THE DIARY: There are happy and sad songs to be sung

A busy week preparing for the "The Word" Literary Festival. In an unguarded moment I seem to have agreed to four separate gigs, including a "master class" in evolution. As if that billing wasn't daunting enough, it's in Darwin's house at Downe in Kent where that genuine master did most of his thinking and all his writing. I'll leave enough time for a Sand Walk pilgrimage, communing with his immortal and gentle memory.

In the evening, my wife, Lalla Ward, and I are reading from Unweaving the Rainbow. This double act started when I was touring America doing readings from a previous book, flying to a different venue daily. Not surprisingly I got laryngitis, and almost cancelled the tour. But then it hit me. My wife is an actress with a beautiful reading voice, not just Dr Who's girl but Hamlet's too. So she stepped into the breach and did the readings to great acclaim, with me answering audience questions in a whispering croak at the end. It worked so well that we did it for the new book too. And again this weekend, for an event at the Oxford University Museum of Natural History to mark the installation of a set of dinosaur footprints on the lawn (as a friend remarked, it gives a whole deeper meaning to "And did those feet in ancient time...")

Next Tuesday, as part of the festival, I am to give the inaugural Westminster Lecture: "What Shall We Tell the Aliens?" It's not such a silly title as it sounds. I suspect that life is out there orbiting other stars, but so sparingly dotted through space and time that no one island race ever encounters another. Never mind, I'll use an imaginary alien visit to help think about principles of life in general. How much shall we have in common with our visitors? How much will be utterly strange and divide us? We must at least share physics and mathematics, because physics is the same all over the universe and our visitors couldn't have travelled here without getting their sums right. Cultural relativism may be fine at home, but there's only one physics capable of reaching escape velocity. If aliens ever get here, they'll certainly have Pythagoras's theorem; their value of pi will be ours, and they'll honour their Newton, Einstein and Faraday. But what of biology? Will our extra-galactics revere their own Darwin (or, as I have heard suggested, will the spaceship be his Beagle and we his Galapagos)? Are there universals in biology? I think so, but whether I shall convince my audience of earthlings in Westminster Central Hall, we shall see.

ON WEDNESDAY I was visited by a charming woman from the New Statesman - a delightful interview, matched by the friendly weather which allowed us to sit in the garden, birdsong competing with a chainsaw for the background wild track of her tape recorder. She endeared herself further by not bringing a photographer and, mirabile dictu, never once mentioning religion. Most reporters won't go home until they've succeeded in goading me into at least one blasphemous insult. Poor old God doesn't need any more insults after last week's news that "Sir" Cliff Richard has appointed himself Tony Blair's Christian Mouthpiece, bringing a Christian dimension to the millennium celebrations (another thing our alien physicists will bring with them, along with Pythagoras's theorem and the calculus, is a proper understanding of what a dimension is).

Having splendidly abstained from religion, it was too much to hope that she'd lay off GM foods too. Or cloning - now there's another field where I must clean up my act. A few weeks ago, a reporter pestered me into agreeing that I loved my daughter enough to want another one just like her (MAD SCIENTIST WANTS TO CLONE HIS DAUGHTER). A Daily Mail headline consequently dubbed me "THE MOST DANGEROUS MAN IN BRITAIN". This upset me when I first saw it, but it was all right because the article turned out to be by Paul Johnson.

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AFTER A 40-year gap I've started trying to play the piano again. As a child, my progress suffered from a naturally good ear coupled with even more natural laziness - it was so easy to play by ear that I never bothered to read music. Now I'm trying harder, though still not hard enough. On Thursday evening I was working haltingly through a book of sentimental songs when I became aware that somebody had quietly joined me. It was my 14-year-old daughter, Juliet, smiling. She looked over my shoulder and sang "The Banks of the Ohio". Then "Greensleeves", "Beautiful Dreamer", "Love's Old Sweet Song" and, most poignantly, "Bury Me Not on the Lone Prairie". I couldn't do justice to her sweet voice, and wished I had practised for this unexpected event - almost tearfully I realised that she hadn't sung with me for more than two years. Not since before her mother went to the specialist...

Juliet is now living with Lalla and me, learning to live with her tragedy. It is today's fashion to tell children everything, say nothing behind closed surgery doors. Despite our initial misgivings, we now think it is the right way. She was involved in every stage of her mother's heroic two-year struggle - the operation, the trial chemotherapies which might have worked, the nausea and hair loss, the grave consultations, the hopes raised and dashed. Then in the final terrible week, such bravery: day and night in the hospital, that calm, soothing, gentle-voiced child nurse, comforting to the end. Only after it came, at 2am on 28 February, did she let herself break down. May I show such defiant humour as her mother did, when my time comes. And may I have such a nurse. Meanwhile, happy as well as sad, there are songs to be sung.

Professor Richard Dawkins's latest book is `Unweaving the Rainbow'. His lecture, `What Shall We Tell the Aliens?', is at Westminster Central Hall, 23 March, 6pm.