Be gentle with the earth.

Share your knowledge. It's a way to achieve immortality.

Once a year, go someplace you've never been before.

In disagreements with loved ones, deal only with the current situation. Don't bring up the past.

Until you dig a hole, you plant a tree, you water it and make it survive, you haven't done a thing. You are just talking.

The earth only has so much bounty to offer and inventing ever larger and more notional prices for that bounty does not change its real value.

How much longer, for instance, can we continue to crowd more and more people into this world? How much longer can we afford to wage senseless, destructive wars…