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> Girls born since 2000 in the developed world are more likely than not to reach the age of 100, with boys likely to enjoy lifespans almost as long. The article "The Biodemography of Human Ageing" by James Vaupel,[2] originally published in the journal Nature in 2010, is a good current reference on the subject.

You or someone else presented this highly speculative claim as fact a long time ago on HN. I've tried to find the comment link, but I can't.

In any case, the support for this supposed fact is very dubious. You link to one article by Vaupel in Nature who, in making this claim, cites only this paper

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2810516/

by Christensen et al. The paper says, in the abstract,

> If the pace of increase in life expectancy in developed countries over the past two centuries continues through the 21st century, most babies born since 2000 in France, Germany, Italy, the UK, the USA, Canada, Japan, and other countries with long life expectancies will celebrate their 100th birthdays.

Very few medical researchers are likely to find that "if" statement at all plausible, so this claim about most newborn girls living to 100 is bogus. If you have a better source for this claim, please present it. Otherwise, stop posting it.

(Thank you for your concern.) How would one prove this claim wrong? There is signal in current mortality and morbidity statistics about how long the individuals now alive will last before they die off. Is anyone interpreting this signal from official medical reports any differently from Vaupel and Christensen? Both Vaupel and Christensen are very well respected demographers (as Vaupel's publication in Nature should adequately suggest to readers familiar with the scientific literature). Paul Graham has a great essay online titled "How to Disagree"[1] and I invite you to apply those steps in any thread on Hacker News where you see a factual claim with which you disagree (as I think I have seen you do in countless thoughtful earlier comments that have been posted here from your keyboard).

If you have a better source for this claim, please present it. Otherwise, stop posting it.

What you seem to be objecting to here is not the factual statement (you have not suggested any reason to doubt the factual statement, and haven't cited anyone who works in demography) but rather the strikingly concrete way in which the statement was made. But that manner of making the statement was chosen by Vaupel (in agreement with Christensen, whose works on the topic I have also read) and I'm just passing on the ideas of recognized experts whose published papers on the topic look plausible to me and look especially plausible to demography researchers on human aging I know locally. I learned about the papers of these two authors from local researchers who sometimes collaborate with Vaupel and Christensen (especially Christensen).

It shouldn't be objectionable here on Hacker News to pass on user-readable citations to published scientific literature that looks plausible to other scientists with a basis of knowledge in the subject. You are asking me to change my overt behavior as one Hacker News participant among thousands. Where in the Hacker News guidelines[2] do you find a problem with behavior like mine here? Hacker News seems very tolerant of predictions of the future, and indeed some of the favorite topics here revolve around predictions of the future.

[1] http://paulgraham.com/disagree.html

[2] http://ycombinator.com/newsguidelines.html

All fields are populated with multiple experts. The opinion of those experts on some issues will be broadly in agreement, and on other issues they will have a wide range.

Finding one expert who presents the conditional claim of another expert as unconditional, and (you) then asserting this claim as accepted fact is highly misleading. This is especially true when that unconditional claim is almost certain to be disputed by the majority of experts. Giving your citations reduces the friction necessary for people to identify how you are being misleading, but it's not a blanket pass to mislead.

Furthermore, it won't always be the case that there will be a nerd like me willing to dive into your citations to show why they don't support your claim. In this case, the veneer of authority that comes with listing many citations can easily overwhelm the benefit they provide, leading to more misinformation than if your speculative claim had been uncited and therefore ignored.

> How would one prove this claim wrong?

You would ask a few of experts if they think it's plausible that life expediencies would follow the same trajectory in developed countries this century as they have the past century. I conjecture that almost all those experts would reply "no", probabaly citing (1) the fact that the mortality rates at elderly ages has leveled off for many decades in developing countries and (2) that almost all the increases in life expectancy comes from reducing infant mortality and the spread of infectious diseases.

Indeed, the soft ceiling on human longevity has not budged much since Psalms 90:10 was written about 3 millennia ago:

> The days of our years are threescore years and ten; and if by reason of strength they be fourscore years, yet is their strength labour and sorrow; for it is soon cut off, and we fly away.

I conjecture that almost all those experts would reply "no"

Have you asked even one? Have you asked any experts at all? This is what is so puzzling to me about this line of questioning--is the question actually prompted by acquaintance with the subject, or is it of a piece with doubting any other scientific claim? What if the projection is correct, even though you have trouble believing it? I have very little trouble believing the projection, having a mother born in the 1930s who has passed her eighty-first birthday, and having an aunt (her older sister) born in the 1920s who has passed her ninety-fourth birthday. Plenty of people from much earlier birth cohorts are already living into extended old age, so what is so daring about a prediction that anyone who meets established long-term patterns of life expectancy will live into an era with more progress in disease prevention and treatment?

(In short, why have you cited no evidence whatever on this point?)

