If a man walks in the woods for love of them half of each day, he is in danger of being regarded as a loafer. But if he spends his days as a speculator, shearing off those woods and making the earth bald before her time, he is deemed an industrious and enterprising citizen.
Henry David Thoreau

The society which scorns excellence in plumbing as a humble activity and tolerates shoddiness in philosophy because it is an exalted activity will have neither good plumbing nor good philosophy: neither its pipes nor its theories will hold water.
John W. Gardner

The human race's prospects of survival were considerably better when we were defenseless against tigers than they are today when we have become defenseless against ourselves.
Arnold J. Toynbee