"The Diagnosis" had ten drafts of very significant changing, where I went through the whole book, wholesale and changed everything. Then the last year or so it was making small changes. I would do something and let it sit for three months... just brood about and decide I needed to slightly change something here or there. Or one character wasn't quite right. But I think everybody goes through this.

Every essay - the subject matter of every essay - is ultimately about the essayist; him or herself. That ultimately, every essayist is writing about his or her view of the world.

In this world, time has three dimensions, like space. Just as an object may move in three perpendicular directions, corresponding to horizontal, vertical, and longitudinal, so an object may participate in three perpendicular futures. Each future moves in a different direction of time. Each future is real. At every point of decision, the world splits into three worlds, each with the same people, but different fates for those people. In time, there are an infinity of worlds.

I am spellbound by the plays of Shakespeare. And I am spellbound by the second law of thermodynamics. The great ideas in science, like the Cro-Magnon paintings and the plays of Shakespeare, are part of our cultural heritage.

With infinite life comes an infinite list of relatives. Grandparents never die, nor do great grandparents, great-aunts…and so on, back through the generations, all alive and offering advice. Sons never escape from the shadows of their fathers. Nor do daughters of their mothers. No one ever comes into his own…Such is the cost of immortality. No person is whole. No person is free.

Suppose time is a circle, bending back on itself. The world repeats itself, precisely, endlessly.

In a world without future, each parting of friends is a death. In a world without future, each loneliness is final. In a world without future, each laugh is the last laugh. In a world without future, beyond the present lies nothingness, and people cling to the present as if hanging from a cliff.