It's too bad we only had the courage to live our lives fully in dreams.

Logic was to cognition as geometry was to landscape

It was not power that corrupted people, but fools who corrupted power.

We should conceive of ourselves not as rulers of Earth, but as highly powerful, conscious stewards: The Earth is given to us in trust, and we can screw it up or make it work well and sustainably.

Life is insanely robust, though we can make species go extinct, and this is the bad thing. So I always make the point that you can't say, 'Is it too late?' That is the terrible question, because either answer promotes inaction. If it's too late, you don't need to act; if it's not too late, you don't need to act.

The only part of an argument that really matters is what we think of the people arguing. X claims a, Y claims b. They make arguments to support their claims with any number of points. But when their listeners remember the discussion, what matters is simply that X believes a and Y believes b. People then form their judgment on what they think of X and Y.

When Reinhold Messner returned from the first solo climb of Everest, he was severely dehydrated, and utterly exhausted; he fell down most of the last part of the descent, and collapsed on the Rongbuk glacier, and he was crawling over it on hands and knees when the woman who was his entire support team reached him; and he looked up at her out of a delirium, and said, “Where are all my friends?