'To my dearest daughter,
Now that you are ten, I want to write to you about something that is important to me. Have you ever wondered how we know the things that we know?'
The letter includes his thoughts on love and evidence, which of course includes parental love:
'There can be plenty of evidence that somebody loves you. All through the day when you are with somebody who loves you, you see and hear lots of little tidbits of evidence, and they all add up. It isn’t purely inside feeling, like the feeling that priests call revelation. There are outside things to back up the inside feeling: looks in the eye, tender notes in the voice, little favors and kindnesses; this is all real evidence.'