Quotes about doubt

The world would be astonished if it knew how great a proportion of its brightest ornaments—of those most distinguished even in popular estimation for wisdom and virtue—are complete sceptics in religion...

It was a horrible feeling to find things in your head and not know how they fitted.

Now the plan was threatend by something more serious than the Mule had ever been. It was to be diverted from a renewal of Empire to something utterly different from anything in history - Galaxia. And he himself had agreed to that. But why? Was there a flaw in the plan? a basic flaw? For one flashing moment, it seemed to Trevize that this flaw did indeed exist and that he knew what it was, that he had known what it was when he made his decision - but the knowledge...if that were what it was...vanished as fast as it came, and left him with nothing.

In order to seek truth, it is necessary once in the course of our life, to doubt, as far as possible, of all things.

Moral certainty is always a sign of cultural inferiority. The more uncivilized the man, the surer he is that he knows precisely what is right and what is wrong. All human progress, even in morals, has been the work of men who have doubted the current moral values, not of men who have whooped them up and tried to enforce them. The truly civilized man is always skeptical and tolerant, in this field as in all others. His culture is based on "I am not too sure."

We are here and it is now: further than that, all human knowledge is moonshine.

In order to cease being a doubtful case, one has to cease being, that's all.

I have always felt that doubt was the beginning of wisdom, and the fear of God was the end of wisdom.

The two ways of contemplation are not unlike the two ways of action commonly spoken of by the ancients: the one plain and smooth in the beginning, and in the end impassable; the other rough and troublesome in the entrance, but after a while fair and even. So it is in contemplation: If a man will begin with certainties, he shall end in doubts; but if he will be content to begin with doubts he shall end in certainties.

How can I tell," said the man, "that the past isn't a fiction designed to account for the discrepancy between my immediate physical sensations and my state of mind?

What if nothing exists and we're all in somebody's dream? Or what's worse, what if only that fat guy in the third row exists?