In a vacuum all photons travel at the same speed. They slow down when travelling through air or water or glass. Photons of different energies are slowed down at different rates. If Tolstoy had known this, would he have recognised the terrible untruth at the beginning of Anna Karenina? 'All happy families are alike; every unhappy family is unhappy in its own particular way.' In fact it's the other way around. Happiness is a specific. Misery is a generalisation. People usually know exactly why they are happy. They very rarely know why they are miserable.

Why did I walk so purposefully in a straight line? Where would it take me? He went round and round and we got there all the same.

Happy Valentines Day to those who have found love, in whatever shape or form, and to those who are still hunting, don't give up. If you feel bad, send yourself a card. You must be worth it.

You are a pool of clear water where the light plays

Today, the sun is everywhere, and everything solid is nothing but its own shadow, I know that the real things in life, the things I remember, the things I turn over in my hands, are not houses, bank accounts, prizes or promotions. What I remember is love -- all love -- love of this dirt road, this sunrise, a day by the river, the stranger I met in a café. Myself, even, which is the hardest thing of all to love, because love and selfishness are not the same thing. It is easy to be selfish. It is hard to love who I am. No wonder I am surprised if you do.

Of course, people will laugh at you, but people laugh at a great many things so there is no need to take it personally.

Every moment you steal from the present is a moment you've lost forever. There is only now.