the part should be humbly proud to sacrifice itself that the whole may live.