It's a long way to forever

 kw: book reviews, nonfiction, life extension, immortality

Life is like a game of Tetris. The blocks just keep coming, and their speed increases, until a player can't keep up and the bin fills. Game over. But there is a twist. In the computer game, there is a maximum speed of block fall. Once you train your reflexes, you can accumulate rather incredible scores. But there still isn't a way to play it forever. Fatigue sets in, if nothing else. In life, we find another twist. There is also a maximum speed, but our reflexes slow down over time, until nobody can keep up. Game Over. Permanently.

I saw The Price of Immortality by Peter Ward, and I thought, "This can't be the geologist." He isn't. He is half the age and in a different field altogether. As writers, both Peter Wards are equally skilled and engaging.

The book begins with a visit to a church, the Church of Perpetual Life. There is no god involved in this religion. The congregants "worship" indefinite life extension. As in more familiar churches (and their analogs, the synagogues, temples and mosques), the social element is strong, and in this case it reigns supreme. They and other immortalists are hoping for a medical or biological "escape velocity" to be reached, such that techniques and technologies for extending life push the End Game out, say, 30-50 years, and within that time, further advances push it further, until eventually, human lives can be extended without limit. This is the basis of a saying made popular in The Prospect of Immortality by Robert Ettinger (1962): "Millions alive today will never die." (He borrowed it from the Jehovah's Witnesses, whose focus is quite different)

The book takes us through the twists and turns of the various movements that surround the obsessive interest in perpetual life, from body-freezing (and head- or brain-freezing for the less prosperous), to digital uploading, to stem cell dreaming; most of the 13 chapters allow us to encounter a different take on the matter. The final take is that of the less-obsessed doctors and researchers: Human life seems to have a built-in limit of 110-120 years, and we ought to focus on extending our health span to match our life span.

Chapter 7, "Know Thyself", discusses the nine hallmarks of aging. It is a difficult discussion, partly because the philosophical and medical discussion takes some getting used to, and even more because we just don't want to hear it. Every one of the nine is being studied by multiple groups, and we are clearly in a learning phase in every case, far from any kind of implementation phase. I'll touch on three of them that I have paid attention to in recent years.

Mitochondrial Dysfunction. Most of the mitochondria in this image show signs of breaking down. A few appear intact. The proportion of failing mitochondria increases as we age. It is not known (so far as I've been able to learn) how the mitochondria that get into a fertilized ovum are rejuvenated. Until we know that, we have no hope of reversing the process for aging humans.

There are certain diseases that occur because of congenital problems with mitochondria. That isn't the situation here. The source of lower energy in the elderly, and eventually, part of the source of their frailty (another is cellular senescence), is the reduced energy produced by failing mitochondria. When your tank runs out, if nothing else has killed you, that will.

Telomere Shortening. It's funny, telomeres are a good-news-bad-news topic. When a cell divides, the telomeres of the daughter cells come out a bit shorter. There are processes that lengthen them, but that's still quite a mystery. It may indeed result in longer life for some people. Cells whose telomeres don't shorten at all are cancer cells. Again, we still don't know why. But when telomeres get to a certain minimum length, cellular senescence (another of the 9) seems to begin, but this is not the only "trigger" for that process.

It seems that telomerase, the enzyme that lengthens telomeres, is very selective. I suspect that, were it to run rampant, we'd encounter another dangerous condition. So far I haven't heard of one.

Bloated Stem Cells. I learned of this matter very recently. The research was published less than 2 months ago, months after the book came out. As I understand it, after the age of 65, a small proportion of our stem cells get larger and more active, and the activity of the rest of them decreases. These bloated cells gradually take over; they seem to have a kind of gene drive. The total amount of new blood produced, however, decreases. You can read about it here. It sounds like a slow kind of body-wide cancer to me.

This phenomenon may be related to another of the nine, stem cell exhaustion. It's too early to tell, because the current research relates only to blood stem cells.

Well, there you have it, three of the 9 (or 10) matters that must be overcome to either halt or reverse aging. I think we are quite far from any "escape velocity", an opinion similar to the author's.

Let's look at another angle for a moment. Suppose we achieve a condition of "death is optional" for every person on Earth. There will always be accidents, I suppose. Maybe the "downloaders" (more in a moment) are hoping for a way to "back up" our consciousness so the backup can be put in a new body (obtained where?) if the "original" is destroyed. But consider, 100 years from now, the 7.7 billion people now alive are nearly all still around, plus perhaps another thirty billion or so who have been born in the meantime, and they are all immortal also. Do you really think immortal people will stop having babies? I think we can supplement accidents with famine. Famine like nobody can imagine. Famine that makes the Biafra and "great leap forward" disasters look like skipping a meal or two.

One poignant story I read a few decades ago revolved around a man who remembered. Everybody was 200-300 years old, or more, but none of them could remember hardly anything that had happened more than 50-70 years earlier. Except this fellow. Who was least fortunate? The story made me consider that "oldster forgetting" is probably mostly a case of the memory running out of room. If true life extension is developed, we may find we must either learn to actively forget a lot of stuff, or find out we're not capable of learning much after a certain age, which is probably around 100 years.

Maybe the digital backup folks can also focus on offloading memories we want to remove from active storage. But my knowledge of computer science makes me skeptical that we'll get very far in the coming century or less. Consider: one cubic millimeter contains about 200,000 neurons in the cerebellum, and about 20,000 of the larger neurons found in the cerebrum (the "thinking" part of our brain). Each cerebral neuron connects to between 1,000 and 100,000 others, with an average of about 4,000; each cerebellar neuron connects to at least 40,000 others. Running the body takes up 75% of our neurons, and 95%+ of the total synapses in our brains: the cerebellum. Our big cerebrum uses the rest. 

The best figure I can learn for the volume of a synapse is about a third of a cubic micron, so if our entire brain volume consisted of synapses, there's room for about 50 trillion. The actual number is probably half that, leaving room for the 16-17 billion cerebral and limbic neurons, and the 70-74 billion cerebellar neurons.

That's a lot of machinery. I have seen it touted a time or two that one or another supercomputer has more transistors in its collection of CPUs than the number of neurons in the brain. Well and good. But it takes more than a transistor to model a neuron. It takes at least a full core of a modern processor to do a good job of modeling a single neuron, with its thousands to tens of thousands of inputs and outputs (synapses in the body, message signals in a computer)…in real time. Neurons cycle at rates between 10Hz and 50Hz. The 8-core CPU in my computer consumes 40 watts. Let's ignore the cerebellum for a moment. Modeling 16 billion cerebral neurons will take 2 billion CPUs, consuming 800 Gigawatts. The brain uses 20 watts. If Moore's Law still held (it doesn't, not for 15-20 years), there's a very long way to go, just to model ONE brain. Let alone billions.

The book gave me a lot to think about. I hope that is true for many more folks. How many of us will react, "Let me live long and well, so I can die with few regrets."

Late brainwave: If Moore's Law were still working, and doubling time of CPU cycles per watt were 2 years, running a brain in a computer could become possible/economical in 64 years. Being able to run a billion of them would take another 30 years. No matter what happens, the year 2116 ought to be an interesting time.