[dahart]

Kurzweil also claims, as the capstone final paragraph in this piece, that human life expectancy is on an exponential curve, which is false. Not just a little wrong, it's all the way wrong, and intentionally misleading, there's no possible way he doesn't know it's false. It's very easy to check the basic facts: https://en.m.wikipedia.org/wiki/Life_expectancy. Lifespan for people who live past 20 (discounting infant mortality) has been around 70 for at least a thousand years. It's gone up a little in developed countries recently, but he intentionally uses only a small window of time, and includes infant mortality in his stats. If we eliminate all infant mortality, still nobody will live forever, and average lifespan will not be on an exponential curve. This intentionally misleading falsehood alone makes me doubt all the rest of his claims about exponential and double exponential trends. (And I don't doubt Moore, only the additional unsupported implications and loose associations that Kurzweil adds to Moore's law.)

[adrianN]

I agree that the claim that lifespan is on an exponential curve is bogus. Modern medicine basically extended extremal lifespan up to the maximum attainable without fixing the underlying causes of aging and then stopped. There is for example some research that shows that the oldest woman's blood was derived from just two stem cells.[1] We currently don't have the technology to fix problems like that

I disagree however that nobody alive today will live "forever". The technology that might allow us to fix aging is on an exponential curve, look for example at the cost of genome sequencing. So the time is ripe for some breakthrough results in aging research that actually address some causes of aging.

[1] https://www.newscientist.com/article/dn25458-blood-of-worlds...

[dahart]

The tech you're talking about can't do anything for the living, it only has potential for the unborn. Either way, there is exactly zero evidence that it's already happening. Kurzweil's claim is pure fantasy.

[adrianN]

This discussion is becoming way to off-topic here. But I was convinced by Aubrey de Grey's arguments, perhaps you will be too. He is easy enough to Google.

[dahart]

So I took your advice and did Google Aubrey, I got his WP page first. It says he's into and wants to fund cryonics. I'm not a a biologist, but that tickles my spidey sense. Any remaining hope I had for cryogenics was firmly buried after listening to this: http://www.thisamericanlife.org/radio-archives/episode/354/m...

The second thing I got was this: http://www2.technologyreview.com/sens/docs/estepetal.pdf

The tl;dr summary is:

However, given the recent successes and highly emotional nature of life extension research, Aubrey de Grey is not the first, nor will he be the last, to promote a hopelessly insufficient but ably camouflaged pipe-dream to the hopeful many. With this in mind, we hope our list provides a general line of demarcation between increasingly sophisticated life extension pretense, and real science and engineering, so that we can focus honestly on the significant challenges before us.

[maxerickson]

I think you are understating the improvements in adult life expectancy. 1000 years ago, the very wealthy (the aristocrats) were getting to their 60s. The population wasn't.

The improvements have mostly come from violence reduction and public health and dealing with disease though, I agree that those things aren't really part of a life extension technology trajectory.

[dahart]

I think you misunderstand my point. If you take away all early mortality factors, lifespan is long, and always has been. Separating the burgeoisie is actually an important piece of this argument, and it reinforces what I'm saying. Healthy adults that don't die of diseases or violence often lived as long as healthy adults today. Aristocrats a thousand years ago, on average lived to 65, but bunches of them made it to 80 and beyond. The same factors you cited lowered the lifespan a little for the entire population, even the adults. If I had data on people that only died of old age, I would use that instead, and that would (and probably still does) favor the rich.

If you solve all of these things, then lifespan is asymptotically something like 80 years. That is plain as day. We might come up with ways to increase lifespan, but we haven't yet, and none of the data Kurzweil shows are a result of increases in lifespan for people who die of old age.

[maxerickson]

I just didn't read carefully enough (missed that you were mostly speaking of potential life span).

[dahart]

All good, my beef is with Kurzweil's unscientific intentional misuse of data.

"Longevity" is the term in the social sciences for average age at death for only people that die of old age. Kurzweil used that word, he said "In the eighteenth century, we added a few days every year to human longevity; during the nineteenth century we added a couple of weeks each year; and now we’re adding almost a half a year every year."

Life expectancy increased. Longevity did not. It's somewhat common to confuse them, so he could be forgiven for a mistake, except that it wasn't a mistake, he knows the difference, and his graph is evidence. That he included numbers from the 1920s and then skipped to 2000, is impossible to do accidentally, and if you include 1940-1990, you'd see lifespan flatlines. But then he'd have to admit neither life expectancy nor longevity are on exponential growth curves. They're not linear or even sublinear either. Longevity has always been flat, and lifespan has historical dips and bumps.

[dahart]

And I regret not linking to WP on longevity earlier, it directly contradicts Kurzweil's statements. https://en.m.wikipedia.org/wiki/Longevity