Of all the mammals currently living on this planet, the human race comes in a variety of diverse forms: a myriad of differing faces, skin colors, body shapes, eye colors, hair colors, heights and weight variations, but all undeniably "human."
All of these identifying features have, until very recently, been a product of evolution and the kaleidoscope of genetic diversity.
Historically, many varieties of hominid have existed, being defined by their most predominant capabilities and gradually evolving into more capable and advanced species: Homo habilis who had basic abilities; Homo erectus who could walk upright and homo sapiens who could think.
All of the other hominid families are now extinct, but we are all surviving members of Homo sapiens who has continued to evolve, focusing more and more on his ability to think and reason. This focus has resulted in technological leaps and bounds that have created the potential for him to control evolution.
The future face of humanity could be in our own hands.
This sounds like science fiction, but this potential is already here: grown-to-order replacement organs and even blood, cosmetic surgery enhancements and astonishingly advanced prostheses for amputees are already commonplace. We are teetering on the brink of the ability to create designer babies, tailored to select for desired traits such as sex, hair color, athletic ability, or intelligence.
Rather than evolving the human race, these advancements look set to pave the way for a totally new, and largely bespoke, post-human culture.
In his book, "Sapiens," Yuval Noah Harari, an Israeli historian, has taken this vision and run with it to a worrying place where society will fall into two distinct categories: standard human, and artificially- enhanced super-human.
The super-humans are likely to consist of the very rich, those who can pay for the latest enhancements to elevate themselves into superior beings with extraordinary skills and capabilities, whereas the standard humans will be those of lesser means, forced to make do with their humble and limited human forms.
The disparity between the two levels of humans is likely to become immense, as more and more advances are made in mechanical, electronic, chemical and genetic progress.
Treatments to correct biological deficits like failed hearts and other organs, or poor hearing and weak eyesight may still be available to the poor, but there are still expensive variations in these now rather mundane augmentations. The most advanced hearing aids are cochlear implants which wire directly into the auditory nervous system, but unless then can afford to pay £40,000 each, these life-enriching options are already denied to the majority of people.
But, says Harari, even these amazing bodily improvements will pale next to procedures that improve overall natural performance, resulting in general biological supremacy.
In an interview with the Guardian, Harari explained his bleak view of the future:
"In the 20th century, the main task of medicine was to bring everybody to a certain level of health and capability. It was by definition an egalitarian aim."
In the 21st century medicine is moving onwards and trying to surpass the norm, to help people live longer, to have stronger memories, to have better control of their emotions. But upgrading like that is not an egalitarian project, it’s an elitist project. No matter what norm you reach, there is always another upgrade which is possible."
Current scientific and medical research projects only serve to add weight to Harari’s claims: implantable devices called brain-computer interfaces (BCIs) are currently being trialed to help disabled people move their defunct limbs or robotic prosthetics, and in the future it is envisaged that eventually, advanced devices will give people direct brain-to-internet access giving them limitless access to information. Genetic engineering is already being used to correct cells with genetic faults; in future all genes could be tailored to improve human performance and intelligence.
"In the 21st century, there is a real possibility of creating biological castes, with real biological differences between rich and poor," said Harari. "The end result could be speciation. We’re used to being the only human species around, but there is no law of nature that says there can only be one species of human. With this kind of upgrading treatment we could have, in the not too distant future, more than one human species on Earth again."
Anders Sandberg, a researcher at the Future of Humanity Institute at the Oxford Martin School, disagrees with Harari’s chilling spectral vision of the Ghost of Human Future. Sandberg said that whilst technology might drive an evolutionary split in humankind, the divide would not separate rich and poor.
"Speciation might well happen, but instead of class, I think it’ll be much more driven by culture. You might get a country that decides it wants to bring down its healthcare budget by subsidising an upgrade that makes people healthier. The end result might be that the Singaporeans become their own species. Or it could be a technological speciation, like Mac users versus PC users, which is probably even more horrifying," Sandberg said.
Harari remains adamant that the rich will always prevail when it comes to procuring the latest biological enhancements. "When the aim is to upgrade, by definition, you want to be better than others. So no matter how much the cost goes down, there will always be the next treatment which is only available to the rich. The differences might become so big that if you miss the train it will be too late."
This concept is reminiscent of the Grays who, it is said, have replaced their body parts so many times that nothing of their original physical being still remains, and who are now almost immortal.
If the human race did become capable of such advanced technologies, time travel would surely pose no problem to such super-humans, who might return to share their technological advances with their poor, primitive predecessors, or to try and recover their original genetic "humanity."
Perhaps they have already returned, and the process has already started; Anne Strieber has mused that the Grays could in fact be us, but from a point in our distant future.
Has Whitley Strieber, then, already seen the future of humanity?
When asked to describe his own personal encounters, he expressed his wonder at being in the presence of a being that was so highly evolved it was almost beyond human comprehension: "I had the impression that what I was engaging with, whether it was alien or not, was at once precise beyond the most perfect machine, and emotionally rich beyond human knowing."