Mbah Gotho is an Indonesian man aged 145, easily the oldest-ever recorded age for a human. However, it is quite possible that advances in human biology in the not-too-distant future will allow humans to live for hundreds of years. Indeed, if/when it becomes possible to upload human consciousness to a computer, it will be conceivable to live forever, either as a cyborg or in an entirely non-biological form.
Any dramatic lengthening of the human lifespan raises many important questions, some of which are pondered by Hillary Rosner in Scientific American.
Biochemistry is steadily advancing its understanding of the molecular biology of the human body and of the ageing process. I see no reason in principle why this knowledge could not be applied to arrest the natural ageing process and maintain the body in the healthy adult phase for a long time. This would entail correcting biological errors that crop up naturally – for example errors that creep into human DNA – sensing the earliest signs of the development of disease and taking corrective action, replacing faulty organs with healthy organs, and so on.
Every part of the human body is complex, soft and susceptible to wear and tear. Our brains, in particular, are fantastically complex, and it is difficult to imagine that a repair and maintenance approach to extending lifespan could maintain brain function indefinitely. On the other hand, if human consciousness could be uploaded on to a computer it is conceivable that, with adequate servicing of the computer hardware and software, we could live forever. We could either live as cyborgs with a non-biological computer-based consciousness plus a biological body augmented with mechanical parts or we could be entirely non-biological, that is, computer-based consciousness and entirely mechanical bodies.
However, it seems to me that much of the current speculation about uploading human consciousness to a computer is wildly optimistic. In order to upload consciousness, one would first have to understand the biological basis of consciousness, and we remain a very long way from such an understanding. The human brain contains 100 billion neurons connected by synapses, and the entire map of these connections obviously contributes hugely to creating our identities. But neurons also interact with each other in different ways besides synapses, and Rosner points out that these connections may also be essential to creating our identities. Some speculate that a human consciousness upload would have to include information on every atom in the brain and the computational power required to achieve this might not be available for thousands of years yet.
Whether or not it will ever be possible for humans to live forever, the question arises, if it were possible, would it be desirable? On the positive side, living indefinitely in a non-biological form would facilitate space travel to distant parts of the universe and colonisation of environments inhospitable to human biology. But, if my consciousness were uploaded into a cyborg, would I still be me? Would I continue to love my family and friends? Would my ethical orientation remain the same, for example would the Golden Rule still make sense to me? How would I look on the natural environment? Would I, in fact, still be human?
Pondering these questions about the limit case of immortality has value because we can be reasonably confident that relatively near-term scientific advances will significantly prolong the human lifespan, perhaps for hundreds of years, and such questions will then begin to have real relevance. If I were given the option now of choosing to live forever, I don’t know how I would respond. Immortality would certainly look unattractive to me unless it was also extended to those people I care most about. Although, in one way the idea of living forever is not that strange in our culture. Most of us were raised as Christians and part of the Apostles’ Creed enjoins Christians to believe in “the resurrection of the body and life everlasting”.
Mbah Gotho, the 145-year-old Indonesian I introduced at the start of this article, looks forward to dying soon. He has survived four wives and three children and his grandchildren are all independent. Incidentally, Mbah is a smoker.
William Reville is an emeritus professor of biochemistry at UCC. http://understandingscience.ucc.ie