This article was written by Jamais Cascio in October of 2004. We're republishing it here as part of our month-long editorial retrospective.

Technology Review reports that MIT Professor Leonard Guarente may have found the genetic factor that allows mice undergoing 'caloric restriction' to live up to 30% longer. It's long been known that cutting down food intake by about 1/3 can extend the lifespan of mammals by up to 50%. Professor Guarente has found that manipulating a single gene -- the SIRT1 gene -- can produce longer mice lives without caloric restriction. What's more, all mammals -- including humans -- have a similar gene.

A 30% longer healthy life -- another 25-30 years, say -- is intriguing, and is on the cusp of being worldchanging. As Alex has noted in the past, a population that regularly lives to (and beyond) the age of 100 forces us to confront questions about work, relationships, family and our society in general. But living to 100, even 140, may be just the tip of the iceberg. What happens when we figure out a way to live much longer lives? Read on for an exploration of this question.

Discoveries like the SIRT1 gene are important steps towards radical longevity, even if they (in and of themselves) don't directly cause it. The logic is straightforward: since new discoveries continue to happen, the longer one lives, the more likely it is that discoveries leading to even longer life will happen during one's lifetime. Even if "true" extreme life extension* isn't figured out for another century, surfing the waves of discoveries could allow one to be here for it.

[*I'm skirting around the otherwise obvious term "immortality" for a few reasons: I consider it inaccurate (an immortal would never die, while someone with a radically long life could still be crushed by a bus); it's mythical (that is, it's a term redolent with symbolism and non-rational implications for many people); and it's presumptuous (even if we figure out how to keep the body going indefinitely, there are still enough questions about how the mind works for me to be uncomfortable about the assumption that it could go on forever).]

It's a good bet that, even if the SIRT1 discovery doesn't lead to a boost to lifespan in the next decade or two, other pathways will. It's not simply because our understanding of human biology is accelerating, although it is. The real driver will be the aging baby boom generation in the United States demanding products and medical services to keep it healthy and active. Pharmaceutical and biotech companies are spending billions on research to find breakthroughs to appeal to this market. They'll be competing with each other to roll out products that do more, last longer, have fewer side-effects, and (ultimately) are cheaper to buy and use. The generations that came after the baby boom, who sometimes find themselves living in the boomers' shadow, will have had life & health extension treatments beta-tested for them.

When improved understanding of human physiology and genetics combines with nanoscale medical tools, we face the possibility of something much bigger than just adding a couple of decades. If aging is largely the result of accumulated cellular insults and the biological processes which evolved to deal with them, as the current thinking suggests, what happens when cellular damage can be repaired and genetic triage code turned off? While such nanomedical life extension is not possible today, we can imagine how it might work -- and it appears to be increasingly plausible.

Of the various radical visions of what this century might hold (including machine intelligence, "uploading," and the singularity), I think that extreme life extension is the most likely. We're starting now to see some of the early indicators that it may be happening in the next few decades. We need to be asking the right questions about what it might mean now to be better prepared when it does happen.

Talk to most people about radical longevity and they'll almost always raise the issue of population. While it may be a common observation, it's not a bad one: many critical implications fall out from it. A growing life-extended population would force us to deal with resource consumption. It also raises employment questions, both "how do younger generations work their way into positions of more authority if the older generation never has to give up those roles?" and "what do people do with themselves when they live so much longer?" What about housing? Taxes?

What about relationships? While many marriages end in divorce, not all do. What does "til death do we part" mean when death may be centuries off? Can you imagine being with your current partner for another fifty years? Hundred years? Three hundred years? What if one of you wants the treatment and the other doesn't?

The economy and power questions are crucial. Who can afford the life extension treatments? Who are they denied to? Are they only available in one country at first? What do those who can't get the longevity treatments think about those who can?

And there are questions about the process itself. How does it work -- is it a single "magic bullet" treatment or an ongoing set of behavioral shifts and medical interventions? To what degree does it change brain plasticity along with overall physiological vigor? Will the aging recipients still think like older people or will they think like younger people again? What about failed pathways -- a treatment that looks good but causes problems a few decades down the road? How can people weigh their decision whether or not to get such a treatment?

Ultimately, there are the cultural questions. How does it change people's behavior if they know that they could live for centuries? Do they become more conservative? More adventurous? Are they less likely to have kids? How do they treat people who won't be living extremely long lives? Do they start thinking long term? Does society stagnate, or is the concept of "stagnation" itself an artifact of short-term thinking?

In Toxic Memes, I explore a bit how much longer lives change the way people think. Late in the book, I include a brief vignette, notes from a young man starting to realize what he has in front of him:

I sit in the cafe at the top of the arcology, looking out over Seattle towards Mt. Rainier. I'm a good "end of the cen" boy, blood full of nano and brain hooked into the global net. So my genome's not top of the line – my parents chose the best they could, at the time. I have worlds at my fingertips and a long life ahead of me.

That's the weird part. When I stop to think about it, think about just how much there is to see and how long I have to see it, I get dizzy. It's like my brain just didn't evolve to deal with the thought of a life lived in so many places and for such a long time. I get this urge to go find a hole somewhere to hide in, turn off my links, and live out a natural six-score-and-ten. I know at least one kid in my pod who did just that, about three weeks ago.

But then another part of me kicks in, and I see the kinds of options I have now, the kinds of opportunities I'll have that my parents never had, and their parents couldn't even imagine. There's another kid in my pod who talks about checking out Alpha Centauri like she's already bought tickets or something, she just can't imagine that such a thing wouldn't be possible sometime in her life. Or, as she sometimes says it, she just can't imagine that her life wouldn't be long enough to see that possibility. She's probably right, too.

I look around at the mass of people here in this arc, and around the world, content just to eat all day, sleep all night, and scrump with their virts when they get bored. That's not the world I want to live in. If my only choices are running away and hiding – in some Isolate hole or in deep space, same difference – or becoming a barely-sentient cow... well, then I need to find another choice, don't I?

      – Chuck Nix, The New Century Sucks And It Hasn't Even Started, 2099

How the economic and social questions unfold is, in part, contingent upon how we get to radical longevity. Four biological approaches to extreme life extension come to mind. Let's set aside, for the moment, any sort of non-biological scenarios -- uploads, singularities and the like. Not that they're categorically impossible, but that their implications are even larger than just living a very, very long time. All of these longevity scenarios are laden with discomfiting questions, and each has its own unique implications.