The defining feature of human life is its impermanence. We only have an average of around 80 years to do all the things we want to do before death comes a-knocking. Each person alive today will only ever experience a tiny fraction of humanity’s existence; however, soon we may have the knowledge and expertise to extend our lives indefinitely.
Why do we age?
Humans have evolved via natural selection. It has selected and refined the best traits for us to improve our chances of survival and reproduction. But after we have reproduced a few times and raised our offspring, there is no natural benefit of us being alive.
Any gene mutations that negatively affect a person after this critical age (around 40) were not weeded out by natural selection, so have persisted and accumulated in our genome. It is the gradual loss of function in multiple bodily mechanisms that causes aging.
This explains why so many health problems become more common in old people: the heart, brain and other organs only need to function reliably for a certain amount of time.
How to stop aging
The most surefire way to stop aging is to replace our biological bodies with artificial ones. We could either transfer our consciousness into an artificial body or transfer it into a computer.
These concepts may seem far-fetched, but a Russian billionaire called Dmitry Itskov aims to achieve cybernetic immortality by 2045 via the 2045 initiative by transferring his consciousness to an artificial carrier.
The problem with consciousness transfers is that they may result in the relative death of the original person, only creating an identical copy of the person, and not really achieving immortality. (see: why mind uploading is impossible).
Fighting aging with modern medicine
We can use medicine to limit the effects of aging. Methods to do so target different aging mechanisms, including the shortening of telomeres, cell senescence and DNA splicing. One group of researchers managed to reverse aging in human cells using small amounts of targeted hydrogen sulphide.
Despite these advancements, there is still no “universal cure” for aging. The mechanisms within our bodies are very complex, so it will be difficult to control all of them in an aging body.
Instead of trying to combat the endless problems of an aging body, we could replace the aging body with a newer model, so that the only aging component of concern becomes the head. This is where head transplants come in. The first successful human head transplant was carried out back in 2017 by Dr Sergio Canavero and took place in China, where medical ethical regulations are more relaxed than elsewhere.
There are a few problems with head transplants, which include a limited number of suitable donors and tissue-type incompatibilities between the donor and acceptor.
To circumvent the problems arising from head transplants, we could clone ourselves; keep the clones in a comatose state until we require their bodies; then transplant our heads onto the younger versions of ourselves.
The technology to clone humans currently exists, but due to tight ethical regulations there have been no reported cases of a human clone being born; although in 2018 researchers managed to clone monkeys.
Back in 2008, some scientists used their own skin cells to create embryonic clones of themselves. They destroyed the embryos after about a week of messing around with them in the lab, but if they had injected them into a surrogate woman, they would have created younger clones of themselves.
There are many barriers preventing us from extending our lives via these ethically-murky methods. Many scientists and governments will only fund medical research if it can be shown to have clear benefits on human health; and life extension does not really come into this category.
It will take the commitment of a few more eccentric billionaires and rogue scientists before we are able to extend our lives indefinitely.