Timeframe for progress in life extension
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Timeframe for progress in life extension
寿命扩展进步的时间框架
[译注：作者用“时间框架”一词，来衡量“寿命扩展的进步”]
This is one of my five FAQ ("Frequently-Asked
Questions") pages: it covers questions about how long people of what
current age may live. The other FAQ pages respond to: -对SENS"可信度"的总挑战， -怎样使SENS成为现实的批评， -打败老化是一个坏主意或至少是一个低度优先的关注，和 -探讨我们如何能帮助SENS的努力。 Note: even though there are links to separate
questions below, I recommend reading this page straight through from start to
finish. 附注：即使 有连结于以下各问题，但我建议还是从头到尾阅读这个网页。 Why do you engender possibly
unwarranted optimism about timescales? 你为什么提出关于时间尺度这个可能是盲目的乐观主义？ 我们什么时候能证明人类老化真的能被修复？ 我们什么时候能有第一个人类返老还童疗法？ 我或我的孩子可以期待活多长？ 我们能不知不觉地停止老年（无论什么年龄）的死亡吗？ 我们会有某些疗法来停止我们在某一年龄的老年死亡吗？（不是同一问题） 我们能使我们自己真正不老吗？ 我们都将死于某一时间吗？ 我们能使我们自己永生吗？ Why do you engender possibly unwarranted
optimism about timescales? 你为什么提出关于时间尺度这个可能是盲目的乐观主义？ That's more of a criticism of how I'm going about
making SENS a reality, so my answer is on that page. 这个问题比怎样使SENS成为现实受到更多的批评，所以我的回答在那页（that page）。 When will we prove that human aging can really
be repaired? 我们什么时候能证明人类老化真的能被修复？ This is the first major SENS milestone, and I
believe it will be achieved with laboratory mice. I also consider that it
will be the point at which society becomes convinced that curing aging is
very urgent, and that it will kick-start a genuine "War on Aging". My estimate for the time until this milestone is
reached, if there is adequate
funding, is ten years from now; almost certainly not as soon as seven
years, but very likely to be less than 20 years. If funding is sluggish this
could be doubled. 这是SENS的第一主要里程碑，我相信能用实验室小鼠来证明。我也考虑，这样一来社会就会相信治愈老化是很急迫的，将会发动一场真正的"对老化宣战"。我估计如果有足够的经费（adequate
funding），从现在起10年内即可达到这一里程碑；几乎可以肯定不会7年那么快，但很可能少于20年。如果资助行动迟缓，这个时间可能要加倍。 The degree of control that I consider sufficient is
the ability to take a cohort of mice of a strain whose normal life expectancy
is three years, do nothing to them until they are two years old, and get them
to live an average of three more years, i.e. tripling their remaining life
expectancy. I often call this "Robust Mouse Rejuvenation" or RMR. 我认为足够的参照度是，把正常寿命期望值为3年的一个品种的一群小鼠搁置2年，然后使它们平均再活3年，就是说，再活它们剩余寿命期望值的3倍。我常常之为"充满生机的小鼠返老还童"（或简称RMR）。 Detailed justification for this prediction can be
found in my publications, which are here. The main reason this milestone matters so much is
that it will be the trigger for enormous social change. Changes of life
choices will not await the arrival of human life extension; they will occur
as soon as that eventuality becomes widely anticipated. 这一预言的详细解释请看我的文章（点击在这里here）。 这个里程碑很要紧，因为它将触发巨大的社会变化。寿命选择的变化不会等待人类寿命延长的到来；一旦该可能性成为广泛期待的事情，寿命选择的变化马上就会发生。 When will we have the first human rejuvenation
therapies? 什么时候我们会有第一个人类返老还童疗法？ This is the second major SENS milestone, and it can
reasonably be defined as the arrival of therapies that confer a postponement
and repair of human aging proportional to that described for mice in
milestone 1, i.e. a tripling of our remaining life expectancy with therapies initiated
on our late fifties or so. Inevitably I call this "Robust Human
Rejuvenation" or RHR. 这是SENS的第二个主要里程碑，它可以合理地被定义为：有了疗法，它能赋予授予人类老化的延缓和修复，相当于在第一里程碑中为小鼠描述的那些，就是说，在我们五六十岁算起的剩余寿命期望值的3倍。不可避免地，我称它"充满生机的人类返老还童"（或简称RHR）。 My estimate for the time until this milestone is
