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I would have thought it's intuitively obvious that there's "no fixed limit on human longevity", and it's therefore obvious that mortality "flattens out": how el

by bloak 8y ago

I would have thought it's intuitively obvious that there's "no fixed limit on human longevity", and it's therefore obvious that mortality "flattens out": how else could it avoid going over 100%? It presumably is possible to say something interesting and non-trivial about the shape of the curve but it seems to be beyond the mathematical competence of the people writing these journalistic reports to do so. Looking at the Wikipedia list of longest-lived people (https://en.wikipedia.org/wiki/List_of_the_verified_oldest_people https://en.wikipedia.org/wiki/List_of_the_verified_oldest_pe...) I get the impression that the top two (Jeanne Calment and Sarah Knauss) don't fit, though I know that the case of Jeanne Calment is very well documented.

mattnewton 8y ago
I don’t find it obvious that there shouldn’t be some hard coded expiration mechanism- lots of insects have effective experation dates, for example.
- bloak 8y ago
  Even if there were a hard-coded expiration mechanism, that mechanism would presumably have limited precision and a non-zero failure rate (assuming it's implemented with biochemistry rather than magic). Looking at the list I linked to, it does rather look as if there were a cunning device to kill people towards the end of their 118th year, and that device failed in two cases... but I can't imagine why there should be such a device or how it might be implemented, so I don't really believe that. Even if the chances of surviving another year did stabilise around 50% after the age of 100, say, you still wouldn't have enough people living beyond 130 for you to be able to measure with reasonable accuracy the mortality rate of people aged over 130. So the hypothesis that a person aged 140 would still have a 50% chance of surviving another year would be totally untestable. If you think about it, there's also no hard limit for how tall or how short an adult human could be. Except the limit of zero for the height. Again, beyond a certain point there will be, in practice, no data available for testing any hypothesis about the distribution.
  - fjsolwmv 8y ago
    Don't forget that two people born around 1900 and living past 118 could also be measurement error or fraud.
tathougies 8y ago
It's not intuitively obvious at all, since each replication of our cells leads to our chromosomes getting ever smaller until presumably it starts eating into genes that do useful things. Unless it's intuitively obvious to you that you could live without genetic material at all, it seems quite obvious that -- given current biological processes -- there is a limit, even if that limit is longer than where we've gone before.
- meowface 8y ago
  There's the natural limit and the theoretical limit. In theory, some future gene therapy may swap out your chromosomes for ones that don't decay (while somehow not causing negative side effects) while you're still an embryo or gamete, and do all sorts of other things to make you nearly biologically immortal. And in some even more distant future, maybe consciousness upload (with the "copy conundrum" somehow resolved) will be a real thing, in which case living for thousands or millions of years seems plausible.
  - bloak 8y ago
    That last case, "consciousness upload", means providing a new definition of "living". Nothing wrong with that, but worth noting, particularly since it's not at all clear what the new definition should be.
    - fjsolwmv 8y ago
      Yes, but it's not so discrete a difference. We change every second of our lives physically and mentally. We have ever increasing complexity of drug, surgical, and bionic therapies.
      - bloak 8y ago
        Running a simulation of a person would probably enable different kinds of change to be made, and some of those may be qualitatively very different from anything that has happened before. One also has to think about running multiple instances of a person, running a person in a non-real-time simulated environment, taking a checkpoint, restoring from back-up, and so on. At what point do you start to treat two instances of the same person as different people? If you stop running any instances of a person, have no particular plan to run one in the future, but you think you still have a snapshot in an archive somewhere, is that person still "living"?

by bloak 8y ago

mattnewton 8y ago

I don’t find it obvious that there shouldn’t be some hard coded expiration mechanism- lots of insects have effective experation dates, for example.

bloak 8y ago
Even if there were a hard-coded expiration mechanism, that mechanism would presumably have limited precision and a non-zero failure rate (assuming it's implemented with biochemistry rather than magic). Looking at the list I linked to, it does rather look as if there were a cunning device to kill people towards the end of their 118th year, and that device failed in two cases... but I can't imagine why there should be such a device or how it might be implemented, so I don't really believe that. Even if the chances of surviving another year did stabilise around 50% after the age of 100, say, you still wouldn't have enough people living beyond 130 for you to be able to measure with reasonable accuracy the mortality rate of people aged over 130. So the hypothesis that a person aged 140 would still have a 50% chance of surviving another year would be totally untestable. If you think about it, there's also no hard limit for how tall or how short an adult human could be. Except the limit of zero for the height. Again, beyond a certain point there will be, in practice, no data available for testing any hypothesis about the distribution.
- fjsolwmv 8y ago
  Don't forget that two people born around 1900 and living past 118 could also be measurement error or fraud.

tathougies 8y ago

It's not intuitively obvious at all, since each replication of our cells leads to our chromosomes getting ever smaller until presumably it starts eating into genes that do useful things. Unless it's intuitively obvious to you that you could live without genetic material at all, it seems quite obvious that -- given current biological processes -- there is a limit, even if that limit is longer than where we've gone before.

meowface 8y ago
There's the natural limit and the theoretical limit. In theory, some future gene therapy may swap out your chromosomes for ones that don't decay (while somehow not causing negative side effects) while you're still an embryo or gamete, and do all sorts of other things to make you nearly biologically immortal. And in some even more distant future, maybe consciousness upload (with the "copy conundrum" somehow resolved) will be a real thing, in which case living for thousands or millions of years seems plausible.
- bloak 8y ago
  That last case, "consciousness upload", means providing a new definition of "living". Nothing wrong with that, but worth noting, particularly since it's not at all clear what the new definition should be.
  - fjsolwmv 8y ago
    Yes, but it's not so discrete a difference. We change every second of our lives physically and mentally. We have ever increasing complexity of drug, surgical, and bionic therapies.
    - bloak 8y ago
      Running a simulation of a person would probably enable different kinds of change to be made, and some of those may be qualitatively very different from anything that has happened before. One also has to think about running multiple instances of a person, running a person in a non-real-time simulated environment, taking a checkpoint, restoring from back-up, and so on. At what point do you start to treat two instances of the same person as different people? If you stop running any instances of a person, have no particular plan to run one in the future, but you think you still have a snapshot in an archive somewhere, is that person still "living"?