Flying has changed how we imagine our planet, which we have seen whole from space, so that even the farthest nations are ecological neighbors. It has changed our ideas about time. When you can gird the earth at 1,000 m.p.h., how can you endure the tardiness of a plumber? Most of all, flying has changed our sense of our body, the personal space in which we live, now elastic and swift. I could be in Bombay for afternoon tea if I wished. My body isn't limited by its own weaknesses; it can rush through space.

One of the keystones of romantic love - and also of the ecstatic religion practiced by mystics - is the powerful desire to become one with the beloved.

On some summer days in New York City, the air hangs thickly visible, like the combined exhalations of eight million souls. Steam rising from vents underground makes you wonder if there isn't one giant sweat gland lodged beneath the city.

One of the things I like best about animals in the wild is that they're always off on some errand. They have appointments to keep. It's only we humans who wonder what we're here for.

Nature is more like a seesaw than a crystal, a never-ending conga line of bold moves and corrections.

I try to give myself passionately, totally, to whatever I'm observing, with as much affectionate curiosity as I can muster, as a means of understanding a little better what being human is.

Part of the irony of environmentalism is questing for solutions when you know you're part of the problem.