The greatest of the changes that science has brought is the acuity of change; the greatest novelty the extent of novelty.

[About the great synthesis of atomic physics in the 1920s:] It was a heroic time. It was not the doing of any one man; it involved the collaboration of scores of scientists from many different lands. But from the first to last the deeply creative, subtle and critical spirit of Niels Bohr guided, restrained, deepened and finally transmuted the enterprise.

Submit an agreement providing for the peaceful absorbtion of a celestial races in such a manner that our culture would remain intact with guarantee that their presence not be revealed." "One must consider the fact that mis-identification of these space craft for a intercontinental missile in a re-entry phase of flight could lead to accidental nuclear war with horrible consequences.

In a free world, if it is to remain free, we must maintain, with our lives if need be, but surely by our lives, the opportunity for a man to learn anything

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

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

You can certainly destroy enough of humanity so that only the greatest act of faith can persuade you that what's left will be human.