This has been a good week for Donald Dewar, and a better week for Boris Yeltsin, but a bad one for Rudy Giulani and Rupert Murdoch: at least that is the obvious conclusion from the excitement over six cloned calves whose cells seem to have been rejuvenated by the cloning process so that they are, on one measure, the youngest calves ever born.
Not even the most optimistic advocates of progress suppose that these experiments will lead to immortality; but if it became possible to produce large quantities of living human replacement tissue, a lot of the problems of the diseases that are caused by things simply wearing out could be solved by using our own cells to grow replacement parts.
So let's order a new heart valve for Donald Dewar, a complete new heart and a liver while we're about it for Mr Yeltsin. It won't help cancer patients, but then lots of us are not going to die of cancer, but of diseases which might, in theory, be simply cured by transplants of rejuvenated tissue. So what is tempting the readers is not the conquest of death, but something even more desirable: the conquest of age, with death at the end something as painless as the end of a video.
The practical snags of such a programme are still considerable. No one knows whether the apparent youth of the cells that make up the cloned calves Lily, Daffodil, Crocus, Forsythia and Rose will in fact translate into longer lives for them as cows. They won't know, in the nature of things, for perhaps another 20 years. And even if we do produce a race of long-lived cows, that is not what the money or excitement is about.
What the stories are really concerned with is the dream of a fountain of youth for newspaper readers. It would be rash to claim that considerable life extension is impossible, even making due allowances for the fact that we want it so much that we have an inbuilt tendency to overestimate its likelihood. Looking back over surveys of the best available expert opinion in these matters, all that I can find have been wildly optimistic. According to the best minds of 1969 we should already be living for 50 years longer on average than we did then.
However, suppose that all these difficulties, and more, are overcome. Biologists know an enormous amount more than they did in 1969, and they have infinitely more powerful computers to help them analyse the data they are getting. They may find themselves in fifty years' time playing with real biological Meccano, able to strip down, debug and rebuild non-functioning human beings; and willing to do so if their patients are rich enough.
It is morally certain that the attempt will be made, and that some of them will go wrong and result in huge suffering to the victims. Bill Gates VI may come into being like his great-grandfather's software - in several versions, and only start working properly around version 3.11. You can defend this prospect: nothing a human experimenter could do could exceed some of the cruelties of nature, and humans at least might learn from their mistakes and care about their victims.
The only justification for playing God is to make a better job of things than God does. The history of medicine over the last 150 years shows that it is perfectly possible to do so; however, it also shows that we often can't be bothered to improve much on the natural order. It would be perfectly possible to wipe out all sorts of ghastly Third-World diseases for a fraction of what the West spends on pet food or cosmetics.
But to judge from the evidence we would rather feed our family pets than other people's children. The contrast is even more striking where old people are concerned. You don't need high-tech medicine to improve an NHS geriatric ward right now. If brain tissue transplants ever do become a reliable technique for curing Alzheimer's disease, then it is a safe bet that the waiting lists will far exceed the life expectancy of most of the Alzheimer's sufferers.
Any science fiction author who has really considered the prospect of immortality has ended up depicting a society in which euthanasia is practised as well. We haven't really faced up to the prospect of a society in which every old person is a wanted old person. But this may be more because it is so distasteful for us to consider than because it is so very unlikely or so distant from what already happens.
A chilling detail from the Shipman case is that no one found anything unnatural or unexpected in the deaths of any of his victims until he made a profit from one after killing perhaps 150 others. It's quite probable that in most human societies already, only wanted old people live to be old.
With all that said, I still think this is a hopeful development. The selfishness of human nature which these example show up can be exploited if it can't be eradicated. To offer the powerful and the very rich another 100 years of middle age, is also to give them a huge personal stake in the future.
They won't be saving the planet just for their grandchildren, but for themselves as well: that may not make them nicer, but it is sure to make them behave as if they were. The greatest gift of this kind of medicine would not be immortality, but to make their self-interest more enlightened.