Terry Pratchett Quotes

There is only one thing about which I am certain, and that is that there is very little about which one can be certain.

We cannot infer that because sciences of things divine and human are full of controversies and quarrels, therefore their whole subject-matter is uncertain ; for there have been many persons so enamoured of contradiction, as to turn into ridicule geometrical axioms.

Il n'est pas certain que tout soit incertain. (Translation: It is not certain that everything is uncertain.)

Truth is something that we can attempt to doubt, and then perhaps, after much exertion, discover that part of the doubt is not justified.

Every sentence I utter must be understood not as an affirmation, but as a question.

If you would be a real seeker after truth, you must at least once in your life doubt, as far as possible, all things.

Doubt is not an agreeable condition, but certainty is an absurd one.

Not to be absolutely certain is, I think, one of the essential things in rationality.

Doubt is the origin of wisdom.

I always admired Niels Bohr for uttering his opinions like one perpetually groping and never like one in the possession of definite truth.

We'd all like to be certain of what we know, but I think the most important question is to ask yourself do you really know what you know?

Except in pure mathematics, nothing is known for certain (although much is certainly false).

I am no lover of disorder and doubt as such. Rather do I fear to lose truth by this pretension to possess it already wholly.

There are no indisputable truths.

He who replies to words of doubt doth put the light of knowledge out.

I've gone through most of my life not believing anything. Either I know or I don't know, or I think.

No one knows anything for sure.

We cannot begin with complete doubt.

Belief in truth begins with doubting all that has hitherto been believed to be true.

We don't need to invest all of our faith in every concept, in every symbol, in every opinion that forms the totality of our knowledge. Faith means to believe in something 100% without a doubt, and to doubt our own knowledge can seem like the most frightening thing that can happen to us.

Is there any knowledge in the world which is so certain that no reasonable man could doubt it?

On the one hand, philosophy is to keep us thinking about things that we may come to know, and on the other hand to keep us modestly aware of how much that seems like knowledge isn't knowledge

Skepticism may undermine beliefs, but never belief.

We need wisdom the most when we believe in it the least.

Guessing isn't knowing.