"One of the painful things about our time is that those who feel certainty are stupid, and those with any imagination and understanding are filled with doubt and indecision."

"The time has already come when each country needs a considered national policy about what size of population, whether larger or smaller than at present or the same, is most expedient. And having settl…"

"I am not interested in the universe as a mere collection of facts, but as a system of relations."

"The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt."

"It is a truism that in this world there is always more misery than happiness."