The desire to build a risk-free society has always been a sign of decadence. It has meant that the nation has given up, that it no longer believes in its destiny, that it has ceased to aspire to greatness, and has retired from history to pet itself. – Henry Fairlie, quoted in Conservation Foundation Letter, November 1981

Time and space – time to be alone, space to move about – these may well become the great scarcities of tomorrow. – Edwin Way Teale, Autumn Across America, 1956

There are no passengers on Spaceship Earth. We are all crew. – Marshall McLuhan, 1964

When a man says to me, “I have the intensest love of nature,” at once I know that he has none. – Ralph Waldo Emerson, Journals, 1857