Grey's Anatomy, Season 4

Bailey:
[voiceover] As doctors, we know more about the human body now than at any point in our history. But the miracle of life itself; why people live and die, why they hurt or get hurt is still a mystery. We want to know the reason, the secret, the answer at the back of the book because the thought of our being all alone down here is just too much for us to bear. But at the end of the day, the fact that we show up for each other, in spite of our differences, no matter what we believe, is reason enough to keep believing.