[When asked 'Dr. Einstein, why is it that when the mind of man has stretched so far as to discover the structure of the atom we have been unable to devise the political means to keep the atom from destroying us?] That is simple, my friend. It is because politics is more difficult than physics.

But when you come right down to it, the reason that we did this job is because it was an organic necessity. If you are a scientist you cannot stop such a thing. If you are a scientist you believe that it is good to find out how the world works; that it is good to find out what the realities are; that it is good to turn over to mankind at large the greatest possible power to control the world and to deal with it according to its lights and values.
Regarding the atomic bomb project.

Coastal sailing as long as it is perfectly safe and easy commands no magic. Overseas expeditions are invariably bound up with ceremonies and ritual. Man resorts to magic only where chance and circumstances are not fully controlled by knowledge.

Harvard Law: Under the most rigorously controlled conditions of pressure, temperature, humidity, and other variables, the organism will do as it damn well pleases.

It does not matter what men say in words, so long as their activities are controlled by settled instincts. The words may ultimately destroy the instincts. But until this has occurred, words do not count.

It is the triumph of civilization that at last communities have obtained such a mastery over natural laws that they drive and control them. The winds, the water, electricity, all aliens that in their wild form were dangerous, are now controlled by human will, and are made useful servants.

Like taxes, radioactivity has long been with us and in increasing amounts; it is not to be hated and feared, but accepted and controlled. Radiation is dangerous, let there be no mistake about that—but the modern world abounds in dangerous substances and situations too numerous to mention. ... Consider radiation as something to be treated with respect, avoided when practicable, and accepted when inevitable.
Recommending the same view towards radiation as the risks of automobile travel.

Suppose that we are wise enough to learn and know—and yet not wise enough to control our learning and knowledge, so that we use it to destroy ourselves? Even if that is so, knowledge remains better than ignorance. It is better to know—even if the knowledge endures only for the moment that comes before destruction—than to gain eternal life at the price of a dull and swinish lack of comprehension of a universe that swirls unseen before us in all its wonder. That was the choice of Achilles, and it is mine, too.

There is nothing distinctively scientific about the hypothetico-deductive process. It is not even distinctively intellectual. It is merely a scientific context for a much more general stratagem that underlies almost all regulative processes or processes of continuous control, namely feedback, the control of performance by the consequences of the act performed. In the hypothetico-deductive scheme the inferences we draw from a hypothesis are, in a sense, its logical output. If they are true, the hypothesis need not be altered, but correction is obligatory if they are false. The continuous feedback from inference to hypothesis is implicit in Whewell's account of scientific method; he would not have dissented from the view that scientific behaviour can be classified as appropriately under cybernetics as under logic.

Unless science is controlled by a greater moral force, it will become the Antichrist prophesied by the early Christians.

[W]e have made a thing, a most terrible weapon, that has altered abruptly and profoundly the nature of the world. We have made a thing that, by all standards of the world we grew up in, is an evil thing. And by doing so, by our participation in making it possible to make these things, we have raised again the question of whether science is good for man, of whether it is good to learn about the world, to try to understand it, to try to control it, to help give to the world of men increased insight, increased power. Because we are scientists, we must say an unalterable yes to these questions; it is our faith and our commitment, seldom made explicit, even more seldom challenged, that knowledge is a good in itself, knowledge and such power as must come with it.