All relationships change the brain - but most important are the intimate bonds that foster or fail us, altering the delicate circuits that shape memories, emotions and that ultimate souvenir, the self.

Nature neither gives nor expects mercy.

I like handling newborn animals. Fallen into life from an unmappable world, they are the ultimate immigrants, full of wonder and confusion.

We think of it as a sort of traffic accident of the heart. It is an emotion that scares us more than cruelty, more than violence, more than hatred. We allow ourselves to be foiled by the vagueness of the word. After all, love requires the utmost vulnerability. We equip someone with freshly sharpened knives; strip naked; then invite him to stand close. What could be scarier?

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.

To begin to understand the gorgeous fever that is consciousness, we must try to understand the senses and what they can tell us about the ravishing world we have the privilege to inhabit.

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.