Factual truth is always related to other people: it concerns events and circumstances in which many are involved; it is established by witnesses and depends upon testimony; it exists only to the extent that it is spoken about, even if it occurs in the domain of privacy. It is political by nature.

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.

Every end in history necessarily contains a new beginning.

Mathematics, the non-empirical science par excellence . . . the science of sciences, delivering the key to those laws of nature and the universe which are concealed by appearances.

Man's chief moral deficiency appears to be not his indiscretions but his reticence.

Nietzsche ... has caused [philosophers] so much confusion.

Absence of thought is indeed a powerful factor in human affairs, statistically speaking the most powerful, not just in the conduct of the many but in the conduct of all.