No particular theory may ever be regarded as absolutely certain.... No scientific theory is sacrosanct.

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.

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.

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.

Seeing everything through different eyes, as I look to the sky with love in my sight, realizing what this ride does to me inside.

The first duty of a human being is to assume the right relationship to society-more briefly to find your real job and do it.

Nonsmokers--this is for you and you only. Ready? Nonsmokers die every day. Sleep tight.

We are the custodians of life's meaning.

When I don't know what to do, I just open my mouth. Why won't anyone date me?

Tanks are new and special weapon-newer than, as special, and certainly as valuable as the airplane.

True religion is slow in growth, and, when once planted, is difficult of dislodgement; but its intellectual counterfeit has no root in itself: it springs up suddenly, it suddenly withers.

Most players don't mind drug testing once they realize they don't have to study for it.

Education must begin with the solution of the teacher-student contradiction, by reconciling the poles of the contradiction so that both are simultaneously teachers and students.

I do not like to repeat successes, I like to go on to other things.