At what moment are you dead

你在哪个时刻算是真正死去

来源视频

For as far back as we can trace our existence,

humans have been fascinated  with death and resurrection.

Nearly every religion in the world  has some interpretation of them,

and from our earliest myths

to the latest cinematic blockbusters, the dead keep coming back.

But is resurrection really possible?

And what is the actual difference between  a living creature and a dead body, anyway?

To understand what death is,  we need to understand what life is.

从人类诞生开始，

人类一直对死亡与复活着迷

几乎每个宗教都对它们有着不同的见解

从早期的神话故事

到最新的电影大片中， 死者在不断的复活

但是复活真的可能吗

生物的生与死的区别到底在哪里

要理解什么是死 我们必须先理解什么是生

One ancient theory  was an idea called vitalism,

which claimed  that living things were unique

because they were filled  with a special substance, or energy,

that was the essence of life.

Whether it was called qi,

lifeblood,

or humors,

the belief in such an essence  was common throughout the world,

and still persists  in the stories of creatures

who can somehow drain life from others,

or some form of magical sources  that can replenish it.

有一个被称为“活力论”的古老的理论

它认为生物体是独特的

因为生物充满特别的物质或能量

这种物质就是生物的本质

不管此物质被称之为气

生命脉

或是幽默

世界各地普遍深信这种物资的存在

而且不时可以听到关于它们

可以从别的生物吸取生命的故事

或是某种神奇的原料可以补充它们

Vitalism began to fade  in the Western world

following the Scientific Revolution  in the 17th century.

René Descartes advanced the notion

that the human body was essentially  no different from any other machine,

brought to life by a divinely created soul located in the brain's pineal gland.

And in 1907, Dr. Duncan McDougall  even claimed that the soul had mass,

weighing patients immediately before and after death in an attempt to prove it.

Though his experiments were discredited, much like the rest of vitalism,

traces of his theory  still come up in popular culture.

在17世纪的科学革命后

“活力论”在西方世界开始失去市场

瑞内‧笛卡尔（René Descartes） 让这种理念更进一步

他主张人类的身体基本上 和任何机器并无两样

由位于脑内的松果体内的 神所创造的灵魂而有生命

在1907年当肯‧迈窦噶儿医生 甚至主张灵魂是有质量的

他以病人在死亡前后的所称的重量来证明

虽然他的实验，和其他活力理论一样， 没有被承认

我们仍能在流行文化中找到其理论的踪迹。

But where do all these discredited  theories leave us?

What we now know is  that life is not contained

in some magical substance or spark,

but within the ongoing  biological processes themselves.

And to understand these processes,

we need to zoom down  to the level of our individual cells.

Inside each of these cells,

chemical reactions  are constantly occurring,

powered by the glucose and oxygen that our bodies convert

into the energy-carrying molecule known as ATP.

Cells use this energy for everything from repair

to growth

to reproduction.

Not only does it take a lot of energy  to make the necessary molecules,

but it takes even more  to get them where they need to be.

除了这些不被接受的理论， 那我们还有什么其他的解释吗？

我们现在知道的是

生命不是被包覆在某种神奇的物资 或火花内

而是不断的生物过程本身

要了解这些过程

我们必须放大到我们的个体细胞上

在每一个细胞里

化学反应不断地在发生

由我们身体转化葡萄糖和氧气

成为携带能量的分子，也叫ATP

细胞用这个能量来做修补，

成长，

繁殖等

制造必须的分子需要消耗许多的能量

把这些分子送到需要的地方消耗更多的能量

The universal phenomenon of entropy

means that molecules will tend  towards diffusing randomly,

moving from areas  of high concentration to low concentration,

or even breaking apart  into smaller molecules and atoms.

So cells must constantly keep  entropy in check

by using energy to maintain  their molecules

in the very complicated formations

necessary for biological functions to occur.

The breaking down of these arrangements  when the entire cell succumbs to entropy

is what eventually results in death.

This is the reason organisms  can't be simply sparked back to life

once they've already died.

宇宙中的熵（entropy）现象

表明分子有随机扩散的趋势

它们会从分子集中的地方 扩散到分子少的地方

或者甚至分裂成更小的分子和原子

所以细胞必须不断的保持着‘熵’

用能量来维持它们的分子们

以非常复杂的构造

使生物功能得以发生

当细胞屈服于‘熵’，这些机制开始瓦解

最后导致生物体死亡

这也是一旦生命体死亡

就不能起死回生的原因

We can pump air into someone's lungs,

but it won't do much good

if the many other processes involved in the respiratory cycle

are no longer functioning.

Similarly, the electric shock from a defibrillator

doesn't jump-start an inanimate heart,

but resynchronizes the muscle cells  in an abnormally beating heart

so they regain their normal rhythm.

This can prevent a person from dying,  but it won't raise a dead body,

or a monster sewn together  from dead bodies.

So it would seem  that all our various medical miracles

can delay or prevent death but not reverse it.

我们可以将空气注入一个人的肺

但如果呼吸系统中的其他过程都失效了

注入再多的空气

那也是无济于事

同样的，除顫器的电击

也无法重启一个死亡的心脏

它只能使心跳异常的心脏 将肌肉细胞重新同步化

让它恢复正常的律动

这是可以防止一个人的死亡， 但它不会使人起死回生

更不用说由死尸缝起来的怪物

所以尽管我们有各种医学奇迹

可以延迟或预防死亡 但不能转死为生

But that's not as simple as it sounds

because constant advancements  in technology and medicine

have resulted in diagnoses such as coma,

describing potentially  reversible conditions,

under which people would have previously  been considered dead.

In the future, the point of no return  may be pushed even further.

Some animals are known  to extend their lifespans

or survive extreme conditions

by slowing down their biological processes

to the point where  they are virtually paused.

And research into cryonics  hopes to achieve the same

by freezing dying people  and reviving them later

when newer technology  is able to help them.

但也不能一概而论

因为科技和医药的不断进步

可将如昏迷的诊断 为有反转的可能性

这些在以前人们会认为已经死亡了

在未来，回生乏力的关键点 可能可再向后推

据我们所知，有些动物可以借由

放慢他们的生物过程，甚至到停止作用

而增长寿命或在极为恶劣的情况下存活

人体冷冻学的研究就是 希望可以达到这个结果

借由将濒死者冷冻

当更新的科技可以帮助他们的时候 再将他们复活

See, if the cells are frozen,  there's very little molecular movement,

and diffusion practically stops.

Even if all of a person's cellular  processes had already broken down,

this could still conceivably be reversed  by a swarm of nanobots,

moving all the molecules  back to their proper positions,

and injecting all of the cells  with ATP at the same time,

presumably causing the body  to simply pick up where it left off.

So if we think of life  not as some magical spark,

but a state of incredibly complex, self-perpetuating organization,

death is just  the process of increasing entropy

that destroys this fragile balance.

And the point at which  someone is completely dead

turns out not to be a fixed constant,

but simply a matter  of how much of this entropy

we're currently capable of reversing.

比如说，当细胞冷冻以后， 就几乎没有分子活动

扩散也基本停止了

即便一个人的细胞流程已经瓦解了

想象中仍然可以借由一群 納米机器人而反转的

将所有分子放回它们的适当位置

也同时将ATP注射在细胞里

这也许可以让生命体可以重新运作

所以如果我们认为生命不是 某种神奇的火花

而是一种无法想象的复杂， 和自我延续的组织的状态

死亡只是熵增过程，

破坏了这个脆弱的平衡的过程

当一个人完全死亡的关键点

不再是一个固定常数

而是由我们现在能够逆转这个‘熵’的程度