Experiment is the sole judge of the validity of any idea.

I was born not knowing and have had only a little time to change that here and there.

Doubt is clearly a value in science. It is important to doubt and that the doubt is not a fearful thing, but a thing of great value.

When a scientist doesn't know the answer to a problem, he is ignorant. When he has a hunch as to what the result is, he is uncertain. And when he is pretty darn sure of what the result is going to be, he is still in some doubt. We have found it of paramount importance that in order to progress we must recognize our ignorance and leave room for doubt. Scientific knowledge is a body of statements of varying degrees of certainty - some most unsure, some nearly sure, but none absolutely certain.

Science is uncertain.

The exception tests the rule.

I don't feel frightened by not knowing things, by being lost in the mysterious universe without any purpose - which is the way it really is, as far as I can tell. Possibly. It doesn't frighten me.