Humans, who generally think pretty well of themselves, have never been able to accept that their death signals the end of the affair. Surely all that experience, the learning, the achievements and the memories, cannot simply vanish like a puff of smoke. That just has to be wrong. Thus every religion supports a more or less detailed belief in life everlasting.
One of the more interesting concepts, developed several thousand years ago in Asia and transmitted to us by the Greeks of the classical period, who conveniently straddled the ancient East and the future West, albeit in utterly different time frames, was that of the “transmigration of souls.” Still preserved in the Brahman tradition, a strong precept is that you should not step on a cockroach, for example, because it might well be your grandfather, working out his time in that guise before adopting a more respectable form on his way to nirvana.
Of course, according to the latest thinking, that is exactly right, though the assertion of a necessary correspondence between present behavior and future form may be a little overstressed. Great insights have a way of demonstrating their validity in unimagined ways. Assuming you have made some effort to reproduce yourself, at least a fiftypercent you, allowing for a few transcription errors, has been installed in a new being, though admittedly all mixed up with half the DNA of your partner. But while this undignified, overcomplicated and not entirely reliable technique has served pretty well to bring us up to the 6 billion mark, it is by no means the only way to live forever.
Those of us who are engaged in DNA analysis are constantly finding short sequences in the genome that clearly originated in another, sometimes long-vanished species, not excluding bacteria. Generally, these exotic nucleotide sequences appear in the so-called “junk DNA” that forms the vast majority of the human genome, but sometimes they perform a crucial function. For example, the mitochondrial bodies, which provide the energy to keep every cell in your body operating by converting polysaccharides, have their own genome derived exclusively from the mother and almost certainly from an ancient bacterium. Without them, we could scarcely exist in our present form.
But there’s another way to live forever: you constantly shed bits of yourself such as hair, skin cells and every kind of interior cell in your body, all eagerly lapped up by a billion mites and bacteria. And the “life force” being what it is, some small part of your genome, like the mitochondria, will become an integral part of the reproductive system of any species consuming or infected by these scavengers. So our Brahman could well be right: the cockroach he spares will almost inevitably contain at least a small immortal part of his grandfather, together with those of millions of other grandfathers, uncles and cousins, both living and dead.
Well, I was going to tell you about my dog Mutley, who I am convinced had the soul of a stand-up comic, but as is the way of old men I wandered from the point and will have to leave it for another time.