Nothing leads so straight to futility as literary ambitions without systematic knowledge.

Books-bright windows in this life of ours, lit by the shining souls of men.

I write as straight as I can, just as I walk as straight as I can, because that is the best way to get there.

Our true nationality is mankind.

In the scientific world I find just that disinterested devotion to great ends that I hope will spread at last through the entire range of human activity.

Patriotism has become a mere national self assertion, a sentimentality of flag-cheering with no constructive duties.

The man who raises a fist has run out of ideas.