Human species, past and future
Evolution results from gradual change to DNA over many generations, as gene mutations continue to occur through cell division. Mutations may be beneficial or harmful, spontaneous and unexplained or caused by environmental factors. Gene variants passed down from interbreeding thousands of years ago between our ancestors and the Neanderthals and Denisovans, two long-extinct human species, still affect our health and traits. The Black Death that ravaged Europe in the fourteenth century may also have influenced genes involved in immune responses and present-day susceptibility to disease, while remnants of ancient viral pandemics are still active in healthy people.
Examples of successful genetic mutations that are still found in specific human populations include the abilities to live at altitudes of 4,000 metres and to deep dive to 70 metres. Genes are also strongly influenced by lifestyle, behaviour and experience, but such changes are epigenetic, so don’t alter our DNA and are not irreversible. Some biologists and philosophers think that current evolutionary biology is too taken up with how genes in a population change over time. They argue that this neglects how animals and organisms shape their environments and adapt themselves to survive and reproduce.
At this stage of our history, scientific advances are giving us an unprecedented ability to make choices about the course of our human evolution. Since the first successful in vitro fertilisation (IVF) procedure in the late 1970s, assistive reproduction methods have led to the birth of more than eight million babies worldwide.
Scientists are now working on reproductive technologies that may be offered in the near future. These include: lab-grown eggs and sperm that are developed from adult skin cells turned into stem cells; gene editing of embryos to prevent heritable conditions; three-person IVF through mitochondrial transfer, where a tiny bit of egg DNA is replaced by donor DNA to eliminate a genetic disease; the creation of synthetic embryos for research; and construction of an artificial womb for premature babies, with close to natural biological conditions and an artificial placenta connected to the umbilical cord. In the medium term, we are also likely to see further developments in response to changing social attitudes, beliefs and expectations. These might include babies who are biologically related to both partners in a same sex couple, children with multiple biological parents and prospective parents who choose to gestate their babies artificially.
The era of techno-humans
Rapid advances in biotechnology and medicine make it almost impossible to determine the limit to human lifespan, even before potential non-biological ways of life extension are taken into consideration. Biomedical scientists have recently suggested 150 and 200 years as realistic future lifespans for people treated with senolytic anti-ageing drugs that are already in development. Other experts offer more conservative predictions, but it looks probable that slowing down or turning off the process of ageing will radically alter the lives of future generations.
Gene therapy, now used to treat specific conditions and diseases, may lead to cell reprogramming for rejuvenation in the coming years. Biotech companies are also exploring the potential of plasma therapies, involving infusion of blood from young people to tackle diseases of ageing and rejuvenate the weakening systems of older humans.
Radical ideas about life extension can spring from recent scientific progress in treating illness or remedying the effects of injuries and congenital conditions. Brain-computer interfaces are developing at pace and starting to enable people with quadriplegia and certain other disabilities to interact with the world and recover lost functional ability. Evolving technologies include machine-learning algorithms that interpret signals from the brain and translate them into bodily responses and movement. Researchers are also working on ways of restoring sight with technologies for bionic eye systems, which are still in early stages.
These advances are happening alongside cultural shifts among young people, some of whom are keen to experiment with their bodies and emphasise their physical individuality (e.g. with extensive tattoos). While prosthetic limbs once had a social stigma, the new bionic versions may be viewed as cool and stylish, leading young disabled people to look for a personalised design with maximum functionality and advanced features, rather than a replacement limb that looks as close as possible to the real thing.
When these sophisticated bionic devices are able to outperform their human equivalents, people without any medical need may decide to replace their body parts in order to enhance their capabilities, and perhaps develop into cyborgs with brain-controlled devices that increase functionality and life expectancy.
Some scientists claim that we are already living in a techno-human era, where humans are becoming components in larger operating systems. One example is the outsourcing of cognitive expertise to smart appliances, high-tech vehicles and online search engines. Changing social patterns, with more people moving into urban areas, also mean that we expect to have a higher number of short-term or fleeting relationships, many of which are conducted online. As dating matches are increasingly made using apps, we are in effect part-delegating our sexual selection to algorithms that aim to recommend suitable new partners.
