Very narrow question: assuming an immortality treatment keeping people at a biological age of a fit 30's, free of infections and cancers & ruling out death by aging, how long would people live (in the US) before dying from an accident (including crimes)? My understanding is that assuming no changes from our current society, the statistical risks set a hard limit around 300 years or so...?

  • 11
    $\begingroup$ Is this a treatment affordable to everyone, or only a few dozen ultra-rich? $\endgroup$
    – Cort Ammon
    Commented Dec 14, 2014 at 16:36
  • 7
    $\begingroup$ does this immortality treatment work against malnutrition/starvation? $\endgroup$
    – guido
    Commented Dec 14, 2014 at 17:51
  • 22
    $\begingroup$ Does this treatment make everyone young and fit, or does it allow people to become frail and fragile but never die of old age? The answer to this will have a significant effect on the accidental death rate. $\endgroup$ Commented Dec 14, 2014 at 18:15
  • 10
    $\begingroup$ Damnit, I've seen this twice in the "Hot Questions" list and both times I misread it as "immorality treatment". $\endgroup$ Commented Dec 14, 2014 at 19:14
  • 4
    $\begingroup$ I read this question wrong: "How long would it be before everyone moved outside of the US once they were immortal?" $\endgroup$
    – IchabodE
    Commented Dec 15, 2014 at 19:31

5 Answers 5


The CDC estimates 187,000 people in the USA die from "injury" every year -- basically that includes homicide, suicide, vehicle accidents, and other forms of accidental death.

This works out to a chance of about 1/1600 of an individual dying from injury in any given year. So the chance of survival is 0.999375.

After 300 years, your chance of remaining alive is $(0.999375)^{300} = 83\%$.

After 1109 years, your chance of survival has dropped to 49.99%.

After 5000 years, your chance of survival is only 4.3%.

After 32,000 years, individual chance of survival is 1 in 488 million. By this time, it is likely that all of the 300 million Americans alive when the immortality serum was discovered would have died off.

Of course, none of this accounts for fairly radical changes in society likely to result from biological immortality (not to mention other social change over thousands of years), which could drastically change the rate of death by injury.

  • 4
    $\begingroup$ Even without the changes resulting from the introduction of immortality, accidental death rates are likely to reduce over the next few decades for a variety of reasons: The phasing out of human driven vehicles will reduce vehicle accidents. There will be a reduction in success rate of attempted homicide and suicide due to surveillance and faster response times and improved medical technology. $\endgroup$ Commented Dec 14, 2014 at 18:13
  • 8
    $\begingroup$ Though it should also be noted that the introduction of an immortality drug would lead to all sorts of deaths in the short term (riots to get the drug? War by other countries?). $\endgroup$
    – Telastyn
    Commented Dec 14, 2014 at 18:47
  • 2
    $\begingroup$ Apparently the rate of fatal injury varies with age. With "stopped aging" the effective age distribution would become pretty narrow. 2012 in the US there were 28,478 fatal injuries for 43,970,060 people of ages 20-29. Maybe that would be a good guess to start with? The adjusted chance of survival is 0,999352. Doubt it really matters. $\endgroup$ Commented Dec 14, 2014 at 19:10
  • 7
    $\begingroup$ you should also consider that this drug would have the effect of increasing population since people are still making babies but they are not dying. Leading to starvation due to the incapacity to feed everyone. $\endgroup$
    – Vincent
    Commented Dec 14, 2014 at 19:20
  • 4
    $\begingroup$ US Military deaths have averaged out at about 5,500 per year since the creation of America. Or an average of 1,200 per year in the last half century. Fairly insignificant (speaking purely statistically) against the death rate of 187,000 per year in accidental death, and is 0.0004% of the US population per year, which is tiny $\endgroup$
    – Jon Story
    Commented Dec 15, 2014 at 15:19

Aside from Royal Canadian Bandit answer to the chance of people dying from accidents there is another problem to consider: how will people's brains age? You might have noticed time seems to speed up as you age. A year when you were 8 years old was nearly endless. But by now you will probably have noticed that years actually do pass in a reasonable amount of time (1 year to be exact). Now as you grow older and older this will likely continue. As you near your 100th birth day it becomes very difficult to actually keep track of what happens around you, this is because your brain has a finite amount of space to store memories in. So you either store less or lose older memories making the years seem shorter. This combines with the fact that you have probably already seen most things in the world by your 150th year. Making the rest of your life seem like a grey bluer. This is likely to result in people not wanting to live beyond 150/200 years. Sure some people can and will choose the longer life but many will cut it short. As such a cure would also greatly increase the population size we can also expect that suicide will become a lot more socially acceptable for those who are 80+ since otherwise we would have to deal with massive overpopulation.

Of course if you have some way of keeping the brain in stasis as well or perhaps offloading memories onto a computer for later retrieval than this could be avoided.

