Doubt Quote by Joel Achenbach

The frontiers of knowledge in the various fields of our subject are expanding at such a rate that, work as hard as one can,…

— James Meade

Education is man's going forward from cocksure ignorance to thoughtful uncertainty.Where there is an open mind there will always be a frontier.

— Charles Kettering

James Baldwin is one of the greatest, North American writers of the second half of the Twentieth Century. A prolific writer and a brilliant…

— Raoul Peck

There [in Afghanistan] is also a growing insurgency threat from al-Qaida, the Taliban and other extremist elements, some of which comes from the tribal…

— David Petraeus

Liberty has restraints but no frontiers.

— David Lloyd George

The frontier of America is on the Rhine.

— Franklin D. Roosevelt

The frontiers we broke into in the '60s are still largely unexplored.

— Ken Kesey

Up to the 20th century, we can say that this whole period was an Earth epoch, 'Earth' meaning the riches of the earth, simple…

— Lech Walesa

If he were allowed contact with foreigners he would discover that they are creatures similar to himself and that most of what he has…

— George Orwell

Fuehrer, we are on the march! Victorious Italian troops crossed the Greco-Albanian frontier at dawn today!

— Benito Mussolini

I believe that the manned space program can engage the public by advancing the space frontier. Every next mission takes you farther out in…

— Neil deGrasse Tyson

In Russia there is an emigration of intelligence: émigrés cross the frontier in order to read and to write good books. But in doing…

— Friedrich Nietzsche