(1) the fact that the mortality rates at elderly ages has leveled off for many decades in developing countries and (2) that almost all the increases in life expectancy comes from reducing infant mortality and the spread of infectious diseases.

That dual statement suggests you have not looked carefully at the link in my original footnote 4

http://www.nature.com/scientificamerican/journal/v307/n3/box...

(Nature's repost of a chart originally available at the Scientific American website, but a dead link there now), in which it is shown that life expectancy has been increasing steadily at ALL ages, including old ages. You really need to read up more on this, or it's hard for anyone to discuss these issues with you here. You are very careful to speak factually on other issues here on Hacker News, so this is taking me a bit by surprise. Do you know of any experts in this domain at all? Whose writings do you recommend?

Hi Token,

I agree with you, it's important to be able to have open scientific discourse about the future. I wouldn't advise you not to post, but to strengthen what you write by being a little bit more critical and scientific.

The concern is focused on the change of "If the pace of increase in life expectancy . . . continues" to the materially different unsubstantiated claim of "more likely than not to reach the age of 100".

It's important to recognize that published literature is often wrong or misleading. We should all be very critical, particularly when relying on a single source. It's also dangerous to present conjecture or prediction as fact as done here.

>How would one prove this claim wrong?

You are highlighting that it's questionably falsifiable. Need I say more?

I am very interested in what you have to say, but when cracks like this show up it throws everything you write into question.

I would suggest that they are only 14 years old right now, so none of them have made it to 100 yet. The truth will be know in 86 years, perhaps sooner.

> Girls born since 2000 in the developed world are more likely than not to reach the age of 100, with boys likely to enjoy lifespans almost as long

I'm sure this is backed up by studies and references, and at the same time I am amused at the hubris of making this statement. It's a cheap prediction to make, given that it will be around 2070 before you can verify it - and how right it is depends on lack-of-catastrohpies (e.g. in 20 years we'll have an idea how the meltdown in Fukushima affects lifespan), same-rate-and-same-kind-and-availability of advances, etc.

And before you criticize me for being "anti-sciece" - I am not, and unlike a lot of other assertions, this might technically be science (I haven't reviewed the source material) - however, it is not useful science because it may take 70 years to falsify.

Furthermore, a lot of -- perhaps most -- extrapolations of past trends had been wrong. At the time of Wallace & Darwin it was "scientifically" extrapolated that food will only grow linearly. And in 1980 climate studies had shown that if we don't do anything (and we didn't) by 2000 quite a few coastal cities will be underwater. If I wasn't anonymous, I'd place a long bet that the data crunching that led to this prediction will turn out to be complete rubish.

It's just a simple projection, it's not meant to be taken so seriously. I expect that it's extremely conservative. We are currently in the dark ages of medicine where we just shoot people up with random chemicals and see what happens. There is a lot of room for improvement. Not to mention the singularity.

Exactly. We are simply molecular machines, and we can and will become masters of our molecular destiny, and I would be happy to make a Simon–Ehrlich type wager with anyone, executed by smart crypto-contract, that the average lifespan of a Female born in 2000 will be > than 100.

I would say that my heir(s) will collect the winnings, but I fully expect medical progress will let me outpace death for quite some time.

"And what do we say to death?"

"Not today!"

I would take that bet and not solely because you failed to exclude third world countries. I would probably hesitate on "in 2050, a 50 year old women has, on average, another 50 years of life" and definitely pass on "in 2075, a 75 year old women has, on average, another 25 years of life."

(not so confident there, someone here is just a doctor's appointment away from catastrophe, could be anyone, even you :-/)

in 1980 climate studies had shown that if we don't do anything (and we didn't) by 2000 quite a few coastal cities will be underwater

Cite?

Well, last time I looked for it, I couldn't find any older studies on the IPCC website that have been shown to be wrong.

However, having lived and read newspapers at the time, I remember the scare mongering, and specifically the mention of the "Marker Tree" in the Maldives, which were projected to to have significant areas under water by 2010, then 2020, now 2100 (spolier: it didn't happen https://uk.answers.yahoo.com/question/index?qid=201107180902...)

A quick googling cannot find the original predictions (days before the web ... go figure), but this interesting discussion http://johncarlosbaez.wordpress.com/2012/03/27/the-1990-ipcc... will give you an idea about the difference between 25 year old predictions and what actually happened. The guy who runs this blog is http://en.wikipedia.org/wiki/John_C._Baez

Other readings: http://www.foxnews.com/science/2013/01/28/un-climate-report-... (yes, it is fox news - so use your debiaser, but do look at the content). Also the responses and links over at http://www.scientificamerican.com/article/climate-assessment...

Re: mildly overweight having better mortality outcomes, see this recent study that was designed to remove the confounding factors of smoking and illness-induced weight loss, and then found excess weight does indeed adversely impact mortality (the study was limited by self-reported weight):

http://wholehealthsource.blogspot.com/2014/04/uncovering-tru...