The optimist thinks this is the best of all possible worlds. The pessimist fears it is true.
A pragmatist is concerned with results, not reality.
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.
When you see something that is technically sweet you go ahead and do it.
There are no secrets about the world of nature. There are secrets about the thoughts and intentions of men.
The history of science is rich in example of the fruitfulness of bringing two sets of techniques, two sets of ideas, developed in separate contexts for the pursuit of new truth, into touch with one another.
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.
Today, it is not only that our kings do not know mathematics, but our philosophers do not know mathematics and – to go a step further – our mathematicians do not know mathematics.
To try to be happy is to try to build a machine with no other specification than that it shall run noiselessly.
There is something irreversible about acquiring knowledge; and the simulation of the search for it differs in a most profound way from the reality.
I can’t think that it would be terrible of me to say – and it is occasionally true – that I need physics more than friends.
Things which stimulate my curiosity are pretty far removed from the practical and therefore from classification.
The theory of our modern technic shows that nothing is as practical as theory.
If we must live with a perpetual sense that the world and the men in it are greater than we and too much for us, let it be the measure of our virtue that we know this and seek no comfort.
I need physics more than friends.
In the material sciences these are and have been, and are most surely likely to continue to be heroic days.
To the confusion of our enemies.
If atomic bombs are to be added as new weapons to the arsenals of a warring world, or to the arsenals of nations preparing for war, then the time will come when mankind will curse the names of Los Alamos and Hiroshima. The people must unite, or they will perish.
We do not believe any group of men adequate enough or wise enough to operate without scrutiny or without criticism.
All history teaches us that these questions that we think the pressing ones will be transmuted before they are answered, that they will be replaced by others, and that the very process of discovery will shatter the concepts that we today use to describe our puzzlement.
It is proper to the role of the scientist that he not merely find new truth and communicate it to his fellows, but that he teach, that he try to bring the most honest and intelligible account of new knowledge to all who will try to learn.