A theory which is not refutable by any conceivable event is non-scientific. Irrefutability is not a virtue of a theory (as people often think) but a vice.

True ignorance is not the absence of knowledge, but the refusal to acquire it.

The growth of knowledge depends entirely upon disagreement.

In so far as a scientific statement speaks about reality, it must be falsifiable; and in so far as it is not falsifiable, it does not speak about reality.

The question is not how to get good people to rule; THE QUESTION IS: HOW TO STOP THE POWERFUL from doing as much damage as they can to us.

If you can't say it simply and clearly, keep quiet, and keep working on it till you can.

The best thing that can happen to a human being us to find a problem, to fall in love with that problem, and to live trying to solve that problem, unless another problem even more lovable appears.

Ignorance is not a simple lack of knowledge but an active aversion to knowledge, the refusal to know, issuing from cowardice, pride, or laziness of mind.

I may be wrong and you may be right, and by an effort, we may get nearer to the truth

The attempt to make heaven on earth invariably produces hell.

Evolution is not a fact. Evolution doesn't even qualify as a theory or as a hypothesis. It is a metaphysical research program, and it is not really testable science.

Don't judge a book by its cover.

Believe in the promise of today, and have hope in the possibilities of tomorrow

As for a picture, if it isn't worth a thousand words, the hell with it.

Thanksgiving reminds us that no matter our differences, we're still one people, part of something bigger than ourselves.

I grew up with four brothers, and in the back of my head I feel pretty masculine. It's always funny when I hear recordings of my voice, because it's so deep when I hear it in my head.

Optimism is denial for chumps with no life experience". "What's pessimism?" I said. "Religion without God.

For myth is at the beginning of literature, and also at its end.

I see myself as a comedian rather than a female comedian. I happen to be a woman, but I am a comedian by trade.

I wasn't frightened of people, but I didn't have a clue about the adult world.

God cannot be solemn, or he would not have blessed man with the incalculable gift of laughter.