To waste, to destroy our natural resources, to skin and exhaust the land instead of using it so as to increase its usefulness, will result in undermining in the days of our children the very prosperity which we ought by right to hand down to them amplified and developed. – Theodore Roosevelt, seventh annual message, 3 December 1907

The command “Be fruitful and multiply” was promulgated, according to our authorities, when the population of the world consisted of two people. – William Ralph Inge, More Lay Thoughts of a Dean, 1931

Every creature is better alive than dead, men and moose and pine trees, and he who understands it aright will rather preserve its life than destroy it. – Henry David Thoreau, "Chesuncook," The Maine Woods, 1848