There is also the widely noted observation that a high proportion of people are immersed with their phones while in a public space. On a different level, novel technologies that reflect an early techno-human era include development of AI to enable deceased people to live on as chatbots, using personal information such as images, voice data and social media posts. How such forms of tech-symbiosis will affect the design and functioning of the human brain and mind, and whether it could lead to a form of radical life extension, is as yet unknown.
Immortality and the afterlife
The ancient Greeks believed that the spirit left the body at death and travelled over the River Styx to the palace of Hades, god of the underworld. In the three main monotheistic religions, there is (simplistically) a split between the fate of the righteous and that of the unworthy: the souls of the former go to heaven or paradise and the souls of the latter endure pain and suffering in hell. In these religions, there are varying beliefs about when and how people are judged and whether there is an intermediate place, such as purgatory, where the soul may be purified and cleansed of sin.
In other present-day religions (again simplistically), the soul is embarked on a spiritual journey, with one’s actions in this life determining the next one. The soul may be reincarnated from one embodied state to the next, through a cycle of birth and death that can ultimately lead to a higher existence. The belief in reincarnation remains alive in 2048, as Suzanne in the Lifespinners novel is a 98-year-old mystic space artist who has been reincarnated several times.
Millions of people have reported a near-death or out-of-body experience, which leads some to believe in an afterlife. These experiences tend to be profoundly vivid and moving, as well as coherent. They are not explained by neuroscience or by the effects of the imagination, fear of death, psychosis, drugs or other causes. Scientists and medics involved in the resuscitation of patients after cardiac arrest are particularly keen to understand what occurs in the brain during these events, which indicate a unique cognitive state with variations of the same features: a strong sense of the spiritual; feeling separated from one’s body and observing it from above; heading towards a destination; reliving one’s life; and seeing (or being approached by) a light.
The desire for immortality and eternal youth has always had the backing of powerful, wealthy citizens, from ancient Chinese emperors to our modern tech entrepreneurs. While in the past there was mysticism and magic attached to the quest, the emphasis now is firmly on scientific, high-tech solutions. Strands that have attracted major financial investment include: cellular rejuvenation; creation of backup copies to replace malfunctioning cells; computer storage of DNA; implanted microchips; and the transhumanist ambition of uploading the mind into a supercomputer and preserving it in digital form.
Preservation and transcendence
A small number of companies offer to cryogenically freeze human bodies or heads, in the hope that customers can be reanimated at a future time when science makes this possible. Some cryonics experts think this could happen through nanobot technology (artificial molecular machines doing repair and reconstruction), but dealing with the effects of the cryopreservation and prior deterioration or disease will be a tall order. While some animals are able to freeze their bodies to survive, humans cannot. It is possible to freeze and thaw a small number of cell types and simpler tissues, such as eggs and sperm for fertility purposes and bone marrow, stem cells and corneas for transplantation, but complete organ transplants depend on chilled, not frozen organs, and brain cryopreservation and revival will require huge research breakthroughs.
Proponents of transhumanism contend that the body and mind can escape biological limitations and transcend into a future without death. Conceptually, enhancing the mind can be viewed as a logical extension to the use of widely accepted body enhancement devices, such as cochlear implants to restore lost hearing and pacemakers to maintain a regular heartbeat. However, the task of uploading the human mind as an entity is at another level. Scientists don’t yet understand how our brain structure and function connect with our subjective, conscious experience, nor how much computing power would be required to operate a computerised mind.
One radical idea is to embalm the brain so that it can be reawakened and linked to a computer, creating a total backup. The intention is to preserve the brain’s contents, keeping all memories and their emotional context intact and ready to be reactivated. Brain emulation technology, which aims to build an equivalent computer neural network from a scanned brain, may offer a different route. An even more far-out idea is to upload the brain to the metaverse and then install it in an artificial body. While some scientists argue that mind uploading can be achieved through extrapolations of existing technology, others challenge the feasibility of separating mind from body and argue against the assumption that consciousness and the mind are explained as functions of the biological brain.
Edited Autumn 2023