reached, starting from the time that the mouse target is achieved, is 15
years; almost certainly not as soon as five years, and could be as much as
100 years. Note that this time I make no caveats about funding, because I
think it is inconceivable that shortage of funds will be allowed to slow down
this work once milestone 1 is achieved. 我估计达到这个里程碑的时间，从小鼠目标达到的时间算起是15年；几乎肯定不会快于5年，可能会是100年。注意：我设定的这个时间没有停止项目资助，因为我认为，一旦达到第一个里程碑，因资金的短缺而放慢这项工作是不可思议的。 The best I can do by way of justifying this is to
consider the scenario in which we reach the mouse milestone without having
made any progress whatsoever on the techniques that would be needed to
translate it to humans. 为了证明这是正确的，我能做的最好事情，是考虑这样的情景：我们达到小鼠里程碑，而没有把已经取得的任何的技术进展可以被照搬到人类。 The main requirement at that stage will be
extremely safe and effective gene therapy, both of the insertional variety
(putting new genes into chromosomes) and the replacement ("gene
targeting") variety (changing an existing sequence). 在这个阶段的主要要求是极其安全和有效的基因疗法，不管是插入类（把新基因插入染色体），还是取代类（"基因打靶"，改变已有的序列）。 Several approaches to these problems are already
the focus of considerable ongoing research, so I feel that a 15-year
timeframe is a reasonable one, at least once funding is increased by the
factor that can be expected when a "war on aging" has been
declared. However, we could of course be as wrong about aging as Nixon was in
1971 about cancer, which is why my upper confidence limit is as large as 100
years. 解决这些问题的几条途径已是当前正在热门研究的焦点，所以我感到，15年的时间框架是合理的，至少一旦增加了可期待的资助（当开始宣布"对老化宣战"时）。当然，我关于老化的想法也可能像尼克讼1971年关于癌症的想法一样错误，这就是为什么我把上限设置到100年之久。 How long can I/my children expect to live? 我或我的孩子们可以期待活多久？ Clearly that depends how old you/they are, but I
feel able to give a pretty definite prediction relative to the previous
milestone. I claim that the average age of death of those born in wealthy
nations no sooner than 40 years before the achievement of milestone 2 will
exceed 5000 years. Of all my predictions, this is the one that most
thoroughly stuns most people -- and, I claim, for the least justified
reasons. My logic here is pretty simple: 显然，这取决于你或你的孩子们多大年纪了，但是，我觉得，按前面的里程碑，我能给出一个很确定的预言。我认为，出生在福利国家而在达到第二里程碑前刚40岁的那些人，其死亡平均年龄会超过5000岁。在我的所有预言中，这是一个完全使大多数人晕倒的预言 -- 我声明，这没有得到太多的证明。在这里，我的逻辑很简单： 1) 1）When we reach milestone 2, those with
access to the relevant therapies will have an absolutely non-increasing risk
of death per unit time -- they will not age. This is because we will be
identifying, characterising and solving aspects of aging that appear at
progressively later ages, faster than they progress to a life-threatening
state. 1）当我们达到第二里程碑时，那些接受相应疗法的人们，他们每单位时间将不会有逐渐增加死亡的风险━━他们不会老。这是因为我们正在鉴定、确定和解决出现在年龄后期的老化的方方面面，其速度快于他们行进到威胁生命的状态。 We have no idea at present what we will need to do
to keep 200-year-olds hale and hearty, but that's OK, because we won't need
that information for at least another 100 years. If we just pay attention to
things that begin to appear in 180-year-olds as soon as we have any, as well
as in 80-year-old chimpanzees as soon as we have them, and given the amount
of effort we'll be putting in, our chances of perpetually keeping one step
ahead of the problem are very good. 目前，我们还没有这样的想法：我们需要做什么事来保持200岁的人们精力充沛、精神饱满，但这不成问题，因为我们不需要至少另一个100年的信息。如果我们密切关注开始出现在180岁的人们以及80岁的老猩猩的事情，又假定我们付出足够的努力，那么我们就有机会永远抢先一步。 2)
