Was yesterday a downer? It wasn't meant to be. When my son Matthew was just a little boy, he had to have a T&A (tonsils and adenoids). As you know, people aren't kept in hospital as long as they used to be and it's a good thing. (C'est difficile, n'est-ce pas?) Matt had to go in the night before his surgery. We went to see him before his bedtime and he was having a ball, running up and down the hall with his new best friends, playing with all the new toys, barely noticing us. Ever the realist, I reminded Matt that although he was having fun now, he mustn't forget that he was in for an operation and he'd wake up with a sore throat.

"Not me," he said, barely missing a beat. "That other guy."

Yup. Me too. You too. The hardest thing in the world for us to contemplate is our own extinction: we cannot imagine it, the loss of consciousness, of self. That is why, of course, that Alzheimer's and related dementia are so threatening. To be here physically and yet not to be here consciously is inconceivable. Perhaps we who are allowed to live so long begin to get some inkling of what it means. We certainly know perfectly well that we are not immortal. We have an address book of crossed-out names to prove it as others are picked off around us.

Well, I'm still here. I hope you are the same.