The world today is made, it is powered by science; and for any man to abdicate an interest in science is to walk with open eyes towards slavery.

We are all afraid for our confidence, for the future, for the world. That is the nature of the human imagination. Yet every man, every civilization, has gone forward because of its engagement with what it has set itself to do.

Dissent is the native activity of the scientist, and it has got him into a good deal of trouble in the last years. But if that is cut off, what is left will not be a scientist. And I doubt whether it will be a man.

We are all shot through with enough motives to make a massacre, any day of the week that we want to give them their head.

We gain our ends only with the laws of nature; we control her only by understanding her laws.

There is no absolute knowledge. And those who claim it, whether they are scientists or dogmatists, open the door to tragedy.

It is very much easier to divide your outlook on the world into two halves, to say that you know this belongs to the daily half and this belongs to the Sunday half.