marcelo_gleiser's picture
Appleton Professor of Natural Philosophy, Dartmouth College; Author, The Island of Knowledge

There is no question more fundamental to us than our mortality. We die and we know it. It is a terrifying, inexorable truth, one of the few absolute truths we can count on. Other noteworthy absolute truths tend to be mathematical, such as in 2+2=4. Nothing horrified the French philosopher and mathematician Blaise Pascal more than "the silence of infinitely open spaces," the nothingness that surrounds the end of time and our ignorance of it.

For death is the end of time, the end of experience. Even if you are religious and believe in an afterlife, things certainly are different then: either you exist in a timeless Paradise (or Hell), or as some reincarnate soul. If you are not religious, death is the end of consciousness. And with consciousness goes the end of tasting a good meal, reading a good book, watching a pretty sunset, having sex, loving someone. Pretty grim in either case.

We only exist while people remember us. I think of my great-grandparents in nineteenth-century Ukraine. Who were they? No writings, no photos, nothing. Just their genes remain, diluted, in our current generation.

What to do? We spread our genes, write books and essays, prove theorems, invent family recipes, compose poems and symphonies, paint and sculpt, anything to create some sort of permanence, something to defy oblivion. Can modern science do better? Can we contemplate a future when we control mortality? I know I am being way too optimistic considering this a possibility, but the temptation to speculate is far too great for me to pass on it. Maybe I'll live for 101 years like Irving Berlin, having still half of my life ahead of me.

I can think of two ways in which mortality can be tamed. One at the cellular level and the other through an integration of body with genetic, cognitive sciences, and cyber technology. I'm sure there are others. But first, let me make clear that at least according to current science, mortality could never be completely stopped. Speculations aside, modern physics forbids time travel to the past. Unfortunately, we can't just jump into a time machine to relive our youth over and over again. (Sounds a bit horrifying, actually.)

Causality is an unforgiving mistress. Also, unless you are a vampire (and there were times in my past when I wished I were one) and thus beyond submitting to the laws of physics, you can't really escape the second law of thermodynamics: even an open system like the human body, able to interact with its external environment and absorb nutrients and energy from it, will slowly deteriorate. In time, we burn too much oxygen. We live and we rust. Herein life's cruel compromise: we need to eat to stay alive. But by eating we slowly kill ourselves.

At the cellular level, the mitochondria are the little engines that convert food into energy. Starving cells live longer. Apparently, proteins from the sirtuin family contribute to this process, interfering with normal apoptosis, the cellular self-destruction program.

Could the right dose of sirtuin or something else be found to significantly slow down aging in humans? Maybe, in a few decades… Still at the cellular level, genetic action may also interfere with the usual mitochondrial respiration. Reduced expression of the mclk1 gene has been shown to slow down aging in mice. Something similar was shown to happen in C. Elegansworms. The results suggest that the same molecular mechanism for aging is shared throughout the animal kingdom.

We can speculate that, say, by 2040, a combination of these two mechanisms may have allowed scientists to unlock the secrets of cellular aging. It's not the elixir of life that alchemists have dreamt of, but the average life span could possibly be increased to 125 years or even longer, a significant jump from the current US average of about 75 years. Of course, this would create a terrible burden on social security. But retirement age by then would be around 100 or so.

A second possibility is more daring and probably much harder to become a reality within my next 50 or so years of life. Combine human cloning with a mechanism to store all our memories in a giant database. Inject the clone of a certain age with the corresponding memories. Voilà! Will this clone be you? No one really knows. Certainly, just the clone without the memories won't do. We are what we remember.

To keep on living with the same identity, we must keep on remembering. Unless, of course, you don't like yourself and want to forget the past. So, assuming such tremendous technological jump is even feasible, we could migrate to a new copy of ourselves when the current one gets old and rusty. Some colleagues are betting such technologies will become available within the century.

Although I'm an optimist by nature, I seriously doubt it. I probably will never know, and my colleagues won't either. However, there is no question that controlling death is the ultimate human dream, the one "thing that can change everything else." I leave the deeply transforming social and ethical upheaval this would cause to another essay. Meanwhile, I take advice from Mary Shelley's Frankenstein. Perhaps there are things we are truly unprepared for.