  • 4
    $\begingroup$ Interesting to point that out. However, I am (and afaik Science, too) not sure if this is not also an effect of the stressfull and unresting life we live. We almost never phase out into boredom, there is constant zest, and people "happily" optimize more and more of their time to get done more and more. The less boredom you experience, the faster time goes by (an effect of this is also "burn out" and depressions). Everytime I travel in holidays, days get longer again (especially when into the mediterranean, where ppl know how to live) $\endgroup$
    – phresnel
    Commented Dec 15, 2014 at 10:54
  • $\begingroup$ ... I bet it is an effect of both; missing boredom as well as an ever increasing amount of used brain. $\endgroup$
    – phresnel
    Commented Dec 15, 2014 at 10:57
  • 1
    $\begingroup$ You're assuming that the passage of time seems to accelerate through life. I'm not sure that's true: I don't feel that my perception of time has changed very much since I finished my undergrad degree *mumble* years ago and stopped having my years subdivided into academic terms. $\endgroup$ Commented Dec 15, 2014 at 10:58
  • 1
    $\begingroup$ My grandma once mentioned that each year seemed longer than the previous, because less survivors came over for a chat that made a day go by, and there were even less and less funerals to attend to each year... $\endgroup$
    – Alexander
    Commented Dec 15, 2014 at 11:26
  • 1
    $\begingroup$ Do you have any quote to support your claim? I can't tell if you're inventing a story or citing an article. $\endgroup$
    – Sheraff
    Commented Dec 15, 2014 at 14:50

Are we talking about a treatment that everyone can afford and everyone has to take only once, so basically everyone who is at adult age today, plus everyone who turns 18 in the future, will never die of old age? And since you cannot age forever, the ageing process would eventually stop?

The problem would be that you can't have an exponentially growing population, so at some point number of deaths and number of births must be the same, one way or another. If this is handled carelessly then there will be initial growth, total destruction of resources, total disaster and a small and possibly primitive civilisation left. If handled careful, there will be either most brutal birth control, or some means to get rid of many people who lived long. Since it is the long living adults and not the newborns making the decision, I'd expect brutal birth control. Secretly having a baby without permission would probably be a good way to end your life and the baby's life. Violent crime, or reckless driving, would likely be seen as 100 times more abhorrent than today and get you culled.

I'd expect some people to be careless and clumsy and die off rather quickly, leading to a different kind of evolution: The fittest would be surviving longest, so you would have some oldies who have already lived very long and carefully, and their numbers slowly filling up with newcomers. So while current statistics could be applied for 50 years, someone who is 200 (and still 25 year old fit) won't die in a skiing accident, or a car crash, or taking drugs easily.

Forgot to answer the actual question: I'd say if all goes well, the ones living dangerously will be taken out of the equation within a short time (I could mention one motorist that I saw a short while ago who will not live for another ten years no matter what immortality drugs you could give him), say 200 years, and the remaining population will be the careful ones who can go on for many thousand years.


As a simple addition to the already good answers, you should think about Suicide. In any culture where life could be extended so long suicide would likely become more accepted. Maybe after 300 years people get bored. Maybe people get physically crippled and the prospect of living like that for an eternity is harder to bear? Maybe suicide is ENCOURAGED, because there aren't enough resources to provide for a constantly growing population and anyone that isn't consuming resources, and making more of the next generation, slows the inevitable over-popluated distopia that would be created. Maybe people would be refused treatment after 300 years just to keep the population slightly controlled.

In any case culturally agreed upon suicide as a way of saying "I lived long enough, I'm bored and want to move on" would likely become a significant impact. It may even be a large percentage of deaths in the world.

  • 1
    $\begingroup$ I agree with this. Whatever reasons one might have for suicide are twice more likely to occur if you live twice as long, and possibly even more likely because of stuff that just "adds up" $\endgroup$ Commented Dec 16, 2014 at 11:28
  • 1
    $\begingroup$ A society may even offer huge rewards for suicide - if the resources required are nothing compared to the resources required for keeping people alive for so long. $\endgroup$ Commented Dec 16, 2014 at 14:02

As long as they want of course, in human measure. The question states that an immortality treatment is a given. So in my view it would include a superior backup of ones body and mind, to start with, otherwise there is not much immortality to discuss. After this the sky is the limit. Probably literally, because our particular Universe is not standing still. We could start attempts to recreate ourselves to -in the end- overcome entropy and break out of the particular surroundings of our dimensions and laws of nature. http://en.wikipedia.org/wiki/Entropy

It would not do to stay as we are, mortals in a mortal Universe. The Multi Universe is out there. http://www.space.com/25100-multiverse-cosmic-inflation-gravitational-waves.html

Our IQ's and other options could use an update to go forward, but for now, in my limited time, -I like to have a coffee-, the question is answered.

  • 1
    $\begingroup$ The question was if you wouldn't die of age or disease, what was your life expectancy with only death by accident left. (though I think murder should be included in that) Just because we might prevent aging doesn't mean we'll be able to make backups of our consciousness. $\endgroup$
    – bowlturner
    Commented Dec 15, 2014 at 20:12
  • $\begingroup$ Why would I read your interpretation in the 14 words of the question above? $\endgroup$
    – Fallon
    Commented Dec 15, 2014 at 20:26
  • 2
    $\begingroup$ By reading the rest of the question besides just the title? $\endgroup$
    – bowlturner
    Commented Dec 15, 2014 at 20:31
  • $\begingroup$ I see what you mean now. The first comment is part of the question. Point taken, but still.. an immortality treatment is just that. It is bound to have implications. So I feel comfortable to stick to my guns. Thanks for your comments, bowlturner. $\endgroup$
    – Fallon
    Commented Dec 15, 2014 at 20:43
  • 1
    $\begingroup$ Not a problem. Glad you didn't take it personally. Welcome to WorldBuilding! Hope to see more answers and questions from you. $\endgroup$
    – bowlturner
    Commented Dec 15, 2014 at 20:46

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .