Who said “Without adventure civilization is in full decay.”?

“Man needs difficulties; they are necessary for health.”

“A large volume of adventures may be grasped within this little span of life, by him who interests his heart in everything.”

“The test of an adventure is that when you're in the middle of it, you say to yourself, "Oh, now I've got myself into an awful mess; I wish I were sitting quietly at home." And the sign that something's wrong with you is when you sit quietly at home wishing you were out having lots of adventure.”

“Adventure is worthwhile.”

“Who dares nothing, need hope for nothing.”

“We think in generalities, but we live in detail.”

“The deepest definition of youth is life as yet untouched by tragedy.”

“Life is an offensive, directed against the repetitious mechanism of the Universe.”

“The art of progress is to preserve order amid change, and to preserve change amid order.”

“Civilization advances by extending the number of important operations which we can perform without thinking.”

“Familiar things happen, and mankind does not bother about them. It requires a very unusual mind to undertake the analysis of the obvious.”