By Bill McKibbenThoreau posed the two practical questions that must come dominate this age if we’re to make those changes: How much is enough? and How do I know what I want? For him, I repeat, those were not environmental questions; they were not even practical questions, exactly. If you could answer them you might improve your own life, but that was the extent of his concern. He could not guess about the greenhouse gas effect. Instead, he was the American avatar in a long line that stretches back at least to Buddha, the line that runs straight through Jesus and St. Francis and a hundred other cranks and gurus.