For most of our history, humans could turn only to prayer and poetry to help cope with this reality. Today we are offered scientistic alternatives--if not for immortality itself, then at least for longevity of biblical proportions. All have some basis in science, but none has achieved anything like scientific confirmation. Here is a short sampling, from the almost sublime to the near ridiculous:
It's true that none of the items he has listed have been confirmed scientifically. This isn't terribly surprising, seeing as they all rely on technology which is proposed for future development or which is currently being developed. The one life-extension method that does currently have some evidence backing it up, which we'll come back to, somehow never makes it onto Shermer's list.
Virtual immortality. According to Tulane University physicist Frank J. Tipler, in the far future we will all be resurrected in a virtual reality whose memory capacity is 10 to the 10123 bytes. If the virtual reality were good enough, it would be indistinguishable from our everyday experience. Boot me up, Scotty. One problem, among many, is that Tipler's resurrection machine requires so much energy that the universe must one day collapse, which present data show is not going to happen.
Tipler's ideas are definitely on the fringe. But resurrection in his proposed "God computer" is not the only way life might be extended via computer. For one thing, we don't need a model of the entire universe.
What we do need is a computer sophisticated enough to model human consciousness and a means of uploading a brain's contents to electronic media. Those are obviously huge requirements, but nothing like the scale of Tipler's machine. Ray Kurzweil predicts that assuming Moore's Law hangs in there in 25 years or so, $1,000 will buy you a machine with the approximate computing power of a human brain. A decade later, that same $1,000 will get you the equivalent of a thousand human brains in a box. There are a number of ways that a human mind might be uploaded into a computer, but the most straightforward approach, and the approach that we will most likely use at first, will start with a sophisticated brain scan. The uploaded mind will function within a virtual copy of the brain.
Seven years ago, a condemned killer allowed his brain and body to be scanned in this way, and you can access all 10 billion bytes of him on the Internet. You can see for yourself every bone, muscle and section of gray matter in his body. But the scan is not yet at a high enough resolution to re-create the interneuronal connections, synapses and neurotransmitter concentrations that are the key to capturing the individuality within a human brain.
Our scanning machines today can clearly capture neural features as long as the scanner is very close to the source. Within 30 years, however, we will be able to send billions of nanobots-blood cell-size scanning machines-through every capillary of the brain to create a complete noninvasive scan of every neural feature. A shot full of nanobots will someday allow the most subtle details of our knowledge, skills and personalities to be copied into a file and stored in a computer.
This may all sound pretty far out, but give me a break. Kurzweil's ideas are much more closely rooted to current capabilities than Tipler's, although Shermer (for some mysterious reason) gives Kurzweil nary a mention.
Genetic immortality. Oh, those pesky telomeres at the ends of chromosomes that prevent cells from replicating indefinitely. If only we could genetically reprogram normal cells to be like cancer cells. Alas, this is no solution, because biological systems are so complex that fixing any one component does not address all the others that play a role in aging.
...and since there's no way of ever getting a handle on what what those other components are, there's really nothing we can do.
Tell it to Aubrey de Grey, Shermer.
De Grey has identified the seven types of cell damage that work together to constitute aging as we know it. Telomeres are just one part of the problem, but the overall problem is understandable and solvable.
Cryonics immortality. Freeze. Wait. Reanimate. It sounds good in theory, but you're still a corpsicle. And when your tissue is thawed, your cells will be mush. Don't forget to pay the electric bill in the meantime.
Oh, for Pete's sake. Get caught up and then we'll talk.
Replacement immortality. First we replace our organs (which today are often rejected), then our cells and molecules nano-a-nano (not yet technologically feasible), eventually exchanging flesh for something more durable, such as silicon. You can't tell the difference, can you?
Shermer's Caveman ancestor:
Okay, first we're going to use this "fire" thing (which we usually can't keep going for long and haven't even figured out how to start yet) to preserve our food and ward off predators. Then we're going to figure out a way to build our own caves in more convenient locations (not yet technically feasible). Then we're going to start making the plants we like to eat grow where we want them to grow, and keeping herds of the animals we like to eat close by so we always have some handy. Ha ha ha ha ha ha ha.
Some might argue that my little caveman digression proves nothing. I would agree, and add that Shermer's "analysis" of life extension via replacement proves nothing. Organ rejection is a major issue, which we will eventually solve by finding a way to re-grow organs or by producing non-rejected synthetic substitutes. It isn't exactly news that we don't yet have sophisticated molecular nanotechnology that would allow us to rebuild cells one at a time. And the crack about replacing flesh with silicon is just plain silly.
Lifestyle longevity. Because this is a goal we can try to implement today, the hucksters are out in force offering all manner of elixirs to extend life. To cut to the chase, S. Jay Olshansky, Leonard Hayflick and Bruce A. Carnes, three leading experts on aging research, have stated unequivocally in the pages of this magazine that "no currently marketed intervention--none--has yet been proved to slow, stop or reverse human aging, and some can be downright dangerous" ["No Truth to the Fountain of Youth," Scientific American; June 2002].
It has never been satisfactorily demonstrated, for example, that antioxidants--taken as supplements to counter the deleterious effects of free radicals on cells--attenuate aging. In fact, free radicals are necessary for cellular physiology. Hormone replacement therapy, another popular antiaging nostrum, helps to counter short-term problems such as loss of muscle mass and strength in older men and postmenopausal women. But the therapy's influence on the aging process is unproved, and the long-term negative side effects are unknown.
I'm not really a proponent of calorie restriction (I think it's too hard), but there is clear scientific evidence that it can be used to extend life, at least in mice. It will be a few years before we learn whether it works with people, but right now all indications are that it will. I wonder why Shermer failed to mention it?
Shermer wraps it up with a few words of wisdom:
As 20th-century English poet Dylan Thomas classically admonished, "Do not go gentle into that good night .../Rage, rage against the dying of the light." Rage all you like, but remember the six billion--and the 100 billion before. Until science finds a solution to prolonging the duration of healthy life, we should instead rave about the time we have, however fleeting.
And what if we enjoy spending the time we have looking for ways to prolong our time? Is that okay with you?
I choose to give Aubrey de Grey the last word. As he so eloquently proclaims from the sidebar:
Well, first of all I have a lot of catching up to do all the films I haven't seen, books I haven't read, etc. while I've been spending every spare minute in the fight against aging. But in addition, there are masses of things that I enjoy doing and will always enjoy spending time with my wife and friends, taking a punt out on the river Cam, playing a game of Othello, etc. and I reckon I'll just carry on doing those things forever. At root, the reason I'm not in favor of aging is because I like life as I know it.