At
present, the risk of death per unit time that Westerners experience in their
early teens is such that if it were maintained indefinitely we would live to
around 1000 years on average. (This calculation has been done many times with
different data and some people get 700, some 1200; 1000 is a fair consensus.) 2）目前，西方的10岁多一点的年轻人每单位时间死亡的风险是，如果照这样下去，我们将平均活1000岁。（这种计算已经进行了好多次，不同的资料有不同的数值，一些人的数值是700岁，一些人的数值是1200岁，1000岁是一个很好的共识。） My expectation is that our risk-aversion will rise
sharply if we perceive our lifespan as indefinite, so that this 1000-year
life expectancy will be extended by a modest factor; a factor of five is my
conservative guess. This of course relies on our risk-aversion being
ubiquitous -- applying to the willingness to go to war, the effort to subvert
new infectious diseases, etc, as well as our attitude to mere accidents --
but I see no reason why that should not be the case. 我的预期是，如果我们认识到我们的寿命是无限的，那么我们防范风险的意识将大大提高，这样，这个1000岁的期望值将被一个适当的系数所扩展，我的保守猜测是，这个系数是5。当然，这取决于我们的普遍风险防范意识 – 适用于自愿参与（抗老）战争、努力制止新的传染病，等等，以及我们对待单纯事故的态度 – 但是，我认为没有理由不这样做。 A lot of people, when they read this, just stop
listening because it's beyond their imagination -- they get the conceptual
"bends". Well, if that's you, please try again -- and if you'd
prefer a more mathematical treatment, focusing not so much on how we will
achieve these very low mortality rates but on what it will mean statistically,
read on. 很多人当他们读到这里就不再听了，因为这超过他们的想象力 – 他们脑子拐不过"弯"。好吧，如果是你的话，请再试一次 – 如果你喜欢更多的数学处理，不要老想我们为什么会达到这么低的死亡率，而是在统计学上它意味着什么，继续读下去吧。 Will we ever stop dying involuntarily of old age
(at whatever age)? 我们能不知不觉地停止老年（无论什么年龄）的死亡吗？ You've doubtless guessed my answer by now: not
exactly stop, but it'll become a very rare occurrence. I've given a short
name to this concept recently: I say that once we get to be improving our
rejuvenation therapies faster than the improvements are needed, as described
in the previous section, we'll have exceeded "life extension escape
velocity". Here's what I mean, in detail. 现在你肯定已猜中我的答案：不是马上停止，而是很少出现。我最近给这个概念以一个短的名称：如果我们改善返老还童的速度快于需要改善的速度，如以上章节所述，我们就会超过"生命扩展逃逸速度"。以下是我要详细阐述的。 1. Actuarial, or Population, escape velocity The first thing to consider is the opposing
influences of aging and biomedical progress on one's risk of death in the
near future (say the next year) as one gets older. 1. 由保险统计或人口统计出来的逃逸速度 要考虑的第一件事是，当活得更老时，老化和生物医学进展对近期（假定下一年）死亡率的相反影响。 In every human population, among people aged
between about 40 and 85 (the age range in which most people die in developed
nations), the proportion of people of a given age who die in a given year is
about 10% greater than the proportion of people a year younger who die that
same year and 10% less than that of people a year older. 在每一个人类群体中，在年龄为40-85岁的人们（在发达国家中这是个大部分人死亡的年龄阶）之间，一定年龄在一定年份的死亡率，年龄大的在同一年份比年龄小的高约10 ％，少一岁的死亡率低约10 ％。 This exponential relationship between age and
mortality rate was noticed about 180 years ago and is phenomenally constant
across all human populations ever examined -- both in the sense that there is
an exponential relationship, and in the exponent of that relationship. 这种年龄与死亡率之间的指数关系大约发现于180年前，凡是检验过的人类群体，这种关系在现象上都是恒定的 – 有指数关系的意义，有该关系的指数。 What's not constant, however, is the "intercept" of
this curve -- the absolute proportion of people of age N who die in year X.
