"There is no doubt that man has a right to control nature, but only in the sense that he controls himself."

"It is not my intention to lead you into a life of morbid contemplation of the future. I want rather to awaken in you a sense of urgency."

"The question is whether any civilization can wage relentless war on life without destroying itself, and without losing the right to be called civilized."

"The public must decide whether it wishes to continue on the present road, and it can do so only when in full possession of the facts."

"There is something infinitely healing in the repeated refrains of nature—the assurance that dawn comes after night, and spring after winter."