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.nAFTER A 40-year gap I've started trying to play the piano again.