Read more: “100,000 AD: Living in the deep future“
THERE’S a famous thought experiment about kidnapping a Cro-Magnon man, bathing and shaving him, dressing him in a suit and putting him on the New York subway. Would anybody bat an eyelid?
Probably not. Though Cro-Magnons lived about 30,000 years ago, they were to all intents and purposes modern humans. Physically they were perhaps a little more robust, but behaviourally they were indistinguishable from us, give or take the effects of thousands of years of technological progress on our lives.
Advertisement
We have undoubtedly come a long way since then. A Cro-Magnon in 21st-century New York would recognise almost nothing except for other human beings. But his modern human brain would eventually adjust to the startling new surroundings, much as the Tierra del Fuego native who became known as “Jeremy Button” took to Victorian London after he was brought there in 1830 by Robert FitzRoy, captain of the Beagle.
Now turn that thought experiment on its head and project it into the deep future. What if somebody alive today could be transported to the equivalent of New York 30,000 years – or even 100,000 years – from now? Even if suitably attired, would they fit in?
Impossible to say, of course. Just because we’ve had more than 1000 generations of biological stasis does not mean we can expect thousands more. If you believe some futurists, we will eventually become cyborgs with prostheses in our brains and nanobots racing around our bloodstream.
Extreme as these technological enhancements may sound, they won’t produce changes to our bodies and minds that will be heritable and so alter our fundamental biology. Each generation will have to choose whether or not to become cyborgs, just as people can opt for laser eye surgery today. For our descendants to be radically different from us, we would have to engineer our own genome or wait for an event that has happened only rarely in our evolutionary line.
One hypothesis to explain the sudden rise in behaviourally modern humans 30,000 to 40,000 years ago is the random appearance of a beneficial genetic mutation, perhaps involved in language. So beneficial in fact, that the mutation swept through the population. Humans without it would have been unable to compete with their more fortunate fellows, and their less fit genomes would have been consigned to the scrap heap of evolution ().
The “great leap forward” mutation, if it ever existed, will probably never be identified as it has completely replaced the version of the gene that preceded it. But we can see signs of similar sweeps that are not yet complete. For example, a mutation in a gene called microcephalin arose around 14,000 years ago and is now carried by 70 per cent of people. It appears to be involved in brain development, though it is not clear what trait it is being selected for since there is no discernible difference between people who carry it and those who don’t.
So it is possible that our descendants could evolve into something similar to Homo sapiens today. But radical change seems a long shot.
Of course, we could eventually decide to take evolution into our own hands. In principle, we could engineer ourselves into obsolescence by creating a new breed of human that would outcompete ourselves. The most plausible technology for starting down this road is to genetically engineer sperm or eggs, or early embryos, in order to install changes in their genomes that will be passed down the generations. This is just about possible with today’s technology, and has been put forward as a way of stamping out genetic diseases such as cystic fibrosis.
Would we go so far as to put desirable traits in rather than just take bad ones out? Even if it were technically possible to do this, it is doubtful that we would collectively agree such changes on a scale that would alter the course of our evolution – unless, of course, engineered humans were so superior that they obliterated the competition.
“It is doubtful that we would genetically engineer ourselves on a scale that would alter the course of human evolution”
These possibilities cannot be ruled out. Surely the most likely option is that our time traveller will find himself among friends, a species of human fundamentally the same as us but with cooler technology. Deep down, they will still be human.