In particular, there is a good deal of progress over time: people in most
developed countries have a much lower mortality rate than people in the same
country, at the same age, 50 years ago. This is mainly as a result of medical
advances. 然而，不恒定的是这个曲线的"截段" – 在年份X死亡的年龄N的人们的绝对比例。特别是，有很大一部分随时间的进步：在大部分发达国家的人们，相同的年龄在50岁之前，死亡率大大低于在同样国家中人们。这主要是医学进步的结果。 Where this gets interesting is when we consider how
this affects real people. Individuals aged N at the beginning of year X are
not also aged N+1, N+2 etc. at the beginning of that same year: they're aged
N+1 at the beginning of year X+1, and so on. So this means that even though
the ratio of N-year-old to N+1-year-old mortality in year X is 1.1, and it is
still 1.1 in year X+1, the ratio of N+1-year-old mortality in year X+1 to
N-year-old mortality in year X is less than 1.1. And that ratio is what
matters to real people. 有趣之处在于当我们考虑这会如何影响真正的人时。在X年开始时年龄为N的个体在那一年开始时不是增加年龄N＋1，N＋2等：他们是在X＋1年开始时增加年龄N＋1，等。那么，这意味着，在X年的从N岁到N＋1的死亡率是1.1，而在X＋1年仍然是1.1，而在从X＋1年的N＋1岁到X年的N岁的死亡率则低于1.1。对于真正的人，这个死亡率莫名其妙。 You can probably see by now where I'm going with
this. How fast does biomedical progress need to be in order to stop people
from having a progressively increasing risk of death in the as they get
older? Obviously, it has to be fast enough that the risk of death of people
aged N in year X+1 is 10% less than that of people aged N in year X. 到现在你可能会看到我带着这个问题走向何方。生物医学需要进展多快才能在明年老一岁时停止人们增一岁的死亡风险？显然，生物医学进展必须足够快，使得在X＋1年时年龄为N岁的人们死亡风险要 10 ％ 地低于在X年时年龄为N岁的人们的死亡风险。 Now, here's the crux: that's not ridiculously fast.
If we look back at the past century or so, we find that mortality rates at
certain ages did indeed decrease rapidly -- not quite 10% per year, but 3%
was seen and 2% was seen often. So, the 10% per year rate of progress is what
I've started to call "escape velocity". It's defined on the
population, looking at mortality rates, so when being precise I call it
"population escape velocity" or "actuarial escape
velocity". 现在，症结所在是：这不是荒唐的快速。如果我们回顾上一世纪，我们就会发现，某年龄的死亡率确实迅速降低 – 没有每年10 ％那么多，但可达到3 ％，常见的是2 ％。所以，每年10 ％的进步速度，我开始称之为"逃逸速度"。就群体看死亡率来下定义，如要说得准确，我称之为"群体逃逸速度"或"保险精密计算师的逃逸速度"。 Of course 10% isn't a ceiling, and we can just as
easily anticipate an actual rate of mortality rate decline of 15% or 20%,
which would mean that someone's risk of death in the coming year was actually
falling as they were getting older. The only limit to this is when aging
ceases to be the main cause of death for most people at the age in question. 当然，10 ％不是封顶，我们可以随便预期一个死亡率降低的实际速率为15 ％ 或 20 ％，这意味着，假设某人会老，那么此人在下一年实际上没有死亡风险。唯一的限制是老化终止成为大多数人在我们正在讨论的这个年龄的死亡的主要原因。 Now, there is a potential problem with this:
inevitably (though very probably not forever -- see below) there will be new
things going wrong with us as we attain unprecedented ages, and we'll only
have a certain amount of time to characterise and work out how to repair
these new things before they start killing people. 现在，这有一个可能的问题：不可避免地（虽然微乎其微，见在下面below），当我们获得空前的年龄时，将会有一些新东西对我们来说不对头，在它们开始杀人前，我们将只有一定量的时间来确定其特征和修补这些新东西。 This might be a real problem -- if it weren't for
monkeys. Monkeys save the day, because they are (a) fabulously similar to us,
(b) unable to speak, which means that given sufficient biomedical imperative
we don't mind putting their lives at risk, and (c) prone to age at least
twice as fast as us. 这可能真是一个问题 – 如果这个问题不是就猴子而言。猴子能节约时间，因为它们是(a)与我们极为相似，(b)不会说话，这意味着，倘若有足够的生物医学指令，我们不必担心让它们的生命去冒险，(c)它们比我们容易老化至少快2倍。 So we don't yet know what 200-year-old humans will
die of, but we don't need to until we have some, and by then we will for some
time have had 100-year-old monkeys that we've been treating in just the same
way that we treat ourselves (bad diet, no exercise, but all the life
extension technology that we use on ourselves). 这样，我们不知道200岁的人将死于什么情况，但我们在有这情况之前不需要知道，到时我们有一些时间，━━我们将有100岁的猴子，我们可以对待它们像对待自己一样（坏食物、不运动，但给予用于我们的所有延长寿命的技术）。 And because of (a), those monkeys will have
exhibited the symptoms that 200-year-old humans exhibit, so we'll have been
working for a long time on fixing them (in monkeys), so by the time they
occur in humans we will know how to fix them well. By the time we reach 300, the
same will be true by an even greater lead-time. This all relies on at least
some of the the monkeys forever getting the same problems that we get but at
under half the age, but that's a pretty safe assumption. 因为(a)那些猴子将展现200岁人所展现的症状，这样，我们有很长的时间在猴子中处理这些症状，所以到这些症状发生于人类时，我们已经知道怎样处理它们。到了我们达到300岁时，情况一样：我们有更多的前置时间。这完全依赖于猴子除了上半部年纪外会有与我们相同的问题，但这是很安全的设想。 2. Individual escape velocity Jay Fox, one of 2004's more conspicuously bright
and energetic arrivals on the life extension scene, has written a very
thoughtful analysis
of the escape velocity concept. In it he pays particular attention to the
important point that escape velocity is defined on populations in terms of
death rates, and thus that it says nothing about how frail people are. This
is always an important thing to reassure people on, so here goes. 2. 个体的逃逸速度 Jay Fox，2004年达到更超群聪敏和生机盎然的生命扩展观之一，写了一篇非常有思想深度的逃逸速度概念的分析（analysis）。在文章中，他特别关注很重要的一点：群体逃逸速度按死亡速率界定，这样，人们的虚弱程度没有提及。而这对于重建人们的信心总是一件重要的事情，所以要从这里着手。 The problem is that biomedical progress in the
future, just as in the past, may reduce people's rate of decline from health
into frailty and also their rate of decline from frailty to death. So in
principle it is possible that escape velocity as defined above -- i.e.,
population escape velocity -- could be achieved by rapid and sustained
improvements in our ability to keep frailer and frailer people alive. 问题是未来生物医学的进步如同过去的进步一样，可以降低人们从健康到虚弱的速度，以及降低人们从虚弱到死亡的速度。所以，从原则上说，可能上述界定的逃逸速度（即群体逃逸速度）可以因我们能力的迅速而持续改善，使越来越虚弱人们保持存活。 That isn't the point at all, of course, and luckily
there is no reason to fear such a scenario, because it is a great deal harder
to keep someone alive in a frail state than to stop them becoming frail in
the first place or even to restore a frail person to robust vitality. This is
demonstrated by, for example the rate of progress in longevity in the past 20
years: the life expectancy of most nations has risen by a couple of years,
but so has the "healthy life expectancy". 当然，那完全不是要点，幸运地，没有理由害怕这样的情景，因为使虚弱人存活较困难，而先停止他们虚弱更容易，甚至使虚弱人重新充满活力也较容易。例如，这一点在过去20年长寿进步速度得以证明：大多数国家寿命期待值提高了若干年，所以有"健康寿命期待值"。 In other words, there has been very little progress
in keeping frail people alive. There's no reason to expect the future to be
any different in that respect. But for the sake of precision, it makes sense
to define a second type of escape velocity, individual escape velocity. 换句话说，几乎还没有维持虚弱人存活的进步。在这个方面，没有理由期待将来会有任何不同。但为准确起见，有必要界定第二型的逃逸速度—个体逃逸速度。 This is the point at which we are beating back
aging fast enough that people's vigour, not just their likelihood of death, is being
maintained as they get older. Vigour is harder to define and to measure
precisely, of course, but we now have pretty established objective measures
of it. 重要的一点是，我们正在足够快地击退老化，使得当他们老了时，其活力（不单是死亡的可能性）能被维持。当然，较难界定和测量活力，但现在我们有已确立了的客观测量它的方法。 Will we ever have therapies that stop us dying
of old age at whatever age? 我们会有某些疗法来停止在某一年龄的老年死亡吗？ One can define other, stronger versions of escape
velocity. Even though we're extremely complex machines, our complexity is
finite, so we can realistically anticipate that there will come a time
(albeit only in the very distant future, many centuries from now) when we can
just stop improving our rejuvenation therapies, because we're already fixing
everything that naturally goes wrong with time. 人们可以界定其它更好的逃逸速度版本。即使我们是极其复杂的机器，但我们的复杂性也是有限的，所以，我们可以很实际地预期：将来会有一天（虽然这一天很遥远，从现在起很多世纪）我们可以停止改善我们的返老还童疗法，因为我们已经把随时间变糟的一切事情都弄好了。 This is the situation we're in with vintage cars:
it's a lot of work to keep a car on the road past its 70th birthday, but if
you're willing to put in that work indefinitely then you'll be able to keep
it going indefinitely -- the number of things you need to fix and the
frequency with which you need to fix them don't rise any further. 这是我们与老爷车打交道的情形：要保持一辆70年的小车在公路上跑，需要花很多时间；但是，如果你愿意使它永远能跑，那么你就能使它永远能跑━━你要修理的数目和你要修理的次数并没有增加。 That's a strengthened version of individual escape
velocity. If you've read this page from the top, you will now
understand my frustration when people persist in ridiculing me for saying
that we will in a few decades have therapies that will let us live to 1000,
when I don't say that at all. 那是一个个体逃逸速度的增强版。如果你从本文开始就阅读这一页，你会理解我的挫败感：人们一直嘲笑我，说我说过我们在几十年内将会有使人活到1000岁的疗法，而我根本没有说过。 Will we ever make ourselves truly non-aging? 我们能使我们自己真正不老吗？ An even more strengthened one would be to reach a
point where not only didn't our therapies need to be further improved as we
get older, they didn't even need to be repeated, because we'd eliminated
aging from our bodies entirely. 还有一个更激进的观点：将会达到一个地步，此时我们若是老了，我们的疗法不但不需要进一步改善，而且不需要重复，因为我们将会从我们身体完全排除老化。 It's conceivable that this could be achieved by
some sort of transformation of our bodies into purely electronic form, with
no actual moving parts, but it's perfectly certain that we would never
achieve it with bodies made out of meat. Unfortunately it could be said that
this most extreme, least realistic version of individual escape velocity is
actually the one with the best analogy to actual escape velocity -- but hey,
analogies are never perfect. 可想而知，要做到这一点，需要将我们的身体进行某种类型的改造，转变为纯电子形式，我们的身体没有实际的可移动部分，但有一点可以肯定，身体将不再有骨有肉。不幸的是，据说，这种极端的、最不现实的个体逃逸速度，实际上是一种最类似于实际的逃逸速度— 但是，唉，这种类似体，太不完美了。 Will we all die some time? 我们都将死于某一时间吗？ An interesting type of escape velocity concerns the
risk of death from all causes, aging-related or otherwise, and is a
strengthened form of actuarial escape velocity. If we achieve actuarial
escape velocity as defined earlier and exceed it by some way for a long time,
we will get to a point where essentially no one is dying of old age and
indeed no one is even frail. But of course there will still be death from all
the familiar age-independent causes. 一个有趣的逃逸速度涉及到所有原因（与老化相关或无关）的死亡风险，是一个精密计算的激进形式。如果我们达到先前界定的精密计算逃逸速度，并以某种方式超过它很长时间，那么我们将会达到一个点，在这里实质上没有人因老而死，甚至没人真会虚弱。当然会有我们熟悉的所有非年龄原因的死亡。 If we suppose that this risk is a constant -- not
only the same in year X for people of any age, but also the same in all years
from X onward for people of any age -- then clearly we all have a
