Of all forms of mental activity, the most difficult to induce even in the minds of the young, who may be presumed not to have lost their flexibility, is the art of handling the same bundle of data as before, but placing them in a new system of relations with one another by giving them a different framework, all of which virtually means putting on a different kind of thinking-cap for the moment. It is easy to teach anybody a new fact...but it needs light from heaven above to enable a teacher to break the old framework in which the student is accustomed to seeing.

Honor is decency without vanity.

In the index to the six hundred odd pages of Arnold Toynbee's A Study of History, abridged version, the names of Copernicus, Galileo, Descartes and Newton do not occur yet their cosmic quest destroyed the medieval vision of an immutable social order in a walled-in universe and transformed the European landscape, society, culture, habits and general outlook, as thoroughly as if a new species had arisen on this planet.

Space-ships and time machines are no escape from the human condition. Let Othello subject Desdemona to a lie-detector test; his jealousy will still blind him to the evidence. Let Oedipus triumph over gravity; he won't triumph over his fate.

Woe unto the defeated, whom history treads into the dust.

Scientists are peeping toms at the keyhole of eternity.

One should either write ruthlessly what one believes to be the truth, or else shut up.