Well, kind of, right?

体はあるが

But, is there a line where this stops being true?

全部が本質ではない

How much of yourself can you remove before you stop being you,

どこからあなたではなくなるのか

and does the question even make sense?

この質問に意味はあるのか

Your physical existence is cells, trillions of them,

物理的には あなたは細胞だ

at least ten times more than there are stars in the Milky Way.

数は天の川銀河の星の10倍以上ある

A cell is a living being, a machine made of up to 50 thousand different proteins.

細胞は生き物で

It has no consciousness, no will, no purpose; it just is,

５万以上のタンパク質で構成される

but it is still an individual.

意識も目的もなく ただ存在する

Together, your cells form huge structures for jobs like preparing food,

でも 生きている

gathering resources, transporting stuff around,

互いに協力して組織を作り

scanning the environment, and so on.

資源を集めたり 物を運んだりして

If you extract cells from your body and put them in the right environment,

真面目に働いている

they will continue to stay alive for a while,

細胞は体から外に取り出しても

so your cells can exist without you, but you can't exist without them.

しばらくは生きている

If we take all the cells away, there is no "you" anymore.

細胞にあなたは必要ないが

Is there a line where a pile of your cells stops being you?

あなたには細胞が必要だ

For example, if you donate an organ, billions of your cells will continue

細胞がなくなったら あなたも消える

to live on inside someone else.

細胞があなたでなくなるのはいつか

Does this mean that a part of you became a part of another person,

提供した臓器は

or is this other body keeping a part of you alive?

他の人の中で生き続けるが

Or, let us imagine an experiment:

それはその人の一部になったのか

you and a random person from the street exchange cells.

それともあなたの一部のままなのか

One at a time, your body gets one of their cells;

特殊な実験で

their body gets one of your cells.

人と細胞を交換するとしよう

At which point would they become you?

お互いの細胞を一個ずつ

Would they ever, or is this just a very slow and gross way to teleport you?

交換していったら

Let's make this more complicated!

いつその人はあなたになるか

The image of ourselves as a static thing is untenable.

いつか意識も交換されるのだろうか

Almost all of your cells have to die during your lifetime.

話を複雑にしよう

Two hundred and fifty million have died since the beginning of this video, alone,

人間という概念は不安定なものだ

between one and three million per second.

人の細胞は死に続けている

In a seven-year period, most of your cells are replaced at least once.

動画が始まってから2.5億個は死んだ

Every time your cells' setup changes, you are slightly different than before,

１秒あたり数百万個だ

so a part of you is dying constantly.

７年の間に

If you are lucky enough to become old,

ほとんどの細胞が入れ替わる

you would have cycled through roughly a million billion cells,

あなたは少しずつ

so what you consider yourself is really just a snapshot,

変わっていっている

but sometimes, cells are broken and don't want to die

常に一部は死に続け

questioning the very nature of the unity of our bodies.

老いたときには

We call them cancer. They cancel the biological social contract

１京個の細胞が入れ替わっている

and become basically immortal.

今のあなたは写真のようなものだ

Cancer is not an outside invader;

だが時々細胞は壊れ 死ななくなる

it's a part of you that puts its own survival over yours,

生物に定められた自然の摂理

but you could also argue that a cancer cell becomes another entity inside us;

ガンだ

another being that just wants to thrive and survive.

生物学の掟を破る不死の細胞である

Can we blame it for that?

ガンは外敵ではなく

A chilling cell story is that of Henrietta Lacks,

細胞の暴走によって生まれる

a young cancer patient who died in 1951.

または自我を持った細胞個人が

Usually, cells only survived for a few days in the lab,

生きていたいだけなのかもしれない

making research very hard.

命は大事だ

Henrietta's cancer cells were immortal.

ヘンリエッタという女性がいた

Over the decades, they were multiplied over and over again

彼女は1951年に亡くなった

and used for countless research projects saving countless lives.

通常 細胞は数日で死ぬため

Henrietta's cells are still alive and overall have been grown to

研究が難しい

at least 20 tons of biomass,

しかし彼女のガン細胞は死なず

so there are living parts around the world from someone who has been

何度も増殖しては研究に使われ

considered dead for decades.

多くの命を救った

How much of Henrietta is in these cells?

今でも生きていて

What makes one of your cells "you," anyway?

彼女の細胞は全部で20トンになる

Maybe the information contained in it, your DNA?

本人が死んだ後も

Until recently, it was believed that all the cells in your body

細胞は生き続けているのだ

had basically the same genetic code,

何倍もの量になって

but it turns out this is wrong.

細胞を作るのは何か

Your genome is mobile, changing over time

設計図が書かれたDNAだ

through mutations and environmental influences.

細胞はすべて

This is especially the case in your brain.

同じ設計図に基づいている…

According to recent discoveries, a single neuron in an adult brain has more than

と思うのは間違いだ

one thousand mutations in its genetic code that are not present

遺伝子は流動的で

in the cells surrounding it, but how much "you" is your DNA, really?

変異や環境により変化する

About eight percent of the human genome is made up of viruses that once

脳の場合は特にそうだ

infected our ancestors and merged with us.

最新の研究で 脳の細胞は

Mitochondria, power plants of the cell, once were bacteria that merged

1000回以上変異し

with the ancestors of your cells. They still have their own DNA.

各自異なることがわかった

An average cell has hundreds of them, hundreds of little things that are

DNAは外からも来ている

not really human, but they still kind of are.

人間のDNAの約８％は

It is confusing. Let's backtrack a bit.

昔感染したウイルスのDNAだ

We know that you're made up of trillions of little things

細菌だったミトコンドリアが

made from more little things that are constantly changing.

遥か昔 私たちの先祖と一体化した

Together, all those little things are not static, but dynamic.

DNAはそのままだ

Their composition and condition is changing constantly,

細胞１つに100個いる

so we might just be a self-sustaining pattern without clear borders

人間ではないものが

that gained self-awareness at some point and now has the ability

私たちの一部なのだ

to think about itself through time and space,

複雑だ　話を整理しよう

but really only exists in this exact very moment.

人は数兆個の粒から成り

Where did this pattern start:

絶え間なく変化している

with your conception, when the first human arose,

集まった粒は活動的で

when life first began conquering our small planet,

その状態は常に変わり続けている

or when the elements that make up your body were forged in a star?

つまり私たちに明快な境界はなく

Our human brains evolved to deal with absolutes.

あるのはパターンだけで

The fuzzy borders that make up reality are hard to grasp.

時間や宇宙について考える意識は

Maybe ideas like beginning and end, life and death, you and me,

まさにこの瞬間にしか存在しない

are really not absolutes, but ideas belonging to a fluent pattern;

パターンはいつ始まったのか

a pattern that is lost in this strange and beautiful universe.

原始時代か

(Shifting to the voice of CGP Grey) The problem of who we are isn't just

生命が惑星を支配し始めた時か

a question of ourselves, but it's also a question of our minds.

星の中で元素が作られた時か

Just as our cells can be divided and separated from us, so can our very brains

脳は明確な違いはわかるが

be divided and separated from us while still in the skull.

現実の曖昧な境界は把握しにくい

Click here to go to my channel and watch the next part.

もしかしたら

Okay, so now, go watch CGP Grey's video.

生と死 あなたと私といった違いは

If you're not yet subscribed to his channel,

実は明確ではなく

you should really change that now.

何か捉えがたいパターンが

Subtitles by the Amara.org community

この美しい宇宙の中には隠れている