# nLab Richard Feynman

## Quotes

### On Doubt

From Feynman 1955:

Of all its $[$science’s$]$ many values, the greatest must be the freedom to doubt

We have found it of paramount importance that in order to progress we must recognize the ignorance and leave room for doubt. Scientific knowledge is a body of statements of varying degree of certainty - some most unsure, some nearly sure, none absolutely certain.

Now, we scientists are used to this, and we take it for granted that it is perfectly consistent to be unsure – that it is possible to live and not know. But I don’t know whether everyone realizes that this is true.

Our freedom to doubt was born of a struggle against authority in the early days of science. It was a very deep and strong struggle. Permit us to question – to doubt, that’s all – not to be sure.

And I think it is important that we do not forget the importance of this struggle and thus perhaps lose what we have gained. Here lies a responsibility to society.

This is not a new idea; this is the idea of the age of reason. $[\ldots]$ that we should arrange a system by which new ideas could be developed, tried out, tossed out, more new ideas brought in; a trial and error system. $[\ldots]$ the openness of the possibilities was an opportunity, and that doubt and discussion were essential to progress into the unknown.

if we suppress all discussion, all criticism, saying “This is it, boys, man is saved!” $[$ we would $]$ doom man for a long time to the chains of authority, confined to the limits of our present imagination. It has been done so many times before.

It is our responsibility as scientists, knowing $[\ldots]$ the great progress that is the fruit of freedom of thought, to proclaim the value of this freedom, to teach how doubt is not to be feared but welcomed and discussed, and to demand this freedom as our duty to all incoming generations.

Now the next subject $[\ldots]$ I really consider the most important and the most serious. And that has to do with the question of uncertainty and doubt.