Optimists think that this is the best of all possible worlds; pessimists fear they are right.

I am become death, the destroyer of worlds.

Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search.

We hunger for nobility: the rare words and acts that harmonize simplicity and truth.

It is not possible to be a scientist unless you believe that it is good to learn... that it is of the highest value to share your knowledge... with anyone who is interested... that the knowledge of the world, and the power which this gives, is a thing which is of intrinsic value to humanity

Sometimes the answer to fear does not lie in trying to explain away the causes, sometimes the answer lies in courage.

Both the man of science and the man of art live always at the edge of mystery, surrounded by it. Both, as a measure of their creation, have always had to do with the harmonization of what is new with what is familiar, with the balance between novelty and synthesis, with the struggle to make partial order in total chaos.... This cannot be an easy life.