Orthodoxy is the grave of intelligence, no matter what orthodoxy it may be.

And if there were a God, I think it very unlikely that He would have such an uneasy vanity as to be offended by those who doubt His existence

Truth is for the gods; from our human point of view, it is an ideal, towards which we can approximate, but which we cannot hope to reach.

Citizens as conceived by governments are persons who admire the status quo and are prepared to exert themselves for its preservation. Oddly enough, while all governments aim at producing men of this type to the exclusion of all other types, their heroes in the past are of exactly the sort that they aim at preventing in the present. Americans admire George Washington and Jefferson, but imprison those who share their political opinions.

So far I have been speaking of theoretical science, which is an attempt to understand the world. Practical science, which is an attempt to change the world, has been important from the first, and has continually increased in importance, until it has almost ousted theoretical science from men's thoughts.

Reason may be a small force, but it is constant, and works always in one direction, while the forces of unreason destroy one another in futile strife.

Perhaps the best hope for the future of mankind is that ways will be found of increasing the scope and intensity of sympathy.