Thief of Time (Discworld, #26; Death, #5)

by Terry Pratchett

“Wen considered the nature of time and understood that the universe is, instant by instant, re-created anew. Therefore, he understood, there is, in truth, no Past, only a memory of the Past. Blink your eyes, and the world you see next did not exist when you closed them. Therefore, he said, the only appropriate state of the mind is surprise. The only appropriate state of the heart is joy. The sky you see now, you have never seen before. The perfect moment is now. Be glad of it.”