Caution in handling generally accepted opinions that claim to explain whole trends of history is especially important for the historian of modern times, because the last century has produced an abundance of ideologies that pretend to be keys to history but are actually nothing but desperate efforts to escape responsibility.

And the distinction between violent and non-violent action is that the former is exclusively bent upon the destruction of the old, and the latter is chiefly concerned with the establishment of something new.

The more dubious and uncertain an instrument violence has become in international relations, the more it has gained in reputation and appeal in domestic affairs, specifically in the matter of revolution.

This is the precept by which I have lived: Prepare for the worst; expect the best; and take what comes.

There are no dangerous thoughts; thinking itself is dangerous.

In order to go on living one must try to escape the death involved in perfectionism.

Education is the point at which we decide whether we love the world enough to assume responsibility for it and by the same token save it from that ruin which, except for renewal, except for the coming of the new and young, would be inevitable.