"half-life", like radioactive materials, which means we all die
eventually, just as all the atoms in such materials decay eventually. If we
all had the mortality rate of present-day Western 11-year-olds, our half-life
would be about 1000 years. 如果我们假定，这个风险是一个常数 – 不仅任何年龄的人在X年时都是相同的，而且从X年增加到任何年龄的人也是相同的，那么，我们所有人显然都有"半命期"，就像放射性物质一样（有半衰期），这意味着，我们最终都会死亡，就像放射性物质里的原子最终都会毁坏一样。假定我们都有现今西方11岁儿童的死亡率，那么我们的"半命期"大约是1000年。 But it is not actually all that realistic to
suppose that our risk of death from age-independent causes will be constant
indefinitely, because we will probably not be very keen on that sort of death
either and we'll be forever working to improve our technological ability to
avoid it. It is dangerous to presume that there are any real limits to what
we may be able to achieve in this regard in the extremely distant future. 但是，假定因与年龄无关的原因而死亡的风险永远是恒定的，那实际上不是全都现实：因为我们可能也不是很热情于这类的死亡，我们将不断努力来改善技术能力以避免它。危险的是假定在遥远的未来我们在这方面会达到任何真正的极限。 Thus, it's worth considering what our life
expectancy would be if we had a continuous -- let's assume constant, for sake
of simplicity -- and indefinite improvement in our ability to avoid death
from any cause. Suppose your chance of dying in the next 1000 years is 0.5,
but if you survive that 1000 years then your chance of dying in the next 1000
years is only 0.25, and if you make it through that 1000 years then the
chance of death in the next 1000 is only 0.125, and so on. 这样就值得考虑，假定我们恒定地（为简单起见说是恒定地）和无限地改善我们避免任何死亡的能力，那么我们的生命期待值将会怎样的。假定你在下一个千年的死亡机会是0.5，假定你活过这个千年，那么你在另一个千年的死亡机会将是0.25，又假定你通过了再一个千年，那么你在再一个千年的死亡机会只是0.125，如此等等。 It turns out that this sequence does not have a
zero asymptote -- you have
a roughly 28% chance of living literally forever, genuinely never dying at
all, even though your chance of dying in any given millennium is always
non-zero. 这就产生一个问题：这样排序不会有零 – 照字面说，你永远有约28 ％存活机会，确实完全不会死，即使在任何一个特定的千年你的死亡机会都是非零。 If the chance of death diminished by a smaller
factor than 2 in each initial half-life -- say it went 0.5, 0.3, 0.18 etc. --
then of course the chance of never dying would not be as high as 28%, and it
it diminished by a greater factor than 2 the chance of never dying would be
higher than 28%. 如果在每一次半命期开始时死亡的机会（假定为0.5, 0.3, 0.18等）为小于2的系数所减少，那么当然不死的机会不会是28 ％那么高，而如果为大于2的系数所减少，那么不死的机会将大于28 ％。 But if it's greater than zero, i.e. you have some
chance of never dying, then it turns out that that means your life expectancy
(the time you have a 50% chance of living) is actually infinite, because the
people whose lifespan really is infinite outweigh the ones whose lifespan is
finite. That's a pretty strong version of escape velocity! 但是，如果它大于零，就是说，你有一定的不死机会，那么就有这样的问题：这意味着你的生命期待值（你有50 ％不死机会的那时）实际上是无限的，因为寿命真正无限的那些人超过寿命有限的那些人。这是逃逸速度的一个很有力的版本！ Will we ever make ourselves immortal? 我们能使自己永生吗？ No. None of the above forms of postponement of
aging and death -- not even the last one -- can correctly be described as
"immortality". Immortality means inability to die, i.e. a certainty
of never dying. Even in the last case above, there is always a non-zero
probability of dying some time -- and indeed a non-zero probability of dying
in any given year. So this last question has an easy answer: no, we will
never make ourselves immortal. 不，上述各种延缓老化和死亡的方案，没有一个（即使是最后一个）都不能正确地被描述为"永生"。永生意味着没有能力死亡，就是说，肯定不死。即使在上述最后一个方案中，有时也总有死亡的非零可能性 – 在任何特定的年份确实都有一个非零的可能性。所以，最后这个问题有一个容易的答案：不，我们不能使我们永生。 |
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