I knew the sound well. Many a night,late at night, when all the world slept, it has welled up from deep within my own chest.

VOA: special.2009.05.16

But think of the various periods during the night in which you are in a deep, deep dreamless sleep.

但请设想你处在这样的夜晚,你处于熟睡，安枕无梦。

耶鲁公开课 - 死亡课程节选